First Edition

The Glocal University

BACHELOR OF SCIENCEMEDICAL

LABORATORY TECHNOLOGY

Written :- GAUTAM KUMAR SAINI(B.Sc MLT)

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Written:- GAUTAM KUMAR SAINIB.Sc MLT

University:- GLOCAL UNIVERSITYAddress:- Behat ,Distt:- Saharanpur , State:- Uthar

Pradesh ,Pin code:- 247121.Email address:- sainigautamkumar456@gmail.com

Contact number:- 9719239723, 7902009292.Helper:- K.lal SAINI ,Arun Saini ,Rahul Saini.

YEAR:-2017-18

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Status

Success is a Science;if you have the conditions,

You get theResult.

G.K.Saini

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Preface to the FIRST EDITION

This book 'Bachelor of science medical laboratory technology, is written at an appropriate time,when the need for such a

suitable book is felt , since the available books were too simple or too

elaborate. This book covered the entire the entire syllabus and also catered

to the needs of student So it was received with great appreciation. the way

such a difficult subject has been discussed in a simple manner is highly

commended. Also , the chapter on -lab rules, pH, normal

value( Hematology, Biochemistry, Pathology and Bacteriology) Test name,

Methods name, world fullform, Classifications, Calculation formule(lab) ,

clinical significances flow sheet etc.

Gautam Kumar Saini

B.Sc MLT

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S.No. Page No. Lab safety rules for students. 5-8

1. pH of body. 9-10 2. Normal range of body fluid. 11-24 3. Biochemistry. 25-29 4. Basic definition and cells size. 30-35 5. Calculation formule of laboratory. 36-40 6. Hematological test. 41-42 7. Components with functions. 43-54 8. Classifications. 55-639. Pathological normal range. 64-7010. Bacteriology. 71-11611.Clinical Significance and test name. 117-175

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CONTENTS

-:Lab safety rules for students:-

Report all accidents, injuries, and breakage of glass or

equipment to instructor immediately. Keep pathways clear by placing extra items (books,

bags, etc.) on the shelves or under the work tables. If under the tables, make sure that these items can not be

stepped on. Long hair (chin-length or longer) must be tied back to

avoid catching fire. Wear sensible clothing including footwear. Loose

clothing should be secured so they do not get caught in a flame or chemicals.

Work quietly — know what you are doing by reading the assigned experiment before you start to work. Pay close

attention to any cautions described in the laboratory exercises

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Do not taste or smell chemicals. Wear safety goggles to protect your eyes when heating

substances, dissecting, etc. Do not attempt to change the position of glass tubing in a

stopper. Never point a test tube being heated at another student or

yourself. Never look into a test tube while you are heating it.

Unauthorized experiments or procedures must not be attempted.

Keep solids out of the sink. Leave your work station clean and in good order before

leaving the laboratory. Do not lean, hang over or sit on the laboratory tables. Do not leave your assigned laboratory station without

permission of the teacher. Learn the location of the fire extinguisher, eye wash

station, first aid kit and safety shower. Fooling around or "horse play" in the laboratory is absolutely forbidden. Students found in violation of this safety rule will be barred from particpating in future labs

and could result in suspension.

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Anyone wearing acrylic nails will not be allowed to work with matches, lighted splints, bunsen burners, etc. Do not lift any solutions, glassware or other types of

apparatus above eye level. Follow all instructions given by your teacher.

Learn how to transport all materials and equipment safely.

No eating or drinking in the lab at any time!

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1. pH of body Definition Table of pH

pH:- A figure expressing the acidity or alkalinity of a solution on a logarithmic scale on which 7 is neutral ,lower values are more acid and higher values more alkaline. The pH is equal to -log10C, where C is the hydrogen ion concentration in moles per litre.

TABLE OF pH Body parts and fluids pH

1. Blood 7.42. Semen 7.1-83. Mouth 6.5

4. Stomach 5-65. Vagina 3.8-4.56. Urine 4.67. Stool 7-88. CSF 7.31-7.34

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9. Gastric analysis 1.6-1.810. Seminal fluid >7.011. Whole blood 7.35-7.45

12. Enzyme 6-713. Saliva 6.5-7.4

14. Healthy skin 5.5-slightly acidic15. Large Intestine 4.0-7.816. Small Intestine 4.0-7.017. Lower stomach 1.5-4.018. Upper stomach 4.0-6.5

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2. Normal range of body fluids

Body fluids(Table) Other body fluids(Table)

1. Body fluids.

TABLEFluids Normal range

1.Red blood cells 4.5-5.5 millions2. White blood cells 6,000-10,000

3. Platelets 2-5 lakhs

4. Hemoglobin Men:- 13-18 g/dlWoman:- 12-16.5 g/dl

Children(up to 1 year):- 11.0-13.0 g/dl

Children(10-12 years):- 11.5-14.5 g/dl

Infants(full term cord blood):-

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13.5-19.5 g/dl

5. PCV (Packed cell volume)

Men:- 0.4-0.5 l/lWoman:- 0.36-0.46 l/l

6. MCV (Mean cell volume)

Men and Women:- 83-101 Famto litre

7. MCH (mean cell volume)

Men and Women:- 27-31pg

8. MCHC (Mean cell hemoglobin

concentration)

Men and Women:- 18-48pg

9. CV (Red) 11.6-14.0%10. As standard deviation(SD)

39.0-46.0 fl

11. Reticulocyte count

0.5-2.5%

12. Neutrophils 40-80%13. Lymphocytes 20-40%14. Monocytes 2-10%15. Eosinophils 1-6%16. Basophils <1-2%

17. Bleeding time:

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I.Ivy's methodII.Template methodIII.Duke's method

IV. Capillary methodV. Lee-white method

2-7 min2.5-9.5 min

1-5 min4-9 min

4-9 min

18. Prothrombin time

11-16 sec

19. APTT(Partial thromboplastin time)

30-40 sec

20. Thrombin time 15-19 sec21. Fibrinogen 200-400 mg/dl

22. Plasma recalcification time:

I. Platelet rich plasma

II. Platelet poor plasma

100-150 sec

135-240 sec

23. Plasma 2.0-4.0 g/dl

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fibrinogen24. Serum Iron 60-150 microgram/dl

25. Serum TIBC 270-380 microgram/dl26. Serum vitamin

B12160-760 ng/l

27. Serum fructose 150-300 mg/dl28. Pleural fluid 70-110 mg/dl

29. Blood sugar(fasting)

80-120 mg/dl

30. Blood sugar(P.P) 2Hrs.after lunch

Up to 140 mg/dl

31. Glycosylated Hb 5-8%32. Serum protein 6-8 g/dl

33. Albumin 3.3-4.8 g/dl34. CSF protein 15-45 mg/dl

35. Plasma/Serum urea nitrogen

Birth to 1 year:- 4-6 mg/dl1 to 40 year:- 7-21 mg/dl

36. Serum Creatinine

0.7-1.7 mg/dl

37. Uric acid Female:- 3-7 mg/dlMale:- 2-6 mg/dl

38. Creatine Male:- 20-50 IU

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phosphokinase(CKP)

Female:- 10-37 IU

39. LDH(lactate dehydrogenase)

70-240 IU

40. Apolipoprotein Male:- 60-138 mg/dlFemale:- 52-129 mg/dl

41. Serum calcium 8.0-10.5 mg/dl42. 24hrs.urinary

excretion of calcium100-300 mg(50-150 mEq)

43. SGOT 5-35 K.U. (ALT)44. Serum alkaline

phosphatesAdults:-20-90 I.U.

Children:- 93-221 I.U.45. Serum acid

phosphataseTotal acid phosphatase:- 0.9-12

I.U.Prostatic acid:- 0-4.0 I.U.

46. Serum amylase 60-180 caraway units47. Serum lactate

dehydrogenase(S.LDH)

70-240 I.U.

48. Creatinine clearance(KFT test)

Male:- 85-125 ml/min.Female:- 75-115 ml/min.

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49. UREA clearance(KFT test)

Maximum:- 60-95 mlStandard:- 40-65 ml

50. GAMMA G.T.(test)

Male:- 4-23 IUFemale:- 3.5-13 IU

51. Bilirubin test Total bilirubin up to 1.0 mg/dl

Direct bilirubin up to 0.5 mg/dl

Indirect bilirubin up to 0.5 mg/dl

52. Serum total cholesterol

150-250 mg/dl

53. Serum HDL Male:- 30-60 mg/dlFemale:- 40-70 mg/dl

54. Serum myoglobin

Male:- 12-78 microgram/litreFemale:- 3-76 microgram/litre

55. Inorganic phosphorus

Adults:- 2.5-4.5 mg/dlChildren:- 4.0-7.0 mg/dl

56. Serum sodium 133-148 mEq/L57. Serum potassium 3.8-5.6 mEq/L58. Serum chlorides

CSF chlorides95-106 mEq/L700-750 mg/dl

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Urinary chlorides 120-250 mEq59. Bicarbonate 21-28 mEq/L

60. T3T4

TSH

86-187 ng/dl4.5-12.5 microgram/dl

0.3-5 micro I.U./ml60. Alphafetoprotein Ref.range:- adults 2-16 ng/ml

61. SGPT 25℃ 30℃

37℃

Male Up to 18 IU

25 IU

37 IU

Female Up to 15 IU

21 IU

31 IU

62. Alpha-HBDH(Hydroxy

butyrate dehydrogenase)

25℃ 30℃ 37℃55-140

IU65-165

IU72-182

IU

63. CK: NAC-Activated

25℃ 30℃ 37℃Male 10-80

IU15-130 IU

24-195 IU

Femal 10-70 15- 27-

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e IU 110 IU

170 IU

64. Serum folate 3-20 mg/l65. Red cell folate 160-640 mg/l

66. Plasma hemoglobin

10-40 mg/l

67. Hb A2 2.2-3.5%68. Hb F <1.0%

69. Methemoglobin<1.0%

70. Amniotic fluid Average:- 800mlAbout:- 600 ml

71. Haptoglobin 60-270 mg/dl72. Ferritin Male:- 30-250 ng/ml

Female:- 10-150 ng/ml73. Iron saturation 20-45 %

74. Iron intake 10-15 mg/day75. Iron loss Male:- 0.5-1.0 mg/day

Female:- 1-2 mg/day76. Iron , Storage 30 %77. Muramidase 5-20 microgram/ml

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78. Haemoglobin A 1c

4-6%

79. Immunoglobulin A 70-350 mg/dl

80. Immunoglobulin D 0-14 mg/dl

81. Immunoglobulin E <0.025 mg/dl

82. Immunoglobulin G 700-1700 mg/dl

83. Immunoglobulin M 50-300 mg/dl

ESR Men-: 0-22 mm/hrFemale-: 0-29 mm/hr

2. Other body fluids. TABLE

Component Conventional:- Ref.value

1. Body volume,water Total

Intracellular

50-70%33%

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Extracellular Interstitial fluid including

lymph fluid Intravascular fluid or blood

plasmaFluid in mesenchymal

tissueTranscellular fluid

27%12%

5%

9%

1%2. Catecholamine

EpinephrineFree catecholamine's

MetanephrineVanillyl mandelic acid

<10 ng/day<100 mg/day<1.3 mg/day<8 mg/day

3. Cerebrospinal fluid (CSF)CSF volumeCSF pressure

Leucocyte

GlucosepH

Protein's

120-150 ml60-150 mm water

0.5 lymphocytes/ml

40-70 mg/dl7.31-7.34

20-50 mg/dl

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4. Figlu <3 mg/day5. Gastric analysis

24hr. VolumepH

Basal acid outputMaximal acid output

After infection of stimulant BAO/MAO ratio

2-3 l1.6-1.8

1-5 mEq/hr5-40 mEq/he

<0.6

6. Glomerularfiltration rate 180 l/day7. 5-HIAA 2-9 mg/day

8. 17-ketosteroidsMales

Females

7-25 mg/dl4-15 mg/dl

9. Microalbumin 0-30 mg/24hr10. Seminal fluid

LiquefactionSperm morphology

Sperm motilitypH

Sperm count

Volume

Within 20 min>70% normal

>60%>7.0

60-150 million/ml1.5-5.0 ml

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11. Stool examinationCoproporphyrin

Faecal fat excretionOccult blood

UrobilinogenD-xylose excretion

Schilling's test

400-1000 mg/day<6.0 g/dl

Negative(<2 ml blood/day) 40-

280 mg/day5-8 g. Within 5hrs after oral dose of

25g.>10% of ingested

dose of 'hot, vitamin B12

12. Urobilinogen Present in 1:20 dilution

13. Urine examinationpH

Specific gravity,quantitative

Protein excretionProtein,qualitative

Glucose excretion,quantative

600-1800 ml5.0-9.0

1.002-1.028

<150 mg/dayNegative

50-300 mg/day

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Glucose,qualitativePorphobilinogenUrobilinogen

Microalbumin uria

NegativeNegative

1.0-3.5 mg/day0-30 mg/24hr.

(0.30 microgram/mg

crea

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3. Biochemistry Definition Field of biochemistry Test with methods(Table) 1. DefinitionBiochemistry:- Biochemistry is a basic science which deals with chemical nature and chemical behaviour of living matter. 'OR,The study of the composition ,properties,and reactions of matter, particularly at the level of atoms and molecules.

2. Field name of biochemistry Enzymology Bioenergetics Molecular biology Clinical biochemistry

3. Test with methodsTABLE

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TEST METHODS1. Blood sugar

2. Plasma glucoseMulti-stepMonostep

3. Semi-Autoanalyzes4. Glycosylated Hb

5. Serum protein

End point reactionIon Exchange

Biuret6. Serum albumin

7. CSF and urinary protein8. Serum urea nitrogen

9. Urea nitrogen

Bromocresol green(BCG)Turbidimetry

Berthelot reactionUV kinetic

13. Serum acid phosphate14. Serum amylase

15. Serum lactate dehydrogenase

Pnitrophenyl phosphateColorimetric:Amyloclastic,Iod

ometric.King's (Colorimetric)

17. Glucose18. Urea

GOD/PODBerthelot

19. Cholesterols Enzymatic20. Uric acid

21. Total proteinUricaseBiuret

22. Triglycerides23. Calcium

EnzymaticCPC

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24. Phosphorus Gomorri25. Bilirubin

26. Alkaline phosphatase27. GAMMA G.T.28. T3, T4, TSH

Molloy EvelynVisible kinetic

End point reactionRIA, ELISA

29. Bicarbonate30. Serum total cholesterol31. Serum HDL cholesterol

32. Serum total lipids33. Serum CK (CKP)

TitrimetricColorimetric(Watson)

ColorimetricSulfo-phosphovanillin

Modified Huge34. SGPT35. LDH

36. Alpha-HBDH (Hydroxy butyrate dehydrogenase)37. CK NAC-Activated

UV kineticSameSame

UV kinetic38. Apolipoprotein Alpha-1

39. Apolipoprotein Beta

40. Serum inorganic phosphorus

T I ATurbidimetric Two point assay

Gomorri's

41. Serum sodium & potassium

Flame photometry

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42. Serum chlorides Scales and Schales43. A F P (Alphafetoprotein) Solid phase

immunoradiometric assay44. P S A ( Prostate specific

antigen)I R M A

A. Amniotic fluid culture Flask methodB. Bleeding time Duke's method

C. Diagnosis of Kala-Azar Chemical:Formal gel testD. Glucose-6-phosphate

dehydrogenaseVisual method

E. Plasma Hemoglobin Peroxidase methodF. Red cell pyruvate kinase Rate of reaction-UV kinetic

G. Reduced Glutathione End point reactionH. Blood clotting time Capillary method

Lee-white methodI. Prothrombin time Quick's method

J. Fibrinogen Kjeldahi Nesslerization method.

K. Urine porphobilinogen Watson's Schwartz test

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4.Basic definition and Cells sizes

1. Definition 2. Cells sizes

1. Definition. A. Blood:- The red liquid that circulates in the arteries and veins of human and other vertebrate animals,carrying oxygen to and carbon dioxide from the tissue of the body.

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B. Red blood cells(RBC):- Red cells contain hemoglobin and it is the hemoglobin which permits them to transport oxygen.Hemoglobin,aside from being a transport molecules,is a pigment. It give the cells their red color. The abbreviation for red blood cells is RBCs.

1 RBC = 27-32 pg( hemoglobin )1RBC life spen = 1 sec.

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RBC life cycle = 100-120 days

C. White blood cells:- Any of the blood cells that are colorless,lack hemoglobin,contain a nucleus, and include the lymphocytes, monocytes, neutrophils, eosinophils and basophil -called also leukocyte,white blood corpuscle,white cell compare red blood cells.

WBC life cycle = 4-30 days, depending of body.

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D. Platelets:- A small colourless disc shaped cell fregment without a nucleus , found in large numbers in blood and involved in clotting.

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Platelet life cycle = 8-9 days.

E. Sperms:- Sperm cells are carried out of the male body in a fluid known as semen . Human sperm cells can survive within the female reproductive tract for more than 5 days post coitus. Semen is produced in the seminal

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vesicles,prostate gland and urethral gland.

2. Cells sizes.TABLE

Cells SizesRed blood cells

PlateletSperms

6-8 micrometer 2-3 micrometer

About 50 micrometer (0.05 millimeter

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ProerythroblastEarly normoblast

Polychromatic normoblastOrthochromatic

normoblastReticulocyte

Matured erythrocytes

15-20 micrometer 13-17 micrometer 11-15 micrometer

8-10 micrometer

7.5-8 micrometer 7.5 micrometer

Sperm head 4.5 micrometer in length

3 micrometer in width 1.5 micrometer in thick

Lymphocytes Small 9-12 micrometer Large 12-16

micrometer

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5. Calculation formule of Laboratory

TABLEComponents Formule

1. Hemoglobin,g/dl =O.D.T/O.D.S ×152. RBC count cu mm(microliter)

=Total number of cells counted × 10,000

3. WBC count =Total number of WBCs counted × 50

4. MCV =PCV×10/RBC in millions5. MCH =Hemoglobin×10/RBC in

millions6. MCHC =Hemoglobin×100/PCV

7. Color Index =Hemoglobin%/RBC%8. Platelet per cu mm(microliter)

=Number of Platelets counted × Dilution/Volume

of fluid

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9. Total number of eosinophils,cu mm(microliter)

=Number of cells counted ×10/0.9

10. Serum Iron, microgram/dl =O.D.T/O.D.S × 22311. Serum TIBC,microgram/dl =O.D.T/O.D.S × 446 12. Plasma hemoglobin,mg/dl =O.D.T/O.D.S × 200

13. Fibrinogen in plasma,mg/dl

=O.D.Test/O.D.Standed × 250

14. Sperms/ml of semen = Sperms counted in four squares × 10 × 20 × 1000/4

15. Semen fructose,mg/dl = O.D.T/O.D.S × 20016. Free acid,mEq/L = Titration reading (x ml) ×

10017. Total acid,mEq/L = Titration reading(y ml) ×

10018. Blood glucose,mg/dl19. Plasma glucose,mg/dl

= O.D.T/O.D.S × 100= O.D.T/O.D.S × 100

20. Glycosylated Hb% = O.D.T/0.029 × 121. Serum protein,g/dl = O.D.T/O.D.S × 622. Serum albumin,g/dl =O.D.Test/O.D.Standed × 423. CSF protein,mg/dl = O.D.Test/O.D.Std × 6024. Urine protein,mg/dl =O. D.Test/O.D.Std × 120

25. Serum urea nitrogen,mg/dl = O.D.T/O.D.S × 20

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26. Serum urea nitrogen,mg/dl(Uv kinetic method

= ∆A'T,/∆A'S,×20

27. Serum creatinine,mg/dl = O.D.Test/O.D.Std × 1.028. Urine creatinine,mg/dl = O.D.T/O.D.S × 10029. Serum uric acid,mg/dl = O.D.T/O.D.S × 530. URINE URIC ACID:-A. Urine uric acid,mg/dl

B. mg/dl,urine uric acid/100 × ml 24hrs.urine excretion

= O.D.T/O.D.S × 100

31.Serum amylase, Caraway units

= O.D. Blank-O.D.Test/O.D.Blank

× 400

32. Serum total cholesterol,mg/dl

= O.D.Test/O.D.Std × 200

33. Serum HDL cholesterol,mg/dl

=O.D.T/O.D.S × 114

34. Serum triglycerides,mg/dl = O.D.T/O.D.S × 10035. Serum total lipids,mg/dl = O.D.T/O.D.S ×100036. Serum CPK activity.IU(Creatine phosphokinase)

=O.D.Test-O.D.Blank/O.D.Std-O.D.Blank × 66.7

37. SGOT,IU =1015×∆A/min

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38. LDH,IU =9807×∆A/min39. CPK activity IU = 4127×∆A/min

40. Alpha-HBDH[SHBD], IU = 5079×∆A/min41. Serum Calcium,mg/dl = O.D.T/O.D.S × 10042. Urine calcium,mg/dl = O.D.T/O.D.S × 10

43. Serum Inorganic phosphorus,mg/dl

O.D.T/O.D.S × 5

44. Urine Inorganic Phosphorus ,mg/dl

= O.D.T/O.D.S × 50

45. Serum phospholipid, mg/dl

= O.D.T/O.D.S ×125

46. 24hrs. Excretion of urine sodium

= Sodium mEq/L × 24hrs. Urine Volume/1000

47. 24hrs. excretion of urine potassium

= Urine potassium,mEq/L × 24hrs. Urine Volume/ 1000

48. Serum chlorides,mEq/l =Xml /Yml ×10049. Bicarbonate, mEq/L =[1-R]×100

50. Glycosylated Hb =O.D.GHb/O.D.GHb × 10 × Temperature factor(TF)

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Note :- 1. TF for assay at 23-25 = 1.0℃ 2. TF for assay at 30 = 0.70℃

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6. Hematological testHematology:- Hematology is branch of medicine that is concerned with the study of blood, the blood forming organs,and blood disease's.

Hematology includes the study of etiology, diagnosis, treatment, prognosis and prevention of blood disease's.

Hematological test of three types:-1. Routine Hematological Test2. Special Hematological Test3. Routine Hematological Test

Complete Hemogram:-HemoglobinErythrocyte count (RBC)Leukocyte count (WBC)Packed cell Volume (PCV)Reticulocyte countPlatelets countComplete blood count (CNC)Mean Platelet Volume (MPV)Platelet large cell ratio (P-LCR)

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Mean cell hemoglobin concentration (MCHC)Mean cell Volume (MCV)Red cell distribution (RDW)Platelet distribution width (PDW)

NoteOther routinely performed hematological tests are as follows:1.Erythrocyte sedimentation rate (ESR)2. Reticulocyte count3. Absolute eosinophil count

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7. Components with function

TABLE Components

and parts Functions

Plasma It's mainly made of water and surrounds the blood cells, carrying them around the body. Plasma helps maintain blood

pressure and regulates body temperature. It contains a complex mix

of substances used by the body to perform important functions. These substances include minerals, salts,

hormones and proteins.Serum Serum includes all proteins not used in

blood clotting (coagulation) and all the electrolytes, antibodies, antigens,

hormones, and any exogenous substances (e.g., drugs and

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microorganisms). ... Such convalescent serum (antiserum) is a form of

immunotherapy.Red blood cells Hemoglobin is the protein inside red

blood cells that carries oxygen. Red blood cells also remove carbon dioxide from your body, transporting it to the

lungs for you to exhale. Red blood cells are made inside your bones, in the bone marrow. They typically live for about

120 days, and then they die.White blood cells White blood cells (WBCs), also called

leukocytes or leucocytes, are the cells of the immune system that are involved

in protecting the body against both infectious disease and foreign invaders. All white blood cells are produced and derived from multipotent cells in the

bone marrow known as hematopoietic stem cells.

Platelets The normal platelet count is 150,000-350,000 per microliter of blood, but

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since platelets are so small, they make up just a tiny fraction of the blood volume. The principal function of

platelets is to prevent bleeding. Red blood cells are the most numerous

blood cell, about 5,000,000 per microliter.

Semen Seminal gland. The seminal gland, more commonly referred to as the

seminal vesicle, holds the liquid that mixes with sperm to form semen.

Semen combines fluid elements from the epididymis, seminal vesicles,

prostate gland, and vas deferens. Each body part plays a key role in semen

production.Blood Blood has three main functions:

transport, protection and regulation. Blood transports the following

substances: Gases, namely oxygen (O2) and carbon dioxide (CO2), between the

lungs and rest of the body. Nutrients

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from the digestive tract and storage sites to the rest of the body.

CSF While the primary function of CSF is to cushion the brain within the skull and

serve as a shock absorber for the central nervous system, CSF also circulates nutrients and chemicals filtered from

the blood and removes waste products from the brain.

Urobilinogen Urobilinogen is a colourless by-product of bilirubin reduction. It is formed in the intestines by bacterial action on

bilirubin. About half of the urobilinogen formed is reabsorbed and taken up via

the portal vein to the liver, enters circulation and is excreted by the

kidney.Myoglobin Myoglobin contains a heme (prosthetic)

group which is responsible for its main function (carrying of oxygen molecules to muscle tissues). Myoglobin can exist

in the oxygen free form,

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deoxymyoglobin, or in a form in which the oxygen molecule is bound, called

oxymyoglobin.Liver The liver and these organs work

together to digest, absorb, and process food. ... The liver also detoxifies

chemicals and metabolizes drugs. As it does so, the liver secretes bile that ends up back in the intestines. The liver also

makes proteins important for blood clotting and other functions.

Kidney The kidneys are two bean-shaped organs that extract waste from blood,

balance body fluids, form urine, and aid in other important functions of the body. They reside against the back

muscles in the upper abdominal cavity. They sit opposite each other on either

side of the spine.Methemoglobin In human blood a trace amount of

methemoglobin is normally produced spontaneously, but when present in

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excess the blood becomes abnormally dark bluish brown. The NADH-

dependent enzyme methemoglobin reductase (diaphorase I) is responsible for converting methemoglobin back to

hemoglobin.Methemoglobinemi

aThis is achieved by providing an

artificial electron acceptor (such as methylene blue or flavin) for NADPH

methemoglobin reductase (RBCs usually don't have one; the presence of methylene blue allows the enzyme to

function at 5× normal levels). The NADPH is generated via the hexose

monophosphate shunt.Haptoglobin Haptoglobin functions to bind free

plasma hemoglobin, which allows degradative enzymes to gain access to the hemoglobin while at the same time

preventing loss of iron through the kidneys and protecting the kidneys

from damage by hemoglobin. For this

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reason, it is often referred to as the suicide protein.

Amniotic fluid Amniotic fluid protects the developing baby by cushioning against blows to the mother's abdomen, allowing for easier

fetal movement and promoting muscular/skeletal development.

Amniotic fluid swallowed by the fetus helps in the formation of the

gastrointestinal tract.Hemoglobin Hemoglobin is contained in red blood

cells, which efficiently carries oxygen from the lungs to the tissues of the body. Hemoglobin also helps in the transportation of carbon dioxide and

hydrogen ions back to the lungs.Immunoglobulin A Immunoglobulin A (IgA, also referred

to as sIgA) is an antibody that plays a crucial role in the immune function of

mucous membranes. The amount of IgA produced in association with mucosal membranes is greater than all other

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types of antibody combined.Immunoglobulin D In B cells, IgD's function is to signal the

B cells to be activated. By being activated, they are ready to take part in the defense of the body in the immune system. During B-cell differentiation, IgM is the exclusive isotype expressed

by immature B cells.Immunoglobulin E IgE's main function is immunity to

parasites such as helminths like Schistosoma mansoni, Trichinella

spiralis, and Fasciola hepatica. IgE is utilized during immune defense against

certain protozoan parasites such as Plasmodium falciparum.

Immunoglobulin G Functions. Antibodies are major components of humoral immunity. IgG is the main type of antibody found in

blood and extracellular fluid allowing it to control infection of body tissues. By binding many kinds of pathogens such

as viruses, bacteria, and fungi, IgG

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protects the body from infection.Immunoglobulin M IgM is present on B cells and its main

function apparently is the control of B-cell activation. Interestingly, it is also the primary antibody against A and B

antigens on red blood cells and responsible for the blood-clotting

reaction during blood-transfusion from wrong donors.

Enzymes Function and structure. Enzymes are very efficient catalysts for biochemical reactions. They speed up reactions by

providing an alternative reaction pathway of lower activation energy.

Like all catalysts, enzymes take part in the reaction - that is how they provide

an alternative reaction pathway.Saliva This lubricative function of saliva

allows the food bolus to be passed easily from the mouth into the

esophagus. Saliva contains the enzyme amylase, also called ptyalin, which is

51

capable of breaking down starch into simpler sugars such as maltose and

dextrin that can be further broken down in the small intestine.

Heart The right side of the heart maintains pulmonary circulation to the nearby lungs while the left side of the heart

pumps blood all the way to the extremities of the body in the systemic circulatory loop. The heart functions by pumping blood both to the lungs and to

the systems of the body.Brain The cerebellum is below and behind the

cerebrum and is attached to the brain stem. It controls motor function, the

body's ability to balance, and its ability to interpret information sent to the brain

by the eyes, ears, and other sensory organs.

Lungs Normal Lung Function. ... Oxygen enters our lungs as part of the air that

we breathe. It goes to the blood vessels

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deep in our lungs and then on to all parts of our body. As our body uses

oxygen, it makes a waste product called carbon dioxide.

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8. ClassificationsPluripotent stem cellLeukocytes [WBCs]ProteinsCarbohydratesSteroidsVitaminsCoenzymesEnzymes

1. Pluripotent stem cells:- Pluripotent stem cells are master cells. They're able to make cells from all three basic body layers, so they can potentially produce any cell or tissue the body needs to repair itself. This “master” property is called pluripotency.

Classifications:- Pluripotent stem cell two types-:A. Committed stem cell Myeloid seriesB. Committed stem cell Lymphocytic series

A. Committed stem cell Myeloid series

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Progenitor cells

B. Committed stem cell Lymphocytic series( Two types) a. T-lymphocyte b. B-lymphocyte

a. T-lymphocyte to four types:-I. BFU-E & BFU-EPronormoblastRed blood cell

II. CFU-GM (Are two types)a. MyeloblastNeutrophilb. MonoblastMonocyte

III. CFU-mega(M) Platelet

IV. CFU-EOEosinophil

b. B-lymphocyte

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2. Leukocytes(WBCs):- Any of the blood cells that are colorless,lack hemoglobin,contain a nucleus, and include the lymphocytes, monocytes, neutrophils, eosinophils and basophil -called also leukocyte,white blood corpuscle,white cell compare red blood cells.

Classification:- Leukocytes are two types 1. Granulocytes, 2. Non-Granulocytes.

1. GranulocytesI. NeutrophilII. EosinophilIII. Basophil

2. Non-GranulocytesI. LymphocytesII. Monocyte

3. Proteins:- Proteins are high molecular weight polypeptides containing alpha amino acids joined together by peptide linkage.(-CO-NH)

Classification:- Proteins are three types- I. Simple proteins, II. Conjugated proteins, III. Derived.

I. Simple proteins(types)

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AlbuminGlobulinGlutelinProlaminesSclero proteinsHistonesProlamines

2. Conjugated proteinsNucleoproteinsPhospho proteinsGlycoproteinsLipoproteinMetallic proteinsChromoproteins

3. Derived proteinsI. Primary derived protein : MetaproteinsII. Secondary derived proteins : a. Proteosesb. Peptonesc. Peptides

4. Carbohydrates:- Carbohydrates are defined as

57

polyhydroxy aldehydes or ketones and their derivatives or substances which yield one of these substances on hydrolysis. Classification of carbohydrates:-I. MonosaccharideII. DisaccharidesIII. OligosaccharideIV. Polysaccharides

5. Lipids:- Lipids are a group of compounds related to fatty acids and are insoluble in water but soluble in organic solvent's. Classification of lipids:- 1. Simple lipids, 2.

Compound lipids, 3. Derived lipids.1. Simple lipids:-FatsWaxes

2. Compound lipids:-PhospholipidGlycolipidsSulfolipidisLipoprotein's

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3. Derived lipids:-Fatty acidsAlcoholsSterols and steroidsPolyisopenoids

6. Steroids:- Steroids are components which have a common structure called as 'cyclopentanoperhydro phenanthrene ring'. Classification of Steroids:-1. SterolsCholesterol7-Dehydro cholesterolErgosterolCalciferol2. Bile acidsCholic acidDeoxycholic acid3. Male sex hormonesAndrogenAndrosteroneTestosterone4. Female sex hormones

59

EstradiolEstroneProgesterone5. MiscellaneousSaponinAdrenocortical hormones cardiac glycosides.

6. Vitamins:- Vitamins are defined as organic compounds present in food and are required in minute quantities for normal growth, maintenance and reproduction. Their absence in food produce specific deficiency disease's. Classification of vitamins:1. Fat soluble vitamins:Vitamin AVitamin DVitamin EVitamin K2. Water soluble vitamins-A. B-Complex group:-ThiamineRiboflavinPantothenic acid

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NiacinPyridoxineBiotinFolic acidLipoic acidCyanocobalamineB. Ascorbic acid:-Vitamin C.7. Coenzymes:- Coenzymes are non-protein organic compounds present in enzymes and associated with them. Coenzymes accelerate enzyme action. Classification of Coenzymes:-A. Group transferring Coenzymes:a. TPPb. Biotinc. Coenzyme AB. Hydrogen transferring Coenzymes:a. NADb. NADPc. FADd. FMN.

8. Enzymes:- Enzymes are biological catalysts. They

61

catalyse biochemistry reactions in living systems. Classification of enzymes:-1. Oxidoreductase. 4. Lyases.2. Transferase. 5. Isomerase. 3. Hydrolases. 6. Ligases.

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9. Pathological normal range

-Definitions-Pathology:- the science of the causes and effects of diseases, especially the branch of medicine that deals with the laboratory examination of samples of body tissue for diagnostic or forensic purposes.

Histology:- the study of the microscopic structure of tissues.

Histopathology:- the study of changes in tissues by disease.

Histochemistry:- the branch of science concerned the identification and distribution of the chemical constituents of tissues by means of stains, indicators, and microscopy.

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Biopsy:- an examination of tissue removed from a living bdy to discover the presence, cause, or extent of a disease.

Autopsy:- a post-mortem examination to discover the cause of death or the extent of disease.

Cytology:- the branches of biology and medicine concerned with the structure and function of plant and animal cells. OrStudy of cells.

Cytopathology:- Cytopathology is a branch of pathology that studies and diagnoses diseases on the cellular level. The discipline was founded by George Nicolas Papanicolaou in 1928.

Adhesion:- the action or process of adhering to a surface or object.-: An abnormal adhering of surfaces due to inflammation or injury.

Autolysis:- the destruction of cells or tissues by their own enzymes, especially those released by lysosomes.

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Fixation:- the action or process of fixing or being fixed.

TABLEORGAN IN ADULTS IN BIRTH

1. Adrenal glandWeight 4-5gm 8-10gm2. Brain

Weight male 1400gm 320-420gmWeight female 1250gm -Measurements 16.5×12.5cm -

Volume of cerebrospinal fluid 120-150ml -3. Heart

Weight male 300-350gm 17-30gmWeight female 250-300gm -

Thickness of right ventricular well

0.3-.0.5cm -

Thickness of left ventricular well

1.3-1.5cm -

Circumference of mitral value 10cm -Circumference of aortic value 7.5cm -Circumference of pulmonary

value8.5cm -

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Circumference of tricuspid value

12cm -

Volume of pericardial fluid 10-30ml -4. Intestines

Length of duodenum 30cm -Total length of small intestine 550-650ml -Total length of large intestine 150-170cm -

5. KidneyWeight each male 150gm -

Weight each female 135gm -Measurements 3.5×5.5×11.5c

m-

6. LiverWeight male 1400-1600gm 100-160gm

Weight female 1200-1400gm -Measurements 27×8×20cm -

7. LungsWeight right 375-500gm 35-55gmWeight left 325-450gm -

Volume of pleural fluid <15 ml -8. Oesophagus

Length 25cm -

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Distance from incisors to gastrooesophageal junction

40cm -

9. OvariesWeight 4-8gm -

Measurements 1×2.5×4.5cm -10. PancreasTotal weight 60-100gm 3-6gm

Weight of endocrine pancreas 1-1.5gm -Measurements 3.8×4.5×18cm -

11. Parotid glandsWeight 30gm -

12. Pituitary glandWeight 500gm -

13. PlacentaWeight of term 400-600gm -

14. ProstateWeight 20gm -

15. SpleenWeight 125-175

(150)gm6-14gm

Measurements 3.5×8.5×13 cm

-

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16. StomachLength 25-30cm -

17. Testis and epididymisWeight(adult) 20-27gm -18. Thymus

Weight 5-10gm 10-35gm19. Thyroid

Weight 15-40gm -20. Uterus

Weight(in non pregnant women)

35-40gm -

Weight(in parous women) 75-125gm -

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10. Bacteriology Definition Size of bacteria Culture Staining Normal bacterial flora Defference between Bacteria and Fungi Difference between molds and yeasts

A. Bacteria:- Bacteria are the plural of bacterium, which are microscopic one-celled organisms. They are found everywhere and can be harmful, as in infections; or they can be beneficial, as in fermentation or decomposition. Five types of bacteria are: Coccus, Bacillus, Spirillum, Rickettsia, and Mycoplasma. Bacteria Examples

CoccusHere are examples of bacteria that are spherical shaped (Coccus):

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Staph aureus S. epidermidis S. saphrophyticus S. haemolyticus S. hominis S. capitis S. schleiferi S. warneri S. lugdenenis Strep pyrogenes (gr. A) S. agalactiae (gr. B) E. faecalis E. faecium S. pneumoniae S. mutans group S. salivarus group S. sanguis group S. mitis group S. angiosus group A. adiacens S. milleri S. bovis

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N. gonorrhea N. meningitides Moraxella catarrhalis BacillusExamples of bacteria that are rod shaped (Bacillus):C. diptheriaeC. jeikeniumC. urealyticumLactobacillus sp.Bacillus anthracisB. cereusListeria monocytogenesErisipelothrix rhusiopathiaeArcanobacterium bemolyticumEscherichia coliKlebsiella pneumoniaeProteus spp.MorganellaProvidenciaC. freundiiC. koseriEnterobacter cloacae

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E. aerogenesS. marcecescensVibrio choleraV. parahaemolyticusV. vulificansAeromonas hydrophilaPlesiomonas shigelloidesStenotrophomonas maltophiliaSpirillumHere are examples of bacteria that are spiral shaped and gram-negative (Spirillum):Treponema pallidumTreponema carateumTreponema denticolaBorrelia burgdorferiBorrelia afzeliiBorrelia hermsiiBorrelia duttoniBorrelia parkeriBorrelia recurrentisLeptospira interrogansSpirillum minus

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Chlamydophila psittaciChlamydophila pneumoniaeChlamydia trachomatisBacteroides fragilisBacteroides forsythusCapnocytophaga canimorsusPorphyromonas gingivalisPrevotella intermediaFusobacterium necrophorumFusobacterium nucleatumFusobacterium polymorphumStreptobacillus moniliformisRickettsiaHere are examples of bacteria that behave like viruses and can’t live outside living cells (Rickettsia):Rickettsia rickettsiiRickettsia akariRickettsia conoriiRickettsia sibiricaRickettsia australisRickettsia felisRickettsia japonica

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Rickettsia africaeRickettsia hoogstraaliiRickettsia prowazekiiRickettsia typhiMycoplasmaHere are examples of bacteria that do not have a cell wall and may be rod shaped or spherical (Mycoplasma):M. buccaleM. fauciumM. fermentansM. gallisepticum M. genitaliumM. haemofelis M. hominis M. hyopneumoniae M. hyorhinisM. incognitusM. lipophilumM. ovipneumoniae M. penetransM. pirum

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M. pneumoniaeM. salivariumBacteria in Fermentation

Here are examples of bacteria used in fermentation:Arthrobacter nicotianaeAcetobacter acetiArthrobacter arilaitensisBacillus cereusBacillus coagulansBacillus licheniformisBacillus pumilusBacillus sphaericusBacillus stearothermophilusBacillus subtilisBifidobacterium adolescentisBrachybacterium tyrofermentansBrevibacterium linensCarnobacterium divergensCorynebacterium flavescensEnterococcus faeciumGluconacetobacter europaeusGluconacetobacter johannae

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Gluconobacter oxydansHafnia alveiHalomonas elongataKocuria rhizophilaLactobacillus acidifarinaeLactobacillus jenseniiLactococcus lactisLactobacillus yamanashiensisLeuconostoc citreumMacrococcus caseolyticusMicrobacterium foliorumMicrococcus lylaeOenococcus oeniPediococcus acidilacticiPropionibacterium acidipropioniciProteus vulgarisPseudomonas fluorescensPsychrobacter celerStaphylococcus condimentiStreptococcus thermophilusStreptomyces griseusTetragenococcus halophilus

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Weissella cibariaWeissella koreensisZymomonas mobilis Bacterial Infections

Here are examples of bacterial infections with the bacteria that cause them: Botulism - Clostridium botulinum Diphtheria - Corynebacterium diphtheriae Gonorrhea - Neisseria gonorrhoeae Legionnaire's Disease - Legionella pneumophila Leprosy - Mycobacterium leprae Leptospirosis - Leptospira interrogans Listeriosis - Listeria monocytogenes Lyme disease - Borrelia burgdorferi Mycoplasma pneumonia.

B. Size of Bacteria:

The average diameter of spherical bacteria is 0.5-2.0µ (Figure 2.1). For rod-shaped or filamentous bacteria, length is 1-10µ and diameter is 0.25-1 .0µ.One group of bacteria, called the Mycoplasmas, have individuals with size much smaller than these

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dimensions.They measure about 0.25 µ and are the smallest cells known so far. They were formerly known as pleuropneumonia-like organisms (PPLO). Viruses are still smaller, but as they are particles rather than cells, Mycoplasmas are considered to be the smallest cells known. Examples: Mycoplasma laidlawii and M. gallisepticum.

CultureCulture media contains nutrients and physical growth parameters necessary for microbial growth. All microorganisms cannot grow in a single culture medium and in fact many can’t grow in any known culture medium.Organisms that cannot grow in artificial culture medium are known as obligate parasites. Mycobacterium leprae, rickettsias, Chlamydias, and Treponema pallidum are obligate parasites. Bacterial culture media can be distinguished on the basis of composition, consistency and purpose.

Classification of culture media used in Microbiology laboratory on the basis of consistency

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1.Solid mediumsolid medium contains agar at a concentration of 1.5-2.0% or some other, mostly inert solidifying agent. Solid medium has physical structure and allows bacteria to grow in physically informative or useful ways (e.g. as colonies or in streaks). Solid medium is useful for isolating bacteria or for determining the colony characteristics of the isolate.2. Semisolid mediaThey are prepared with agar at concentrations of 0.5% or less. They have soft custard like consistency and are useful for the cultivation of microaerophilic bacteria or for determination of bacterial motility.3. Liquid (Broth) mediumThese media contains specific amounts of nutrients but don’t have trace of gelling agents such as gelatin or agar. Broth medium serves various purposes such as propagation of large number of organisms, fermentation studies, and various other tests. e.g. sugar fermentation tests, MR-VR broth.

Classification of culture media based on the basis of

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composition

1. Synthetic or chemically defined mediumA chemically defined medium is one prepared from purified ingredients and therefore whose exact composition is known.2. Non synthetic or chemically undefined mediumNon-synthetic medium contains at least one component that is neither purified nor completely characterized nor even completely consistent from batch to batch. Often these are partially digested proteins from various organism sources. Nutrient broth, for example, is derived from cultures of yeasts.

3. Synthetic medium may be simple or complex depending up on the supplement incorporated in it. A simple non-synthetic medium is capable of meeting the nutrient requirements of organisms requiring relatively few growth factors where as complex non-synthetic medium support the growth of more fastidious microorganisms.

Classification of Bacterial Culture Media based on the basis of purpose/ functional use/ application

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Many special purpose media are needed to facilitate recognition, enumeration, and isolation of certain types of bacteria. To meet these needs, numerous media are available.

1. General purpose media/ Basic mediaBasal media are basically simple media that supports most non-fastidious bacteria. Peptone water, nutrient broth and nutrient agar are considered as basal medium. These media are generally used for the primary isolation of microorganisms.

Niturient agar2. Enriched medium (Added growth factors):

Blood AgarAddition of extra nutrients in the form of blood, serum, egg yolk etc, to basal medium makes them enriched media. Enriched media are used to grow nutritionally exacting (fastidious) bacteria. Blood agar, chocolate agar, Loeffler’s serum slope etc are few of the enriched media. Blood agar is prepared by adding 5-10% (by volume) blood to a blood agar base. Chocolate agar is also known as heated blood agar or

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lysed blood agar.

3. Selective and enrichment media :- Selective and enrichment mediaare designed to inhibit unwanted commensal or contaminating bacteria and help to recover pathogen from a mixture of bacteria. While selective media are agar based, enrichment media are liquid in consistency. Both these media serve the same purpose. Any agar media can be made selective by addition of certain inhibitory agents that don’t affect the pathogen of interest. Various approaches to make a medium selective include addition of antibiotics, dyes, chemicals, alteration of pH or a combination of these.

a. Selective mediumPrinciple: Differential growth suppressionSelective medium is designed to suppress the growth of some microorganisms while allowing the growth of others. Selective medium are agar based (solid) medium so that individual colonies may be isolated.

Examples of selective media include:

Thayer Martin Agar used to recover N.gonorrhoeae contains antibiotics; vancomycin, colistin and nystatin.

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Mannitol Salt Agar and Salt Milk Agar used to recover S.aureus contains 10% NaCl.Potassium tellurite medium used to recover C.diphtheriae contains 0.04% potassium tellurite.MacConkey’s Agar used for Enterobacteriaceae members contains bile salt that inhibits most gram positive bacteria.Pseudosel Agar (Cetrimide Agar) used to recover P. aeruginosa contains cetrimide (antiseptic agent).Crystal Violet Blood Agar used to recover S. pyogenes contains 0.0002% crystal violet.Lowenstein Jensen Medium used to recover M.tuberculosis is made selective by incorporating malachite green.Wilson and Blair’s Agar for recovering S. typhi is rendered selective by the addition of dye brilliant green.Selective media such as TCBS Agar used for isolating V. cholerae from fecal specimens have elevated pH (8.5-8.6), which inhibits most other bacteria.b. Enrichment culture medium medium is used to increase the relative concentration of certain microorganisms in the culture prior to plating on solid selective medium. Unlike selective media, enrichment culture is typically used as broth medium. Enrichment media are

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liquid media that also serves to inhibit commensals in the clinical specimen. Selenite F broth, tetrathionate broth and alkaline peptone water (APW) are used to recover pathogens from fecal specimens.

4. Differential/ indicator medium: differential appearance:Certain media are designed in such a way that different bacteria can be recognized on the basis of their colony colour. Various approaches include incorporation of dyes, metabolic substrates etc, so that those bacteria that utilize them appear as differently coloured colonies. Such media are called differential media or indicator media. Differential media allow the growth of more than one microorganism of interest but with morphologically distinguishable colonies.Examples of differential media include:

Mannitol salts agar (mannitol fermentation = yellow)Blood agar (various kinds of hemolysis i.e. α, β and γ hemolysis)Mac Conkey agar (lactose fermenters, pink colonies whereas non- lactose fermenter produces pale or colorless colonies.TCBS (Vibrio cholerae produces yellow colonies due to

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fermentation of sucrose)

5. Transport media:Clinical specimens must be transported to the laboratory immediately after collection to prevent overgrowth of contaminating organisms or commensals. This can be achieved by using transport media. Such media prevent drying (desiccation) of specimen, maintain the pathogen to commensal ratio and inhibit overgrowth of unwanted bacteria. Some of these media (Stuart’s & Amie’s) are semi-solid in consistency. Addition of charcoal serves to neutralize inhibitory factors.

Cary Blair transport medium and Venkatraman Ramakrishnan (VR) medium are used to transport feces from suspected cholera patients.Sach’s buffered glycerol saline is used to transport feces from patients suspected to be suffering from bacillary dysentery.Pike’s medium is used to transport streptococci from throat specimens.

6. Anaerobic media:Anaerobic bacteria need special media for growth because they need low oxygen content, reduced oxidation –reduction

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potential and extra nutrients.

Media for anaerobes may have to be supplemented with nutrients like hemin and vitamin K. Such media may also have to be reduced by physical or chemical means. Boiling the medium serves to expel any dissolved oxygen. Addition of 1% glucose, 0.1% thioglycollate, 0.1% ascorbic acid, 0.05% cysteine or red hot iron filings can render a medium reduced. Before use the medium must be boiled in water bath to expel any dissolved oxygen and then sealed with sterile liquid paraffin.

Robertson Cooked Meat (RCM) medium that is commonly used to grow Clostridium spps contains a 2.5 cm column of bullock heart meat and 15 ml of nutrient broth. Thioglycollate broth contains sodium thioglycollate, glucose, cystine, yeast extract and casein hydrolysate.

Methylene blue or resazurin is an oxidation-reduction potential indicator that is incorporated in the medium. Under reduced condition, methylene blue is colorless.

7. Assay mediaThese media are used for the assay of vitamins, amino acids

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and antibiotics. E.g. antibiotic assay media are used for determining antibiotic potency by the microbiological assay technique.Other types of medium includes

Media for enumeration of Bacteria,Media for characterization of Bacteria,Maintenance media etc.

StainingStaining:- Mark or discolour with something that is not easily removed. Or Colour (a material or object) by applying a penetrative

dye or chemical.The following points highlight the top five types of Staining. The types are: 1. Simple Staining 2. Differential Staining 3. Gram Staining 4. Acid Fast Staining 5. Endospore Staining.

Staining Type # 1. Simple Staining:

Colouration of microorganisms by applying single dye to a fixed smear is termed simple staining. One covers the

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fixed smear with stain for specific period, after which this solution is washed off with water and slide blotted

dry.

Basic dyes like crystal violet, methylene blue and carbolfuchsin are frequently used in simple staining to determine the size, shape and arrangement of prokaryotic cells. (Fig 5.1)

Staining Type # 2. Differential Staining:

These staining procedures are used to distinguish

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organisms based on staining properties. They are slightly more elaborate than simple staining techniques that the cells may be exposed to more than one dye or stain, for instance use of Gram staining which divides bacteria into two classes-Gram negative and Gram positive.

Staining Type # 3. Gram Staining:

It is one of the most important and widely used differential staining techniques in microbiology. This technique was introduced in 1884 by Danish Physician Christian Gram.

In the first step the smear is stained with basic dye crystal violet (Primary stain) followed by treatment with iodine solution functioning as mordant.

Iodine increases the interaction between cell & dye so that cell stains strongly. The smear is next decolourized by washing with ethanol or acetone. This step generates the differential aspect of Gram stains. Gram positive bacteria retain crystal violet and become colourless.

Finally smear is counter-stained with a simple basic dye different in color from Crystal violet. Safranin is the

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most common counter stain which colours Gram negative bacteria pink to red and leaves Gram positive bacteria dark purple. (Fig 5.2)

The differences in staining responses to the Gram stain can be related to chemical and physical difference of cell walls. The Gram-negative bacterial cell wall is thin, complex multilayered structure and contains relatively high lipid contents in addition to protein and mucopeptide.

The higher amount of lipid is readily dissolved by alcohol, resulting information of large pore in the cell wall, thus facilitate leakage of crystal- violet – iodine (CV-I) complex which results in decolorization of the bacterial cell.

Which later take counter stain and appears red. In contrast the cell wall of gram+ve bacteria is thick and chemically simple, composed mainly of mucopeptides. When treated with alcohol, it causes dehydration and closure of cell wall pore, thereby does not allow the loss of (CV-I) complex and cell remain purple.

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Staining Type # 4. Acid Fast Staining:

It is another important differential staining procedure. It is most commonly used to identify Mycobacterium spp. These bacteria have cell wall with high lipid content such as mycolic acid -a group of branched chain hydroxy lipids, which prevent dyes from readily binding to cells.

ADVERTISEMENTS:

They can be stained by Ziehl-Nulsen method, which uses heat and phenol to derive basic fuchsin into the cells. Mycrobacterium spp. were penetrated with basic fuchsin, not easily decolourized by acidified alcohol (acid alcohol) and thus are said to be acid fast.

Non arid fast bacteria are decolourized by arid alcohol and thus are stained blue by methylene blue counter stain.

Staining Type # 5. Endospore Staining:

Spore formation takes place in some bacterial genera to withstand unfavourable conditions. All bacteria cannot form spores, only few bacterial genera including

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Bacillus, Clostridium, Desulfotomaculum produce

sporulating structure inside vegetative cells called endospore.

Endospore morphology and location vary with species and are valuable for identification Endospores are not stained well by most dyes, but once stained, they strongly resist decolorization.

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-:Normal bacterial flora

TABLE-:Body sites:- -: Bacterial flora:-

1. Mouth Enterobacteriaceae Neisseria sp.

Lactobacillus sp. Corynebacterium sp. Staphyococcus aureus

Staphyococcus epidermidis Hemophilus sp.

2. Nose and nasopharynx

Neisseria sp. Corynebacterium sp.

Hemophilus sp. Staphyococcus aureus

Staphyococcus epidermoid Staphyococcus pneumoniae

3. Conjunctive Neisseria sp. Staphyococcus epidermoid

Corynebacterium sp. Hemophilus influenzae Streptococcus viridans

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4. Urethra Candida sp. Mycoplasma sp.

Mycobacterium smegmatis Acinetobacter sp.

5. Large intestine and lower ileum

Staphyococcus sp. Lactobacillus sp. Clostridium sp. Escherichia coli

Proteus sp. Enterbacter aerogenes

Kledasiella pneumoniae Pseudomonas aeruginosa

Mycoplasma sp. Candida albicans

Streptococcus fecalia6. External ear Corynebacterium sp.

Staphyococcus epidermoid Staphyococcus aureus

7. Skin Micrococcus sp. Corynebacterium sp.

Staphyococcus epidermoid

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8. Vagina (Between puberty and menopause

acid pH)

Lactobacillus sp. Staphyococcus sp. Clostridium sp.

Corynebacterium sp. Gardnerella vaginalis

9. Before puberty and after

menopause(alkaline pH)

Staphyococcus Epidermidis Micrococcus

Enterbacteres sp. Viridans streptococci.

-: Important pathogens and disease's caused by them.

TABLE-: Organism -: Morphology -: Disease's

1. Staphyococcus aureus

Cocci in groups Pneumonia,Boils,Meningitis,Food

poisoning2. Streptococcus

pneumoniaeCapsulated diplococci

Meningitis,Pleurisy,Labar

pneumonia,Otitis

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media.3. Streptococcus

fecalisCocci in chains Urinary tract

infection,Woundand ulcer

infection,Septicemia.

4. Streptococcus agalactiae

Cocci in chains Pneumonia,Neonatel meningitis

5. Viridans streptococci

Cocci in chains Bacterial endocarditis, Tooth

decay. 6. Staphyococcus

saprophyticCocci in group Urinary tract

infection7. Streptococcus

pyogenesCocci in chains Sore throat,Otitis

media,Meningitis, Post-

stereptococcal-glomerulonephritis,

Rheumatic fever.-:Gram Negative

cocci8. Neisseria Intracellular Gonorrhea, Eye

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diplococci infection in newbron

9. Neisseria meningitidis

Intracellular diplococci

Meningitis, Septicemia

-:Gram positive rods10.

Corynebacterium diptheriae

Nonmotile rods joined at angles

Diptheria of the throat

11. Clostridium tetani

Nonmotile rods with round

terminal spores

Tetanus

12. Clostridium botulinum

Nonmotile rods with subterminal

spores

Severe food poisoning

13. Clostridium perfringens

Nonmotile brick shaped rode

Gas gangrene,Food poisoning,

Septicemia14. Bacillus

anthracisLarge spore

forming capsulated bacilli

Anthrax

-:Gram Negative

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Rods15. Escherichia

coliMotile or

nonmotile rodsUrinary tract

infection,Wound infection,

Gastroenteritis16. Kledasiella

pneumoniaeNonmotile

capsulated rodsChest infection,

Urinary infection, wound infection,

meningitis, Endocarditis

17. Proteus species Motile rods Urinary,Wound,Chest,

Wound and chest infection,

Meningitis.18. Pseudomonas

pseudomalleiMotile rods Melioidosis

(Pneumoenteritis)19.

Shigella speciesNonmotile rods or

coccobacilliBacillary dysentery

-:Gram Negative Rods

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20. Salmonella species

Motile rods Enteric fiver, Food poisoning, Septicemia,

meningitis, Bone infections.

21. Uibrio cholerae Motile rods Cholera22. Pseudomonas

aeruginosaMotile rods Urinary,

respiratory, ear and wound, Burns,

Septicemia23. Uibrio

parahemolyticusMotile rods Gastroenteritis

-: Acid fast bacilli24. Mycobacterium

lepraeNonmotile bacilli Leprosy

25. Mycobacterium tuberculosis

Nonmotile bacilli Tuberculosis

-: Spirochetes26. Treponema

pallidumMotile delicate

treponemesSyphilis

27. Leptospira interrogans

Motile thin lepospires

Weil's disease

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28. Spirillum minus

Motile, rigid spirals with

flagella

Rat bite fever

29. Rickettsia species

Intercellular organisms

Typhus fever

30. Chlamydia species

Inclusion bodies in epithelial cells

Trachoma, Inclusion

conjunctivitis, Nongonococcal,

Urethritis

-: Bacterial Enzymes

TABLE-:Organism -:Enzymes

1. Streptococcus Streptokinase2. Staphyococcus Staphylokinase:- These jinase break

down the protective Barrie's of body such as fibrin.

3. Staphyococcus aureus

Coagulase:- By coagulating plasma, fibrin formation protects S. aureus from phagocytosis by host cells.

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4. Clostridium perfringens

Hyaluronidase:- It acts on hyaluronic acid of connective tissue and breaks it. It helps the organisms

to spread through the tissue.5. Staphyococcus

aureus and Neisseria gonorreae

Betalactamases-: These enzymes are able to destory penicilline and

cepbalosporins.

-: Diseases caused by spotted fever group organisms.

-: Organism -: Disease's1. R. Siberica Siberian tick typhus

Indian tick typhusMediterranean tick typhusKenyon tick typhusSouth Africa tick typhus

2. R. Australis Queensland tick typhus

3. R. Japonica Oriental spotted fever

4. R. Africae Tick bite fever

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5. R. Akari Miteborne rickettsial pox.

-:Bacteria vs Fungi All living organisms are classified as either prokaryotes or eukaryotes according to the location the DNA exists. Prokaryotic cells do not have nuclear membrane enclosing the nucleus whereas eukaryotic nucleus is enclosed with a nuclear membrane. According to this classification, bacteria are prokaryotic, and fungi are eukaryotic. However, bacteria and fungi have similarities too. Both of them have characteristics such as living and reproducing. Most of them are microscopic. Some of bacteria and fungi are parasitic.

BacteriaThis is the most ancient group of living organisms. They have very simple cell structure. Most of them are unicellular, but may have special features; having chains or clusters. Mainly, they do not have nucleus enclosed with the nuclear membrane; so, they are called prokaryotes. The length of a bacterium ranges from

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0.1µm to 10µm. They have circular naked DNA, which is not covered with histone proteins. 70s ribosomes are associated with cells, synthesizing proteins. Although few organelles can be seen in bacteria cells, they are not covered with membranes. The cell wall is made up of murein, which composed of polysaccharide with amino acids. Due to the differences in cell wall structure bacteria can be divided into two groups called Gram negative and Gram positive. Many bacteria have flagella, and they are motile.

Bacteria reproduce asexually by binary fission and sexual reproduction also occurs by genetic recombination. Bacteria occupy many environments such as soil, air, water, dust. They may occur at extreme environments such as volcanoes, deep-sea, alkaline or acid water. Bacteria are either photoautotrophs or heterotrophs.

FungiAlthough plant and animal fungi are eukaryotes, which have a true nucleus, they have been grouped separately for animals and plants. Fungi have a unique body

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structure, which can be distinguished from other kingdoms (Taylor, 1998). Fungi consist of hyphae, which are thread like, and all hyphae together are called mycelium (mold). Fungi can be found as unicellular organisms such as yeast (Saccharomyces) or in multi cellular form such as Penicillium. All these two types of fungi have rigid cell wall made up of chitin which is a nitrogen containing polysaccharide (Taylor, 1998). These fungi cells contain eukaryotic organelles, Golgi bodies, ribosomes, vacuoles, and endoplasmic reticulum. They have enveloped with a membrane or two. Genetic material is DNA which is covered with histone proteins.

Fungi have sexual reproduction as well as asexual reproduction by mean of spores. Fungi are classified according to the method of reproduction. Zygomycota, Ascomycota, Basidiomycota, and Deuteromycota are four phyla of fungi. Fungi can occur in dead material, soil, also in water. Fungi have heterotrophic nutrition because of lacking chlorophylls like plants; they are not photoautotrophs.

Difference between Bacteria and Fungi

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• The main difference between bacteria and fungi is bacteria are prokaryotes whereas fungi are eukaryotes.

• Bacteria do not have nucleus enclosed with nuclear membrane, but fungi have.

• Bacteria do not have hyphae whereas fungi have hyphae, and all hyphae together form the mycelium.

• The cell wall of bacteria is made of murein, which composed of polysaccharide with amino acids (peptidoglycan), whereas fungi cell walls are made up from chitin which is a nitrogen containing polysaccharides.

• These fungi cells contain eukaryotic organelles, Golgi bodies, ribosomes, vacuoles, and endoplasmic reticulum which have enveloped with a membrane or two while bacteria have only few organelles which are not enveloped with membranes.

• Bacteria may occur at extreme environments such as volcanoes, deep-sea, alkaline or acid water while fungi are not occurring at such harsh environments.

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• Bacteria are either photoautotrophs or heterotrophs, but fungi are only heterotrophs.

Molds vs Yeasts As both mold and yeast are fungi that can be found almost everywhere and as some fungi could be hazardous to health, knowing the difference between molds and yeasts can be useful.Yeast and yeasts are both eukaryotic fungi. Though some fungi are parasitic, not all of them are bad, some molds and yeasts are helpful to human. These microorganisms, as small as they are, help humans in their daily lives such as in the preparation of food as well as in various medications. Another service to human that some fungi give is the decomposition of organic bodies to maintain the ecosystem. However, it is good to have a clear understanding on mold and yeast so as to be safe from the health hazardous organisms. Therefore, let us have a look at what they are and how to identify the difference between molds and yeasts.

MoldsMolds are multicellular microorganisms that grow in a

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form called hyphae. They reproduce through spores asexually and sometimes, sexually as well. A network of these molds, the hyphae forming tubular branches, contains the same genetic information and is considered as a single organism. In the food, molds can be observed to have a fuzzy appearance causing discoloration. They cause biodegradation of natural materials while playing an important part in biotechnology. While molds can be a health hazard, as spore inhalation can potentially cause allergic reactions and respiratory problems, there are cultured molds that help with food production. Also, molds are used in medicine preparation such as antibiotics.

YeastsYeasts are single cell fungi that reproduce asexually or through binary fusion with over 1500 species described so far. They are commonly found in the ocean and are used popularly in food and beverage preparation. Yeasts are used in the production of beer and other alcoholic beverages such as Japanese sake; this is done by the

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yeast Saccharomyces cerevisiae, which converts carbohydrates to carbon dioxide and alcohol. The most common use of yeast, however, would be for bread as a leavening agent. There is, however, some yeasts that are pathogenic, but they only affect people with compromised immune systems.

Difference between Molds and YeastsMolds are multicellular microorganisms with some being colorful. They are harmful when consumed and cause a myriad of health issues such as allergic reactions and respiratory problems. Yeasts are single cellular, colorless. microorganisms. While typically harmless, they still spoil food, usually those with low pH levels and those with high sugar content, and could cause harm to people with weak immune systems.

Summary:

Molds vs Yeasts

• Yeasts are single cellular while molds are multicellular microorganisms.

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• Yeasts are colorless fungi while some molds are colorful.

• Yeasts reproduce asexually while molds can reproduce asexually or sexually and spread through spores.

• Yeasts are mostly harmless and helpful in the preparation of food and some beverages. However, there are yeasts that affect immune-compromised people.

• Molds are harmful to our health in large quantities and it is best to keep them in check. There are some molds, however, that help in preparation of certain medicines such as Penicillin.

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11. Clinical Significance and test name

-:Table:-Test Clinical Significance

PROFILESLYTES Why get tested?

To detect a problem with the body's electrolyte balance.

When to get tested?As part of routine health screening,or when your doctor suspects that you

have an excess or deficit of one of the electrolytes (usually sodium or

potassium),or if your doctor suspects an acid base imbalance.

BASIC METABOLIC

PANEL

The Basic Metabolic Panel (BMP) is a group of 8 tests (or 110sometimes 7 tests) that is ordered

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(BMP)111as a screening tool to check for conditions, such as diabetes and kidney disease. The BMP uses a tube of blood collected by inserting a needle into a vein in your arm. Fasting for 10 to 12 hours prior to the blood draw may be preferred. The BMP is often ordered in the hospital emergency 111

BASIC METABOLIC

PANEL

(BMP)111

room setting because its components give your

doctor important information about the current status of your

kidneys, electrolyte and acid/base balance, and blood sugar level. Significant changes in these test

results can indicate acute problems, such as kidney failure,insulin shock or diabetic coma,

respiratory distress, or heart rhythm changes.

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The BMP is also used to monitor some known conditions, such as hypertension and hypokalemia (low potassium level). If your

doctor is interested in following two or more individual BMP

components, he may order the entire BMP because it offers more

information. Alternatively, he may order an electrolyte panel to monitor your sodium, potassium, chloride, and CO2. If your doctor wants even more information, he may order a complete metabolic

panel. 112112 112COMPREHENSI

VE

METALBOIC PANEL (CMP)

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The Comprehensive Metabolic Panel (CMP) is a frequently ordered group of 14 tests that gives your doctor important information about thecurrent status of your kidneys, liver, and electrolyte and acid/

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base balance as well as of your 113113COMPREHENSI

VE

METALBOIC PANEL (CMP)

113

blood sugar and blood proteins. Abnormal results,and especially combinations ofabnormal results, can indicate a problem that needs to be addressed. The CMP is used as a broad screening tool to check for conditions such as diabetes, liver disease, and kidney disease. It is also used to monitor complications of diseases or side effects of medications used to treat diseases. The CMP is routinely ordered as part of a blood work-up for a medicalexam or yearly physical and iscollected by inserting a needle into a vein in your arm. Usually fasting for 10 to 12 hours prior to the blood draw is preferred. While

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the tests are sensitive, they do not usually tell your doctor specifically what is wrong. Abnormal test results or groups of test results are usually followed-up with other specific tests to confirm or rule out a suspected diagnosis. The CMP is also used to monitor some known problems, such as hypertension, and drug therapies, such as cholesterol-lowering drugs. If your doctor is interested in following two or more individual CMP components, s/he may order the entire CMP because it 114114 114 114

COMPREHENSIVE METALBOIC

PANEL (CMP) (CON’T) 114

offers more information. 114

114

LIPID PANEL 115 The lipid profile is a group of tests that are often ordered together to determine risk of coronary heart disease. The tests that make up a lipid profile are tests that have been shown to be good indicators of whether someone is likely to have a heart attack or stroke caused by blockage of blood vessels (hardening of the arteries). 115

LIVER PANEL 115

A liver panel, also knownas liver (hepatic) function tests or LFT, is used to detect liver damage or disease. It usually includes seven tests that are run at the same time on a blood sample.115

CHEMISTRY

115

ALBUMIN INCREASED absolute serum albumin content is not seen as a natural condition. Relative increase may occur in hemoconcentration. Absolute increase may occur artificially by infusion of hyperoncotic albumin suspensions.

DECREASED serum albumin is seen in states of decreased synthesis (malnutrition, malabsorption, liver disease, and other chronic diseases), increased loss (nephritic syndrome, many GI conditions, thermal burns, etc.), and increased catabolism (thyrotoxicosis,116

116

ALBUMIN (CON’T) 117

cancer chemotherapy, Cushing’s disease, familialhypoproteinemia). 117

ALKALINE PHOSPHATASE

117

INCREASED serumalkaline phosphatase is seen in states of increased osteoblastic activity (hyperparathyroidism, osteomalacia, primary and metastatic neoplasms), hepatobiliary diseases characterized by some degree of intra- or extrahepatic cholestasis,and in sepsis, chronic inflammatory bowel disease, and thyrotoxicosis. Isoenzymes determination may help determine the organ/tissue responsible for an alkaline phosphatase elevation.

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DECREASED serum alkaline phosphatase may not be clinically significant. However, decreased serumlevels have been observed in hypothyroidism, scurvy,kwashiorkor, achrondroplastic dwarfism, deposition of radioactive materials in bone, and in therare genetic condition hypophosphatasia. There are probably more variations in the way in which alkaline phosphatase is assayed than any other enzyme. Therefore, the reporting units vary from place to place. The reference range for the assaying laboraotory must

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be carefully studied when interpreting any individual result.119

ALT (SGPT) 119 INCREASE of serum alanine aminotransferase(ALT, formerly called “SGPT”) is seen in any condition involving necrosis of hepatocytes,myocardial cells,erythrocytes, or skeletalmuscle cells. 119

AMYLASE 119 Why get tested?To diagnose pancreatitis or other pancreatic diseases.

When to get tested?If you have symptoms of a pancreatic disorder, such as severe abdominal pain, fever, loss of appetite, or nausea119

119

AST (SGOT) 120 INCREASE of aspartate aminotransferase (AST, formerly called “SGOT”) is seen in any condition involving necrosis of hepatocytes, myocardial cells, or skeletal muscle cells.

DECREASED serum AST is of no known clinical significance. 120

ASO, TITER 120 Antistreptolysin O (ASO) titer is a blood test used to help diagnose a current or past infection with Group A strep (Streptococcus pyogenes). It detects antibodies to streptolysin O, one of the many strep antigens. This test is rarely ordered now compared to

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thirty years ago. For an acute strep throat infection,this test is not performed;the throat culture is used. However, if a doctor is trying to find out if someone had a recent strep.

BUN Serum urea nitrogen (BUN) is INCREASED in acute and chronic intrinsic renal disease, in state characterized by decreased effective circulating blood volume with decreased renal perfusion, in postrenal obstruction of urine flowand in high protein intake states.

DECREASED serum urea nitrogen (BUN) is seen in high carbohydrate/low

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protein diets, statescharacterized by increased anabolic demand (late pregnancy, infancy, acromegaly), malabsorption states and severe liver damage. 122

TOTAL BILIRUBIN

DIRECT BILIRUBIN

INDIRECT BILIRUBIN122

Serum total bilirubin is INCREASED in hepatocellular damage (infectious hepatitis, alcoholic and other toxic hepatopathy, neoplasms), intra- and extrahepatic biliary hemolysis, physiologic neonatal jaundice, Crigler-Najjar syndrome, Gilbert’s disease, Dubin-Johnson syndrome, and fructose intolerance. Disproportionate 122

122

TOTAL BILIRUBIN

DIRECT BILIRUBIN

INDIRECT BILIRUBIN

(CON’T) 123

ELEVATION of direct (conjugated) bilirubin is seen in cholestasis and late in the course of chronic liver disease. Indirect(unconjugated) bilirubintends to predominate in hemolysis and Gilbert’s disease.

DECREASED serum total bilirubin is probably not of clinical significance but has been observed in iron deficiency anemia. 123

BNP Why get tested?To help diagnose the presence and severity of heart failureWhen to get tested?If you have symptoms of heart failure, such as

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shortness of breath and fatigue, or if you are being treated for heart failure 124

CALCIUM HYPERCALCEMIA is seen in malignant neoplasms (with or without bone involvement), primary and tertiary hyperparathyroidism, sarcoidosis, Vitamin D intoxication, milk-alkali syndrome, Paget’s disease of bone (with immobilization), thyrotoxicosis, acromegaly, and diuretic phase of renal acute tubular necrosis. For a given total calcium level, acidosis increases the physiologically active ionized form of calcium. Prolonged tourniquet

124

pressure during venipuncture may125

CALCIUM (CON’T) 125

spuriously increase total calcium. Drugs producinghypercalcemia includealkaline antacids, DES,diuretics (chronic administration), estrogens(including oralcontraceptives) and progesterone.HYPOCALCEMIA mustbe interpreted in relation to serum albumin concentration. Truedecrease in thephysiologically active ionized form of Ca++ occurs in may situations, includinghypoparathyroidism, Vitamin D deficiency,

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chronic renal failure, magnesium deficiency, prolonged anticonvulsant therapy, acute pancreatitis, massive transfusion, alcoholism, etc. Drugs producing hypocalcemia include most diuretics, estrogens, fluorides, glucose, insulin, excessive laxatives, magnesium salts, methicillin and phosphates. 126

CEA Why get tested?To determine whethercancer is present in thebody and to monitor cancer treatment

When to get tested?When your doctor thinks your symptoms suggest the possibility of cancer and

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before starting cancer treatment as well as at intervals during and after therapy127

CHOLESTEROL127

Total cholesterol has been found to correlate with total127

CHOLESTEROL (CON’T)127

found to correlate with total and cardiovascular mortality in the 30-50 year age group. Cardiovascular mortality increases 9% for each 10 mg/dL increase in total cholesterol over the baseline value of 180 mg/dL. Approximately 80% of the adult male population has values greater than this, so the use of median 95% of the population to establish normal range (as is traditional in lab medicine

127

in general) has no utility for this test. Excess mortality has been shown not to correlate with cholesterol levels in the >50 years age group, probably because of the depressive effects on cholesterol levels expressed by various chronic diseases to which older individuals are prone. 128

CK Why get tested?To determine if you have had a heart attack and if other muscles in your body have been damaged.

When to get tested?If you have chest pain or muscle pain and weakness; immediately after a suspected heart attack and

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every few hours for a total of 3 or 4 tests 129

CREATININE

CREATININE CLEARANCE

129

Serum creatinine level and “creatinine clearance” are different ways of determining kidney function. Creatinine is a protein produced by muscle and released into the blood. 129

CREATININE

CREATININE CLEARANCE (CON’T)129

The amount produced is relatively stable in a given person. The creatinine level in the serum is therefore determined by the rate it is being removed, which is roughly a measure of kidney function. If kidney function falls (say a kidney is removed to donate to a relative), the creatinine level will rise. Normal is

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about 1 for an average adult. Infants that have little muscle will have lower normal levels (0.2). Muscle bound weight lifters may have a higher normal creatinine. Serum creatinine only reflects renal function in a steady state. After removing a kidney, if the donor’s blood is checked right away the serum creatinine will still be 1. In the next day the creatinine will rise to a new steady state (usually about 1.8). If both kidneys were removed (say for cancer) the creatinine would continue to rise daily until dialysis is begun. How fast it rises depends on

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creatinine production, which is again related to how much muscle one has. Creatinine clearance is technically the amount of blood that is “cleared” of creatinine per time period. It is usually expressed in mL per minute. Normal is 120 mL/min for an adult. It is roughly, inversely related 131to serum creatinine: If theclearance drops to one half of the old level, the serum creatinine doubles (in the steady state). So for an adult, serum creatinine of 2 is roughly a creatinine clearance of 60 mL/min; creatinine 3 is roughly a clearance of 30; creatinine of 4 is roughly a clearance

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of 15, etc. So why didn’t the creatinine rise to only 2 when a kidney was removed? The answer is that the remaining kidney “hyperfilters” and seems to work harder, therefore kidney function is not quite halved. Usually, an adult will need dialysis because symptoms of kidney failure appear at a clearance of less than 10 mL/min. Creatinine clearance has to be measured by urine collection (usually 12 or 24 hours). It is a more precise estimate of kidney function than serum creatinine since it does not depend on the amount of muscle one has. 132

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CRP Why get tested?To identify the presence ofinflammation and to monitor response to treatment [Note: to test for your risk of heart disease, a more sensitive test (hs-CRP) is used.]

When to get tested?When your doctor suspects that you might be suffering from an inflammatorydisorder (as with certain 133

CRP (CON’T)133 types of arthritis and autoimmune disorders or inflammatory bowel disease) or to check for the presence of infection(especially after surgery)133

HIGH SENSITIVITY

CRP 133

Why get tested?May be helpful in assessingrisk of developing heart

133

disease

When to get testedNo current consensus existson when to get tested; the test is most often done inconjuction with other tests that are ordered to assess risk of heart disease, suchas lipid profiles.134

DLDL To help determine your risk of developing heart diseaseand to monitor lipid lowering lifestyle changes and drug therapies. Toaccurately determine yourlow-density lipoprotein(LDL) level when you arenonfasting. 134

FERRITIN 134 The test is done to learn about your body’s ability to store iron for later use.

134

You should get tested when your doctor suspects you may not have enough iron or too much iron in yoursystem 135

VITAMIN B12 135

Why get tested?To help diagnose the cause of anemia or neuropathy(nerve damage), to evaluatenutritional status in somepatients, to monitor effectiveness of treatment for B12 or folate deficiency.

When to get tested?When you have large red 135

VITAMIN B12 (CON’T) 135

blood cells, when you have symptoms of anemia and/or of neuropathy. When you are being treated for B12 or folate deficiency. 135

135

FOLATE 136 Why get tested?To help diagnose the cause of anemia or neuropathy (nerve damage), to evaluate nutritional status in some patients, to monitor effectiveness of treatment for B12 or folate deficiency.

When to get tested?When you have large red blood cells, when you have symptoms of anemia and/or of neuropathy. When you are being treated for B12 or folate deficiency136

GLUCOSE 136 Why get tested?To determine whether or not your blood glucose level is within normal ranges; to screen for,

136

diagnose, and monitor diabetes, pre-diabetes, and hypoglycemia (low blood glucose)

When to get tested?As part of a yearly physical and when you have symptoms suggesting hyperglycemia (high blood glucose) or hypoglycemia, or if you are pregnant; if you are diabetic, up to several times a day tomonitor glucose levels 137

HEMOGLOBIN A1C

(GLYCOHEMOGLOBIN) 137

Why get tested?To monitor a person’s diabetes and to aid in treatment decisions

When to get tested?137When first diagnosed with diabetes and then 2 to 4

137

times per year 138IRON Iron is needed to help form

adequate numbers of normal red blood cells, which carry oxygen throughout the body. Iron is a critical part of hemoglobin, the protein in red blood cells that binds oxygen in the lungs and releases it as blood travels to other parts of the body. Iron is also needed by other cells, especially muscle (which contains another oxygen binding protein called myoglobin). Low iron levels can lead to anemia, in which the body does not have enough red blood cells. Other conditions can cause you to

138

have too much iron in your blood. Serum Iron level measures the level of iron in the liquid part of your blood. 139

IMMUNOELECTROPHORESIS

139

Why get tested?To help diagnose and monitor multiple myelomaand a variety of other conditions that affect protein absorption, production, and loss as seenin severe organ disease and altered nutritional states When to get tested?If you have an abnormal total protein or albuminlevel or if your doctor suspects that you have a condition that affects protein concentrations in

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the blood and/or causes 140IMMUNOELECT

ROPHORESIS (CON’T)140

protein loss through the urine 140

LD Why get tested?To help identify the cause and location of tissue damage in the body, and to monitor its progress; historically, has been used to help diagnose and monitor a heart attack, buttroponin has largely replaced LDH in this role.

When to get tested?Along with other tests, when your doctor suspectsthat you have an acute or chronic condition that is causing tissue or cellular destruction and he wants to

140

identify and monitor the problem. 141

LIPASE 141 Why get tested?To diagnose pancreatitis or other pancreatic disease

When to get tested?If you have symptoms of a pancreatic disorder, such as severe abdominal pain, fever, loss of appetite, or nausea 141

MAGNESIUM 141

Why get tested?To evaluate the level of magnesium in your blood and to help determine the cause of abnormal calcium and/or potassium levels

When to get tested?If you have symptoms (such as weakness, irritability, cardiac arrhythmia, nausea,

141

and/or diarrhea) that may be due to too much or too little magnesium or if you have abnormal calcium or potassium levels 142

PHOSPHOROUS 142

Why get tested?To evaluate the level of phosphorus in your blood and to aid in the diagnosis of conditions known to cause abnormally high or low levels

When to get tested?As a follow-up to an abnormal calcium level, if you have a kidney disorderor uncontrolled diabetes, and if you are taking calcium or phosphate supplements 142

POTASSIUM 142 Why get tested?

142

To diagnose levels of potassium that are too high (hyperkalemia) or too low (hypokalemia)

When to get tested?As part of a routine medical exam or to investigate a serious illness, such as high blood pressure or kidney disease143

PROSTATIC SPECIFIC ANTIGEN (PSA) 143

Why get tested?To get screened for -- and to monitor -- prostate cancer

When to get tested?There is some debate over this (see prostate cancer screening). Generally, for men over 50, as recommended by your physician (may be annually

143

or less frequently); annually starting at age 45 for African-American men and men with a family history of prostate cancer. 144

RHEUMATOID FACTOR 144

Why get tested?To help diagnose rheumatoid arthritis (RA)144

RHEUMATOID FACTOR

(CON’T)144

and Sjögren’s syndrome

When to get tested?If your doctor thinks that you have symptoms of RA or Sjögren’s syndrome 144

TRANSFERRIN 144

Why get tested?To learn about your body’s ability to transport iron

When to get tested?When your doctor suspects you may have too much or too little iron in your body because of a variety of

144

conditions; the test also helps to monitor liver function and nutrition145

TOTAL PROTEIN 145

Why get tested?To determine your nutritional status or to screen for certain liver and kidney disorders as well as other diseases

When to get tested?If you experience unexpected weight loss or fatigue or if your doctor thinks that you have symptoms of a liver or kidney disorder 145

URIC ACID 145 Why get tested?To detect high levels of uric acid, which could be a sign of the condition gout

When to get tested?

145

When your doctor thinks that you might have gout or when monitoring certain chemotherapy or radiation therapies for cancer146

URINE CHEMISTRY146MICROALBUMI

N146Why get tested?To get screened for a possible kidney disorder

When to get tested?Annually after a diagnosis of diabetes or hypertension 146

ENDOCRINOLOGY146

CORTISOL146 Why get tested?To help diagnose Cushing syndrome or Addison disease

When to get tested?If your doctor suspects

146

damage to the adrenal gland147HCG,

QUALITATIVE AND

QUANTITATIVE 147

Why get tested?To confirm and monitor pregnancy or to diagnose trophoblastic disease orgerm cell tumors

When to get tested?As early as 10 days after a missed menstrual period (some methods can detect hCG even earlier, at one week after conception) or if a doctor thinks that your symptoms suggest ectopic pregnancy, a failing pregnancy, trophoblastic disease, or germ cell tumors 147

FOILICLE STIMULATING

HORMONE (FSH)147

Why get tested?To evaluate your pituitary function, especially in terms of fertility issues

147

When to get tested?If you are having difficulty getting pregnant or are having irregular menstrual periods or if your doctor thinks that you have symptoms of a pituitary or hypothalamic disorder 148

LUTEINIZING HORMONE

(LH) 148

Why get tested?To evaluate your pituitary function, especially in terms of fertility issues

When to get tested?If you are having difficultygetting pregnant or are having irregular menstrual periods or if your doctor thinks that you have 148

LUTEINIZING HORMONE

(LH) (CON’T) 148

symptoms of a pituitary or hypothalamic disorder 148

148

PROLACTIN 149 Why get tested?To determine whether or not your prolactin levels are higher (or occasionally lower) than normal

When to get tested?When you have symptoms of an elevated prolactin, such as: galactorrhea and/or visual disturbances and headaches, as part of aworkup for female and male infertility, and for follow up of low testosterone in men. 149

TESTOSTERONE, TOTAL 149

Why get tested?To determine if your testosterone levels are abnormal, which may help to explain difficulty getting an erection (erectile

149

dysfunction), inability of your partner to get pregnant (infertility), or premature or delayed puberty if you are male, or masculine physical features if you are female

When to get tested?If you are male and your doctor thinks that you may be infertile or if you are unable to get or maintain an erection; if you are a boy with either early or delayed sexual maturity; if you are a female but have male traits, such as a low voice or excessive body hair, or are infertile150

THYROID STIMULATING

HORMONE

Why get tested?To screen for and diagnose thyroid disorders; to

150

(TSH) 151 monitor treatment of hypothyroidism

When to get tested?151For screening: There is no consensus within the medical community as to atwhat age adult screening should begin or whether it should even be done; however, newborn screening is widely recommended. For monitoring treatment: as directed by your doctor. Otherwise: as symptoms present. 151

T4 DRAW IN A

PLAIN RED TOP TUBE. THE GEL

IN THE GOLD

Why get tested?To diagnose hypothyroidism or hyperthyroidism in adults; to screen for

151

TOPS CAUSE INTERFERENCE

152

hypothyroidism in newborns.

When to get tested?Usually is ordered in response to an abnormal TSH test result. Commonly performed on newborns. 152

URINALYSIS152URINALYSIS SPECIMEN

GOOD FOR 8 HOURS

REFRIGERATED OR 1 HOUR AT

ROOM TEMP.152

Why get tested?To screen for metabolic and kidney disorders

When to get tested?Regularly on admission to a hospital; in a work-up for aplanned surgery; as part of an annual physical exam; orwhen evaluating a newpregnancy. May be done if you have abdominal pain, back pain, frequent or painful urination, or blood

152

in the urine. 153HEMATOLOGY/COAGULATION

153HEMOGLOBIN/HEMATOCRIT

(H&H)153

Why get tested?If you have anemia (too few red blood cells) or 153

HEMOGLOBIN/HEMATOCRIT (H&H) (CON’T)

CLOTTED SPECIMENS

HAVE TO BE REJECTED.

153

polycythemia (too many red blood cells), to assess its severity, and to monitor response to treatment

When to get tested?As part of a complete blood count (CBC), which may be ordered for a variety of reasons153

PLATELET COUNT

CLOTTED SPECIMENS

HAVE TO

Why get tested?To diagnose a bleeding disorder or a bone marrodisease

When to get tested?

153

BE REJECTED154

As part of a regular complete blood count (CBC) or to diagnose/monitor a bone marrow/blood disease 154

COMPLETE BLOOD COUNT

(CBC) CLOTTED

SPECIMENS HAVE TO

BE REJECTED. 154

Why get tested?To determine general health status and to screen for avariety of disorders, such as anemia and infection, aswell as nutritional statusand exposure to toxic substances

When to get tested?As part of a routine medical exam or as determined by your doctor 154

COMPLETE BLOOD COUNT

WITHDIFFERENTIAL

Why get tested?To diagnose an illness affecting your immunesystem, such as an infection

154

(CBCD) CLOTTED

SPECIMENS HAVE TO

BE REJECTED.155

When to get tested?As part of a complete bloodcount (CBC), which may beordered for a variety of reasons155

ESR (SEDIMENTATI

ON RATE) SPECIMEN CAN BE HELD FOR 12

HOURS IF REFRIGERATED

.155

Why get tested?To detect and monitor the activity of inflammation asan aid in the diagnosis of the underlying cause

When to get tested?155

ESR (SEDIMENTATI

ON RATE) (CON’T) 155

When your doctor thinks that you might have a condition that causesinflammation and to help diagnose and follow the course of temporal arteritis or polymyalgia rheumatica155

PROTHROMBIN Why get tested?

155

TIME (PT)

PROTHROMBIN TIME IS GOOD FOR 24 HOURS

REFRIGERATED.

TUBE MUST BE FILLED

COMPLETELY156

To check how well blood-thinning medications (anti-coagulants) are working to prevent blood clots; to helpdetect and diagnose ableeding disorder

When to get tested?If you are taking an anticoagulant drug or if your doctor suspects that youmay have a bleeding disorder156

PARTIAL THROMBOPLAS

TIN TIME (PTT)

PTT MUST BE RUN WITHIN 4

HOURS. TUBE MUST BE

Why get tested?As part of an investigation of a bleeding or thrombotic episode. To help evaluateyour risk of excessive bleeding prior to a surgicalprocedure. To monitorheparin anticoagulant therapy.

156

FILLED COMPLETELY.1

57

When to get tested?When you have unexplained bleeding or blood clotting. When you are on heparin anticoagulant therapy. Sometimes as part of a presurgical screen. 157

WHITE BLOOD CELL COUNT

(WBC) 157

Why get tested?If your doctor thinks thatyou might have an infection or allergy and to monitor treatment

When to get tested?As part of a complete blood count (CBC), which may be ordered for a variety of reasons 157157

D-DIMER157 Why get tested?To help diagnose or rule out thrombotic (blood clot producing) diseases and

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conditions

When to get testedWhen you have symptoms of a disease or condition that causes acute and/or chronic inappropriate bloodclot formation such as:DVT (Deep VeinThrombosis), PE (Pulmonary Embolism), orDIC (DisseminatedIntravascular Coagulation), and to monitor the progress and treatment of DIC andother thrombotic conditions. 158

SEROLOGY158ANTI-NUCLEAR

ANTIBODY (ANA) 158

Why get tested?To help diagnose systemic lupus erythematosus (SLE)and drug-induced lupus and

158

rule out certain other autoimmune diseases

When to get tested?If your doctor thinks that you have symptoms of SLE or drug-induced lupus 159

HIV Why get tested?To determine if you are infected with HIV

When to get tested?Three to six months after you think you may have been exposed to the virus159

H. PYLORI ANTIBODY SCREEN159

Why get tested?To diagnose an infection with Helicobacter pylori

When to get tested?If you have gastrointestinal pain or symptoms of an ulcer159

159

MONO SCREEN 160

Why get tested?To get screened for mononucleosis

When to get tested?If you have symptoms of mononucleosis, including fever, sore throat, swollen glands, and fatigue 160

FLU A&B 160 Why get tested?To determine whether or not you have the influenza A or B; to help your doctormake rapid treatmentdecisions; and to help determine whether or not the flu has come to your community.

When to get tested?When it is flu season andyour doctor wants to determine whether your flulike

160

symptoms are due to influenza A or B, or to other causes. Within 48 hours of the onset of your symptoms, to help determine treatment options.161

MICROBIOLOGY 161

URINE CULTURE 161

Why get tested?To diagnose a urinary tract infection (UTI)

When to get tested?If you experience symptoms of a UTI, such as pain during urination 161

AFB CULTURE 161

Why get tested?To help identify a mycobacterial infection, to diagnose tuberculosis (TB), to monitor the effectiveness

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of treatment

When to get tested?When you have symptoms, such as a chronic cough, weight loss, fever, chills, and weakness, that may be due to TB or due to another mycobacterial infection. When your doctor suspects that you have active TB. When your doctor wants to monitor the effectiveness of TB treatment. 162

HERPES CULTURE 162

Why get tested?To screen for or diagnoseinfection with the herpessimplex virus

When to get tested?If you have symptoms of an infection with the herpessimplex virus, such as

162

blisters or sores around your mouth or in the genital area163

RAPID BETA SCREEN 163

Why get tested?To determine if a sore throat (pharyngitis) is caused by a Group A streptococcal bacteria(“strep throat”)

When to get tested?If you have a sore throat and fever and your doctor thinks it may be due to an upper respiratory infection163

CHLAMYDIA SCREEN163

Why get tested?To screen for or diagnose chlamydia infection

When to get tested?If you are sexually active, pregnant, have one or more risk factors for developing

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chlamydia, or have a cervical infection; depending on your risk factors, may be annually 164

GC SCREEN 164 Why get tested?To screen for Neisseria gonorrhoeae, which causes the sexually transmitted 164

GC SCREEN (CON’T) 164

GC SCREEN (CON’T) disease gonorrhea When to get tested?If you have symptoms of gonorrhea or are pregnant164

MRSA SCREEN 164

The goal of laboratory testing for staph wound infections is to identify the presence of S. aureus, todetermine whether it is a MRSA strain, and to evaluate the staph’s

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susceptibility to available antibiotics. If an infection is due to MRSA, it should be investigated to determinewhere it came from and how it was acquired. This is especially important in CA-MRSA to prevent further cases from occurring. 165

VRE SCREEN 165

VRE are specific types of antimicrobial-resistant staph bacteria. While moststaph bacteria are susceptible to the antimicrobial agent vancomycin some have developed resistance. VRE cannot be successfully treated with vancomycinbecause these organisms are no longer susceptibile to vancomycin. However, to

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date, all VRE isolates havebeen susceptible to other Food and Drug Administration (FDA) approved drugs. 166

FECAL ANALYSIS166

BLOOD Why get tested?To screen for gastrointestinal bleeding, which may be an indicator of colon cancer

When to get tested?As part of a routine 166

BLOOD (CON’T) 166

examination, annually after age 50 (as recommended bythe American Cancer Society and other major organizations), and as directed by your doctor 166

C DIFFICILE Why get tested?

166

TOXIN 167 To detect the presence of Clostridium difficile toxin

When to get tested?When a patient has acute diarrhea that persists for several days, abdominal pain, fever, and/or nausea following antibiotic therapy167

GIARDIA SPECIFIC

ANTIGEN 167

This test detects protein structures on the giardia parasite. It is more sensitiveand specific for this particular parasite than the O&P microscopic exam. 167

WBC'S Stool WBC (white blood cells) may be present in the stool when there is a bacterial infection. 167

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12. Hematological disease's

This is an incomplete list, which may never be able to satisfy certain standards for completion.

There are many conditions of or affecting the human hematologic system — the biological system that includes plasma, platelets, leukocytes, and erythrocytes, the major components of blood and the bone marrow.

Anemias

Blood cancers

Coagulation, purpura, and other hemorrhagic conditions

Infection-related

Immune system regulation-related

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References

-:First-:Anemias:-

An anemia is a decrease in number of red blood cells (RBCs) or less than the normal quantity of hemoglobin in the blood.[2][3] However, it can include decreased oxygen-binding ability of each hemoglobin molecule due to deformity or lack in numerical development as in some other types of hemoglobin deficiency.

Anemia is the most common disorder of the blood. There are several kinds of anemia, produced by a variety of underlying causes. Anemia can be classified in a variety of ways, based on the morphology of RBCs, underlying etiologic mechanisms, and discernible clinical spectra, to mention a few. The three main classes of anemia include excessive blood loss (acutely such as a hemorrhage or chronically

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through low-volume loss), excessive blood cell destruction (hemolysis) or deficient red blood cell production (ineffective hematopoiesis). Based on 2005-2006 estimates, the Centers for Disease Control and Prevention has stated that approximately 5.5 million Americans a year are either admitted to a hospital or seen by a physician, with some form of anemia as their primary diagnosis.

Nutritional anemiasA nutritional anemia is a type of anemia that can be directly attributed to either a nutritional disorder or a nutritional deficiency.

Iron-deficiency anemiaIron-deficiency anemia, also spelled iron-deficiency anaemia,is anemia caused by a lack of iron. Anemia is defined as a decrease in the number of red blood cells or the amount of hemoglobin in the blood. When anemia comes on slowly, the symptoms are often vague and may include feeling tired, weakness, shortness of breath or poor ability to exercise. Anemia that comes on quickly often has greater

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symptoms which may include: confusion, feeling like one is going to pass out, and increased thirst. There needs to be significant anemia before a person becomes noticeably pale. There may be additional symptoms depending on the underlying cause.

Iron-deficiency anemia

-: Red blood cells :-It is caused by insufficient dietary intake and absorption of

iron, or iron loss from bleeding. Bleeding can be from a

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range of sources such as the intestinal, uterine or urinary tract. The most common cause of iron-deficiency anemia in children in developing countries is parasitic worms.[citation needed] Worms cause intestinal bleeding, which is not always noticeable in feces, and is especially damaging to children.Malaria, hookworms and vitamin A deficiency contribute to anemia during pregnancy in most underdeveloped countries.In women over 50 years old, the most common cause of iron-deficiency anemia is chronic gastrointestinal bleeding from nonparasitic causes, such as gastric ulcers, duodenal ulcers or gastrointestinal cancer.

Iron deficiency causes approximately half of all anemia cases worldwide, and affects women more often than men. Iron-deficiency anemia affected 1.2 billion people in 2013.In 2013 anemia due to iron deficiency resulted in about 183,000 deaths – down from 213,000 deaths in 1990.

Signs and symptoms

Iron-deficiency anemia is characterized by the sign of pallor (reduced oxyhemoglobin in skin or mucous membranes), and the symptoms of fatigue, lightheadedness, and weakness. None of the symptoms (or any of the others below) are

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sensitive or specific. Pallor of mucous membranes (primarily the conjunctiva) in children indicates anemia with the best correlation to the actual disease, but in a large study was found to be only 28% sensitive and 87% specific (with high predictive value) in distinguishing children with anemia [hemoglobin (Hb) <11.0 g/dl] and 49% sensitive and 79% specific in distinguishing severe anemia (Hb < 7.0 g/dl).[9] Thus, this sign is reasonably predictive when present, but not helpful when absent, as only one-third to one-half of children who are anemic (depending on severity) will show pallor. Iron-deficiency must be diagnosed by laboratory testing.

Because iron deficiency tends to develop slowly, adaptation occurs and the disease often goes unrecognized for some time, even years; patients often adapt to the systemic effects that anemia causes. In severe cases, dyspnea (trouble breathing) can occur. Unusual obsessive food cravings, known as pica, may develop. Pagophagia or pica for ice has been suggested to be specific, but is actually neither a specific or sensitive symptom, and is not helpful in diagnosis. When present, it may (or may not) disappear with correction of iron-deficiency anemia.

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Other symptoms and signs of iron-deficiency anemia include:

Anxiety often resulting in OCD-type compulsions and obsessions

Irritability or a low feeling Angina Constipation Sleepiness/Hypersomnia Tinnitus Mouth ulcers Palpitations Hair loss Fainting or feeling faint Depression Breathlessness Twitching muscles Pale yellow skin Tingling, numbness, or burning sensations Missed menstrual cycle Slow social development Glossitis (inflammation or infection of the tongue) Angular cheilitis (inflammatory lesions at the mouth's

corners)

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Koilonychia (spoon-shaped nails) or nails that are weak or brittle

Poor appetite Pruritus (itchiness) Dysphagia due to formation of esophageal webs

(Plummer-Vinson syndrome) Insomnia Restless legs syndrome

Infant developmentIron-deficiency anemia for infants in their earlier stages of development may have greater consequences than it does for adults. An infant made severely iron-deficient during its earlier life cannot recover to normal iron levels even with iron therapy. In contrast, iron deficiency during later stages of development can be compensated with sufficient iron supplements. Iron-deficiency anemia affects neurological development by decreasing learning ability, altering motor functions, and permanently reducing the number of dopamine receptors and serotonin levels. Iron deficiency during development can lead to reduced myelination of the spinal cord, as well as a change in myelin composition. Additionally, iron-deficiency anemia has a negative effect

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on physical growth. Growth hormone secretion is related to serum transferrin levels, suggesting a positive correlation between iron-transferrin levels and an increase in height and weight. This is also linked to pica, as it can be a cause.

CauseA diagnosis of iron-deficiency anemia then requires further investigation as to its cause. It can be caused by increased iron demand / loss or decreased iron intake,[11] and can occur in both children and adults. The cause of chronic blood loss should all be considered, according to the patient's sex, age, and history, and anemia without an attributable underlying cause is sufficient for an urgent referral to exclude underlying malignancy. In babies and adolescents, rapid growth may outpace dietary intake of iron, and result in deficiency without disease or grossly abnormal diet.[11] In women of childbearing age, heavy or long menstrual periods can also cause mild iron-deficiency anemia.

Parasitic diseaseThe leading cause of iron deficiency worldwide is a

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parasitic disease known as a helminthiasis caused by infestation with parasitic worms (helminths) such as tapeworms, flukes, and roundworms.[citation needed] The World Health Organization estimates that "approximately two billion people are infected with soil-transmitted helminths worldwide."[12] Parasitic worms cause both inflammation and chronic blood loss.

Blood lossBlood contains iron within red blood cells, so blood loss leads to a loss of iron. There are several common causes of blood loss: Women with menorrhagia (heavy menstrual periods) are at risk of iron-deficiency anemia because they are at higher-than-normal risk of losing a larger amount blood during menstruation than is replaced in their diet. Slow, chronic blood loss within the body — such as from a peptic ulcer, angiodysplasia, a colon polyp or gastrointestinal cancer, excessively heavy periods — can cause iron-deficiency anemia. Gastrointestinal bleeding can result from regular use of some groups of medication, such as NSAIDs (e.g. aspirin), anticoagulants such as clopidogrel and warfarin, although these are required in some patients, especially those with states causing

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thrombophilia.

DietThe body normally gets the iron it requires from foods. If a person consumes too little iron, or iron that is poorly absorbed (non-heme iron), they can become iron deficient over time. Examples of iron-rich foods include meat, eggs, leafy green vegetables and iron-fortified foods. For proper growth and development, infants and children need iron from their diet, too.[13] A high intake of cow’s milk is associated with an increased risk of iron deficiency anemia.[14] Other risk factors for iron deficiency include low meat intake and low intake of iron-fortified products.[14]

Iron absorption

Iron from food is absorbed into the bloodstream in the small intestine, especially the duodenum and proximal ileum. Many intestinal disorders can reduce the body's ability to absorb iron. There are different mechanisms that may be present.

In cases where there has been a reduction in surface area of

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the bowel, such as in celiac disease, inflammatory bowel disease or post-surgical resection, the body can absorb iron, but there is simply insufficient surface area.[citation needed]

If there is insufficient production of hydrochloric acid in the stomach, hypochlorhydria/achlorhydria can occur (often due to chronic H. pylori infections or long-term proton pump inhibitor therapy). Ferrous and ferric iron salts will precipitate out of solution in the bowel and be poorly absorbed.

In cases where systemic inflammation is present, iron will be absorbed into enterocytes but, due to the reduction in basolateral ferroportin molecules which allow iron to pass into the systemic circulation, iron is trapped in the enterocytes and is lost from the body when the enterocytes are sloughed off. Depending on the disease state, one or more mechanisms may occur.

Pregnancy

Without iron supplementation, iron deficiency anemia occurs in many pregnant women because their iron stores need to serve their own increased blood volume as well as be a

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source of hemoglobin for the growing fetus, and for placental development.[13]

Other less common causes are intravascular hemolysis and hemoglobinuria.

MechanismAnemia is one result of significant iron deficiency. When the body has sufficient iron to meet its needs (functional iron), the remainder is stored for later use in all cells, but mostly in the bone marrow, liver, and spleen. These stores are called ferritin complexes and are part of the human (and other animals) iron metabolism systems. Ferritin complexes in humans carry about 4500 iron atoms and form into 24 protein subunits of two different types.

Diagnosis

Blood smear of a person with iron-deficiency anemia at 40X enhancement

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HistoryAnemia may be diagnosed from symptoms and signs, but

when it is mild, it may not be

diagnosed from mild nonspecific symptoms.

The diagnosis of iron-deficiency anemia will be suggested by appropriate history (e.g., anemia in a menstruating woman or an athlete engaged in long-distance running), the presence of occult blood (i.e., hidden blood) in the stool, and often by additional history.[16] For example, known celiac disease can cause malabsorption of iron. A travel history to areas in which hookworms and whipworms are endemic may be helpful in guiding certain stool tests for parasites or their eggs.[citation needed]

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Blood testsChange in lab values in iron deficiency anemiaChangeParameterDecrease ferritin, hemoglobin, MCVIncrease TIBC, transferrin, RDWAnemia is often first shown by routine blood tests, which generally include a complete blood count (CBC) which is performed by an instrument which gives an output as a series of index numbers. A sufficiently low hemoglobin (Hb) by definition makes the diagnosis of anemia, and a low hematocrit value is also characteristic of anemia. Further studies will be undertaken to determine the anemia's cause. If the anemia is due to iron deficiency, one of the first abnormal values to be noted on a CBC, as the body's iron stores begin to be depleted, will be a high red blood cell distribution width (RDW), reflecting an increased variability in the size of red blood cells (RBCs). In the course of slowly depleted iron status, an increasing RDW normally appears even before anemia appears.

A low mean corpuscular volume (MCV) often appears next during the course of body iron depletion. It corresponds to a

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high number of abnormally small red blood cells. A low MCV, a low mean corpuscular hemoglobin or mean corpuscular hemoglobin concentration, and the appearance of the RBCs on visual examination of a peripheral blood smear narrows the problem to a microcytic anemia (literally, a "small red blood cell" anemia). The numerical values for these measures are all calculated by modern laboratory equipment.

The blood smear of a person with iron deficiency shows many hypochromic (pale and relatively colorless) and rather small RBCs, and may also show poikilocytosis (variation in shape) and anisocytosis (variation in size). With more severe iron-deficiency anemia, the peripheral blood smear may show hypochromic pencil-shaped cells, and occasionally small numbers of nucleated red blood cells.[17] Very commonly, the platelet count is slightly above the high limit of normal in iron deficiency anemia (this is mild thrombocytosis). This effect was classically postulated to be due to high erythropoietin levels in the body as a result of anemia, cross-reacting to activate thrombopoietin receptors in the precursor cells that make platelets; however, this process has not been corroborated. Such slightly increased

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platelet counts present no danger, but remain valuable as an indicator even if their origin is not yet known.[citation needed]

Body-store iron deficiency is diagnosed by tests such as a low serum ferritin, a low serum iron level, an elevated serum transferrin and a high total iron binding capacity. A low serum ferritin is the most sensitive lab test for iron deficiency anemia. However, serum ferritin can be elevated by any type of chronic inflammation and so is not always a reliable test of iron status if it is within normal limits (i.e. this test is meaningful if abnormally low, but less meaningful if normal).Serum iron levels (i.e. iron not part of the hemoglobin in red cells) may be measured directly in the blood, but these levels increase immediately with iron supplementation (the patient must stop supplements for 24 hours), and pure blood-serum iron concentration, in any case, is not as sensitive as a combination of total serum iron, along with a measure of the serum iron-binding protein levels (TIBC). The ratio of serum iron to TIBC (called iron saturation or transferrin saturation index or percent) is the most specific indicator of iron deficiency when it is sufficiently low. The iron saturation (or

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transferrin saturation) of < 5% almost always indicates iron deficiency, while levels from 5% to 10% make the diagnosis of iron deficiency possible but not definitive. A transferrin saturation of 12% or more (taken alone) makes the diagnosis unlikely. Normal saturations are usually slightly lower for women (>12%) than for men (>15%), but this may indicate simply an overall slightly poorer iron status for women in the "normal" population.[citation needed]

Iron-deficiency anemia and thalassemia minor present with many of the same lab results. It is very important not to treat a people with thalassemia with an iron supplement, as this can lead to hemochromatosis (accumulation of iron in various organs, especially the liver). A hemoglobin electrophoresis provides useful evidence for distinguishing these two conditions, along with iron studies.[citation needed]

ScreeningIt is unclear if screening pregnant women for iron deficiency during pregnancy improves outcomes in the developing world.[18]

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Gold standardConventionally, a definitive diagnosis requires a demonstration of depleted body iron stores obtained by bone marrow aspiration, with the marrow stained for iron.[19][20] Because this is invasive and painful, while a clinical trial of iron supplementation is inexpensive and not traumatic, patients are often treated based on clinical history and serum ferritin levels without a bone marrow biopsy. Furthermore, a study published April 2009[21] questions the value of stainable bone marrow iron following parenteral iron therapy.

TreatmentSee also: Lucky iron fishAnemia is sometimes treatable, but certain types of anemia may be lifelong. If the cause is a dietary iron deficiency, eating more iron-rich foods, such as beans, lentils or red meat, or taking iron supplements will usually correct the anemia. Alternatively, intravenous iron (or blood transfusions) can be administered.

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Ascorbic acidThe difference between iron intake and iron absorption, also known as bioavailability, can be great. Iron absorption problems are worsened when iron is taken in conjunction with milk, tea, coffee and other substances. A number of methods that can help mitigate this, including:

Fortification with ascorbic acid increases bioavailability in both presence and absence of inhibiting substances, but is subject to deterioration from moisture or heat. Ascorbic acid fortification is usually limited to sealed, dried foods, but individuals can easily take ascorbic acid with a basic iron supplement for the same benefits. The primary benefit over ascorbic acid is durability and shelf life, particularly for

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products like milk, which undergo heat treatment.Microencapsulation with lecithin binds and protects the iron particles from the action of inhibiting substances.Using an iron amino acid chelate, such as NaFeEDTA, similarly binds and protects the iron particles. A study by the hematology unit of the University of Chile indicated chelated iron (ferrous bis-glycine chelate) can work with ascorbic acid to achieve even higher absorption levels.Separating intake of iron and inhibiting substances by a few hoursUsing nondairy milk (such as soy, rice, or almond milk) or goats' milk instead of cows' milkGluten-free diets can resolve some instances of iron-deficiency anemia if it is a result of celiac disease.Heme iron, found only in animal foods, such as meat, fish, and poultry, is more easily absorbed than nonheme iron, found in plant foods and supplements.[22][23]Iron bioavailability comparisons require stringent controls because the largest factor affecting bioavailability is the subject's existing iron level. Informal studies on bioavailability usually do not take this factor into account, so exaggerated claims from health supplement companies based

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on this sort of evidence should be ignored. Scientific studies are still in progress to determine which approaches yield the best results and the lowest costs.

If anemia does not respond to oral treatments, it may be necessary to administer iron parenterally using a drip or hemodialysis. Parenteral iron involves risks of fever, chills, backache, myalgia, dizziness, syncope, rash, and with some preparations, anaphylactic shock. The total incidence of adverse events is much lower than that with oral tablets (where the dose needs to be reduced or treatment stopped in over 40% of subjects) and blood transfusions.

A follow-up blood test is important to demonstrate whether the treatment has been effective; it can be undertaken after two to four weeks. With oral iron, this usually requires a delay of three months for tablets to have a significant effect.

Iron supplementation and infection riskBecause one of the functions of elevated ferritin (an acute phase reaction protein) in acute infections is thought to be to sequester iron from bacteria, it is generally thought that parenteral iron supplementation (which circumvents this mechanism) should be avoided in patients who have active

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bacterial infections (bacteraemia). Replacement of iron stores is seldom such an emergency situation that it cannot wait for such infections to be treated, although occasionally cases will arise where this is not possible, such as chronic osteomyelitis.

Iron deficiency protects against infection by creating an unfavorable environment for bacterial growth. Some studies have found iron supplementation can lead to an increase in infectious disease morbidity in areas where bacterial infections or where malaria are common. For example, children receiving iron-enriched foods have demonstrated an increased rate in diarrhea overall and enteropathogen shedding. Nevertheless, while iron deficiency might lessen infections by certain pathogenic diseases, it also leads to a reduction in resistance to other strains of viral or bacterial infections, such as Salmonella typhimurium or Entamoeba histolytica. Overall, it is sometimes difficult to decide whether iron supplementation will be beneficial or harmful to an individual in an environment prone to many infectious diseases; however, this is a different question than the question of supplementation in individuals who are already ill with a bacterial infection.[citation needed]

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Iron replacementWhen adjusting daily iron supplementation regimens, lowering the daily iron dose requires a longer duration of therapy. The estimated total dose of elemental iron may be used to guide therapy, and replacement may be provided in cycles. Based on this approach, the person should participate in their own care by determining the iron formulation and dose schedule that they are able to tolerate. The amount of elemental iron that is absorbed in the gut is not constant, and can change significantly depending on several factors, including hemoglobin level and body iron stores. The amount of iron absorbed decreases as the iron deficiency is corrected. Therefore, it is not possible to predict the exact amount of iron that will be absorbed, but it is recommended that approximately 10%-20% of an oral iron dose will be absorbed in the beginning of the therapy.

For ferrous sulfate, one cycle consists of 75 pills or three pills daily for 25 days. Among people with moderate levels of anemia, a single cycle of should be enough and partial replacement of iron stores. If the anemia is not severe and there is no complicating feature such as ongoing blood loss or enteropathies, additional iron supplementation cycles are

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not going to be required for correcting the anemia. Re-evaluation of the anemia after completion of the first cycle

should be performed to see if additional iron supplementation

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is necessary. If a person is predicted to have ongoing iron deficits (e.g. menorrhagia), maintenance dosing of iron supplements can easily be devised. The key feature of the cycled dosing strategy proposed here is that several factors including the cause of iron deficiency Anemia, the total iron deficit, replacement iron formulations, and the predicted duration of replacement therapy are integrated for implementation of an individualized therapeutic plan.

Notes

^ The anemia and anaemia difference is a regional variation; the hyphen is optional (several major dictionaries use it and several do not).

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Plummer–Vinson syndromePlummer–Vinson syndrome (PVS), also called Paterson–Brown–Kelly syndrome or sideropenic dysphagia, is a rare disease characterized by difficulty in swallowing, iron deficiency anemia, glossitis, cheilosis and esophageal webs. Treatment with iron supplementation and mechanical widening of the esophagus generally provides an excellent outcome.

While exact data about the epidemiology is unknown, this syndrome has become extremely rare. The reduction in the prevalence of PVS has been hypothesized to be the result of improvements in nutritional status and availability in countries where the syndrome was previously described. It generally occurs in postmenopausal women. Its identification and follow-up is considered relevant due to increased risk of squamous cell carcinomas of the esophagus and pharynx.

Presentation

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Angular stomatitisPVS sufferers often complain of a burning sensation with the tongue and oral mucosa, and atrophy of lingual papillae produces a smooth, shiny, red, dorsum of the tongue. Symptoms include:

Dysphagia (difficulty in swallowing)PainWeaknessOdynophagia (painful swallowing)

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Atrophic glossitisAngular stomatitisSerial contrasted gastrointestinal radiography or upper gastrointestinal endoscopy may reveal the web in the esophagus. Blood tests show a hypochromic microcytic anemia that is consistent with an iron-deficiency anemia. Biopsy of involved mucosa typically reveals epithelial atrophy (shrinking) and varying amounts of submucosal chronic inflammation. Epithelial atypia or dysplasia may be present.

Causes

The cause of PVS is unknown; however, genetic factors and nutritional deficiencies may play a role. It is more common in women,[2] particularly in middle age (peak age is over 50). In these patients, esophageal squamous cell carcinoma risk is increased;[1] therefore, it is considered a premalignant process.[citation needed]

The condition is associated with koilonychia, glossitis, inflammation of the lips (cheilitis), and splenomegaly. Esophageal web in Plummer-Vinson syndrome is found at upper end of esophagus(post cricoid region)

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and Schatzki ring may be found at the lower end of esophagus.

Diagnosis

Following clinical presentations may be used in the diagnosis of this condition.

1. Dizziness2. Pallor of the conjuctiva and face3. Erathematous oral mucosa with burning sensation4. Breathelessness5. Atropic and smooth tongue6. Peripheral rhaggades around the oral cavity7. The following tests are helpful in the diagnosis of

Plummer-Vinson syndrome.

Lab testscomplete blood cell (CBC) counts, peripheral blood smears, and iron studies (eg, serum iron, total iron-binding capacity [TIBC], ferritin, saturation percentage) to confirm iron deficiency, with or without hypochromic microcytic anemia.

Imaging

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Barium esophagography and videofluoroscopy will help to detect esophageal webs. Esophagogastroduodenoscopy will enable visual confirmation of esophageal webs.

Prevention

Good nutrition with adequate intake of iron may prevent this disorder. Good nutrition should also include balanced diet and exercise.

Treatment

Treatment is primarily aimed at correcting the iron-deficiency anemia. Patients with PVS should receive iron supplementation in their diet. This may improve dysphagia and pain.[1] If not, the web can be dilated during upper endoscopy to allow normal swallowing and passage of food.[4]

PrognosisPatients generally respond well to treatment. Iron supplementation usually resolves the anemia, and corrects the glossodynia (tongue pain).

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Complications

There is risk of perforation of the esophagus with the use of dilators for treatment. Furthermore, it is one of the risk factors for developing squamous cell carcinoma of the oral cavity, esophagus, and hypopharynx.

History

The disease is named after two Americans: the physician Henry Stanley Plummer and the surgeon Porter Paisley Vinson.[6][7][8] It is occasionally known as Paterson-Kelly or Paterson-Brown Kelly syndrome in the UK, after Derek Brown-Kelly and Donald Ross Paterson.[9] however, Plummer–Vinson syndrome is still the most commonly used name.

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Vitamin B12

Vitamin B12, also called cobalamin, is a water-soluble vitamin that has a key role in the normal functioning of the brain and nervous system, and the formation of red blood cells. It is one of eight B vitamins. It is involved in the metabolism of every cell of the human body, especially affecting DNA synthesis, fatty acid and amino acid metabolism.[1] No fungi, plants, or animals (including humans) are capable of producing vitamin B12. Only bacteria and archaea have the enzymes needed for its synthesis. Some substantial sources of B12 include animal products (shellfish, meat), fortified food products, and dietary supplements.[2][3] B12 is the largest and most structurally complicated vitamin and can be produced industrially only through bacterial fermentation synthesis, typically used to manufacture B12 for fortified foods and supplements.

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Vitamin B12 consists of a class of chemically related compounds (vitamers), all of which show pharmacological activity. It contains the biochemically rare element cobalt (chemical symbol Co) positioned in the center of a planar tetra-pyrrole ring called a corrin ring. The vitamer is produced by bacteria as hydroxocobalamin, but conversion between different forms of the vitamin occurs in the body

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after consumption.

Vitamin B12 was discovered[4] as a result of its relationship to the disease pernicious anemia, an autoimmune disease in which parietal cells of the stomach responsible for secreting intrinsic factor are destroyed; these cells are also responsible for secreting acid in the stomach. Because intrinsic factor is crucial for the normal absorption of B12, its lack in the presence of pernicious anemia causes a vitamin B12 deficiency. Many other subtler kinds of vitamin B12 deficiency and their biochemical effects have since been elucidated.[5] Due to impairment of vitamin B12 absorption during aging, people over age 60 are at risk of deficiency.

UsesDietary Reference IntakeThe Food and Nutrition Board of the U.S. Institute of Medicine (IOM) updated Estimated Average Requirements (EARs) and Recommended Dietary Allowances (RDAs) for vitamin B12 in 1998. The current EAR for vitamin B12 for women and men ages 14 and up is 2.0 μg/day; the RDA is 2.4

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μg/day. RDAs are higher than EARs so as to identify amounts that will cover people with higher than average requirements. RDA for pregnancy equals 2.6 μg/day. RDA for lactation equals 2.8 μg/day. For infants up to 12 months the Adequate Intake (AI) is 0.4-0.5 μg/day. and for children ages 1–13 years the RDA increases with age from 0.9 to 1.8 μg/day. Because 10 to 30 percent of older people may be unable to effectively absorb vitamin B12 naturally occurring in foods, it is advisable for those older than 50 years to meet their RDA mainly by consuming foods fortified with vitamin B12 or a supplement containing vitamin B12. Collectively the EARs, RDAs and ULs are referred to as Dietary Reference Intakes.[6] As for safety, the IOM sets Tolerable Upper Intake Levels (known as ULs) for vitamins and minerals when evidence is sufficient. In the case of vitamin B12 there is no UL, as there is no human data for adverse effects from high doses. The European Food Safety Authority reviewed the same safety question and also reached the conclusion that there was not sufficient evidence to set a UL for vitamin B12.[7]

For U.S. food and dietary supplement labeling purposes the amount in a serving is expressed as a percent of Daily Value

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(%DV). For vitamin B12 labeling purposes 100% of the Daily Value was 6.0 μg, but as of May 2016 has been revised downward to 2.4 μg. A table of the old and new adult Daily Values is provided at Reference Daily Intake. Food and supplement companies have until July 28, 2018 to comply with the change.

DeficiencyMethylcobalamin (shown) is a form of vitamin B12.

Physically it resembles the other forms of vitamin B12, occurring as dark red crystals that freely form cherry-colored transparent solutions in water.

Vitamin B12 deficiency can potentially cause severe and irreversible damage, especially to the brain and nervous system.[8] At levels only slightly lower than normal, a range of symptoms such as fatigue, lethargy, depression, poor memory, breathlessness, headaches, and pale skin, among others, may be experienced, especially in elderly people (over age 60)[2][9] who produce less stomach acid as they age, thereby increasing their probability of B12 deficiencies.[5] Vitamin B12 deficiency can also cause symptoms of mania and psychosis.[10][11]

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Vitamin B12 deficiency is most commonly caused by low intakes, but can also result from malabsorption, certain intestinal disorders, low presence of binding proteins, and use of certain medications. Vitamin B12 is rare from plant sources, so vegetarians are most likely to suffer from vitamin B12 deficiency. Infants are at a higher risk of vitamin B12 deficiency if they were born to vegetarian mothers. The elderly who have diets with limited meat or animal products are vulnerable populations as well. Vitamin B12 deficiency may occur in between 40% to 80% of the vegetarian population.[12] In Hong Kong and India, vitamin B12 deficiency has been found in roughly 80% of the vegan population as well.

Vitamin B12 is a co-substrate of various cell reactions involved in methylation synthesis of nucleic acid and neurotransmitters. Synthesis of the trimonoamine neurotransmitters can enhance the effects of a traditional antidepressant.[14] The intracellular concentrations of vitamin B12 can be inferred through the total plasma concentration of homocysteine, which can be converted to methionine through an enzymatic reaction that uses 5-

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methyltetrahydrofolate as the methyl donor group. Consequently, the plasma concentration of homocysteine falls as the intracellular concentration of vitamin B12 rises. The active metabolite of vitamin B12 is required for the methylation of homocysteine in the production of methionine, which is involved in a number of biochemical processes including the monoamine neurotransmitters metabolism. Thus, a deficiency in vitamin B12 may impact the production and function of those neurotransmitters.

MedicalVitamin B12 is used to treat vitamin B12 deficiency, cyanide poisoning, and hereditary deficiency of transcobalamin II.[16] It is given as part of the Schilling test for detecting pernicious anemia.[16]

For cyanide poisoning, a large amount of hydroxocobalamin may be given intravenously and sometimes in combination with sodium thiosulfate.[17] The mechanism of action is straightforward: the hydroxycobalamin hydroxide ligand is displaced by the toxic cyanide ion, and the resulting harmless B12 complex is excreted in urine. In the United States, the Food and Drug Administration approved (in 2006) the use of

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hydroxocobalamin for acute treatment of cyanide poisoning.

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Vitamin B12 deficiency

Vitamin B12 deficiency is the medical condition of low blood levels of vitamin B12.[4] A wide variety of signs and

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symptoms may occur including a decreased ability to think and behavioural and emotional changes such as depression, irritability, and psychosis. Abnormal sensations, changes in reflexes, and poor muscle function can also occur as may inflammation of the tongue, decreased taste, low red blood cells, reduced heart function, and decreased fertility.[1] In young children symptoms include poor growth, poor development, and difficulties with movement.[2] Without early treatment some of the changes may be permanent.Common causes include poor absorption from the stomach or intestines, decreased intake, and increased requirements. Decreased absorption may be due to pernicious anemia, surgical removal of the stomach, chronic inflammation of the pancreas, intestinal parasites, certain medications, and some genetic disorders. Decreased intake may occur in those who eat a vegan diet or are malnourished. Increased requirements occur in HIV/AIDS and in those with rapid red blood cell breakdown.[1] Diagnosis is typically based on vitamin B12 blood levels below 120–180 picomol/L (170–250 pg/mL) in adults. Elevated methylmalonic acid levels (values >0.4 micromol/L) may also indicate a deficiency. A type of low red blood cells known as megaloblastic anemia is often but

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not always present.Supplementation is recommended to prevent deficiency in vegetarians who are pregnant.[2] Once identified it is easily treated with supplementation by mouth or injection.[3] There are no concerns from excess vitamin B12 among those who are otherwise healthy.[2] Some cases may also be helped by treating the underlying cause.[6] Other cases may require ongoing supplementation as the underlying cause is not curable.[7] Vitamin B12 deficiency is common.[1] It is estimated to occur in about 6% of those under the age of 60 and 20% of those over the age of 60. Rates may be as high as 80% in parts of Africa and Asia.

Signs and symptoms Edit

Vitamin B12 deficiency can lead to anemia and neurologic dysfunction.[8] A mild deficiency may not cause any discernible symptoms, but as the deficiency becomes more significant, symptoms of anemia may result, such as weakness, fatigue, light-headedness, rapid heartbeat, rapid breathing and pale color to the skin. It may also cause easy bruising or bleeding, including bleeding gums. GI side effects including sore tongue, stomach upset, weight loss, and

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diarrhea or constipation. If the deficiency is not corrected, nerve cell damage can result. If this happens, vitamin B12 deficiency may result in tingling or numbness to the fingers and toes, difficulty walking, mood changes, depression, memory loss, disorientation and, in severe cases, dementia.

The main syndrome of vitamin B12 deficiency is pernicious anemia. It is characterized by a triad of symptoms:

Anemia with bone marrow promegaloblastosis (megaloblastic anemia). This is due to the inhibition of DNA synthesis (specifically purines and thymidine)Gastrointestinal symptoms: alteration in bowel motility, such as mild diarrhea or constipation, and loss of bladder or bowel control.[9] These are thought to be due to defective DNA synthesis inhibiting replication in a site with a high turnover of cells. This may also be due to the autoimmune attack on the parietal cells of the stomach in pernicious anemia. There is an association with GAVE syndrome (commonly called watermelon stomach) and pernicious anemia.Neurological symptoms: Sensory or motor deficiencies (absent reflexes, diminished vibration or soft touch sensation), subacute combined degeneration of spinal cord,

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seizures,[11][12][13][14] or even symptoms of dementia[15] and or other psychiatric symptoms may be present. The presence of peripheral sensory-motor symptoms or subacute combined degeneration of spinal cord strongly suggests the presence of a B12 deficiency instead of folate deficiency. Methylmalonic acid, if not properly handled by B12, remains in the myelin sheath, causing fragility. Dementia and depression have been associated with this deficiency as well, possibly from the under-production of methionine because of the inability to convert homocysteine into this product. Methionine is a necessary cofactor in the production of several neurotransmitters.Each of those symptoms can occur either alone or along with others. The neurological complex, defined as myelosis funicularis, consists of the following symptoms:1.Impaired perception of deep touch, pressure and vibration, loss of sense of touch, very annoying and persistent paresthesias2.Ataxia of dorsal chord type3.Decrease or loss of deep muscle-tendon reflexesPathological reflexes — Babinski, Rossolimo and others, also severe paresis

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4. Vitamin B12 deficiency can cause severe and irreversible damage, especially to the brain and nervous system. These symptoms of neuronal damage may not reverse after correction of hematological abnormalities, and the chance of complete reversal decreases with the length of time the neurological symptoms have been present.

Tinnitus may be associated with vitamin B12 deficiency.PsychologicalVitamin B12 deficiency can also cause symptoms of mania and psychosis, fatigue, memory impairment, irritability, depression, ataxia, and personality changes.[17][18][19] In infants symptoms include irritability, failure to thrive, apathy, anorexia, and developmental regression.

Causes Inadequate dietary intake of vitamin B12. Vitamin B12

occurs in animal products (eggs, meat, milk) and recent research indicates it may also occur in some algae, such as Chlorella[22][23][24] and Susabi-nori (Porphyra yezoensis).[25][26] B12 isolated from bacterial cultures is also added to many fortified foods, and available as a

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dietary supplement.[27] Vegans, and also vegetarians but to a lesser degree, may be at risk for B12 deficiency due to inadequate dietary intake of B12, if they do not supplement. However, B12 deficiency can occur even in people who consume meat, poultry, and fish.[28] Children are at a higher risk for B12 deficiency due to inadequate dietary intake, as they have fewer vitamin stores and a relatively larger vitamin need per calorie of food intake.

Selective impaired absorption of vitamin B12 due to intrinsic factor deficiency. This may be caused by the loss of gastric parietal cells in chronic atrophic gastritis (in which case, the resulting megaloblastic anemia takes the name of "pernicious anemia"), or may result from wide surgical resection of stomach (for any reason), or from rare hereditary causes of impaired synthesis of intrinsic factor.

Impaired absorption of vitamin B12 in the setting of a more generalized malabsorption or maldigestion syndrome. This includes any form of structural damage or wide surgical resection of the terminal ileum (the principal site of vitamin B12 absorption).

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Forms of achlorhydria (including that artificially induced by drugs such as proton pump inhibitors and histamine 2 receptor antagonists) can cause B12 malabsorption from foods, since acid is needed to split B12 from food proteins and salivary binding proteins.[29] This process is thought to be the most common cause of low B12 in the elderly, who often have some degree of achlorhydria without being formally low in intrinsic factor. This process does not affect absorption of small amounts of B12 in supplements such as multivitamins, since it is not bound to proteins, as is the B12 in foods.

Surgical removal of the small bowel (for example in Crohn's disease) such that the patient presents with short bowel syndrome and is unable to absorb vitamin B12. This can be treated with regular injections of vitamin B12.

Long-term use of ranitidine hydrochloride may contribute to deficiency of vitamin B12.[31]

Untreated celiac disease may also cause impaired absorption of this vitamin, probably due to damage to the small bowel mucosa. In some people, vitamin B12 deficiency may persist despite treatment with a gluten-

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free diet and require supplementation.[32] Some bariatric surgical procedures, especially those that

involve removal of part of the stomach, such as Roux-en-Y gastric bypass surgery. (Procedures such as the adjustable gastric band type do not appear to affect B12 metabolism significantly).[citation needed]

Bacterial overgrowth in parts of the small bowel are thought to be able to absorb B12. An example occurs in so-called blind loop syndrome.[citation needed]

The diabetes medication metformin may interfere with B12 dietary absorption.[33]

Hereditary causes such as severe MTHFR deficiency, homocystinuria, and transcobalamin deficiency.[citation needed]

Malnutrition of alcoholism. Nitrous oxide abuse.[34] Infection with the Diphyllobothrium latum tapeworm.

MechanismThe total amount of vitamin B12 stored in the body is between two and five milligrams in adults. Approximately

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50% is stored in the liver, but approximately 0.1% is lost each day, due to secretions into the gut—not all of the vitamin in the gut is reabsorbed. While bile is the main vehicle for B12 excretion, most of the B12 secreted in bile is recycled via enterohepatic circulation. Due to the extreme efficiency of this mechanism, the liver can store three to five years worth of vitamin B12 under normal conditions and functioning.[35] However, the rate at which B12 levels may change when dietary intake is low depends on the balance between several variables.[36]

MetabolicVitamin B12 deficiency causes particular changes to the metabolism of 2 clinically relevant substances in humans:

Homocysteine (homocysteine to methionine, catalysed by methionine synthase) leading to hyperhomocysteinemia may lead to varicose veins[citation needed]Methylmalonic acid (methylmalonyl-CoA to succinyl-CoA, of which methylmalonyl-CoA is made from methylmalonic acid in a preceding reaction)Methionine is activated to S-adenosyl methionine, which aids in purine and thymidine synthesis, myelin production,

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protein/neurotransmitters/fatty acid/phospholipid production and DNA methylation. 5-Methyl tetrahydrofolate provides a methyl group, which is released to the reaction with homocysteine, resulting in methionine. This reaction requires cobalamin as a cofactor. The creation of 5-methyl tetrahydrofolate is an irreversible reaction. If B12 is absent, the forward reaction of homocysteine to methionine does not occur, and the replenishment of tetrahydrofolate stops.[37]

Because B12 and folate are involved in the metabolism of homocysteine, hyperhomocysteinuria is a non-specific marker of deficiency. Methylmalonic acid is used as a more specific test of B12 deficiency.

PathomorphologyA spongiform state of neural tissue along with edema of fibers and deficiency of tissue. The myelin decays, along with axial fiber. In later phases, fibric sclerosis of nervous tissues occurs. Those changes apply to dorsal parts of the spinal cord and to pyramidal tracts in lateral cords. The pathophysiologic state of the spinal cord is called subacute combined degeneration of spinal cord.[38]

In the brain itself, changes are less severe: They occur as

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small sources of nervous fibers decay and accumulation of astrocytes, usually subcortically located, and also round hemorrhages with a torus of glial cells. Pathological changes can be noticed as well in the posterior roots of the cord and, to lesser extent, in peripheral nerves. Abnormalities might be observed in MRI.

Diagnosis

MRI image of the brain in an axial view showing the “precontrast FLAIR image”. Note the abnormal lesions (circled) in the per ventricular area suggesting white matter pathology in someone with vitamin B12 deficiency.Serum B12 levels are often low in B12 deficiency, but if

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other features of B12 deficiency are present with normal B12 then further investigation is warranted. One possible explanation for normal B12 levels in B12 deficiency is antibody interference in people with high titres of intrinsic factor antibody.[40] Some researchers propose that the current standard norms of vitamin B12 levels are too low.[41] One Japanese study states the normal limits as 500–1,300 pg/mL.[42] Range of vitamin B12 levels in humans is considered as normal: >300 pg/mL; moderate deficiency: 201–300 pg/mL; and severe deficiency: <201 pg/mL.[43]

Serum vitamin B12 tests results are in pg/mL (picograms/milliliter) or pmol/L (picomoles/liter). The laboratory reference ranges for these units are similar, since the molecular weight of B12 is approximately 1000, the difference between mL and L. Thus: 550 pg/mL = 400 pmol/L.

Serum homocysteine and methylmalonic acid levels are considered more reliable indicators of B12 deficiency than the concentration of B12 in blood.[44] The levels of these substances are high in B12 deficiency and can be helpful if the diagnosis is unclear.

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Routine monitoring of methylmalonic acid levels in urine is an option for people who may not be getting enough dietary B12, as a rise in methylmalonic acid levels may be an early indication of deficiency.[45]

If nervous system damage is suspected, B12 analysis in cerebrospinal fluid is possible, though such an invasive test should be considered only if blood testing is inconclusive.[46]

The Schilling test has been largely supplanted by tests for antiparietal cell and intrinsic factor antibodies.[citation needed]

Effect of folic acid EditThe National Institutes of Health has found that "Large amounts of folic acid can mask the damaging effects of vitamin B12 deficiency by correcting the megaloblastic anemia caused by vitamin B12 deficiency without correcting the neurological damage that also occurs", there are also indications that "high serum folate levels might not only mask vitamin B12 deficiency, but could also exacerbate the anemia and worsen the cognitive symptoms associated with vitamin B12 deficiency".[2] Due to the fact that in the United

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States legislation has required enriched flour to contain folic acid to reduce cases of fetal neural-tube defects, consumers may be ingesting more than they realize.[47] To counter the masking effect of B12 deficiency the NIH recommends "folic acid intake from fortified food and supplements should not exceed 1,000 μg daily in healthy adults."[2] Most importantly, B12 deficiency needs to be treated with B12 repletion. Limiting folic acid will not counter the irrevocable neurological damage that is caused by untreated B12 deficiency.

TreatmentB12 can be supplemented by pill or injection and appear to be equally effective in those with low levels due to absorption problems.[3]

When large doses are given by mouth its absorption does not rely on the presence of intrinsic factor or an intact ileum. Generally 1 to 2 mg daily is required as a large dose.[48] Even pernicious anemia can be treated entirely by the oral route.[49][50][51] These supplements carry such large doses of the vitamin that 1% to 5% of high oral doses of free

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crystalline B12 is absorbed along the entire intestine by passive diffusion.

EpidemiologyIn the developing world the deficiency is very widespread, with significant levels of deficiency in Africa, India, and South and Central America. This is theorized to be due to low intakes of animal products, particularly among the poor.[52]

B12 deficiency is more common in the elderly.[52] This is because B12 absorption decreases greatly in the presence of atrophic gastritis, which is common in the elderly.

The 2000 Tufts University study found no correlation between eating meat and differences in B12 serum levels, likely due to a combination of fortified foods and B12 absorption disorders.

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Vitamin B12 deficiency Anemia

Vitamin B12 deficiency anemia, of which pernicious anemia is a type,[8] is a disease in which not enough red blood cells are present due to a lack of vitamin B12.[5] The most common initial symptom is feeling tired. Other symptoms may include shortness of breath, pale skin, chest pain, numbness in the hands and feet, poor balance, a smooth red tongue, poor reflexes, and confusion.[4] Without treatment some of these problems may become permanent.Although pernicious anemia technically refers to cases resulting from not enough intrinsic factor, it is often used to describe all cases of anemia due to not enough vitamin B12.[5] Lack of intrinsic factor is most commonly due to an autoimmune attack on the cells that make it in the stomach. It can also occur following the surgical removal of part of the stomach or from an inherited disorder. Other causes of low vitamin B12 include a poor diet, celiac disease, and a tapeworm infection.[9] When suspected, diagnosis is made by blood and, occasionally, bone marrow tests. Blood tests may show fewer but larger red blood cells, low numbers of

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young red blood cells, low levels of vitamin B12, and antibodies to intrinsic factor.[6]

Pernicious anemia, due to lack of intrinsic factor, is not preventable. Vitamin B12 deficiency due to other causes may be prevented with a balanced diet or with supplements.[10] Pernicious anemia can be easily treated with either injections or pills of vitamin B12. If the symptoms are severe, injections are typically recommended initially. For those who have trouble swallowing pills, a nasal spray is available.[7] Often, treatment is lifelong.[11]

Pernicious anemia due to autoimmune problems occurs in about one per 1000 people. Among those over the age of 60, about 2% have the condition.[1] It more commonly affects people of northern European descent.[2] Women are more commonly affected than men.[12] With proper treatment, most people live normal lives.[5] Due to a higher risk of stomach cancer, those with pernicious anemia should be checked regularly for this.[11] The first clear description was by Thomas Addison in 1849.The term "pernicious" means "deadly", and was used as before the availability of treatment the disease was often fatal.

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Signs and symptoms

A hand of a person with severe anemia (left) compared to one without (right)The symptoms of pernicious anemia come on slowly. Untreated, it can lead to neurological complications, and in

serious cases, death. Many of the signs and symptoms are due to anemia itself, when anemia is present.[16] Symptoms may consist of the triad of tingling or other skin sensations

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(paresthesia), tongue soreness (glossitis), and fatigue and general weakness.[17][18][19][page needed] It presents with a number of further common symptoms,[19][page needed][20][page needed] including depressive mood, low-grade fevers, diarrhea, dyspepsia, weight loss,[17] neuropathic pain, jaundice, sores at the corner of the mouth (angular cheilitis), a look of exhaustion with pale and dehydrated or cracked lips and dark circles around the eyes, as well as brittle nails,[18] and thinning and early greying of the hair.[18] Because PA may affect the nervous system, symptoms may also include difficulty in proprioception,[21] memory changes,[20][page needed] mild cognitive impairment (including difficulty concentrating and sluggish responses, colloquially referred to as brain fog), and even psychoses, impaired urination,[17] loss of sensation in the feet, unsteady gait,[21] difficulty in walking,[18] muscle weakness[19][page needed] and clumsiness.[17] Anemia may also lead to tachycardia (rapid heartbeat),[17] cardiac murmurs, a yellow waxy pallor,[18] altered blood pressure (low or high), and a shortness of breath (known as "the sighs").[19][page needed] The deficiency also may present with thyroid disorders.[19][page needed] In severe cases, the anemia may cause

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evidence of congestive heart failure.[20][page needed] A complication of severe chronic PA is subacute combined degeneration of spinal cord, which leads to distal sensory loss (posterior column), absent ankle reflex, increased knee reflex response, and extensor plantar response.[22] Other than anemia, hematological symptoms may include cytopenias, intramedullary hemolysis, and pseudothrombotic microangiopathy.[1] Pernicious anemia can contribute to a delay in physical growth in children, and may also be a cause for delay in puberty for adolescents.

CausesVitamin B12 cannot be produced by the human body, and must be obtained from the diet. When foods containing B12 are eaten, the vitamin is usually bound to protein and is released by proteases released by the pancreas in the small bowel. Following its release, most B12 is absorbed by the body in the small bowel (ileum) after binding to a protein known as intrinsic factor. Intrinsic factor is produced by parietal cells of the gastric mucosa (stomach lining) and the intrinsic factor-B12 complex is absorbed by cubilin receptors on the ileum epithelial cells.[23][24] PA is characterised by

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B12 deficiency caused by the absence of intrinsic factor.[25]

PA may be considered as an end stage of immune gastritis, a disease characterised by stomach atrophy and the presence of antibodies to parietal cells and intrinsic factor.[26] A specific form of chronic gastritis, type A gastritis or atrophic body gastritis, is highly associated with PA. This autoimmune disorder is localised to the body of the stomach, where parietal cells are located.[25] Antibodies to intrinsic factor and parietal cells cause the destruction of the oxyntic gastric mucosa, in which the parietal cells are located, leading to the subsequent loss of intrinsic factor synthesis. Without intrinsic factor, the ileum can no longer absorb the B12.[27]

Although the exact role of Helicobacter pylori infection in PA remains controversial, evidence indicates H. pylori is involved in the pathogenesis of the disease. A long-standing H. pylori infection may cause gastric autoimmunity by a mechanism known as molecular mimicry. Antibodies produced by the immune system can be cross-reactive and may bind to both H. pylori antigens and those found in the gastric mucosa. The antibodies are produced by activated B cells that recognise both pathogen and self-derived peptides.

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The autoantigens believed to cause the autoreactivity are the alpha and beta subunits of the H+/K+-ATPase.[27][28]

Less commonly, H. pylori and Zollinger-Ellison syndrome may also cause a form of nonautoimmune gastritis that can lead to pernicious anemia.[29]

Impaired B12 absorption can also occur following gastric removal (gastrectomy) or gastric bypass surgery. In these surgeries, either the parts of the stomach that produce gastric secretions are removed or they are bypassed. This means intrinsic factor, as well as other factors required for B12 absorption, are not available. However, B12 deficiency after gastric surgery does not usually become a clinical issue. This is probably because the body stores many years' worth of B12 in the liver and gastric surgery patients are adequately supplemented with the vitamin.[30][31]

Although no specific PA susceptibility genes have been identified, a genetic factor likely is involved in the disease. Pernicious anemia is often found in conjunction with other autoimmune disorders, suggesting common autoimmune susceptibility genes may be a causative factor.[25] In spite of that, previous family studies and case reports focusing on PA

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have suggested that there is a tendency of genetic heritance of PA in particular, and close relatives of the PA patients seem to have higher incidence of PA and associated PA conditions.[32][33][34] Moreover, it was further indicated that the formation of antibodies to gastric cells was autosomal dominant gene determined, and the presence of antibodies to the gastric cells might not be necessarily related to the occurrence of atrophic gastritis related to PA.

PathophysiologyAlthough the healthy body stores three to five years' worth of B12 in the liver, the usually undetected autoimmune activity in one's gut over a prolonged period of time leads to B12 depletion and the resulting anemia. B12 is required by enzymes for two reactions: the conversion of methylmalonyl CoA to succinyl CoA, and the conversion of homocysteine to methionine. In the latter reaction, the methyl group of 5-methyltetrahydrofolate is transferred to homocysteine to produce tetrahydrofolate and methionine. This reaction is catalyzed by the enzyme methionine synthase with B12 as an essential cofactor. During B12 deficiency, this reaction cannot proceed, which leads to the accumulation of 5-

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methyltetrahydrofolate. This accumulation depletes the other types of folate required for purine and thymidylate synthesis, which are required for the synthesis of DNA. Inhibition of DNA replication in red blood cells results in the formation of large, fragile megaloblastic erythrocytes. The neurological aspects of the disease are thought to arise from the accumulation of methylmalonyl CoA due to the requirement of B12 as a cofactor to the enzyme methylmalonyl CoA mutase.

Diagnosis Immunofluorescence staining pattern of gastric parietal

cell antibodies on a stomach section PA may be suspected when a patient's blood smear

shows large, fragile, immature erythrocytes, known as

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megaloblasts. A diagnosis of PA first requires

demonstration of megaloblastic anemia by conducting a full blood count and blood smear, which evaluates the mean corpuscular volume (MCV), as well the mean corpuscular hemoglobin concentration (MCHC). PA is identified with a high MCV (macrocytic anemia) and a normal MCHC (normochromic anemia).[38] Ovalocytes are also typically seen on the blood smear, and a pathognomonic feature of megaloblastic anemias (which include PA and others) is hypersegmented neutrophils.[18]

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Serum vitamin B12 levels are used to detect its deficiency, but they do not distinguish its causes. Vitamin B12 levels can be falsely high or low and data for sensitivity and specificity vary widely. Normal serum levels may be found in cases of deficiency where myeloproliferative disorders, liver disease, transcobalamin II deficiency, or intestinal bacterial overgrowth are present. Low levels of serum vitamin B12 may be caused by other factors than B12 deficiency, such as folate deficiency, pregnancy, oral contraceptive use, haptocorrin deficiency, and myeloma.[39][40]

The presence of antibodies to gastric parietal cells and intrinsic factor is common in PA. Parietal cell antibodies are found in other autoimmune disorders and also in up to 10% of healthy individuals, making the test nonspecific. However, around 85% of PA patients have parietal cell antibodies, which means they are a sensitive marker for the disease. Intrinsic factor antibodies are much less sensitive than parietal cell antibodies, but they are much more specific. They are found in about half of PA patients and are very rarely found in other disorders. These antibody tests can distinguish between PA and

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food-B12 malabsorption.[40] The combination of both tests of intrinsic factor antibodies and parietal cell antibodies may improve overall sensitivity and specificity of the diagnostic results.[41]

A buildup of certain metabolites occurs in B12 deficiency due to its role in cellular physiology. Methylmalonic acid (MMA) can be measured in both the blood and urine, whereas homocysteine is only measured in the blood. An increase in both MMA and homocysteine can distinguish between B12 deficiency and folate deficiency because only homocysteine increases in the latter.

Elevated gastrin levels can be found in around 80-90% of PA cases, but they may also be found in other forms of gastritis. Decreased pepsinogen I levels or a decreased pepsinogen I to pepsinogen II ratio may also be found, although these findings are less specific to PA and can be found in food-B12 malabsorption and other forms of gastritis.[42]

The diagnosis of atrophic gastritis type A should be confirmed by gastroscopy and stepwise biopsy.[43]

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About 90% of individuals with PA have antibodies for parietal cells; however, only 50% of all individuals in the general population with these antibodies have pernicious anemia.[44]

Forms of vitamin B12 deficiency other than PA must be considered in the differential diagnosis of megaloblastic anemia. For example, a B12-deficient state which causes megaloblastic anemia and which may be mistaken for classical PA may be caused by infection with the tapeworm Diphyllobothrium latum, possibly due to the parasite's competition with host for vitamin B12.[45]

The classic test for PA, the Schilling test, is no longer widely used, as more efficient methods are available. This historic test consisted, in its first step, of taking an oral dose of radiolabelled vitamin B12, followed by quantitation of the vitamin in the patient's urine over a 24-hour period via measurement of the radioactivity. A second step of the test repeats the regimen and procedure of the first step, with the addition of oral intrinsic factor. A patient with PA presents lower than normal amounts of intrinsic factor; hence, addition of intrinsic factor in the

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second step results in an increase in vitamin B12 absorption (over the baseline established in the first). The Schilling test distinguished PA from other forms of B12 deficiency,[23] specifically, from Imerslund-Grasbeck Syndrome (IGS), a vitamin B12-deficiency caused by mutations in the cobalamin receptor.

PrognosisA person with well-treated PA can live a healthy life. Failure to diagnose and treat in time, however, may result in permanent neurological damage, excessive fatigue, depression, memory loss, and other complications. In severe cases, the neurological complications of pernicious anemia can lead to death - hence the name, "pernicious", meaning deadly.

An association has been observed between pernicious anemia and certain types of gastric cancer, but a causal link has not been established.

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Megaloblastic anemia

Megaloblastic anemia (or megaloblastic anaemia) is an anemia (of macrocytic classification) that results from inhibition of DNA synthesis during red blood cell production.[1] When DNA synthesis is impaired, the cell cycle cannot progress from the G2 growth stage to the mitosis (M) stage. This leads to continuing cell growth without division, which presents as macrocytosis. Megaloblastic anemia has a rather slow onset, especially when compared to that of other anemias. The defect in red cell DNA synthesis is most often due to hypovitaminosis, specifically a deficiency of vitamin B12 and/or folic acid. Vitamin B12 deficiency alone will not cause the syndrome in the presence of sufficient folate, as the mechanism is loss of B12 dependent folate recycling, followed by folate-deficiency loss of nucleic acid synthesis (specifically thymine), leading to defects in DNA synthesis. Folic acid supplementation in the absence of vitamin B12 prevents this type of anemia (although other vitamin B12-specific pathologies may be present). Loss of micronutrients

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may also be a cause. Copper deficiency resulting from an excess of zinc from unusually high oral consumption of zinc-containing denture-fixation creams has been found to be a cause.[2]

Megaloblastic anemia

Peripheral blood smear showing hypersegmented neutrophils,

characteristic of megaloblastic anemia.Megaloblastic anemia not due to hypovitaminosis may be

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caused by antimetabolites that poison DNA production directly, such as some chemotherapeutic or antimicrobial agents (for example azathioprine or trimethoprim).

The pathological state of megaloblastosis is characterized by many large immature and dysfunctional red blood cells (megaloblasts) in the bone marrow[3] and also by hypersegmented neutrophils (those exhibiting five or more nuclear lobes ("segments"), with up to four lobes being normal). These hypersegmented neutrophils can be detected in the peripheral blood (using a diagnostic smear of a blood sample).

CausesVitamin B12 deficiency leading to folate deficiency:Achlorhydria-induced malabsorptionDeficient intakeDeficient intrinsic factor, a molecule produced by cells

in the stomach that is required for B12 absorption (pernicious anemia or gastrectomy)

Coeliac diseaseBiological competition for vitamin B12 by

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diverticulosis, fistula, intestinal anastomosis, or infection by the marine parasite Diphyllobothrium latum (fish tapeworm)

Selective vitamin B12 malabsorption (congenital—juvenile megaloblastic anemia 1—and drug-induced)

Chronic pancreatitis Ileal resection and bypassNitrous oxide anesthesia (usually requires repeated

instances).Folate deficiency:AlcoholismDeficient intake Increased needs: pregnancy, infant, rapid cellular

proliferation, and cirrhosisMalabsorption (congenital and drug-induced) Intestinal and jejunal resection (indirect) Deficient thiamine and factors (e.g., enzymes)

responsible for folate metabolism.Combined Deficiency: vitamin B12 & folate. Inherited Pyrimidine Synthesis Disorders: Orotic

aciduria Inherited DNA Synthesis Disorders

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Toxins and Drugs:Folic acid antagonists (methotrexate)Purine synthesis antagonists (6-mercaptopurine)Pyrimidine antagonists (cytarabine)PhenytoinNitrous OxideErythroleukemia Inborn genetic mutations of the Methionine synthase

gene.

Hematological findingsThe blood film can point towards vitamin deficiency:

Decreased red blood cell (RBC) count and hemoglobin levels[4]Increased mean corpuscular volume (MCV, >100 fL) and mean corpuscular hemoglobin (MCH)Normal mean corpuscular hemoglobin concentration (MCHC, 32–36 g/dL)The reticulocyte count is decreased due to destruction of fragile and abnormal megaloblastic erythroid precursor.The platelet count may be reduced.[citation needed]

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Neutrophil granulocytes may show multisegmented nuclei ("senile neutrophil"). This is thought to be due to decreased production and a compensatory prolonged lifespan for circulating neutrophils, which increase numbers of nuclear segments with age.[citation needed]Anisocytosis (increased variation in RBC size) and poikilocytosis (abnormally shaped RBCs).Macrocytes (larger than normal RBCs) are present.Ovalocytes (oval-shaped RBCs) are present.Howell-Jolly bodies (chromosomal remnant) also present.Blood chemistries will also show:

An increased lactic acid dehydrogenase (LDH) level. The isozyme is LDH-2 which is typical of the serum and hematopoetic cells.Increased homocysteine and methylmalonic acid in Vitamin B12 deficiencyIncreased homocysteine in folate deficiencyNormal levels of both methylmalonic acid and total homocysteine rule out clinically significant cobalamin deficiency with virtual certainty.[5]

Bone marrow (not normally checked in a patient suspected

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of megaloblastic anemia) shows megaloblastic hyperplasia.[6]

DiagnosisThe gold standard for the diagnosis of Vitamin B12 deficiency is a low blood level of Vitamin B12. A low level of blood Vitamin B12 is a finding that normally can and should be treated by injections, supplementation, or dietary or lifestyle advice, but it is not a diagnosis. Hypovitaminosis B12 can result from a number of mechanisms, including those listed above. For determination of cause, further patient history, testing, and empirical therapy may be clinically indicated.

A measurement of methylmalonic acid (methylmalonate) can provide an indirect method for partially differentiating Vitamin B12 and folate deficiencies. The level of methylmalonic acid is not elevated in folic acid deficiency. Direct measurement of blood cobalamin remains the gold standard because the test for elevated methylmalonic acid is not specific enough. Vitamin B12 is one necessary prosthetic group to the enzyme methylmalonyl-coenzyme

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A mutase. Vitamin B12 deficiency is but one among the conditions that can lead to dysfunction of this enzyme and a buildup of its substrate, methylmalonic acid, the elevated level of which can be detected in the urine and blood.

Due to the lack of available radioactive Vitamin B12, the Schilling test is now largely a historical artifact.[citation needed] The Schilling test was performed in the past to help determine the nature of the vitamin B12 deficiency. An advantage of the Schilling test was that it often included Vitamin B12 with intrinsic factor.

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Folate deficiency

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Folate deficiency is a low level of folic acid and derivatives in the body. Also known as vitamin B9, folate is involved in adenosine, guanine, and thymidine synthesis (part of DNA synthesis). Signs of folate deficiency are often subtle. Anemia is a late finding in folate deficiency and folate deficiency anemia is the term given for this medical condition.[1] It is characterized by the appearance of large-sized, abnormal red blood cells (megaloblasts), which form when there are inadequate stores of folic acid within the body.

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Signs and symptomsLoss of appetite and weight loss can occur. Additional signs are weakness, sore tongue, headaches, heart palpitations, irritability, and behavioral disorders.[3] In adults, anemia (macrocytic, megaloblastic anemia) can be a sign of advanced folate deficiency.

In infants and children, folate deficiency can slow growth rate. Women with folate deficiency who become pregnant are more likely to give birth to low birth weight premature infants, and infants with neural tube defects.

CausesA deficiency of folate can occur when the body's need for folate is increased, when dietary intake of folate is inadequate, or when the body excretes (or loses) more folate than usual. Medications that interfere with the body's ability to use folate may also increase the need for this vitamin.[4][5][6][7][8][9] Some research indicates that exposure to ultraviolet light, including the use of tanning beds, can lead to a folate deficiency.[10][11] The deficiency is more common in pregnant women, infants,

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children, and adolescents. May also be due to poor diet or a consequence of alcoholism.[12]

Additionally, a defect in homocysteine methyltransferase or a deficiency of B-12 may lead to a so-called "methyl-trap" of tetrahydrofolate (THF), in which THF is converted to a reservoir of methyl-THF which thereafter has no way of being metabolized, and serves as a sink of THF that causes a subsequent deficiency in folate.[13] Thus, a deficiency in B-12 can generate a large pool of methyl-THF that is unable to undergo reactions and will mimic folate deficiency.

Folate (pteroylmonoglutamate) is absorbed throughout the small intestine, though mainly in the Jejunum, binding to specific receptor proteins. Diffuse inflammatory or degenerative diseases of the small intestine, such as Crohn's disease, coeliac disease, chronic enteritis or entero-enteric fistulae, may reduce the activity of pteroyl polyglutamase (PPGH), a specific hydrolase required for folate absorption, and thereby leading to folate deficiency.

Situational

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Some situations that increase the need for folate include the following:

hemorrhage kidney dialysis liver disease malabsorption, including celiac disease and fructose

malabsorption pregnancy and lactation (breastfeeding) tobacco smoking alcohol consumptionMedicationMedications can interfere with folate utilization, including:

anticonvulsant medications (such as phenytoin, primidone, carbamazepine or valproate )metformin (sometimes prescribed to control blood sugar in type 2 diabetes)methotrexate, an anti-cancer drug also used to control inflammation associated with Crohn's disease, ulcerative colitis and rheumatoid arthritis.sulfasalazine (used to control inflammation associated

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with Crohn's disease, ulcerative colitis and rheumatoid arthritis)triamterene (a diuretic)birth control pillsWhen methotrexate is prescribed, folic acid supplements are sometimes given with the methotrexate. The therapeutic effects of methotrexate are due to its inhibition of dihydrofolate reductase and thereby reduce the rate de novo purine and pyrimidine synthesis and cell division. Methotrexate inhibits cell division and is particularly toxic to fast dividing cells, such as rapidly dividing cancer cells and the progenitor cells of the immune system. Folate supplementation is beneficial in patients being treated with long-term, low-dose methotrexate for inflammatory conditions, such as rheumatoid arthritis (RA) or psoriasis, to avoid macrocytic anemia caused by folate deficiency. Folate is often also supplemented before some high dose chemotherapy treatments in an effort to protect healthy tissue. However, it may be counterproductive to take a folic acid supplement with methotrexate in cancer treatment.

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Prevention and treatment

Folate is found in leafy green vegetables. Multi-vitamins also tend to include Folate as well as many other B vitamins. B vitamins, such as Folate, are water-soluble and excess is excreted in the urine.

When cooking, use of steaming or of a food steamer can help keep more folate content in the cooked foods, thus helping to prevent folate deficiency (see USDA reference in the steaming article).

Folate deficiency during human pregnancy has been associated with an increased risk of infant neural tube defects.[15] Such deficiency during the first four weeks of gestation can result in structural and developmental problems. NIH guidelines[16] recommend oral B vitamin supplements to decrease these risks near the time of conception and during the first month of pregnancy.

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ScurvyScurvy is a disease resulting from a lack of vitamin C.[1]

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Early symptoms include weakness, feeling tired, curly hair, and sore arms and legs.[1][2] Without treatment, decreased red blood cells, gum disease, and bleeding from the skin may occur.[1] As scurvy worsens there can be poor wound healing, personality changes, and finally death from infection or bleeding.

Scurvy is caused by not enough vitamin C in the diet.[1] It typically takes at least a month of little to no vitamin C before symptoms occur.[1][2] In modern times, it occurs most commonly in people with mental disorders, unusual eating habits, alcoholism, and old people who live alone. Other risk factors include intestinal malabsorption and dialysis. Humans and certain other animals require vitamin C in their diets to make the building blocks for collagen. Diagnosis is typically based on physical signs, X-rays, and improvement after treatment.[2]

Treatment is with vitamin C supplements taken by mouth.[1] Improvement often begins in a few days with complete recovery in a few weeks. Sources of vitamin C in the diet include citrus fruit and a number of vegetables

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such as tomatoes and potatoes. Cooking often decreases vitamin C in foods.[2]

Scurvy is currently rare. It occurs more often in the developing world in association with malnutrition.[2] Rates among refugees are reported at 5% to 45%.[3] Scurvy was described as early as the time of ancient Egypt.[2] It was a limiting factor in long distance sea travel, often killing large numbers of people.[4] A Scottish surgeon in the Royal Navy, James Lind, was the first to prove it could be treated with citrus fruit in a 1753 publication.[2][5] His experiments represented the first controlled trial. It took another 40 years before the British Navy began giving out lemon juice routinely.

Signs and symptomsEarly symptoms are malaise and lethargy. Even earlier might be a pain in a section of the gums which interferes with digestion. After 1–3 months, patients develop shortness of breath and bone pain. Myalgias may occur because of reduced carnitine production. Other symptoms include skin changes with roughness, easy

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bruising and petechiae, gum disease, loosening of teeth, poor wound healing, and emotional changes (which may appear before any physical changes). Dry mouth and dry eyes similar to Sjögren's syndrome may occur. In the late stages, jaundice, generalized edema, oliguria, neuropathy, fever, convulsions, and eventual death are frequently seen.[7]

A child presenting a "scorbutic tongue" due to what proved to be a vitamin C deficiency.

Cause

Scurvy or subclinical scurvy is caused by the lack of vitamin C. In modern Western societies, scurvy is rarely present in adults, although

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infants and elderly people are affected.[8] Virtually all commercially available baby formulas contain added vitamin C. Human breast milk contains sufficient vitamin C, if the mother has an adequate intake.

Scurvy is one of the accompanying diseases of malnutrition (other such micronutrient deficiencies are beriberi or pellagra) and thus is still widespread in areas of the world depending on external food aid.[9] Though rare, there are also documented cases of scurvy due to poor dietary choices by people living in industrialized nations.

Pathogenesis

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X-ray of the knee joint (arrow indicates scurvy line).Ascorbic acid is needed for a variety of biosynthetic pathways, by accelerating hydroxylation and amidation

reactions. In the synthesis of collagen, ascorbic acid is required as a cofactor for prolyl hydroxylase and lysyl hydroxylase. These two enzymes are responsible for the hydroxylation of the proline and lysine amino acids in

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collagen. Hydroxyproline and hydroxylysine are important for stabilizing collagen by cross-linking the propeptides in collagen. Defective collagen fibrillogenesis impairs wound healing. Collagen is an important part of bone, so bone formation is affected. Defective connective tissue leads to fragile capillaries, resulting in abnormal bleeding. Untreated scurvy is invariably fatal.

Prevention

Scurvy can be prevented by a diet that includes vitamin C-rich foods such as bell peppers (sweet peppers), blackcurrants, broccoli, guava, kiwifruit, and parsley. Other sources rich in vitamin C are fruits such as lemons, oranges, papaya, and strawberries. It is also found in vegetables, such as brussels sprouts, cabbage, potatoes, and spinach. Some fruits and vegetables not high in vitamin C may be pickled in lemon juice, which is high in vitamin C. Though redundant in the presence of a balanced diet,[16] various nutritional supplements are available that provide ascorbic acid well in excess of that required to prevent scurvy.

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Some animal products, including liver, Muktuk (whale skin), oysters, and parts of the central nervous system, including the adrenal medulla, brain, and spinal cord, contain large amounts of vitamin C, and can even be used to treat scurvy. Fresh meat from animals which make their own vitamin C (which most animals do) contains enough vitamin C to prevent scurvy, and even partly treat it. In some cases (notably French soldiers eating fresh horse meat), it was discovered that meat alone, even partly cooked meat, could alleviate scurvy. Conversely, in other cases, a meat-only diet could cause scurvy.[17]

Scott's 1902 Antarctic expedition used lightly fried seal meat and liver, whereby complete recovery from incipient scurvy was reported to have taken less than two weeks.

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Non-nutritional (hemolytic, aplastic and other) anemias

AcanthocyteFor other uses, see Acanthocyte (disambiguation).

Acanthocytes, from peripheral blood, under light

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microscopy. Note the irregularly shaped, non-circular cells in the image.Acanthocyte (from the Greek word ἄκανθα acantha, meaning 'thorn'), in biology and medicine, refers to a form of red blood cell that has a spiked cell membrane, due to abnormal thorny projections.[1][2] A similar term is spur cells. Often they may be confused with echinocytes or schistocytes.

Acanthocytes have coarse, weirdly spaced, variably sized crenations, resembling many-pointed stars. They are seen on blood films in, among others abetalipoproteinemia,[3] liver disease, chorea acanthocytosis, McLeod syndrome, and several inherited neurological and other disorders, such as neuroacanthocytosis,[4] anorexia nervosa, infantile pyknocytosis, hypothyroidism, idiopathic neonatal hepatitis, alcoholism, congestive splenomegaly, Zieve syndrome, and chronic granulomatous disease.

UsageSpur cells may refer synonymously to acanthocytes,[6] or may refer in some sources to a specific subset of

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'extreme acanthocytes' that have undergone splenic modification whereby additional cell membrane loss has blunted the spicules and the cells have become spherocytic ('spheroacanthocyte'), as seen in some patients with severe liver disease.[7]

Acanthocytosis can refer generally to the presence of this type of crenated red blood cell, such as may be found in severe cirrhosis or pancreatitis,[6] but can refer specifically to abetalipoproteinemia, a clinical condition with acanthocytic red blood cells, neurologic problems and steatorrhea.[8] This particular cause of acanthocytosis (also known as abetalipoproteinemia, apolipoprotein B deficiency, and Bassen-Kornzweig syndrome) is a rare, genetically inherited, autosomal recessive condition due to the inability to fully digest dietary fats in the intestines as a result of various mutations of the microsomal triglyceride transfer protein (MTTP) gene.

Pathophysiology

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Acanthocytosis in a patient with abetalipoproteinemiaAcanthocytes arise from either of two mechanisms. Alterations in membrane lipids are seen in

abetalipoproteinemia and liver dysfunction. Alteration in membrane structural proteins are seen in neuroacanthocytosis and McLeod syndrome.

In liver dysfunction, apolipoprotein A-II deficient lipoprotein accumulates in plasma causing increased cholesterol in RBCs. This causes abnormalities of membrane of RBC causing remodeling in spleen and formation of

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acanthocytes.

In abetalipoproteinemia, there is deficiency of lipids and vitamin E causing abnormal morphology of RBCs.

Differential diagnosesAcanthocytosis can be seen in: acute or chronic anemia, hepatitis A, B, and C, hepatorenal syndrome, hypopitutarism, malabsorption syndromes, and malnutrition[10] Acanthocytosis secondary to malnourishment, such as anorexia nervosa and cystic fibrosis, remits with resolution of the nutritional deficiency.[11] Acanthocyte-like cells may be found in hypothyroidism, after splenectomy, and in myelodysplasia.[11]

Acanthocytes should be distinguished from echinocytes, which are also called 'burr cells', which although crenated are dissimilar in that they have multiple, small, projecting spiculations at regular intervals on the cell membrane.[7][11] Burr cells usually imply uremia, but are seen in many

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conditions, including mild hemolysis in hypomagnesemia and hypophosphatemia, hemolytic anemia in long-distance runners, and pyruvate kinase deficiency.[10] Burr cells can also arise in vitro due to elevated pH, blood storage, ATP depletion, calcium accumulation, and contact with glass.[10] Acanthocytes should also be distinguished from keratocytes, also called 'horn cells' which have a few very large protuberances.[11]

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Acute posthemorrhagic anemia

Acute posthemorrhagic anemia or acute blood loss anemia is a condition in which a person quickly loses a large volume of circulating hemoglobin. Acute blood loss is usually associated with an incident of trauma or a severe injury resulting in a large loss of blood. It can also occur during or after a surgical procedure.

Alpha-thalassemiaAlpha-thalassemia (α-thalassemia, α-thalassaemia) is a form of thalassemia involving the genes HBA1[1] and HBA2.[2] Alpha-thalassemia is due to impaired production of alpha chains from 1,2,3, or all 4 of the alpha globin genes, leading to a relative excess of beta globin chains. The degree of impairment is based on which clinical phenotype is present (how many genes are affected).

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Signs/symptoms

The presentation of individuals with alpha-thalassemia consists of:

1.Jaundice2.Fatigue3.Pronounced forehead4.Gallstones5.Hypertension (during pregnancy)

CauseAlpha-thalassemias are most commonly inherited in a Mendelian recessive manner. They are also associated with deletions of chromosome 16p.[6] Alpha thalassemia can also be acquired under rare circumstances.

Pathophysiology

The mechanism sees that α thalassemias results in decreased alpha-globin production, therefore fewer alpha-globin chains are produced, resulting in an excess of β chains in adults and excess γ chains in newborns.

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The excess β chains form unstable tetramers called hemoglobin H or HbH of four beta chains. The excess γ chains form tetramers which are poor carriers of O2 since their affinity for O2 is too high, so it is not dissociated in the periphery. Homozygote α0 thalassaemias, where numerous γ4 but no α-globins occur at all (referred to as Hb Barts), often result in death soon after birth.

Diagnosis

Diagnosis of alpha-thalassemia is primarily by laboratory evaluation and haemoglobin electrophoresis. Alpha-thalassemia can be mistaken for iron-deficiency anaemia on a full blood count or blood film, as both conditions have a microcytic anaemia. Serum iron and serum ferritin can be used to exclude iron-deficiency anaemia.[3]

TypesTwo genetic loci exist for α globin, thus four genes are in diploid cells. Two genes are maternal and two genes are paternal in origin. The severity of the α-thalassemias is correlated with the number of affected

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α-globin; genes: the greater, the more severe will be the manifestations of the disease. When noting the genotype, an "α" indicates a functional alpha chain.

Treatment

Treatment for alpha-thalassemia may consist of blood transfusions, and possible splenectomy; additionally, gallstones may be a problem that would require surgery. Secondary complications from febrile episode should be monitored, and most individuals live without any need for treatment[5][11]

Additionally, stem cell transplantation should be considered as a treatment (and cure), which is best done in early age. Other options, such as gene therapy, are still being developed.

Epidemiology

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MalariaIn terms of epidemiology, worldwide distribution of inherited alpha-thalassemia corresponds to areas of malaria exposure, suggesting a protective role. Thus, alpha-thalassemia is common in sub-Saharan Africa, the Mediterranean Basin, and generally tropical (and subtropical) regions. The epidemiology of alpha-thalassemia in the US reflects this global distribution pattern. More specifically, HbH disease is seen in Southeast Asia and the Middle East, while Hb Bart hydrops fetalis is acknowledged in Southeast Asia only.[13] The data indicate that 15% of the Greek and Turkish Cypriots are carriers of beta-thalassaemia genes, while 10% of the population carry alpha-thalassaemia genes.

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Anemia

For other uses, see Anemia

(disambiguation).Anemia, also spelled anaemia, is usually defined as a decrease in the total amount of red blood cells (RBCs) or hemoglobin in the blood.[3][4] It can also be defined as a lowered ability of the blood to carry oxygen.[5] When anemia comes on slowly, the symptoms are often vague and may include feeling tired, weakness,

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shortness of breath or a poor ability to exercise. Anemia that comes on quickly often has greater symptoms, which may include confusion, feeling like one is going to pass out, loss of consciousness, or increased thirst. Anemia must be significant before a person becomes noticeably pale. Additional symptoms may occur depending on the underlying cause.The three main types of anemia are due to blood loss, decreased red blood cell production, and increased red blood cell breakdown. Causes of blood loss include trauma and gastrointestinal bleeding, among others. Causes of decreased production include iron deficiency, a lack of vitamin B12, thalassemia, and a number of neoplasms of the bone marrow. Causes of increased breakdown include a number of genetic conditions such as sickle cell anemia, infections like malaria, and certain autoimmune diseases. It can also be classified based on the size of red blood cells and amount of hemoglobin in each cell. If the cells are small, it is microcytic anemia. If they are large, it is macrocytic anemia while if they are normal sized, it is normocytic anemia.[1] Diagnosis in men is based on a hemoglobin

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of less than 130 to 140 g/L (13 to 14 g/dL), while in women, it must be less than 120 to 130 g/L (12 to 13 g/dL).[1][6] Further testing is then required to determine the cause.[1]

Certain groups of individuals, such as pregnant women, benefit from the use of iron pills for prevention.[1][7] Dietary supplementation, without determining the specific cause, is not recommended. The use of blood transfusions is typically based on a person's signs and symptoms.[1] In those without symptoms, they are not recommended unless hemoglobin levels are less than 60 to 80 g/L (6 to 8 g/dL).[1][8] These recommendations may also apply to some people with acute bleeding.[1] Erythropoiesis-stimulating medications are only recommended in those with severe anemia.[8]

Anemia is the most common blood disorder, affecting about a third of the global population.[2][1] Iron-deficiency anemia affects nearly 1 billion people.[9] In 2013, anemia due to iron deficiency resulted in about 183,000 deaths – down from 213,000 deaths in 1990.[10] It is more common in women than men,[9] during

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pregnancy, and in children and the elderly.[1] Anemia increases costs of medical care and lowers a person's productivity through a decreased ability to work.[6] The name is derived from Ancient Greek: ἀναιμία anaimia, meaning "lack of blood", from ἀν- an-, "not" and αἷμα haima, "blood".

Signs and symptomsAnemia goes undetected in many people and symptoms can be minor. The symptoms can be related to an underlying cause or the anemia itself. Most commonly, people with anemia report feelings of weakness or tired, and sometimes poor concentration. They may also report shortness of breath on exertion. In very severe anemia, the body may compensate for the lack of oxygen-carrying capability of the blood by increasing cardiac output. The patient may have symptoms related to this, such as palpitations, angina (if pre-existing heart disease is present), intermittent claudication of the legs, and symptoms of heart failure. On examination, the signs exhibited may include pallor (pale skin, lining mucosa, conjunctiva and nail beds), but this is not a reliable sign. There may be signs of specific causes of

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anemia, e.g., koilonychia (in iron deficiency), jaundice (when anemia results from abnormal break down of red blood cells — in hemolytic anemia), bone deformities (found in thalassemia major) or leg ulcers (seen in sickle-cell disease). In severe anemia, there may be signs of a hyperdynamic circulation: tachycardia (a fast heart rate), bounding pulse, flow murmurs, and cardiac ventricular hypertrophy (enlargement). There may be signs of heart failure. Pica, the consumption of non-food items such as ice, but also paper, wax, or grass, and even hair or dirt, may be a symptom of iron deficiency, although it occurs often in those who have normal levels of hemoglobin. Chronic anemia may result in behavioral disturbances in children as a direct result of impaired neurological development in infants, and reduced academic performance in children of school age. Restless legs syndrome is more common in those with iron-deficiency anemia.

Causes

Figure shows normal red blood cells flowing freely in a

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blood vessel. The inset image shows a cross-section of a normal red blood cell with normal hemoglobin.[13]The causes of anemia may be classified as impaired red blood cell (RBC) production, increased RBC destruction (hemolytic anemias), blood loss and fluid overload (hypervolemia). Several of these may interplay to cause anemia eventually. Indeed, the most common cause of anemia is blood loss, but this usually does not cause any lasting symptoms unless a relatively impaired RBC production develops, in turn most

commonly by iron deficiency.[14] (See Iron deficiency

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anemia)

Impaired productionDisturbance of proliferation and differentiation of stem cells

Pure red cell aplasia[15] Aplastic anemia[15] affects all kinds of blood cells.

Fanconi anemia is a hereditary disorder or defect featuring aplastic anemia and various other abnormalities.

Anemia of renal failure[15] by insufficient erythropoietin production

Anemia of endocrine disorders[medical citation needed]

Disturbance of proliferation and maturation of erythroblasts

Pernicious anemia[15] is a form of megaloblastic anemia due to vitamin B12 deficiency dependent on impaired absorption of vitamin B12. Lack of dietary B12 causes non-pernicious megaloblastic anemia

Anemia of folic acid deficiency,[15] as with vitamin B12, causes megaloblastic anemia

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Anemia of prematurity, by diminished erythropoietin response to declining hematocrit levels, combined with blood loss from laboratory testing, generally occurs in premature infants at two to six weeks of age.

Iron deficiency anemia, resulting in deficient heme synthesis[15]

Thalassemias, causing deficient globin synthesis[15]

Congenital dyserythropoietic anemias, causing ineffective erythropoiesis

Anemia of renal failure[15] (also causing stem cell dysfunction)

Other mechanisms of impaired RBC production Myelophthisic anemia[15] or myelophthisis is a

severe type of anemia resulting from the replacement of bone marrow by other materials, such as malignant tumors or granulomas.

Myelodysplastic syndrome[15] anemia of chronic inflammation

Increased destruction

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Further information: Hemolytic anemiaAnemias of increased red blood cell destruction are

generally classified as hemolytic anemias. These are generally featuring jaundice and elevated lactate dehydrogenase levels.[medical citation needed]

Intrinsic (intracorpuscular) abnormalities[15] cause premature destruction. All of these, except paroxysmal nocturnal hemoglobinuria, are hereditary genetic disorders.[16]

Hereditary spherocytosis[15] is a hereditary defect that results in defects in the RBC cell membrane, causing the erythrocytes to be sequestered and destroyed by the spleen.

Hereditary elliptocytosis[15] is another defect in membrane skeleton proteins.

Abetalipoproteinemia,[15] causing defects in membrane lipids

Enzyme deficienciesPyruvate kinase and hexokinase deficiencies,[15]

causing defect glycolysisGlucose-6-phosphate dehydrogenase deficiency

and glutathione synthetase deficiency,[15] causing

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increased oxidative stressHemoglobinopathiesSickle cell anemia[15]Hemoglobinopathies causing unstable

hemoglobins[15]Paroxysmal nocturnal hemoglobinuria[15]Extrinsic (extracorpuscular) abnormalitiesAntibody-mediatedWarm autoimmune hemolytic anemia is caused by

autoimmune attack against red blood cells, primarily by IgG. It is the most common of the autoimmune hemolytic diseases.[17] It can be idiopathic, that is, without any known cause, drug-associated or secondary to another disease such as systemic lupus erythematosus, or a malignancy, such as chronic lymphocytic leukemia.[18][18]

Cold agglutinin hemolytic anemia is primarily mediated by IgM. It can be idiopathic[19] or result from an underlying condition.

Rh disease,[15] one of the causes of hemolytic disease of the newborn

Transfusion reaction to blood transfusions[15]

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Mechanical trauma to red cellsMicroangiopathic hemolytic anemias, including

thrombotic thrombocytopenic purpura and disseminated intravascular coagulation[15]

Infections, including malaria[15]Heart surgery[medical citation needed]Haemodialysis[medical citation needed]

Blood loss

Anemia of prematurity from frequent blood sampling for laboratory testing, combined with insufficient RBC productionTrauma[15] or surgery, causing acute blood lossGastrointestinal tract lesions,[15] causing either acute bleeds (e.g. variceal lesions, peptic ulcers) or chronic blood loss (e.g. angiodysplasia)Gynecologic disturbances,[15] also generally causing chronic blood lossFrom menstruation, mostly among young women or older women who have fibroidsInfection by intestinal nematodes feeding on blood, such as hookworms[20] and the whipworm Trichuris

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trichiura.[21]The roots of the words anemia and ischemia both refer to the basic idea of "lack of blood", but anemia and ischemia are not the same thing in modern medical terminology. The word anemia used alone implies widespread effects from blood that either is too scarce (e.g., blood loss) or is dysfunctional in its oxygen-supplying ability (due to whatever type of hemoglobin or erythrocyte problem). In contrast, the word ischemia refers solely to the lack of blood (poor perfusion). Thus ischemia in a body part can cause localized anemic effects within those tissues.

Fluid overload

Fluid overload (hypervolemia) causes decreased hemoglobin concentration and apparent anemia:

General causes of hypervolemia include excessive sodium or fluid intake, sodium or water retention and fluid shift into the intravascular space.[22]Intestinal inflammation

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Certain gastrointestinal disorders can cause anemia. The mechanisms involved are multifactorial and not limited to malabsorption but mainly related to chronic intestinal inflammation, which causes dysregulation of hepcidin that leads to decreased access of iron to the circulation.[23][24][25]

Helicobacter pylori infection.[26]Gluten-related disorders: untreated celiac disease[26][25] and non-celiac gluten sensitivity.[27] Anemia can be the only manifestation of celiac disease, in absence of gastrointestinal or any other symptoms.[28]Inflammatory bowel disease.

Diagnosis

Peripheral blood smear microscopy of a patient with iron-deficiency anemiaDefinitionsThere are a number of definitions of anemia; reviews provide comparison and contrast of them.[31] A strict but broad definition is an absolute decrease in red blood cell mass,[32] however, a broader definition is a

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lowered ability of the blood to carry oxygen.[5] An operational definition is a decrease in whole-blood hemoglobin concentration of more than 2 standard deviations below the mean of an age- and sex-matched reference range.[33]

It is difficult to directly measure RBC mass,[34] so the hematocrit (amount of RBCs) or the hemoglobin (Hb) in the blood are often used instead to indirectly estimate the value.[35] Hemotocrit; however, is concentration dependent and is therefore not completely accurate. For example, during pregnancy a woman's RBC mass is normal but because of an increase in blood volume the hemoglobin and hematocrit are diluted and thus decreased. Another example would be bleeding where the RBC mass would decrease but the concentrations of hemoglobin and hematocrit initially remains normal until fluids shift from other areas of the body to the intravascular space.

The anemia is also classified by severity into mild (110 g/L to normal), moderate (80 g/L to 110 g/L), and severe anemia (less than 80 g/L) in adult males and

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adult non pregnant females.[36] Different values are used in pregnancy and children.[36]

TestingAnemia is typically diagnosed on a complete blood count. Apart from reporting the number of red blood cells and the hemoglobin level, the automatic counters also measure the size of the red blood cells by flow cytometry, which is an important tool in distinguishing between the causes of anemia. Examination of a stained blood smear using a microscope can also be helpful, and it is sometimes a necessity in regions of the world where automated analysis is less accessible.[medical citation needed]

In modern counters, four parameters (RBC count, hemoglobin concentration, MCV and RDW) are measured, allowing others (hematocrit, MCH and MCHC) to be calculated, and compared to values adjusted for age and sex. Some counters estimate hematocrit from direct measurements.Reticulocyte counts, and the "kinetic" approach to anemia, have become more common than in the past in

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the large medical centers of the United States and some other wealthy nations, in part because some automatic counters now have the capacity to include reticulocyte counts. A reticulocyte count is a quantitative measure of the bone marrow's production of new red blood cells. The reticulocyte production index is a calculation of the ratio between the level of anemia and the extent to which the reticulocyte count has risen in response. If the degree of anemia is significant, even a "normal" reticulocyte count actually may reflect an inadequate response. If an automated count is not available, a reticulocyte count can be done manually following special staining of the blood film. In manual examination, activity of the bone marrow can also be gauged qualitatively by subtle changes in the numbers and the morphology of young RBCs by examination under a microscope. Newly formed RBCs are usually slightly larger than older RBCs and show polychromasia. Even where the source of blood loss is obvious, evaluation of erythropoiesis can help assess whether the bone marrow will be able to compensate for the loss, and at what rate. When the cause is not

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obvious, clinicians use other tests, such as: ESR, ferritin, serum iron, transferrin, RBC folate level, serum vitamin B12, hemoglobin electrophoresis, renal function tests (e.g. serum creatinine) although the tests will depend on the clinical hypothesis that is being investigated. When the diagnosis remains difficult, a bone marrow examination allows direct examination of the precursors to red cells, although is rarely used as is painful, invasive and is hence reserved for cases where severe pathology needs to be determined or excluded.[medical citation needed]

Red blood cell size EditIn the morphological approach, anemia is classified by the size of red blood cells; this is either done automatically or on microscopic examination of a peripheral blood smear. The size is reflected in the mean corpuscular volume (MCV). If the cells are smaller than normal (under 80 fl), the anemia is said to be microcytic; if they are normal size (80–100 fl), normocytic; and if they are larger than normal (over 100 fl), the anemia is classified as macrocytic. This scheme quickly exposes some of the most common

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causes of anemia; for instance, a microcytic anemia is often the result of iron deficiency. In clinical workup, the MCV will be one of the first pieces of information available, so even among clinicians who consider the "kinetic" approach more useful philosophically, morphology will remain an important element of classification and diagnosis. Limitations of MCV include cases where the underlying cause is due to a combination of factors – such as iron deficiency (a cause of microcytosis) and vitamin B12 deficiency (a cause of macrocytosis) where the net result can be normocytic cells.[medical citation needed]

Production vs. destruction or lossEditThe "kinetic" approach to anemia yields arguably the most clinically relevant classification of anemia. This classification depends on evaluation of several hematological parameters, particularly the blood reticulocyte (precursor of mature RBCs) count. This then yields the classification of defects by decreased RBC production versus increased RBC destruction or loss. Clinical signs of loss or destruction include abnormal peripheral blood smear with signs of

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hemolysis; elevated LDH suggesting cell destruction; or clinical signs of bleeding, such as guaiac-positive stool, radiographic findings, or frank bleeding.[medical citation needed] The following is a simplified schematic of this approach:[medical citation needed]

1. For instance, sickle cell anemia with superimposed iron deficiency; chronic gastric bleeding with B12 and folate deficiency; and other instances of anemia with more than one cause.2.Confirm by repeating reticulocyte count: ongoing combination of low reticulocyte production index, normal MCV and hemolysis or loss may be seen in bone marrow failure or anemia of chronic disease, with superimposed or related hemolysis or blood loss.Other characteristics visible on the peripheral smear may provide valuable clues about a more specific diagnosis; for example, abnormal white blood cells may point to a cause in the bone marrow.

MicrocyticMain article: Microcytic anemiaMicrocytic anemia is primarily a result of hemoglobin

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synthesis failure/insufficiency, which could be caused by several etiologies:

Heme synthesis defectIron deficiency anemia (microcytosis is not always present)Anemia of chronic disease (more commonly presenting as normocytic anemia)Globin synthesis defectAlpha-, and beta-thalassemiaHbE syndromeHbC syndromeVarious other unstable hemoglobin diseasesSideroblastic defectHereditary sideroblastic anemiaAcquired sideroblastic anemia, including lead toxicity[38]Reversible sideroblastic anemiaIron deficiency anemia is the most common type of anemia overall and it has many causes. RBCs often appear hypochromic (paler than usual) and microcytic (smaller than usual) when viewed with a microscope.

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Iron deficiency anemia is due to insufficient dietary intake or absorption of iron to meet the body's needs. Infants, toddlers, and pregnant women have higher than average needs. Increased iron intake is also needed to offset blood losses due to digestive tract issues, frequent blood donations, or heavy menstrual periods.[39] Iron is an essential part of hemoglobin, and low iron levels result in decreased incorporation of hemoglobin into red blood cells. In the United States, 12% of all women of childbearing age have iron deficiency, compared with only 2% of adult men. The incidence is as high as 20% among African American and Mexican American women.[40] Studies have shown iron deficiency without anemia causes poor school performance and lower IQ in teenage girls, although this may be due to socioeconomic factors.[41][42] Iron deficiency is the most prevalent deficiency state on a worldwide basis. It is sometimes the cause of abnormal fissuring of the angular (corner) sections of the lips (angular stomatitis).In the United States, the most common cause of iron deficiency is bleeding or blood loss, usually from the

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gastrointestinal tract. Fecal occult blood testing, upper endoscopy and lower endoscopy should be performed to identify bleeding lesions. In older men and women, the chances are higher that bleeding from the gastrointestinal tract could be due to colon polyps or colorectal cancer.Worldwide, the most common cause of iron deficiency anemia is parasitic infestation (hookworms, amebiasis, schistosomiasis and whipworms).[43]The Mentzer index (mean cell volume divided by the RBC count) predicts whether microcytic anemia may be due to iron deficiency or thallasemia, although it requires confirmation.[citation needed]

MacrocyticMain article: Macrocytic anemiaMegaloblastic anemia, the most common cause of macrocytic anemia, is due to a deficiency of either vitamin B12, folic acid, or both. Deficiency in folate or vitamin B12 can be due either to inadequate intake or insufficient absorption. Folate deficiency normally does not produce neurological symptoms, while B12 deficiency does.

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Pernicious anemia is caused by a lack of intrinsic factor, which is required to absorb vitamin B12 from food. A lack of intrinsic factor may arise from an autoimmune condition targeting the parietal cells (atrophic gastritis) that produce intrinsic factor or against intrinsic factor itself. These lead to poor absorption of vitamin B12.Macrocytic anemia can also be caused by removal of the functional portion of the stomach, such as during gastric bypass surgery, leading to reduced vitamin B12/folate absorption. Therefore, one must always be aware of anemia following this procedure.HypothyroidismAlcoholism commonly causes a macrocytosis, although not specifically anemia. Other types of liver disease can also cause macrocytosis.Drugs such as Methotrexate, zidovudine, and other substances may inhibit DNA replication such as heavy metals (e.g., lead)Macrocytic anemia can be further divided into "megaloblastic anemia" or "nonmegaloblastic macrocytic anemia". The cause of megaloblastic

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anemia is primarily a failure of DNA synthesis with preserved RNA synthesis, which results in restricted cell division of the progenitor cells. The megaloblastic anemias often present with neutrophil hypersegmentation (six to 10 lobes). The nonmegaloblastic macrocytic anemias have different etiologies (i.e. unimpaired DNA globin synthesis,) which occur, for example, in alcoholism. In addition to the nonspecific symptoms of anemia, specific features of vitamin B12 deficiency include peripheral neuropathy and subacute combined degeneration of the cord with resulting balance difficulties from posterior column spinal cord pathology.[44] Other features may include a smooth, red tongue and glossitis. The treatment for vitamin B12-deficient anemia was first devised by William Murphy, who bled dogs to make them anemic, and then fed them various substances to see what (if anything) would make them healthy again. He discovered that ingesting large amounts of liver seemed to cure the disease. George Minot and George Whipple then set about to isolate the curative substance chemically and ultimately were able to isolate the

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vitamin B12 from the liver. All three shared the 1934 Nobel Prize in Medicine.[45]

NormocyticMain article: Normocytic anemiaNormocytic anemia occurs when the overall hemoglobin levels are decreased, but the red blood cell size.

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Anemia of chronic diseaseAnemia of chronic disease, or anemia of chronic inflammation, is a form of anemia seen in chronic infection, chronic immune activation, and malignancy. These conditions all produce massive elevation of Interleukin-6, which stimulates hepcidin production and release from the liver, which in turn reduces the iron carrier protein ferroportin so that access of iron to the circulation is reduced. Other mechanisms may also play a role, such as reduced erythropoiesis.

Anemia of chronic inflammation is the preferred term since not all chronic diseases are associated with this form of anemia.

PathophysiologyAnemia is considered when RBCs count :

< 4.5 million in males< 3.9 million in femalesOr Hemoglobin ( Hb ) content :

< 13.5 gm % in males

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< 11.5 gm % in femalesIn response to inflammatory cytokines, increasingly IL-6,[1] the liver produces increased amounts of hepcidin. Hepcidin in turn causes increased internalisation of ferroportin molecules on cell membranes which prevents release from iron stores. Inflammatory cytokines also appear to affect other important elements of iron metabolism, including decreasing ferroportin expression, and probably directly blunting erythropoiesis by decreasing the ability of the bone marrow to respond to erythropoietin.

Before the recent discovery of hepcidin and its function in iron metabolism, anemia of chronic disease was seen as the result of a complex web of inflammatory changes. Over the last few years, however, many investigators have come to feel that hepcidin is the central actor in producing anemia of chronic inflammation. Hepcidin offers an attractive Occam's Razor (parsimonious) explanation for the condition, and more recent descriptions of human iron metabolism and hepcidin function reflect this view.[2]

In addition to effects of iron sequestration, inflammatory cytokines promote the production of white blood cells.

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Bone marrow produces both white blood cells and red blood cells from the same precursor stem cells. Therefore, the upregulation of white blood cells causes fewer stem cells to differentiate into red blood cells. This effect may be an important additional cause for the decreased erythropoiesis and red blood cell production seen in anemia of inflammation, even when erythropoietin levels are normal, and even aside from the effects of hepcidin. Nonetheless, there are other mechanisms that also contribute to the lowering of hemoglobin levels during inflammation: (i) Inflammatory cytokines suppress the proliferation of erythroid precursors in the bone marrow.;[3] (ii) inflammatory cytokines inhibit the release of erythropoietin (EPO) from the kidney; and (iii) the survival of circulating red cells is shortened.[citation needed]

In the short term, the overall effect of these changes is likely positive: it allows the body to keep more iron away from bacterial pathogens in the body, while producing more immune cells to fight off infection. Almost all bacteria depend on iron to live and multiply. However, if inflammation continues, the effect of locking up iron stores is to reduce the ability of the bone marrow to produce red

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blood cells. These cells require iron for their massive amounts of hemoglobin which allow them to transport oxygen.[citation needed]

Because anemia of chronic disease can be the result of non-infective causes of inflammation, future research is likely to investigate whether hepcidin antagonists might be able to treat this problem.

Anemia of chronic disease may also be due to neoplastic disorders and non-infectious inflammatory diseases.[4] Neoplastic disorders include Hodgkin’s disease lung and breast carcinoma and non-infectious inflammatory diseases include rheumatoid arthritis and systemic lupus erythematosus.

Anemia of chronic disease as it is now understood is to at least some degree separate from the anemia seen in renal failure in which anemia results from poor production of erythropoietin, or the anemia caused by some drugs (like AZT, used to treat HIV infection) that have the side effect of inhibiting erythropoiesis. In other words, not all anemia seen in people with chronic disease should be diagnosed as anemia of chronic disease. On the other hand, both of these

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examples show the complexity of this diagnosis: HIV infection itself can produce anemia of chronic disease, and renal failure can lead to inflammatory changes that also can produce anemia of chronic disease.

Survival advantageLimiting some microbes' access to iron can reduce their virulence, thereby potentially reducing the severity of infection. Blood transfusion to patients with anemia of chronic disease is associated with a higher mortality, supporting the concept.

SeverityAnemia of chronic disease is usually mild but can be severe. It is usually normocytic, but can be microcytic.[4] The presence of both anemia of chronic disease and dietary iron deficiency in the same patient results in a more severe anemia.

DiagnosisWhile no single test is reliable to distinguish iron deficiency anemia from the anemia of chronic

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inflammation, there are sometimes some suggestive data:

In anemia of chronic inflammation without iron deficiency, ferritin is normal or high, reflecting the fact that iron is sequestered within cells, and ferritin is being produced as an acute phase reactant. In iron deficiency anemia ferritin is low.[4]Total iron-binding capacity (TIBC) is high in iron deficiency, reflecting production of more transferrin to increase iron binding; TIBC is low or normal in anemia of chronic inflammation.

TreatmentThe ideal treatment for anemia of chronic disease is to treat the chronic disease successfully, but this is rarely possible.

Parenteral iron is increasingly used for anemia in chronic renal disease[6] and inflammatory bowel disease.[7][8]

Erythropoietin can be helpful, but this is costly and may be dangerous.[9][10] Erythropoietin is advised either in conjunction with adequate iron replacement which in practice is intravenous, or when IV iron has proved ineffective.

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Erythropoietin

Erythropoietin (/ɪˌrɪθroʊˈpɔɪᵻtən/ or /ɪˌrɪθroʊpoʊˈɛtɪn, -rə-, -ˈiː-, -tən/;[3][4][5]), also known as EPO, hematopoietin, or hemopoietin, is a glycoprotein hormone that controls erythropoiesis, or red blood cell production. It is a cytokine (protein signaling molecule) for erythrocyte (red blood cell) precursors in the bone marrow. Human EPO has a molecular weight of 34 kDa.

Erythropoietin is produced by interstitial fibroblasts in the

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kidney in close association with peritubular capillary and proximal convoluted tubule. It is also produced in perisinusoidal cells in the liver. While liver production predominates in the fetal and perinatal period, renal production is predominant during adulthood.

Exogenous erythropoietin can be provided to people whose kidneys cannot make enough. Recombinant human erythropoietin (rhEPO) is produced by recombinant DNA technology in cell culture. Several different pharmaceutical agents are available with a variety of glycosylation patterns and are collectively called erythropoiesis-stimulating agents (ESA). Major examples are epoetin alfa and epoetin beta. The specific details for labeled use vary between the package inserts, but ESAs have been used in the treatment of anemia in chronic kidney disease, anemia in myelodysplasia, and in anemia from cancer chemotherapy. Boxed warnings include a risk of death, myocardial infarction, stroke, venous thromboembolism, and tumor recurrence.[6] rhEPO has been used illicitly as a performance-enhancing drug;[7] it can often be detected in blood, due to slight differences from the endogenous protein, for example, in features of posttranslational modification.

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FunctionRed blood cell productionErythropoietin is an essential hormone for red blood cell production. Without it, definitive erythropoiesis does not take place. Under hypoxic conditions, the kidney will produce and secrete erythropoietin to increase the production of red blood cells by targeting CFU-E, proerythroblast and basophilic erythroblast subsets in the differentiation. Erythropoietin has its primary effect on red blood cell progenitors and precursors (which are found in the bone marrow in humans) by promoting their survival through protecting these cells from apoptosis, or cell death.

Erythropoietin is the primary erythropoietic factor that cooperates with various other growth factors (e.g., IL-3, IL-6, glucocorticoids, and SCF) involved in the development of erythroid lineage from multipotent progenitors. The burst-forming unit-erythroid (BFU-E) cells start erythropoietin receptor expression and are sensitive to erythropoietin. Subsequent stage, the colony-forming unit-erythroid (CFU-E), expresses maximal erythropoietin receptor density and is completely dependent on erythropoietin for further

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differentiation. Precursors of red cells, the proerythroblasts and basophilic erythroblasts also express erythropoietin receptor and are therefore affected by it.

Nonhematopoietic rolesErythropoietin was reported to have a range of actions beyond stimulation of erythropoiesis including vasoconstriction-dependent hypertension, stimulating angiogenesis, and promoting cell survival via activation of Epo receptors resulting in anti-apoptotic effects on ischemic tissues. However this proposal is controversial with numerous studies showing no effect.[8] It is also inconsistent with the low levels of Epo receptors on those cells. Clinical trials in humans with ischemic heart, neural and renal tissues have not demonstrated the same benefits seen in animals. In addition some research studies have shown its neuroprotective effect on diabetic neuropathy, however these data were not confirmed in clinical trials that have been conducted on the deep peroneal, superficial peroneal, tibial and sural nerves.

Mechanism of actionErythropoietin has been shown to exert its effects by binding

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to the erythropoietin receptor (EpoR).[10][11]

EPO is highly glycosylated (40% of total molecular weight), with half-life in blood around five hours. EPO's half-life may vary between endogenous and various recombinant versions. Additional glycosylation or other alterations of EPO via recombinant technology have led to the increase of EPO's stability in blood (thus requiring less frequent injections). EPO binds to the erythropoietin receptor on the red cell progenitor surface and activates a JAK2 signaling cascade. This initiates the STAT5, PIK3 and Ras MAPK pathways. This results in differentiation, survival and proliferation of the erythroid cell.[12] SOCS1, SOCS3 and CIS are also expressed which act as negative regulators of the cytokine signal.[13] High level erythropoietin receptor expression is localized to erythroid progenitor cells. While there are reports that EPO receptors are found in a number of other tissues, such as heart, muscle, kidney and peripheral/central nervous tissue, those results are confounded by nonspecificity of reagents such as anti-EpoR antibodies. In controlled experiments, EPO receptor is not detected in those tissues. In the bloodstream, red cells themselves do not express erythropoietin receptor, so cannot respond to EPO. However,

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indirect dependence of red cell longevity in the blood on plasma erythropoietin levels has been reported, a process termed neocytolysis.[citation needed]

Synthesis and regulationErythropoietin levels in blood are quite low in the absence of anemia, at around 10 mU/ml. However, in hypoxic stress, EPO production may increase up to 1000-fold, reaching 10,000 mU/ml of blood. In adults, EPO is synthesized mainly by interstitial cells in the peritubular capillary bed of the renal cortex, with additional amounts being produced in the liver,[14][15][16] and the pericytes in the brain.[17] Regulation is believed to rely on a feedback mechanism measuring blood oxygenation and iron availability.[18] Constitutively synthesized transcription factors for EPO, known as hypoxia-inducible factors, are hydroxylated and proteosomally digested in the presence of oxygen and iron. During normoxia GATA2 inhibits the promoter region for EPO. GATA2 levels decrease during hypoxia and allow the promotion of EPO production.[19]

Medical uses

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Main article: Erythropoiesis-stimulating agentErythropoietins available for use as therapeutic agents are produced by recombinant DNA technology in cell culture, and include Epogen/Procrit (epoetin alfa) and Aranesp (darbepoetin alfa); they are used in treating anemia resulting from chronic kidney disease, chemotherapy induced anemia in patients with cancer, inflammatory bowel disease (Crohn's disease and ulcerative colitis)[20] and myelodysplasia from the treatment of cancer (chemotherapy and radiation). The package inserts include boxed warnings of increased risk of death, myocardial infarction, stroke, venous thromboembolism, and tumor recurrence, particularly when used to increase the hemoglobin levels to more than 11 to 12 g/dl.[6]

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Anemia of prematurityAnemia of prematurity refers to a form of anemia affecting preterm infants[1] with decreased hematocrit.

PathophysiologyPreterm infants are often anemic and typically experience heavy blood losses from frequent laboratory testing in the first few weeks of life. Although their anemia is multifactorial, repeated blood sampling and reduced erythropoiesis with extremely low serum levels of erythropoietin (EPO) are major determining factors.[3][4][5] Blood sampling done for laboratory testing can easily remove enough blood to produce anemia. Obladen, Sachsenweger and Stahnke (1987) studied 60 very low birth weight infants during the first 28 days of life. Infants were divided into 3 groups, group 1 (no ventilator support, 24 ml/kg blood loss), group 2(minor ventilated support, 60 ml/kg blood loss), and group 3(ventilated support for respiratory distress syndrome, 67 ml/kg blood loss). Infants were checked for clinical symptoms and laboratory signs of anemia 24 hours before and after the blood transfusion. The study found that groups 2 and 3 who had significant amount of blood loss, showed poor

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weight gain, pallor and distended abdomen. These reactions are the most frequent symptoms of anemia.[6]

During the first weeks of life, all infants experience a decline in circulating red blood cell (RBC) volume generally expressed as blood hemoglobin concentration (Hb).[7] As anemia develops, there is even more of a significant reduction in the concentration of hemoglobin.[8] Normally this stimulates a significant increased production of erythropoietin (EPO), but this response is diminished in premature infants. Dear, Gill, Newell, Richards and Schwarz (2005) conducted a study to show that there is a weak negative correlation between EPO and Hb. The researchers recruited 39 preterm infants from 10 days of age or as soon as they could manage without respiratory support. They estimated total EPO and Hb weekly and 2 days after a blood transfusion. The study found that when Hb>10, EPO mean was 20.6 and when Hb≤10, EPO mean was 26.8. As Hb goes down, EPO goes up.[9] While the reason for this decreased response is not fully understood, Strauss (n.d.) states that it results from both physiological factors (e.g., the rapid rate of growth and need for a commensurate increase in RBC mass to accompany the increase in blood volume) and, in sick

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premature infants, from phlebotomy blood losses. In premature infants this decline occurs earlier and more pronounced that it does in healthy term infants. Healthy term infants Hb rarely falls below 9 g/dL at an age of approximately 10–12 weeks, while in premature infants, even in those without complicating illnesses, the mean Hb falls to approximately 8g/dL in infants of 1.0-1.5 kg birth weight and to 7g/dL in infants <1.0 kg. Because this postnatal drop in hemoglobin level is universal and is well tolerated in term infants, it is commonly referred to as the “physiologic” anemia of infancy. However, in premature infants the decline in Hb may be associated with abnormal clinical signs severe enough to prompt transfusions.

TreatmentTransfusionAOP is usually treated by blood transfusion but the indications for this are still unclear. Blood transfusions have the risk of incompatibility and transfusion reactions as well as viral infections. Also, blood transfusions are costly and add to parental anxiety. The best treatment in prevention is minimizing the amount of blood drawn from the infant. It is found that since blood loss attributable to laboratory testing

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is the primary cause of anemia among preterm infants during the first weeks of life, we quantified blood lost attributable to phlebotomy overdraw, something that might be avoided. A study was done to see when and if overdraw was a problem. They recorded all of the data that could be of influence such as the test performed, the blood collection container used, the infants location (neonatal intensive care unit (NICU) and intermediate intensive care unit), the infant’s weight sampling and the phlebotomist’s level of experience, work shift, and clinical role. Infants were classified by weight into 3 groups: <1 kg, 1 to 2 kg, and >2 kg. The volume of blood removed was calculated by subtracting the weight of the empty collection container from that of the container filled with blood. They found that the mean volume of blood drawn for the 578 tests exceeded that requested by the hospital laboratory by 19.0% ± 1.8% per test. The main factors of overdraw was: collection in blood containers without fill-lines, lighter weight infants and critically ill infants being cared for in the NICU.[citation needed]

EPO

Recombinant EPO (r-EPO) may be given to premature

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infants to stimulate red blood cell production. Brown and Keith (1999) studied two groups of 40 very low birth weight (VLBW) infants to compare the erythropoietic response between two and five times a week dosages of recombinant human erythropoietin (r-EPO) using the same dose. They established that more frequent dosing of the same weekly amount of r-EPO generated a significant and continuous increase in Hb in VLBW infants. The infants that received five dosages had 219,857 mm³ while infants that received two dosages only had 173,361 mm³. However, the response to r-EPO typically takes up to two weeks and the higher dosages lead to higher Hb. Brown and Keith (1999) study also showed responses between two dosage schedules (two times a week and five times a week). Infants were recruited for gestational age—age since conception—≤27 weeks and 28 to 30 weeks and then randomized into the two groups, each totaling 500 U/kg a week. Brown and Keith found that after two weeks of r-EPO administration, Hb counts had increased and leveled off; the infants who received r-EPO five times a week had significantly higher Hb counts. This was present at four weeks for all infants ≤30 weeks gestation and at 8 weeks for infants ≤27 weeks gestation.[10]

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To date, studies of r-EPO use in premature infants have had mixed results. Ohls et al. examined the use of early r-EPO plus iron and found no short-term benefits in two groups of infants (172 infants less than 1000 g and 118 infants 1000–1250 g). All r-EPO treated infants received 400 U/g three times a week until they reached 35 weeks gestational age. The use of r-EPO did not decrease the average number of transfusions in the infants born at less than 1000 g, or the percentage of infants in the 1000 to 1250 group. A multi-center European trial studied early versus late r-EPO in 219 infants with birth weights between 500 and 999 g. An r-EPO close of 750 U/kg/week was given to infants in both the early (1–9 weeks) and late (4–10 weeks) groups. The two r-EPO groups were compared to a control group who did not receive r-EPO. Infants in all three groups received 3 to 9 mg/kg of enteral iron. These investigators reported a slight decrease in transfusion and donor exposures in the early r-EPO group (1–9 weeks): 13% early, 11% late and 4% control group.[11] It is likely that only a carefully selected subpopulation of infants may benefit from its use. Contrary to what just said, Bain and Blackburn (2004) also state in another study the use of r-EPO does not appear to have a significant effect on reducing the

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numbers of early transfusions in most infants, but may be useful to reduce numbers of late transfusion in extremely low-birth-weight infants. A British task force to establish transfusion guidelines for neonates and young children and to help try to explain this confusion recently concluded that “the optimal dose, timing, and nutritional support required during EPO treatment has yet to be defined and currently the routine use of EPO in this patient population is not recommended as similar reduction in blood use can probably be achieved with appropriate transfusion protocols.”[citation needed]

Transfusion managementOther strategies involve the reduction of blood loss during phlebotomy.[12]

Another treatment used is therapeutic strategies. These strategies are aimed at reducing transfusions have assessed the use of strict blood transfusions guidelines and EPO therapy, but reduction of blood loss is most important.[citation needed] For extremely low birth weight infants, laboratory blood testing using bedside devices offers a unique opportunity to reduce blood transfusions. This practice has been referred to as point-of-care testing. Use of

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these kind of devices to measure the most common ordered blood tests could significantly decrease phlebotomy loss and lead to a reduction in the need for blood transfusions among critically ill premature neonates. A study was done by Adams, Benitz, Geaghan, Kumar, Madan and Widness (2005) to test this theory by conducting a retrospective chart review on all inborn infants <1000g admitted to the NICU during two separate years. Conventional bench top laboratory analysis during the first year was done using Radiometer Blood Gas and Electrolyte Analyzer. Bedside blood gas analysis during the second year was performed using a point-of-care analyzer. An estimated blood loss in the two groups was determined based on the number of specific blood tests on individual infants. The study found that there was an estimated 30% reduction in the total volume of blood removed for the blood tests. This study concluded that there is modern technology that can be used instead of blood transfusions and r-EPO.

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Aplastic anemiaPage issuesAplastic anemia is a rare disease in which the bone marrow and the hematopoietic stem cells that reside there are damaged.[1] This causes a deficiency of all three blood cell types (pancytopenia): red blood cells (anemia), white blood cells (leukopenia), and platelets (thrombocytopenia).[2][3] Aplastic refers to inability of the stem cells to generate mature blood cells.

It is most prevalent in people in their teens and twenties, but is also common among the elderly. It can be caused by heredity, immune disease, or exposure to chemicals, drugs, or radiation. However, in about half the cases, the cause is unknown.[2][3]

The definitive diagnosis is by bone marrow biopsy; normal

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bone marrow has 30–70% blood stem cells, but in aplastic anemia, these cells are mostly gone and replaced by fat.[2][3]

First line treatment for aplastic anemia consists of immunosuppressive drugs, typically either anti-lymphocyte globulin or anti-thymocyte globulin, combined with corticosteroids and ciclosporin. Hematopoietic stem cell transplantation is also used, especially for patients under 30 years of age with a related matched marrow donor.[2][3]

Signs and symptomsAnemia may lead to malaise, pallor and associated symptoms such as palpitations.[4]

Low platelet counts (thrombocytopenia) if present is associated with an increased risk of hemorrhage, bruising and petechiae. Low white blood cell counts (leukocytopenia) if present leads to an increased risk of infections which can be severe.[4]

A world famous case of Aplastic anemia struck the Fleay Family, in Perth, Western Australia. On April 19, 1946, William Arnold Fleay died after receiving 192 pints of blood on a regular basis, in order to keep him alive.

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CausesAplastic anemia can be caused by exposure to certain chemicals, drugs, radiation, infection, immune disease; in about half the cases, yet a defintive cause is unknown. It is not a familial line hereditary condition, nor is it contagious. It can be acquired due to exposure to other conditions but if a person develops the condition, their offspring would not develop it by virtue of their gene connection.[2][3]

Aplastic anemia is also sometimes associated with exposure to toxins such as benzene, or with the use of certain drugs, including chloramphenicol, carbamazepine, felbamate, phenytoin, quinine, and phenylbutazone. Many drugs are associated with aplasia mainly according to case reports, but at a very low probability. As an example, chloramphenicol treatment is followed by aplasia in less than one in 40,000 treatment courses, and carbamazepine aplasia is even rarer.[citation needed]

Exposure to ionizing radiation from radioactive materials or radiation-producing devices is also associated with the development of aplastic anemia. Marie Curie, famous for her pioneering work in the field of radioactivity, died of aplastic

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anemia after working unprotected with radioactive materials for a long period of time; the damaging effects of ionizing radiation were not then known.[5]

Aplastic anemia is present in up to 2% of patients with acute viral hepatitis.[6]

One known cause is an autoimmune disorder in which white blood cells attack the bone marrow.[citation needed]

Short-lived aplastic anemia can also be a result of parvovirus infection.[7] In humans, the P antigen (also known as globoside), one of the many cellular receptors that contribute to a person's blood type, is the cellular receptor for parvovirus B19 virus that causes erythema infectiosum (fifth disease) in children. Because it infects red blood cells as a result of the affinity for the P antigen, Parvovirus causes complete cessation of red blood cell production. In most cases, this goes unnoticed, as red blood cells live on average 120 days, and the drop in production does not significantly affect the total number of circulating red blood cells. In people with conditions where the cells die early (such as sickle cell disease), however, parvovirus infection can lead to severe anemia.[citation needed]

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More frequently parvovirus B19 is associated with aplastic crisis which involves only the red blood cells ( despite the name). Aplastic anemia involves all different cell lines.

In some animals, aplastic anemia may have other causes. For example, in the ferret (Mustela putorius furo), it is caused by estrogen toxicity, because female ferrets are induced ovulators, so mating is required to bring the female out of heat. Intact females, if not mated, will remain in heat, and after some time the high levels of estrogen will cause the bone marrow to stop producing red blood cells.[citation needed]

DiagnosisThe condition needs to be differentiated from pure red cell aplasia. In aplastic anemia, the patient has pancytopenia (i.e., leukopenia and thrombocytopenia) resulting in decrease of all formed elements. In contrast, pure red cell aplasia is characterized by reduction in red cells only. The diagnosis can only be confirmed on bone marrow examination. Before this procedure is undertaken, a patient will generally have had other blood tests to find diagnostic clues, including a

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complete blood count, renal function and electrolytes, liver enzymes, thyroid function tests, vitamin B12 and folic acid levels.

The following tests aid in determining differential diagnosis for aplastic anemia:

1. Bone marrow aspirate and biopsy: to rule out other causes of pancytopenia (i.e. neoplastic infiltration or significant myelofibrosis).

2. History of iatrogenic exposure to cytotoxic chemotherapy: can cause transient bone marrow suppression

3. X-rays, computed tomography (CT) scans, or ultrasound imaging tests: enlarged lymph nodes (sign of lymphoma), kidneys and bones in arms and hands (abnormal in Fanconi anemia)

4. Chest X-ray: infections5. Liver tests: liver diseases6. Viral studies: viral infections7. Vitamin B12 and folate levels: vitamin deficiency8. Blood tests for paroxysmal nocturnal hemoglobinuria9. Test for antibodies: immune competency

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TreatmentTreating immune-mediated aplastic anemia involves suppression of the immune system, an effect achieved by daily medicine intake, or, in more severe cases, a bone marrow transplant, a potential cure.[8] The transplanted bone marrow replaces the failing bone marrow cells with new ones from a matching donor. The multipotent stem cells in the bone marrow reconstitute all three blood cell lines, giving the patient a new immune system, red blood cells, and platelets. However, besides the risk of graft failure, there is also a risk that the newly created white blood cells may attack the rest of the body ("graft-versus-host disease"). In young patients with an HLA matched sibling donor, bone marrow transplant can be considered as first-line treatment, patients lacking a matched sibling donor typically pursue immunosuppression as a first-line treatment, and matched unrelated donor transplants are considered a second-line therapy.

Medical therapy of aplastic anemia often includes a course of antithymocyte globulin (ATG) and several months of treatment with ciclosporin to modulate the immune system. Chemotherapy with agents such as cyclophosphamide may

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also be effective but has more toxicity than ATG. Antibody therapy, such as ATG, targets T-cells, which are believed to attack the bone marrow. Corticosteroids are generally ineffective,[citation needed] though they are used to ameliorate serum sickness caused by ATG. Normally, success is judged by bone marrow biopsy 6 months after initial treatment with ATG.[9]

One prospective study involving cyclophosphamide was terminated early due to a high incidence of mortality, due to severe infections as a result of prolonged neutropenia.[9]

In the past, before the above treatments became available, patients with low leukocyte counts were often confined to a sterile room or bubble (to reduce risk of infections), as in the case of Ted DeVita.[10]

Follow-upRegular full blood counts are required on a regular basis to determine whether the patient is still in a state of remission.

Many patients with aplastic anemia also have clones of cells characteristic of the rare disease paroxysmal nocturnal hemoglobinuria (PNH, anemia with thrombopenia and/or

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thrombosis), sometimes referred to as AA/PNH. Occasionally PNH dominates over time, with the major manifestation intravascular hemolysis. The overlap of AA and PNH has been speculated to be an escape mechanism by the bone marrow against destruction by the immune system. Flow cytometry testing is performed regularly in people with previous aplastic anemia to monitor for the development of PNH.

PrognosisUntreated, severe aplastic anemia has a high risk of death. Modern treatment, by drugs or stem cell transplant, has a five-year survival rate that exceeds 85%, with younger age associated with higher survival.[11]

Survival rates for stem cell transplant vary depending on age and availability of a well-matched donor. Five-year survival rates for patients who receive transplants have been shown to be 82% for patients under age 20, 72% for those 20–40 years old, and closer to 50% for patients over age 40. Success rates are better for patients who have donors that are matched siblings and worse for patients who receive their marrow from unrelated donors.[12]

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Older people (who are generally too frail to undergo bone marrow transplants), and people who are unable to find a good bone marrow match, undergoing immune suppression have five-year survival rates of up to 75%.[citation needed]

Relapses are common. Relapse following ATG/ciclosporin use can sometimes be treated with a repeated course of therapy. In addition, 10-15% of severe aplastic anemia cases evolve into MDS and leukemia.[citation needed] According to a study, for children who underwent immunosuppressive therapy, about 15.9% of children who responded to immunosuppressive therapy encountered relapse.[13]

Milder disease can resolve on its own.

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Autoimmune hemolytic anemiaAutoimmune hemolytic anemia (or autoimmune haemolytic anaemia; AIHA) occurs when antibodies directed against the person's own red blood cells (RBCs) cause them to burst (lyse), leading to an insufficient number of oxygen-carrying red blood cells in the circulation. The lifetime of the RBCs is reduced from the normal 100–120 days to just a few days in serious cases.[1][2] The intracellular components of the RBCs are released into the circulating blood and into tissues, leading to some of the characteristic symptoms of this condition. The antibodies are usually directed against high-incidence antigens, therefore they also commonly act on allogenic RBCs (RBCs originating from outside the person themselves, e.g. in the case of a blood transfusion).[3] AIHA is a relatively rare condition, affecting one to three people per 100,000 per year.

Autoimmune hemolytic anemia (or autoimmune haemolytic anaemia; AIHA) occurs when antibodies directed against the person's own red blood cells (RBCs) cause them to burst (lyse), leading to an insufficient

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number of oxygen-carrying red blood cells in the circulation. The lifetime of the RBCs is reduced from the normal 100–120 days to just a few days in serious cases.[1][2] The intracellular components of the RBCs are released into the circulating blood and into tissues, leading to some of the characteristic symptoms of this condition. The antibodies are usually directed against high-incidence antigens, therefore they also commonly act on allogenic RBCs (RBCs originating from outside the person themselves, e.g. in the case of a blood transfusion).[3] AIHA is a relatively rare condition, affecting one to three people per 100,000 per year.

ClassificationAIHA is classified as either warm autoimmune hemolytic anemia or cold autoimmune hemolytic anemia, which includes cold agglutinin disease and paroxysmal cold hemoglobinuria. These classifications are based on the characteristics of the autoantibodies involved in the pathogenesis of the disease. Each has a different underlying cause, management, and prognosis, making classification important when treating a patient with AIHA.

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CausesThe causes of AIHA are poorly understood. The disease may be primary, or secondary to another underlying illness. The primary illness is idiopathic (the two terms used synonymously). Idiopathic AIHA accounts for approximately 50% of cases.[9] Secondary AIHA can result from many other illnesses. Warm and cold type AIHA each have their own more common secondary causes. The most common causes of secondary warm-type AIHA include lymphoproliferative disorders (e.g., chronic lymphocytic leukemia, lymphoma) and other autoimmune disorders (e.g., systemic lupus erythematosus, rheumatoid arthritis, scleroderma, crohn's disease, ulcerative colitis). Less common causes of warm-type AIHA include neoplasms other than lymphoid, and infection. Secondary cold type AIHA is also caused primarily by lymphoproliferative disorders, but is also commonly caused by infection, especially by mycoplasma, viral pneumonia, infectious mononucleosis, and other respiratory infections. Less commonly, it can be caused by concomitant autoimmune disorders.[10]

Drug-induced AIHA, though rare, can be caused by a number

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of drugs, including α-methyldopa and penicillin. This is a type II immune response in which the drug binds to macromolecules on the surface of the RBCs and acts as an antigen. Antibodies are produced against the RBCs, which leads to complement activation. Complement fragments, such as C3a, C4a and C5a, activate granular leukocytes (e.g., neutrophils), while other components of the system (C6, C7, C8, C9) either can form the membrane attack complex (MAC) or can bind the antibody, aiding phagocytosis by macrophages (C3b). This is one type of "penicillin allergy".

DiagnosisDiagnosis is made by first ruling out other causes of hemolytic anemia, such as G6PD, thalassemia, sickle-cell disease, etc. Clinical history is also important to elucidate any underlying illness or medications that may have led to the disease.

Following this, laboratory investigations are carried out to determine the etiology of the disease. A positive DAT test has poor specificity for AIHA (having many differential diagnoses); so supplemental serological testing is required to ascertain the cause of the positive reaction. Hemolysis must

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also be demonstrated in the lab. The typical tests used for this are a complete blood count (CBC) with peripheral smear, bilirubin, lactate dehydrogenase (LDH) (in particular with isoenzyme 1), haptoglobin and urine hemoglobin.[3]

Evidence for hemolysisThe following findings maybe present:[12][full citation needed]

Increased red cell breakdown Elevated serum bilirubin (unconjugated) Excess urinary urobilinogen Reduced plasma haptoglobin Raised serum lactic dehydrogenase (LDH) Hemosiderinuria Methemalbuminemia Spherocytosis Increased red cell production: Reticulocytosis Erythroid hyperplasia of the bone marrow Specific investigations Positive direct Coombs test

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Much literature exists regarding the treatment of AIHA. Efficacy of treatment depends on the correct diagnosis of either warm- or cold-type AIHA.

Warm-type AIHA is usually a more insidious disease, not treatable by simply removing the underlying cause. Corticosteroids are first-line therapy. For those who fail to respond or have recurrent disease, splenectomy may be considered. Other options for recurrent or relapsed disease include immunosuppressants such as rituximab, danazol, cyclophosphamide, azathioprine, or cyclosporine.

Cold agglutinin disease is treated with avoidance of cold exposure. Patients with more severe disease (symptomatic anemia, transfusion dependence) may be treated with rituximab. Steroids and splenectomy are less efficacious in cold agglutinin disease.[13]

Paroxysmal cold hemoglobinuria is treated by removing the underlying cause, such as infection.

In childrenIn general, AIHA in children has a good prognosis and is

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self-limiting. However, if it presents within the first two years of life or in the teenage years, the disease often follows a more chronic course, requiring long-term immunosuppression, with serious developmental consequences. The aim of therapy may sometimes be to lower the use of steroids in the control of the disease. In this case, splenectomy may be considered, as well as other immunosuppressive drugs. Infection is a serious concern in patients on long-term immunosuppressant therapy, especially in very young children (less than two years).

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Beta thalassemiaBeta thalassemias (β thalassemias) are a group of inherited blood disorders. They are forms of thalassemia caused by reduced or absent synthesis of the beta chains of hemoglobin that result in variable outcomes ranging from severe anemia to clinically asymptomatic individuals. Global annual incidence is estimated at one in 100,000.[1] Beta thalassemias are caused by mutations in the HBB gene on chromosome 11, inherited in an autosomal recessive fashion. The severity of the disease depends on the nature of the mutation.

HBB blockage over time leads to decreased beta-chain synthesis. The body's inability to construct new beta-chains leads to the underproduction of HbA.[3] Reductions in HbA available overall to fill the red blood cells in turn leads to microcytic anemia. Microcytic anemia ultimately develops in respect to inadequate HBB protein for sufficient red blood cell functioning.[4] Due to this factor, the patient may require blood transfusions to make up for the blockage in the beta-chains. Repeated blood

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transfusions can lead to build-up of iron overload, ultimately resulting in iron toxicity. This iron toxicity can cause various problems, including myocardial siderosis and heart failure leading to the patient’s death.

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The hand of a person with severe anemia (left, wearing ring) compared to one withoutThree main forms have been described: thalassemia major, thalassemia intermedia, and thalassemia minor. All people with thalassemia are susceptible to health complications that involve the spleen (which is often enlarged and frequently removed) and gallstones.[6] These complications are mostly found in thalassemia major and intermedia patients. Individuals with beta thalassemia major usually present within the first two years of life with severe anemia, poor growth, and skeletal abnormalities during infancy. Untreated thalassemia major eventually leads to death, usually by heart failure; therefore, birth screening is very important.[7]

Excess iron causes serious complications within the liver, heart, and endocrine glands. Severe symptoms include liver cirrhosis, liver fibrosis, and in extreme cases, liver cancer.[8] Heart failure, growth impairment, diabetes and osteoporosis are life-threatening contributors brought upon by TM.[9] The main cardiac abnormalities seen to have resulted from thalassemia and iron overload include left

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ventricular systolic and diastolic dysfunction, pulmonary hypertension, valveulopathies, arrhythmias, and pericarditis. Increased gastrointestinal iron absorption is seen in all grades of beta thalassemia and increased red blood cell destruction by the spleen due to ineffective erythropoiesis further releases additional iron into the bloodstream.

CauseMutationsTwo major groups of mutations can be distinguished:

Nondeletion forms: These defects, in general, involve a single base substitution or small insertions near or upstream of the β globin gene. Most often, mutations occur in the promoter regions preceding the beta-globin genes. Less often, abnormal splice variants are believed to contribute to the disease.[11]Deletion forms: Deletions of different sizes involving the β globin gene produce different syndromes such as (βo) or hereditary persistence of fetal hemoglobin syndromes.

Name Description

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Thalassemia minor Heterozygous form: Only one of β globin alleles bears a mutation. Individuals will suffer from microcytic anemia. Detection usually involves lower than normal mean corpuscular volume value (<80 fL).

Thalassemia intermedia

Affected individuals can often manage a normal life but may need occasional transfusions, e.g., at times of illness or pregnancy, depending on the severity of their anemia.

Thalassemia major Homozygous form: Occurs when both alleles have thalassemia mutations. This is a severe microcytic, hypochromic anemia. Untreated, it causes anemia, splenomegaly and severe bone deformities. It progresses to death before age 20. Treatment consists of periodic blood transfusion; splenectomy for splenomegaly and chelation of transfusion-related iron overload.

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mRNA assembly

Protein HBB PDB 1a00: this is a healthy Beta Globin ProteinBeta thalassemia is a hereditary disease affecting hemoglobin. As with about half of all hereditary diseases,[16] an inherited mutation damages the assembly of the messenger-type RNA (mRNA) that is transcribed from a chromosome. DNA contains both the instructions (genes) for stringing amino acids together into proteins, as well as stretches of DNA that play important roles in regulating produced protein levels.[17]

In thalassemia, an additional, contiguous length or a discontinuous fragment of non-coding instructions are included in the mRNA. This happens because the mutation

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obliterates the boundary between the intronic and exonic portions.[18] Because all the coding sections may still be present, normal hemoglobin may be produced and the added material, if it produces pathology, instead disrupts regulatory functions enough to produce anemia.Hemoblogin's normal alpha and beta subunits each have an iron-containing central portion (heme) that allows the protein chain of a subunit to fold around it. Normal adult hemoglobin contains 2 alpha and 2 beta subunits.[19] Thalassemias typically affect only the mRNAs for production of the beta chains (hence the name). Since the mutation may be a change in only a single base (a "Single Nucleotide Polymorphism"), on-going efforts seek gene therapies to make that single correction.

Risk FactorsFamily history and ancestry are factors that increase the risk of beta thalassemia. Depending on your family history, if your parents or grandparents suffered from beta thalassemia there is a high probability of the mutated gene being inherited by an offspring. Even if a child does not have beta thalassemia major, they can still be a carrier

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resulting in future offspring having beta thalassemia. Another risk factor is because of certain ancestry. Beta thalassemia occurs most often in people of Italian, Greek, Middle Eastern, Southern Asian, and African ancestry.

DiagnosisAbdominal pain due to hypersplenism and splenic infarction and right-upper quadrant pain caused by gallstones are major clinical manifestations. However, diagnosing thalassemiæ from symptoms alone is inadequate. Physicians note these signs as associative due to this disease's complexity.[23] The following associative signs can attest to the severity of the phenotype: pallor, poor growth, inadequate food intake, splenomegaly, jaundice, maxillary hyperplasia, dental malocclusion, cholelithiasis, systolic ejection murmur in the presence of severe anemia and pathologic fractures. Based on symptoms, tests are ordered for a differential diagnosis. These tests include complete blood count; hemoglobin electrophoresis; serum transferrin, ferritin, total iron-binding capacity; urine urobilin and urobilogen; peripheral blood smear, which may show codocytes, or target cells;[24] hematocrit; and serum bilirubin.[25][26]

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DNA analysisAll beta thalassemias may exhibit abnormal red blood cells, a family history is followed by DNA analysis.[27] This test is used to investigate deletions and mutations in the alpha- and beta-globin-producing genes. Family studies can be done to evaluate carrier status and the types of mutations present in other family members. DNA testing is not routine, but can help diagnose thalassemia and determine carrier status. In most cases the treating physician uses a clinical prediagnosis assessing anemia symptoms: fatigue, breathlessness and poor exercise tolerance.[28] Further genetic analysis may include HPLC should routine electrophoresis prove difficult.

PreventionBeta thalassemia is a hereditary disease allowing for a preventative treatment by carrier screening and prenatal diagnosis. It can be prevented if one parent has normal genes, giving rise to screenings that empower carriers to select partners with normal hemoglobin. A study aimed at detecting the genes that could give rise to offspring with sickle cell disease. Patients diagnosed with beta thalassemia have MCH ≤ 26 pg and an RDW < 19. Of 10,148 patients, 1,739 patients

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had a hemoglobin phenotype and RDW consistent with beta thalassemia. After the narrowing of patients, the HbA2 levels were tested presenting 77 patients with beta thalassemia.[29] This screening procedure proved insensitive in populations of West African ancestry because of the indicators has high prevalence of alpha thalassemia. Countries have programs distributing information about the reproductive risks associated with carriers of haemoglobinopathies. Thalassemia carrier screening programs have educational programs in schools, armed forces, and through mass media as well as providing counseling to carriers and carrier couples.[30] Screening has showed reduced incidence; by 1995 the prevalence in Italy reduced from 1:250 to 1:4000, and a 95% decrease in that region. The decrease in incidence has benefitted those affected with thalassemia, as the demand for blood has decreased, therefore improving the supply of treatment.

TreatmentBeta thalassemia major

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Surgically removed spleen of a Thalassemic child. It is about 15 times larger than normal.Affected children require regular lifelong blood transfusion and can have complications, which may involve the spleen. Bone marrow transplants can be curative for some children.[31] Patients receive frequent blood transfusions that lead to or potentiate iron overload.[32] Iron chelation treatment is necessary to prevent damage to internal organs. Advances in iron chelation treatments allow patients with thalassemia major to live long lives with access to proper treatment. Popular chelators include deferoxamine and deferiprone.[33][34]

The most common patient deferoxamine complaint is that they are painful and inconvenient. The oral chelator deferasirox was approved for use in 2005 in some countries,

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[35][36] it offers some hope with compliance at a higher cost. Bone marrow transplantation is the only cure and is indicated for patients with severe thalassemia major. Transplantation can eliminate a patient's dependence on transfusions. Absent a matching donor, a savior sibling can be conceived by preimplantation genetic diagnosis (PGD) to be free of the disease as well as to match the recipient's human leukocyte antigen (HLA) type.[37]

Scientists at Weill Cornell Medical College have developed a gene therapy strategy that could feasibly treat both beta-thalassemia and sickle cell disease. The technology is based on delivery of a lentiviral vector carrying both the human β-globin gene and an ankyrin insulator to improve gene transcription and translation, and boost levels of β-globin production.[38]

SurgicalPatients with thalassemia major are more inclined to have a splenectomy. The medical cases of splenectomies have been declining in recent years due to decreased prevalence of hypersplenism in adequately transfused patients. Patients with hypersplenism are inclined to have a lower amount of

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healthy blood cells in their body than normal and reveal symptoms of anemia. Iron rich patients need a splenectomy to reduce the probability of an iron overload. The different surgical techniques are the open and laparoscopic method.[39] The laparoscopic method requires longer operating time but a shorter recovery period with no surgical scar. If it is unnecessary to remove the entire spleen a partial splenectomy may occur; this method preserves some of the immune function while reducing the probability of hypersplenism. Surgeons who chose Laparoscopic splenectomy must administer an appropriate immunization at least two weeks before the surgery. On the operating table the patient must be placed at a 30˚ to 40˚ position with his or her left arm elevated above the head to properly make the incision. The camera is inserted along with four other trocars: one placed in the left subcostal area, one inserted at the midpoint between the first and third, one 4 cm right of the midline, and the fourth positioned on the midline to retract the spleen.[40] Removing the spleen, an organ in under a person’s rib cage on the upper left side of its abdominal, allows the body to regulate the correct amount of healthy cells in the body.

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TherapeuticLong-term transfusion therapy to maintain the patient’s hemoglobin level above 9-10 g/dL (normal levels are 13.8 for males, and 12.1 for females). Patients are transfused by meeting strict criteria ensuring their safety. They must have: confirmed laboratory diagnosis of thalassemia major, and hemoglobin levels less than 7g/dL, to be eligible for the transfusion. To ensure quality blood transfusions, the packed red blood cells should be leucoreduced with a minimum of 40g of hemoglobin content. By having leucoreduced blood packets, the patient is at a lower risk to develop adverse reactions by contaminated white cells and preventing platelet alloimmunisation.[41] Pre-storage filtration of whole blood offers high efficiency for removal and low residual of leukocytes; It is the preferred method of leucoreduction compared to pre-transfusion and bedside filtration. Patients with allergic transfusion reactions or unusual red cell antibodies must received “washed red cells” or “cryopreserved red cells.” Washed red cells have been removed of plasma proteins that would have become a target of the patient’s antibodies allowing the transfusion to be carried out safely. Cryopreserved red cells are used to

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maintain a supply of rare donor units for patients with unusual red cell antibodies or missing common red cell antigens. The transfusion programs available involve lifelong regular blood transfusion to main the pre-transfusion hemoglobin level above 9-10 g/gL.[39] The monthly transfusions promote normal growth, physical activities, suppress bone marrow activity, and minimize iron accumulation.

PharmaceuticalIron overload is an unavoidable consequence of chronic transfusion therapy, necessary for patients with beta thalassemia. Iron chelation is a medical therapy that avoids the complications of iron overload. The iron overload can be removed by Deferasirox, an oral iron chelator, which has a dose- dependent effect on iron burden. Every unit of transfused blood contains 200–250 mg of iron and the body has no natural mechanism to remove excess iron Deferasirox is a vital part in the patients health after blood transfusions.[42] During normal iron homeostasis the circulating iron is bound to transferrin, but with an iron overload, the ability for transferrin to bind iron is exceeded and non-transferrin bound iron is formed. It represents a potentially toxic iron form due

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to its high propensity to induce oxygen species and is responsible for cellular damage. The prevention of iron overload protects patients from morbidity and mortality. The primary aim is to bind to and remove iron from the body and a rate equal to the rate of transfusional iron input or greater than iron input.[43] During clinical trails patients that received Deferasirox experienced no drug-related neutropenia or agranulocytosis, which was present with other iron chelators. Its long half life requires it to be taken once daily and provides constant chelation. Cardiac failure is a main cause of illness from transfusional iron overload but deferasirox demonstrated the ability to remove iron from iron-loaded myocardial cells protecting beta thalassemia patients from effects of required blood transfusions.

Beta thalassemia intermediaPatients may require episodic blood transfusions. Transfusion-dependent patients develop iron overload and require chelation therapy[44] to remove the excess iron. Transmission is autosomal recessive; however, dominant mutations and compound heterozygotes have been reported. Genetic counseling is recommended and prenatal diagnosis may be offered.[45] Alleles without a mutation that reduces

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function are characterized as (β). Mutations are characterized as (βo) if they prevent any formation of β chains,[46] mutations are characterized as (β+) if they allow some β chain formation to occur.

Beta thalassemia minorPatients are often monitored without treatment. While many of those with minor status do not require transfusion therapy, they still risk iron overload, particularly in the liver. A serum ferritin test checks iron levels and can point to further treatment.[47] Although not life-threatening on its own, it can affect quality of life due to the anemia. Minor often coexists with other conditions such as asthma and can cause iron overload of the liver and in those with non-alcoholic fatty liver disease, lead to more severe outcomes.

EpidemiologyThe beta form of thalassemia is particularly prevalent among the Mediterranean peoples and this geographical association is responsible for its naming: thalassa (θάλασσα) is the Greek word for sea and haema (αἷμα) is the Greek word for blood. In Europe, the highest concentrations of the disease are found in Greece and the Turkish coastal regions. The major

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Mediterranean islands (except the Balearics) such as Sicily, Sardinia, Corsica, Cyprus, Malta and Crete are heavily affected in particular.[49][50] Other Mediterranean peoples, as well as those in the vicinity of the Mediterranean, also have high incidence rates, including people from West Asia and North Africa. The data indicate that 15% of the Greek and Turkish Cypriots are carriers of beta-thalassaemia genes, while 10% of the population carry alpha-thalassaemia genes.[51]

Evolutionary adaptationThe thalassemia trait may confer a degree of protection against malaria,[52] which is or was prevalent in the regions where the trait is common, thus conferring a selective survival advantage on carriers (known as heterozygous advantage), thus perpetuating the mutation. In that respect, the various thalassemias resemble another genetic disorder affecting hemoglobin, sickle-cell disease.

IncidenceThe disorder affects all genders but is more prevalent in certain ethnicities and age groups. 20 people die per year causing thalassemia to be listed as a “rare disease”. In the

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United States, thalassemia’s prevalence is approximately 1 in 272,000 or 1,000 people. There have been 4,000 hospitalized cases in England in 2002 and 9,233 consultant episodes for thalassemia. Men accounted for 53% of hospital consultant episodes and women accounted for 47%. The mean patient age is 23 with only 1% of consultants the patient is older than 75 and 69% were 15-59 year olds. The Children’s Hospital Oakland formed an international network to combat thalassemia.[54] “It is the world’s most common genetic blood disorder and is rapidly increasing”. 7% of the world’s population are carriers and 400,000 babies are born with the trait annually. It is usually fatal in infancy if blood transfusion are not initiated immediately.

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Diamond–Blackfan anemia

Diamond–Blackfan anemia (DBA), also known as Blackfan-Diamond anemia, inherited pure red cell aplasia[1] and as inherited erythroblastopenia,[2] is a congenital erythroid aplasia that usually presents in infancy.[3] DBA causes low red blood cell counts (anemia), without substantially affecting the other blood components (the platelets and the white blood cells), which are usually normal. This is in contrast to Shwachman–Bodian–Diamond syndrome, in which the bone marrow defect results primarily in neutropenia, and Fanconi anemia, where all cell lines are affected resulting in pancytopenia.A variety of other congenital abnormalities may also occur in DBA.

Signs/symptomsDiamond–Blackfan anemia is characterized by normocytic or macrocytic anemia (low red blood cell counts) with decreased erythroid progenitor cells in the bone marrow. This usually develops during the neonatal period. About 47% of

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affected individuals also have a variety of congenital abnormalities, including craniofacial malformations, thumb or upper limb abnormalities, cardiac defects, urogenital malformations, and cleft palate. Low birth weight and generalized growth delay are sometimes observed. DBA patients have a modest risk of developing leukemia and other malignancies.

GeneticsMost pedigrees suggest an autosomal dominant mode of inheritance[1] with incomplete penetrance.[4] Approximately 10–25% of DBA occurs with a family history of disease.

About 25-50% of the causes of DBA have been tied to abnormal ribosomal protein genes.[1][5] The disease is characterized by genetic heterogeneity, affecting different ribosomal gene loci:[6] Exceptions to this paradigm have been demonstrated, such as with rare mutations of transcription factor GATA1[7][8] and advanced alternative splicing of a gene involved in iron metabolism, SLC49A1 (FLVCR1).In 1997, a patient was identified who carried a rare balanced chromosomal translocation involving chromosome 19 and

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the X chromosome. This suggested that the affected gene might lie in one of the two regions that were disrupted by this cytogenetic anomaly. Linkage analysis in affected families also implicated this region in disease, and led to the cloning of the first DBA gene. About 20–25% of DBA cases are caused by mutations in the ribosome protein S19 (RPS19) gene on chromosome 19 at cytogenetic position 19q13.2. Some previously undiagnosed relatives of DBA patients were found to carry mutations, and also had increased adenosine deaminase levels in their red blood cells, but had no other overt signs of disease.

A subsequent study of families with no evidence of RPS19 mutations determined that 18 of 38 families showed evidence for involvement of an unknown gene on chromosome 8 at 8p23.3-8p22.[19] The precise genetic defect in these families has not yet been delineated.

Malformations are seen more frequently with DBA6 RPL5 and DBA7 RPL11 mutations.[4]

The genetic abnormalities underpinning the combination of DBA with Treacher Collins syndrome (TCS)/mandibulofacial dysostosis (MFD) phenotypes are heterogeneous, including

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RPS26 (the known DBA10 gene), TSR2 which encodes a direct binding partner of RPS26, and RPS28.[18]

Molecular basisThe phenotype of DBA patients suggests a hematological stem cell defect specifically affecting the erythroid progenitor population. Loss of ribosomal function might be predicted to affect translation and protein biosynthesis broadly and impact many tissues. However, DBA is characterized by dominant inheritance, and arises from partial loss of ribosomal function, so it is possible that erythroid progenitors are more sensitive to this decreased function, while most other tissues are less affected.

Typically, a diagnosis of DBA is made through a blood count and a bone marrow biopsy.

A diagnosis of DBA is made on the basis of anemia, low reticulocyte (immature red blood cells) counts, and diminished erythroid precursors in bone marrow. Features that support a diagnosis of DBA include the presence of congenital abnormalities, macrocytosis, elevated fetal hemoglobin, and elevated adenosine deaminase levels in red blood cells.[20]

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Most patients are diagnosed in the first two years of life. However, some mildly affected individuals only receive attention after a more severely affected family member is identified.[citation needed]About 20–25% of DBA patients may be identified with a genetic test for mutations in the RPS19 gene.

TreatmentCorticosteroids can be used to treat anemia in DBA. In a large study of 225 patients, 82% initially responded to this therapy, although many side effects were noted.[21] Some patients remained responsive to steroids, while efficacy waned in others. Blood transfusions can also be used to treat severe anemia in DBA. Periods of remission may occur, during which transfusions and steroid treatments are not required. Bone marrow transplantation (BMT) can cure hematological aspects of DBA. This option may be considered when patients become transfusion-dependent because frequent transfusions can lead to iron overloading and organ damage. However, adverse events from BMTs may exceed those from iron overloading.[22] A 2007 study[23] showed the efficacy of leucine and isoleucine

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supplementation in one patient. Larger studies are being conducted.

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Congenital dyserythropoietic anemiaCongenital dyserythropoietic anemia (CDA) is a rare blood disorder, similar to the thalassemias. CDA is one of many types of anemia, characterized by ineffective erythropoiesis, and resulting from a decrease in the number of red blood cells (RBCs) in the body and a less than normal quantity of hemoglobin in the blood.[1]

Signs/

symptomsThe symptoms and signs of congenital dyserythropoietic anemia are consistent with:[1]

1. Tiredness (fatigue)2. Weakness3. Pale skin

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Congenital dyserythropoietic anemia type I-is defined by moderate to severe macrocytic anemia (commonly in neonates as intrauterine growth retardation).[2]

Congenital dyserythropoietic anemia type II-is defined by moderate anemia, splenomegaly,and hepatomegaly.[3]

Congenital dyserythropoietic anemia type III- is defined by mild anemia and retinal degeneration.[3]

Congenital dyserythropoietic anemia type IV- is defined by having severe anemia at birth (type V and VI are recognized).

GeneticsCDA may be transmitted by both parents autosomal recessively or dominantly and has over four different subtypes, but CDA Type I, CDA Type II, CDA Type III, and CDA Type IV are the most common. CDA type II (CDA II) is the most frequent type of congenital dyserythropoietic anemias. More than 300 cases have been described, but with the exception of a report by the International CDA II Registry, these reports include only small numbers of cases and no data on the lifetime

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evolution of the disease.

DiagnosisThe diagnosis of congenital dyserythropoietic anemia can be done via sequence analysis of the entire coding region, types I,[12] II,[13] III[14] and IV ( is a relatively new form of CDA that had been found, just 4 cases have been reported[5]) according to the genetic testing registry.

Treatment

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DeferasiroxTreatment of individuals with CDA usually consist of frequent blood transfusions, but this can vary depending on the type that the individual has.[15] Patients report going every 2–3 weeks for blood transfusions.[11] In addition, they must undertake chelation therapy to survive;[16] either deferoxamine, deferasirox, or deferiprone to eliminate the excess iron that accumulates.[17] Removal of the spleen[18] and gallbladder[19] are common. Hemoglobin levels can run anywhere between 8.0 g/dl and 11.0 g/dl in untransfused patients, the amount of blood received by the patient is not as important as their baseline pre-transfusion hemoglobin level.[20] This is true for ferritin levels and iron levels in the organs as well, it is important for patients to go regularly for transfusions in order to maximize good health, normal ferritin levels run anywhere between 24 and 336 ng/ml,[21] hematologists generally do not begin chelation therapy until ferritin levels reach at least 1000 ng/ml.[22] It is more important to check iron levels in the organs through MRI scans, however, than to simply get regular blood tests to check ferritin levels,

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which only show a trend, and do not reflect actual organ iron content.[17]

Gene therapyGene therapy, as well as, bone marrow transplant are also possible treatments for the disorder, but each have their own risks at this point in time. Bone marrow transplantation is the more used method between the two, whereas researchers are still trying to definitively establish the results of gene therapy treatment. It generally requires a 10/10 HLA matched donor, however, who is usually a sibling. As most patients do not have this, they must rely on gene therapy research to potentially provide them with an alternative.[medical citation needed] CDA at both clinical and genetic aspects are part of a heterogeneous group of genetic conditions. Gene therapy is still experimental and has largely only been tested in animal models until now. This type of therapy has promise, however, as it allows for the autologous transplantation of the patient's own healthy stem cells rather than requiring an outside donor, thereby bypassing any potential for graft vs. host disease (GVHD).[19][23]

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In the United States, the FDA approved clinical trials on Beta thalassemia patients in 2012. The first study, which took place in July 2012, recruited human subjects with thalassemia major,[24] and ended in 2014.

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Drug-induced autoimmune hemolytic anemia

Drug-induced autoimmune hemolytic anemia is a form of hemolytic anemia.In some cases, a drug can cause the immune system to mistakenly think the body's own red blood cells are dangerous, foreign substances. Antibodies then develop against the red blood cells. The antibodies attach to red blood cells and cause them to break down too early. Drugs that can cause this type of hemolytic anemia include:

1. Cephalosporins (a class of antibiotics) – most common cause[citation needed]

2. Dapsone3. Levodopa4. Levofloxacin5. Methyldopa6. Nitrofurantoin7. Nonsteroidal anti-inflammatory drugs (NSAIDs)8. Phenazopyridine (pyridium)

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9. QuinidinePenicillin in high doses can induce immune mediated hemolysis[2] via the hapten mechanism in which antibodies are targeted against the combination of penicillin in association with red blood cells. Complement is activated by the attached antibody leading to the removal of red blood cells by the spleen.[citation needed]

The drug itself can be targeted by the immune system, e.g. by IgE in a Type I hypersensitivity reaction to penicillin, rarely leading to anaphylaxis.

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Drug-induced nonautoimmune hemolytic anemia

Drug-induced nonautoimmune hemolytic anemia is a form of hemolytic anemia.Non-immune drug induced hemolysis can occur via oxidative mechanisms. This is particularly likely to occur when there is an enzyme deficiency in the antioxidant defense system of the red blood cells. An example is where antimalarial oxidant drugs like primaquine[1] damage red blood cells in Glucose-6-phosphate dehydrogenase deficiency in which the red blood cells are more susceptible to oxidative stress due to reduced NADPH production consequent to the enzyme deficiency.

Some drugs cause RBC (red blood cell) lysis even in normal individuals. These include dapsone[2] and sulfasalazine.

Non-immune drug-induced hemolysis can also arise from drug-induced damage to cell volume control mechanisms; for example drugs can directly or indirectly impair

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regulatory volume decrease mechanisms, which become activated during hypotonic RBC swelling to return the cell to a normal volume. The consequence of the drugs actions are irreversible cell swelling and lysis (e.g. ouabain at very high doses).

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Glucose-6-phosphate dehydrogenase deficiency

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Glucose-6-phosphate dehydrogenase deficiency (G6PD deficiency), also known as favism (after the fava bean), is an X-linked recessive inborn error of metabolism that predisposes to hemolysis (spontaneous destruction of red blood cells) and resultant jaundice in response to a number of triggers, such as certain foods, illness, or medication. It is particularly common in people of Mediterranean and African origin. The condition is characterized by abnormally low levels of glucose-6-phosphate dehydrogenase, an enzyme involved in the pentose phosphate pathway that is especially important in the red blood cell. G6PD deficiency is the most common human enzyme condition.[1] There is no specific treatment, other than avoiding known triggers. In the United States, no genetic screening of prospective parents is recommended, as the symptoms only show in part of the carriers and when that is the case, they can be prevented or controlled, and as a result the condition generally has no impact on the lifespan of those affected.[2] However, globally G6PD deficiency has resulted in 4,100 deaths in 2013 and 3,400 deaths in 1990.

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protected against malaria, with some cases of affected individuals showing complete immunity to the disease. This accounts for the persistence of the allele in certain populations in that it confers a selective advantage in those areas with a high prevalence of malaria.

Signs and symptomsMost individuals with G6PD deficiency are asymptomatic.

Symptomatic patients are almost exclusively male, due to the X-linked pattern of inheritance, but female carriers can

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be clinically affected due to unfavorable lyonization, where random inactivation of an X-chromosome in certain cells creates a population of G6PD-deficient red blood cells coexisting with unaffected red blood cells. A non-intersex female with one affected X chromosome will show the deficiency in approximately half of her red blood cells. However, in rare cases, including double X-deficiency, the ratio can be much more than half, making the individual almost as sensitive as non-intersex males.

Red blood cell breakdown (also known as hemolysis) in G6PD deficiency can manifest in a number of ways, including the following: Prolonged neonatal jaundice, possibly leading to

kernicterus (arguably the most serious complication of G6PD deficiency)

Hemolytic crises in response to: Illness (especially infections) Certain drugs (see below) Certain foods, most notably broad beans from which the

word favism derives Certain chemicals Diabetic ketoacidosis

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Very severe crises can cause acute kidney failureFavism may be formally defined as a hemolytic response to the consumption of fava beans, also known as broad beans. Important to note is that all individuals with favism show G6PD deficiency, but not all individuals with G6PD deficiency show favism. The condition is known to be more prevalent in infants and children, and G6PD genetic variant can influence chemical sensitivity.[5] Other than this, the specifics of the chemical relationship between favism and G6PD are not well understood.

6-phosphogluconate dehydrogenase (6PGD) deficiency has similar symptoms and is often mistaken for G6PD deficiency, as the affected enzyme is within the same pathway, however these diseases are not linked and can be found within the same patient.

GeneticsTwo variants (G6PD A− and G6PD Mediterranean) are the most common in human populations. G6PD A− has an occurrence of 10% of Africans and African-Americans while G6PD Mediterranean is prevalent in the Middle East. The known distribution of the mutated allele is largely

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limited to people of Mediterranean origins (Spaniards, Italians, Greeks, Armenians, Sephardi Jews and other Semitic peoples).[6] Both variants are believed to stem from a strongly protective effect against Plasmodium falciparum and Plasmodium vivax malaria.[7] It is particularly frequent in the Kurdish population, wherein approximately 1 in 2 males have the condition and the same rate of females are carriers.[2] It is also common in African American, Saudi Arabian, Sardinian males, some African populations, and Asian groups.[2]

All mutations that cause G6PD deficiency are found on the long arm of the X chromosome, on band Xq28. The G6PD gene spans some 18.5 kilobases.[8]

TriggersCarriers of the underlying mutation do not show any symptoms unless their red blood cells are exposed to certain triggers, which can be of three main types:

Foods (fava beans is the hallmark trigger for G6PD mutation carriers),Medicines and other chemicals such as those derived from quinine (see below), or

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Stress from a bacterial or viral infection.[2]In order to avoid the hemolytic anemia, G6PD carriers have to avoid a large number of drugs and foods.[2] List of such "triggers" can be obtained from medical providers.[2]

DrugsMany substances are potentially harmful to people with G6PD deficiency. Variation in response to these substances makes individual predictions difficult. Antimalarial drugs that can cause acute hemolysis in people with G6PD deficiency include primaquine, pamaquine, and chloroquine. There is evidence that other antimalarials may also exacerbate G6PD deficiency, but only at higher doses. Sulfonamides (such as sulfanilamide, sulfamethoxazole, and mafenide), thiazolesulfone, methylene blue, and naphthalene should also be avoided by people with G6PD deficiency as they antagonize folate synthesis, as should certain analgesics (such as phenazopyridine and acetanilide) and a few non-sulfa antibiotics (nalidixic acid, nitrofurantoin, isoniazid, dapsone, and furazolidone).[1][8][9] Henna has been known to cause hemolytic crisis in G6PD-deficient infants.[10] Rasburicase is also contraindicated in G6PD deficiency. High dose intravenous

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vitamin C has also been known to cause haemolysis in G6PD deficiency carriers,[11][12] thus G6PD deficiency testing is routine before infusion of doses of 25g or more.

Pathophysiology

Glucose-6-phosphate dehydrogenase (G6PD) is an enzyme in the pentose phosphate pathway (see image, also known as the HMP shunt pathway). G6PD converts glucose-6-phosphate into 6-phosphoglucono-δ-lactone and is the rate-limiting enzyme of this metabolic pathway that supplies reducing energy to cells by maintaining the level of the reduced form of the co-enzyme nicotinamide adenine dinucleotide phosphate (NADPH). The NADPH in turn maintains the supply of reduced glutathione in the cells that is used to mop up free radicals that cause oxidative damage.

The G6PD / NADPH pathway is the only source of reduced glutathione in red blood cells (erythrocytes). The role of red cells as oxygen carriers puts them at substantial risk of damage from oxidizing free radicals except for the protective effect of G6PD/NADPH/glutathione.

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People with G6PD deficiency are therefore at risk of hemolytic anemia in states of oxidative stress. Oxidative stress can result from infection and from chemical exposure to medication and certain foods. Broad beans, e.g., fava beans, contain high levels of vicine, divicine, convicine and isouramil, all of which create oxidants - Eur. J. Biochem. 127, 405-409 (1982).

When all remaining reduced glutathione is consumed, enzymes and other proteins (including hemoglobin) are subsequently damaged by the oxidants, leading to cross-bonding and protein deposition in the red cell membranes. Damaged red cells are phagocytosed and sequestered (taken out of circulation) in the spleen. The hemoglobin is metabolized to bilirubin (causing jaundice at high concentrations). The red cells rarely disintegrate in the circulation, so hemoglobin is rarely excreted directly by the kidney, but this can occur in severe cases, causing acute renal failure.

Deficiency of G6PD in the alternative pathway causes the buildup of glucose and thus there is an increase of advanced glycation endproducts (AGE). The deficiency

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also reduces the amount of NADPH, which is required for the formation of nitric oxide (NO). The high prevalence of diabetes mellitus type 2 and hypertension in Afro-Caribbeans in the West could be directly related to the incidence of G6PD deficiency in those populations.[13]

Although female carriers can have a mild form of G6PD deficiency (dependent on the degree of inactivation of the unaffected X chromosome – see lyonization), homozygous females have been described; in these females there is co-incidence of a rare immune disorder termed chronic granulomatous disease (CGD).

DiagnosisThe diagnosis is generally suspected when patients from certain ethnic groups (see epidemiology) develop anemia, jaundice and symptoms of hemolysis after challenges from any of the above causes, especially when there is a positive family history.

Generally, tests will include:

Complete blood count and reticulocyte count; in active G6PD deficiency, Heinz bodies can be seen in red blood

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cells on a blood film; Liver enzymes (to exclude other causes of jaundice); Lactate dehydrogenase (elevated in hemolysis and a

marker of hemolytic severity) Haptoglobin (decreased in hemolysis); A "direct antiglobulin test" (Coombs' test) – this should

be negative, as hemolysis in G6PD is not immune-mediated;

When there are sufficient grounds to suspect G6PD, a direct test for G6PD is the "Beutler fluorescent spot test", which has largely replaced an older test (the Motulsky dye-decolouration test). Other possibilities are direct DNA testing and/or sequencing of the G6PD gene.

The Beutler fluorescent spot test is a rapid and inexpensive test that visually identifies NADPH produced by G6PD under ultraviolet light. When the blood spot does not fluoresce, the test is positive; it can be falsely negative in patients who are actively hemolysing. It can therefore only be done 2–3 weeks after a hemolytic episode.

When a macrophage in the spleen identifies a RBC with a Heinz body, it removes the precipitate and a small piece of

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the membrane, leading to characteristic "bite cells". However, if a large number of Heinz bodies are produced, as in the case of G6PD deficiency, some Heinz bodies will nonetheless be visible when viewing RBCs that have been stained with crystal violet. This easy and inexpensive test can lead to an initial presumption of G6PD deficiency, which can be confirmed with the other tests.

ClassificationThe World Health Organization classifies G6PD genetic variants into five classes, the first three of which are deficiency states.[14]

Class I: Severe deficiency (<10% activity) with chronic (nonspherocytic) hemolytic anemia

Class II: Severe deficiency (<10% activity), with intermittent hemolysis

Class III: Mild deficiency (10-60% activity), hemolysis with stressors only

Class IV: Non-deficient variant, no clinical sequelae Class V: Increased enzyme activity, no clinical sequelae

Treatment

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The most important measure is prevention – avoidance of the drugs and foods that cause hemolysis. Vaccination against some common pathogens (e.g. hepatitis A and hepatitis B) may prevent infection-induced attacks.[15]

In the acute phase of hemolysis, blood transfusions might be necessary, or even dialysis in acute kidney failure. Blood transfusion is an important symptomatic measure, as the transfused red cells are generally not G6PD deficient and will live a normal lifespan in the recipient's circulation. Those affected should avoid drugs such as aspirin.

Some patients may benefit from removal of the spleen (splenectomy),[16] as this is an important site of red cell destruction. Folic acid should be used in any disorder featuring a high red cell turnover. Although vitamin E and selenium have antioxidant properties, their use does not decrease the severity of G6PD deficiency.

EpidemiologyG6PD deficiency is the most common human enzyme defect, being present in more than 400 million people worldwide.[17] G6PD deficiency resulted in 4,100 deaths

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in 2013 and 3,400 deaths in 1990.[3] African, Middle Eastern and South Asian people are affected the most, including those who have these ancestries.[18] A side effect of this disease is that it confers protection against malaria,[19] in particular the form of malaria caused by Plasmodium falciparum, the most deadly form of malaria. A similar relationship exists between malaria and sickle-cell disease. One theory to explain this is that cells infected with the Plasmodium parasite are cleared more rapidly by the spleen. This phenomenon might give G6PD deficiency carriers an evolutionary advantage by increasing their fitness in malarial endemic environments. In vitro studies have shown that the Plasmodium falciparum is very sensitive to oxidative damage. This is the basis for another theory, that is that the genetic defect confers resistance due to the fact that the G6PD-deficient host has a higher level of oxidative agents that, while generally tolerable by the host, are deadly to the parasite.

PrognosisG6PD-deficient individuals do not appear to acquire any illnesses more frequently than other people, and may have

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less risk than other people for acquiring ischemic heart disease and cerebrovascular disease.

CultureIn both legend and mythology, Favism has been known since antiquity. The priests of various Greco-Roman era cults were forbidden to eat or even mention beans, and Pythagoras had a strict rule that to join the society of the Pythagoreans one had to swear off beans.[22] This ban was supposedly because beans resembled male genitalia, but it is possible that this was because of a belief that beans and humans were created from the same material.

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Hemoglobinopathy

Hemoglobinopathy is a kind of genetic defect that results in abnormal structure of one of the globin chains of the hemoglobin molecule.[1] Hemoglobinopathies are inherited single-gene disorders; in most cases, they are inherited as autosomal co-dominant traits.[2] Common hemoglobinopathies include sickle-cell disease. It is estimated that 7% of world's population (420 million) are carriers, with 60% of total and 70% pathological being in Africa. Hemoglobinopathies are most common in populations from Africa, the Mediterranean basin and Southeast Asia.

Hemoglobinopathies imply structural abnormalities in the globin proteins themselves.[3] Thalassemias, in contrast, usually result in underproduction of normal globin proteins, often through mutations in regulatory genes. The two conditions may overlap, however, since some conditions which cause abnormalities in globin proteins (hemoglobinopathy) also affect their production

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(thalassemia). Thus, some hemoglobinopathies are also thalassemias, but most are not.

Either hemoglobinopathy or thalassemia, or both, may cause anemia. Some well-known hemoglobin variants such as sickle-cell anemia and congenital dyserythropoietic anemia are responsible for diseases, and are considered hemoglobinopathies. However, many hemoglobin variants do not cause pathology or anemia, and thus are often not classed as hemoglobinopathies, because they are not considered pathologies. Hemoglobin variants are a part of the normal embryonic and fetal development, but may also be pathologic mutant forms of hemoglobin in a population, caused by variations in genetics. Other variants cause no detectable pathology, and are thus considered non-pathological variants.

Migration patternsMigration patterns (Alkaline Electrophoresis)In general on alkaline electrophoresis in order of increasings A2, E=O=C, G=D=S=Lepore, F, A, K, J, Bart's, N, I, and H.

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In general a sickling test (sodium bisulfite) is performed on abnormal hemoglobins migrating in the S location to see if the red cells precipitate in solution.

Migration patterns (Acid Electrophoresis)In general on acid electrophoresis in order of increasing mobility are hemoglobins F, A=D=G=E=O=Lepore, S, and C.

This is how abnormal hemoglobin variants are isolated and identified using these two methods. For example a Hgb G-Philadelphia would migrate with S on alkaline electrophoresis and would migrate with A on acid electrophoresis, respectively

use of iso electric focusing to determine quantitative differences in globin chain synthesis and high performance liquid chromatograpgy that separates hemoglobins based on their various affinities for the column.

Hemoglobin VariantsHb SHb CHb E

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Hb Bart'sHb D-PunjabHb O-ArabHb G-PhiladelphiaHb HHb Constant SpringHb HasharonHb Korle-BuHb LeporeHb MHb Kansas[6][7]Hb JHb N-BaltimoreHb HopeHb Pisa

Hemoglobinopathy and evolutionSome hemoglobinopathies (and also related diseases like glucose-6-phosphate dehydrogenase deficiency) seem to have given an evolutionary benefit, especially to heterozygotes, in areas where malaria is endemic. Malaria parasites live inside red blood cells, but subtly disturb

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normal cellular function. In patients predisposed for rapid clearance of red blood cells, this may lead to early destruction of cells infected with the parasite and increased chance of survival for the carrier of the trait.

Hemoglobin functions:

Transport of oxygen from the lungs to the tissues: This is due to the peculiar cooperation of the globin chains that allows the molecule to take in more oxygen where there is increased oxygen and to release oxygen in low concentration of oxygen.

Transport of carbon dioxide from the tissues to the lungs: The end product of tissue metabolism is acidic which increases hydrogen ions in solution. The hydrogen ions combine with bicarbonates to produce water and carbon dioxide. The carbon dioxide is mop up by hemoglobin to favor this reversible reaction.

Transport of nitric oxide: Nitric oxide is a vasodilatator. This assists in the regulation of vascular reaction in times of stress as experienced during inflammation.

Pathology and organic structural abnormalities may lead to any of the following disease processes:

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Anemia due to reduced life span of the red cells of reduced production of the cells e. g. hemoglobin S, C and E.

Increased oxygen affinity: The red blood cells do not release their oxygen content readily in hypoxic conditions. The bone marow therefore needs to produce more red blood cells and there is polycythemia.

Unstable hemoglobins: Red blood cells are easily destroyed under stress and hemolysis occurs with possible jaundice.

Methemoglobinemia: The iron in the heme portion of hemoglobin is easily oxidised and this reduces the ability of hemoglobin to bind oxygen. More deoxygenated hemoglobin are formed and the blood becomes cyanotic.

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Hemolytic anemiaHemolytic anemia or haemolytic anaemia is a form of anemia due to hemolysis, the abnormal breakdown of red blood cells (RBCs), either in the blood vessels (intravascular hemolysis) or elsewhere in the human body (extravascular). It has numerous possible consequences, ranging from relatively harmless to life-threatening. The general classification of hemolytic anemia is either inherited or acquired. Treatment depends on the cause and nature of the breakdown.Symptoms of hemolytic anemia are similar to other forms of anemia (fatigue and shortness of breath), but in addition, the breakdown of red cells leads to jaundice and increases the risk of particular long-term complications, such as gallstones and pulmonary hypertension.

Signs and symptomsIn general, signs of anemia (pallor, fatigue, shortness of breath, and potential for heart failure) are present. In small children, failure to thrive may occur in any form of anemia. Certain aspects of the medical history can

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suggest a cause for hemolysis, such as drugs, consumption of fava beans due to Favism, the presence of prosthetic heart valve, or other medical illness.

Chronic hemolysis leads to an increased excretion of bilirubin into the biliary tract, which in turn may lead to gallstones. The continuous release of free hemoglobin has been linked with the development of pulmonary hypertension (increased pressure over the pulmonary artery); this, in turn, leads to episodes of syncope (fainting), chest pain, and progressive breathlessness. Pulmonary hypertension eventually causes right ventricular heart failure, the symptoms of which are peripheral edema (fluid accumulation in the skin of the legs) and ascites (fluid accumulation in the abdominal cavity).

CausesMain articles: Congenital hemolytic anemia and Acquired hemolytic anemiaThey may be classified according to the means of hemolysis, being either intrinsic in cases where the cause is related to the red blood cell (RBC) itself, or extrinsic

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in cases where factors external to the RBC dominate.[1] Intrinsic effects may include problems with RBC proteins or oxidative stress handling, whereas external factors include immune attack and microvascular angiopathies (RBCs are mechanically damaged in circulation).

Intrinsic causesHereditary (inherited) hemolytic anemia can be due to :

Defects of red blood cell membrane production (as in hereditary spherocytosis and hereditary elliptocytosis)

Defects in hemoglobin production (as in thalassemia, sickle-cell disease and congenital dyserythropoietic anemia)

Defective red cell metabolism (as in glucose-6-phosphate dehydrogenase deficiency and pyruvate kinase deficiency)

Extrinsic causesAcquired hemolytic anemia may be caused by immune-mediated causes, drugs and other miscellaneous causes.

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Immune-mediated causes could include transient factors as in Mycoplasma pneumoniae infection (cold agglutinin disease) or permanent factors as in autoimmune diseases like autoimmune hemolytic anemia (itself more common in diseases such as systemic lupus erythematosus, rheumatoid arthritis, Hodgkin's lymphoma, and chronic lymphocytic leukemia).

Paroxysmal nocturnal hemoglobinuria (PNH), sometimes referred to as Marchiafava-Micheli syndrome, is a rare, acquired, potentially life-threatening disease of the blood characterized by complement-induced intravascular hemolytic anemia.

Spur cell hemolytic anemia Any of the causes of hypersplenism (increased activity

of the spleen), such as portal hypertension. Acquired hemolytic anemia is also encountered in

burns and as a result of certain infections. Lead poisoning resulting from the environment causes

non-immune hemolytic anemia. Runners can suffer hemolytic anemia due to

"footstrike hemolysis", owing to the destruction of red

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blood cells in feet at foot impact.[2][3] Low-grade hemolytic anemia occurs in 70% of

prosthetic heart valve recipients, and severe hemolytic anemia occurs in 3%.

MechanismHemolytic anemia involves the following:

Abnormal and accelerated destruction of red cells and, in some anemias, their precursorsIncreased breakdown of hemoglobin, which may result in:increased bilirubin level (mainly indirect-reacting) with jaundiceincreased fecal and urinary urobilinogenHemoglobinemia, methemalbuminemia, hemoglobinuria and hemosiderinuria (where there is significant intravascular hemolysis).Bone marrow compensatory reaction:Erythroid hyperplasia with accelerated production of red cells, reflected by reticulocytosis, and slight macrocytosis in peripheral blood

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Expansion of bone marrow in infants and children with severe chronic hemolysis - changes in bone configuration visible on X-rayThe balance between red cell destruction and marrow compensation determines the severity of anemias.In a healthy person, a red blood cell survives 90 to 120 days in the circulation, so about 1% of human red blood cells break down each day[citation needed]. The spleen (part of the reticulo-endothelial system) is the main organ that removes old and damaged RBCs from the circulation. In healthy individuals, the breakdown and removal of RBCs from the circulation is matched by the production of new RBCs in the bone marrow.

In conditions where the rate of RBC breakdown is increased, the body initially compensates by producing more RBCs; however, breakdown of RBCs can exceed the rate that the body can make RBCs, and so anemia can develop. Bilirubin, a breakdown product of hemoglobin, can accumulate in the blood, causing jaundice.

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In general, hemolytic anemia occurs as a modification of the RBC life cycle. That is, instead of being collected at the end of its useful life and disposed of normally, the RBC disintegrates in a manner allowing free iron-containing molecules to reach the blood. With their complete lack of mitochondria, RBCs rely on glycolysis for the materials needed to reduce oxidative damage. Any limitations of glycolysis can result in more susceptibility to oxidative damage and a short or abnormal lifecycle. If the cell is unable to signal to the reticuloendothelial phagocytes by externalizing phosphatidylserine, it is likely to lyse through uncontrolled means.[5][6][7]

The distinguishing feature of intravascular hemolysis is the release of RBC contents into the blood stream. The metabolism and elimination of these products, largely iron-containing compounds capable of doing damage through Fenton reactions, is an important part of the condition. Several reference texts exist on the elimination pathways, for example.[8][9] Free hemoglobin can bind to haptoglobin, and the complex is cleared from the circulation; thus, a decrease in

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haptoglobin can support a diagnosis of hemolytic anemia. Alternatively, hemoglobin may oxidize and release the heme group that is able to bind to either albumin or hemopexin. The heme is ultimately converted to bilirubin and removed in stool and urine.[8] Hemoglobin may be cleared directly by the kidneys resulting in fast clearance of free hemoglobin but causing the continued loss of hemosiderin loaded renal tubular cells for many days.

Additional effects of free hemoglobin seem to be due to specific reactions with NO.

DiagnosisThe diagnosis of hemolytic anemia can be suspected on the basis of a constellation of symptoms and is largely based on examination of a peripheral blood smear and a number of laboratory studies. Symptoms of hemolytic anemia include those that can occur in all anemias as well as the specific consequences of hemolysis. All anemias can cause fatigue, shortness of breath, decreased ability to exercise when severe. Symptoms specifically related to hemolysis include

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jaundice and dark colored urine due to the presence of hemoglobin (hemaglobinuria). When restricted to the morning hemaglobinuria may suggest paroxysmal nocturnal haemoglobinuria. Direct examination of blood under a microscope in a peripheral blood smear may demonstrate red blood cell fragments called schistocytes, red blood cells that look like spheres (spherocytes), and/or red blood cells missing small pieces (bite cells). An increased number of newly made red blood cells (reticulocytes) may also be a sign of bone marrow compensation for anemia. Laboratory studies commonly used to investigate hemolytic anemia include blood tests for breakdown products of red blood cells, bilirubin and lactate dehydrogenase, a test for the free hemoglobin binding protein haptoglobin, and the direct Coombs test to evaluate antibody binding to red blood cells suggesting autoimmune hemolytic anemia.

TreatmentDefinitive therapy depends on the cause:

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Symptomatic treatment can be given by blood transfusion, if there is marked anemia. A positive Coombs test is a relative contraindication to transfuse the patient. In cold hemolytic anemia there is advantage in transfuse warmed blood

In severe immune-related hemolytic anemia, steroid therapy is sometimes necessary.

In steroid resistant cases, consideration can be given to rituximab or addition of an immunosuppressant ( azathioprine, cyclophosphamide)

Association of methylprednisolone and intravenous immunoglobulin can control hemolysis in acute severe cases

Sometimes splenectomy can be helpful where extravascular hemolysis, or hereditary spherocytosis, is predominant (i.e., most of the red blood cells are being removed by the spleen).

Other animalsHemolytic anemia affects nonhuman species as well as humans. It has been found, in a number of animal species, to result from specific triggers.[12]

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Some notable cases include hemolytic anemia found in black rhinos kept in captivity, with the disease, in one instance, affecting 20% of captive rhinos at a specific facility.[13][14][15] The disease is also found in wild rhinos.[16]

Dogs and cats differ slightly from humans in some details of their RBC composition and have altered susceptibility to damage, notably, increased susceptibility to oxidative damage from consumption of onion. Garlic is less toxic to dogs than onion.

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Congenital hemolytic anemiaCongenital hemolytic anemia (or hereditary hemolytic anemia) refers to hemolytic anemia which is primarily due to congenital disorders.

TypesBasically classified by causative mechanism, types of congenital hemolytic anemia include:

I. Genetic conditions of RBC MembraneII. Hereditary spherocytosisIII. Hereditary elliptocytosisIV.Genetic conditions of RBC metabolism (enzyme

defects). This group is sometimes called congenital nonspherocytic (hemolytic) anemia, which is a term for a congenital hemolytic anemia without spherocytosis, and usually excluding hemoglobin abnormalities as well, but rather encompassing defects of glycolysis in the erythrocyte.[2]

V.Glucose-6-phosphate dehydrogenase deficiency (G6PD or favism)

VI. Pyruvate kinase deficiency

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VII. Aldolase A deficiencyVIII. Hemoglobinopathies[3]/genetic conditions of

hemoglobinIX. Sickle cell anemiaX. Congenital dyserythropoietic anemiaXI. Thalassemia

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Fanconi anemiaNot to be confused with Fanconi syndrome.Fanconi anaemia (FA) is a rare genetic disease. Among those affected the majority develop cancer, most often acute myelogenous leukemia, and 90% develop bone marrow failure (the inability to produce blood cells) by age 40. About 60–75% of people have congenital defects, commonly short stature, abnormalities of the skin, arms, head, eyes, kidneys, and ears, and developmental disabilities. Around 75% of people have some form of endocrine problem, with varying degrees of severity.FA is the result of a genetic defect in a cluster of proteins responsible for DNA repair.[1]

Treatment with androgens and hematopoietic (blood cell) growth factors can help bone marrow failure temporarily, but the long-term treatment is bone marrow transplant if a donor is available.[2] Because of the genetic defect in DNA repair, cells from people with FA are sensitive to drugs that treat cancer by DNA

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crosslinking, such as mitomycin C. The typical age of death was 30 years in 2000.[2]

FA occurs in about 1 per 130,000 births, with a slightly higher frequency in Ashkenazi Jews in Israel and Afrikaners in South Africa.[3] The disease is named after the Swiss pediatrician who originally described this disorder, Guido Fanconi.[4][5] It should not be confused with Fanconi syndrome, a kidney disorder also named after Fanconi.

Signs and symptomsDuring childhood, short stature and skin pigmentation, including café au lait spots, may become apparent. The first sign of a hematologic problem is usually petechiae and bruises, with later onset of pale appearance, feeling tired, and infections. Because macrocytosis usually precedes a low platelet count, patients with typical congenital anomalies associated with FA should be evaluated for an elevated red blood cell mean corpuscular volume.[6]

Genetics

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Fanconi anemia has an autosomal recessive pattern of inheritance.FA is primarily an autosomal recessive genetic disorder. This means that two mutated alleles (one from each parent) are required to cause the disease. There is a 25% risk that each subsequent child will have FA. About 2%

of FA cases are X-linked recessive, which means that if the mother carries one mutated Fanconi anemia allele on

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one X chromosome, there is a 50% chance that male offspring will present with Fanconi anemia.

Scientists have identified 17 FA or FA-like genes: FANCA, FANCB, FANCC, FANCD1 (BRCA2), FANCD2, FANCE, FANCF, FANCG, FANCI, FANCJ (BRIP1), FANCL, FANCM, FANCN (PALB2), FANCP (SLX4), FANCS (BRCA1), RAD51C, and XPF. FANCB is the one exception to FA being autosomal recessive, as this gene is on the X chromosome. These genes are involved in DNA repair.

The carrier frequency in the Ashkenazi Jewish population is about 1/90.[7] Genetic counseling and genetic testing is recommended for families that may be carriers of Fanconi anemia.

Because of the failure of hematologic components to develop—white blood cells, red blood cells and platelets—the body's capabilities to fight infection, deliver oxygen, and form clots are all diminished.

Pathogenesis

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Clinically, hematological abnormalities are the most serious symptoms in FA. By the age of 40, 98% of FA patients will have developed some type of hematological abnormality. However, there are a few cases in which older patients have died without ever developing them. Symptoms appear progressively, and often lead to complete bone marrow failure. While at birth, blood count is usually normal, macrocytosis/megaloblastic anemia, defined as unusually large red blood cells, is the first detected abnormality, often within the first decade of life (median age of onset is 7 years). Within the next 10 years, over 50% of patients presenting haematological abnormalities will have developed pancytopenia, defined as abnormalities in two or more blood cell lineages. This is in contrast to Diamond–Blackfan anemia, which affects only erythrocytes, and Shwachman–Diamond syndrome, which primarily causes neutropenia. Most commonly, a low platelet count (thrombocytopenia) precedes a low neutrophil count (neutropenia), with both appearing with relative equal frequencies. The deficiencies cause increased risk of hemorrhage and recurrent infections, respectively.[citation needed]

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As FA is now known to affect DNA repair, specifically nonhomologous end joining, and given the current knowledge about dynamic cell division in the bone marrow, it is not surprising to find patients are more likely to develop bone marrow failure, myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML).

Myelodysplastic syndromesMDS, formerly known as preleukemia, are a group of bone marrow neoplastic diseases that share many of the morphologic features of AML, with some important differences. First, the percentage of undifferentiated progenitor cells, blast cells, is always less than 20%, and there is considerably more dysplasia, defined as cytoplasmic and nuclear morphologic changes in erythroid, granulocytic and megakaryocytic precursors, than what is usually seen in cases of AML. These changes reflect delayed apoptosis or a failure of programmed cell death. When left untreated, MDS can lead to AML in about 30% of cases. Due the nature of the FA pathology, MDS diagnosis cannot be made solely through cytogenetic analysis of the marrow. Indeed, it is only when morphologic analysis of marrow cells is

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performed, that a diagnosis of MDS can be ascertained. Upon examination, MDS-afflicted FA patients will show many clonal variations, appearing either prior or subsequent to the MDS. Furthermore, cells will show chromosomal aberrations, the most frequent being monosomy 7 and partial trisomies of chromosome 3q 15. Observation of monosomy 7 within the marrow is well correlated with an increased risk of developing AML and with a very poor prognosis, death generally ensuing within 2 years (unless prompt allogeneic hematopoietic progenitor cell transplant is an option).

Acute myeloid leukemiaFA patients are at elevated risk for the development of acute myeloid leukemia (AML), defined as presence of 20% or more of myeloid blasts in the marrow or 5 to 20% myeloid blasts in the blood. All of the subtypes of AML can occur in FA with the exception of promyelocytic. However, myelomonocytic and acute monocytic are the most common subtypes observed. Many MDS patients will evolve into AML if they survive long enough. Furthermore, the risk of developing AML increases with the onset of bone marrow failure.

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Although risk of developing either MDS or AML before the age of 20 is only 27%, this risk increases to 43% by the age of 30 and 52% by the age of 40. Historically, even with a marrow transplant, about 1/4 of FA patients diagnosed with MDS/ALS have died from MDS/ALS-related causes within two years (Butturini, A et al. 1994. Blood. 84:1650-4), although more recent published evidence suggests that earlier allogeneic hematopoietic progenitor cell transplantation in children with Fanconi anemia is leading to better outcomes over time.[9]

Bone marrow failureThe last major haematological complication associated with FA is bone marrow failure, defined as inadequate blood cell production. Several types of failure are observed in FA patients, and generally precede MDS and AML. Detection of decreasing blood count is generally the first sign used to assess necessity of treatment and possible transplant. While most FA patients are initially responsive to androgen therapy and haemopoietic growth factors, these have been shown to promote leukemia, especially in patients with clonal cytogenetic

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abnormalities, and have severe side effects, including hepatic adenomas and adenocarcinomas. The only treatment left would be bone marrow transplant; however, such an operation has a relatively low success rate in FA patients when the donor is unrelated (30% 5-year survival). It is therefore imperative to transplant from an HLA-identical sibling. Furthermore, due to the increased susceptibility of FA patients to chromosomal damage, pretransplant conditioning cannot include high doses of radiations or immunosuppressants, and thus increase chances of patients developing graft-versus-host disease. If all precautions are taken, and the marrow transplant is performed within the first decade of life, 2-year probability of survival can be as high as 89%. However, if the transplant is performed at ages older than 10, 2-year survival rates drop to 54%.[citation needed]

A recent report by Zhang et al. investigates the mechanism of bone marrow failure in FANCC-/- cells.[10] They hypothesize and successfully demonstrate that continuous cycles of hypoxia-reoxygenation, such as those seen by haemopoietic and progenitor cells as they

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migrate between hyperoxic blood and hypoxic marrow tissues, leads to premature cellular senescence and therefore inhibition of haemopoietic function. Senescence, together with apoptosis, may constitute a major mechanism of haemopoietic cell depletion occurred in bone marrow failure.

Molecular basisRecombinational repair of DNA double-strand damage - some key steps. ATM (ATM) is a protein kinase that is recruited and activated by DNA double-strand breaks. DNA double-strand damages also activate the Fanconi anemia core complex (FANCA/B/C/E/F/G/L/M).[11] The FA core complex monoubiquitinates the downstream targets FANCD2 and FANCI.[12] ATM activates (phosphorylates) CHEK2 and FANCD2[13] CHEK2 phosphorylates BRCA1.[14] Ubiquinated FANCD2 complexes with BRCA1 and RAD51.[15] The PALB2 protein acts as a hub,[16] bringing together BRCA1, BRCA2 and RAD51 at the site of a DNA double-strand break, and also binds to RAD51C, a member of the RAD51 paralog complex RAD51B-RAD51C-RAD51D-

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XRCC2 (BCDX2). The BCDX2 complex is responsible for RAD51 recruitment or stabilization at damage sites.[17] RAD51 plays a major role in

homologous recombinational repair of DNA during double strand break repair. In this process, an ATP dependent DNA strand exchange takes place in which a single strand invades base-paired strands of homologous

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DNA molecules. RAD51 is involved in the search for homology and strand pairing stages of the process.

There are 19 genes responsible for FA, one of them being the breast-cancer susceptibility gene BRCA2. They are involved in the recognition and repair of damaged DNA; genetic defects leave them unable to repair DNA. The FA core complex of 8 proteins is normally activated when DNA stops replicating because of damage. The core complex adds ubiquitin, a small protein that combines with BRCA2 in another cluster to repair DNA (see Figure Recombinational repair of DNA double-strand damage). At the end of the process, ubiquitin is removed.[2]

Recent studies have shown that eight of these proteins, FANCA, -B, -C, -E, -F, -G, -L and –M assemble to form a core protein complex in the nucleus. According to current models, the complex moves from the cytoplasm into the nucleus following nuclear localization signals on FANCA and FANCE. Assembly is activated by replicative stress, particularly DNA damage caused by cross-linking agents (such as mitomycin C or cisplatin)

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or reactive oxygen species (ROS) that is detected by the FANCM protein.[18]

Following assembly, the protein core complex activates FANCL protein which acts as an E3 ubiquitin-ligase and monoubiquitinates FANCD2.[19][20][21][22]

Monoubiquitinated FANCD2, also known as FANCD2-L, then goes on to interact with a BRCA1/BRCA2 complex (see Figure Recombinational repair of DNA double-strand damage). Details are not known, but similar complexes are involved in genome surveillance and associated with a variety of proteins implicated in DNA repair and chromosomal stability.[23][24] With a crippling mutation in any FA protein in the complex, DNA repair is much less effective, as shown by its response to damage caused by cross-linking agents such as cisplatin, diepoxybutane[25] and Mitomycin C. Bone marrow is particularly sensitive to this defect.

In another pathway responding to ionizing radiation, FANCD2 is thought to be phosphorylated by protein complex ATM/ATR activated by double-strand DNA breaks, and takes part in S-phase checkpoint control.

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This pathway was proven by the presence of radioresistant DNA synthesis, the hallmark of a defect in the S phase checkpoint, in patients with FA-D1 or FA-D2. Such a defect readily leads to uncontrollable replication of cells and might also explain the increase frequency of AML in these patients.

SpermatogenesisIn humans, infertility is one of the characteristics of individuals with mutational defects in the FANC genes.[26] In mice, spermatogonia, preleptotene spermatocytes, and spermatocytes in the meiotic stages of leptotene, zygotene and early pachytene are enriched for FANC proteins.[26] This finding suggests that recombinational repair processes mediated by the FANC proteins are active during germ cell development, particularly during meiosis, and that defects in this activity can lead to infertility.

Neural stem cell homeostasisMicrophthalmia and microcephaly are frequent congenital defects in FA patients. The loss of FANCA and FANCG in mice causes neural progenitor apoptosis

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both during early developmental neurogenesis and later during adult neurogenesis. This leads to depletion of the neural stem cell pool with aging.[27] Much of the Fanconi anemia phenotype might be interpreted as a reflection of premature aging of stem cells

TreatmentThe first line of therapy is androgens and hematopoietic growth factors, but only 50-75% of patients respond. A more permanent cure is hematopoietic stem cell transplantation.[28] If no potential donors exist, a savior sibling can be conceived by preimplantation genetic diagnosis (PGD) to match the recipient's HLA type.

PrognosisMany patients eventually develop acute myelogenous leukemia (AML). Older patients are extremely likely to develop head and neck, esophageal, gastrointestinal, vulvar and anal cancers.[31] Patients who have had a successful bone marrow transplant and, thus, are cured of the blood problem associated with FA still must have regular examinations to watch for signs of cancer. Many patients do not reach adulthood.

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The overarching medical challenge that Fanconi patients face is a failure of their bone marrow to produce blood cells. In addition, Fanconi patients normally are born with a variety of birth defects. A good number of Fanconi patients have kidney problems, trouble with their eyes, developmental retardation and other serious defects, such as microcephaly (small head).

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Hereditary spherocytosis

This article is about aspects of spherocytosis specific to the hereditary form of the disorder. For details that apply generally to this variant as well as others, see Spherocytosis.Hereditary spherocytosis (also known as Minkowski–Chauffard syndrome) is an autosomal dominant abnormality of erythrocytes. The disorder is caused by mutations in genes relating to membrane proteins that allow for the erythrocytes to change shape. The abnormal erythrocytes are sphere-shaped (spherocytosis) rather than the normal biconcave disk shaped. Dysfunctional membrane proteins interfere with the cell's ability to be flexible to travel from the arteries to the smaller capillaries. This difference in shape also makes the red blood cells more prone to rupture.[1] Cells with these dysfunctional proteins are taken for degradation at the spleen. This shortage of erythrocytes results in hemolytic anemia.

Hereditary spherocytosis

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Peripheral blood smear from patient with hereditary

spherocytosisIt was first described in 1871 and is the most common cause of inherited hemolysis in Europe and North America within the Caucasian population, with an incidence of 1 in 5000 births. The clinical severity of HS varies from symptom-free carrier to severe haemolysis because the disorder exhibits incomplete penetrance in its expression.

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Symptoms include anemia, jaundice, splenomegaly, and fatigue. On a blood smear, Howell-Jolly bodies may be seen within red blood cells. Primary treatment for patients with symptomatic HS has been total splenectomy, which eliminates the hemolytic process, allowing normal hemoglobin, reticulocyte and bilirubin levels.

Signs and symptomsAs in non-hereditary spherocytosis, the spleen destroys the spherocytes. This process of red blood cells rupturing directly results in varying degrees of anemia (causing a pale appearance and fatigue), high levels of bilirubin in the blood (causing jaundice), and splenomegaly.

Acute cases can threaten to cause hypoxia through anemia and acute kernicterus through high blood levels of bilirubin, particularly in newborns. Most cases can be detected soon after birth. An adult with this disease should have their children tested, although the presence of the disease in children is usually noticed soon after birth. Occasionally, the disease will go unnoticed until

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the child is about 4 or 5 years of age. A person may also be a carrier of the disease and show no signs or symptoms of the disease. Other symptoms may include abdominal pain that could lead to the removal of the spleen and/or gallbladder.

Chronic symptoms include anemia, increased blood viscosity, and splenomegaly.[2] Furthermore, the detritus of the broken-down blood cells – unconjugated or indirect bilirubin – accumulates in the gallbladder, and can cause pigmented gallstones or "sludge" to develop. In chronic patients, an infection or other illness can cause an increase in the destruction of red blood cells, resulting in the appearance of acute symptoms, a hemolytic crisis. Spherocytosis patients who are heterozygous for a hemochromatosis gene may suffer from iron overload despite the hemochromatosis genes being recessive.

Signs and symptomsAs in non-hereditary spherocytosis, the spleen destroys the spherocytes. This process of red blood cells rupturing directly results in varying degrees of anemia (causing a

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pale appearance and fatigue), high levels of bilirubin in the blood (causing jaundice), and splenomegaly.

Acute cases can threaten to cause hypoxia through anemia and acute kernicterus through high blood levels of bilirubin, particularly in newborns. Most cases can be detected soon after birth. An adult with this disease should have their children tested, although the presence of the disease in children is usually noticed soon after birth. Occasionally, the disease will go unnoticed until the child is about 4 or 5 years of age. A person may also be a carrier of the disease and show no signs or symptoms of the disease. Other symptoms may include abdominal pain that could lead to the removal of the spleen and/or gallbladder.

Chronic symptoms include anemia, increased blood viscosity, and splenomegaly.[2] Furthermore, the detritus of the broken-down blood cells – unconjugated or indirect bilirubin – accumulates in the gallbladder, and can cause pigmented gallstones or "sludge" to develop. In chronic patients, an infection or other illness can cause an increase in the destruction of red blood cells,

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resulting in the appearance of acute symptoms, a hemolytic crisis. Spherocytosis patients who are heterozygous for a hemochromatosis gene may suffer from iron overload despite the hemochromatosis genes being recessive.

PathophysiologyHereditary spherocytosis can be an autosomal recessive or autosomal dominant trait.[8] Hereditary spherocytosis is most commonly (though not exclusively) found in Northern European and Japanese families, although an estimated 25% of cases are due to spontaneous mutations. A patient has a 50% chance of passing the mutation onto each of his/her offspring.

Hereditary spherocytosis is caused by a variety of molecular defects in the genes that code for the red blood cell proteins spectrin (alpha and beta), ankyrin,[9] band 3 protein, protein 4.2,[10] and other red blood cell membrane proteins:These proteins are necessary to maintain the normal shape of a red blood cell, which is a biconcave disk. The integrating protein that is most commonly defective is

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ankyrin which is responsible for incorporation and binding of spectrin, thus in its dysfunction cytoskeletal instabilities ensue.

The primary defect in hereditary spherocytosis is a deficiency of membrane surface area. Decreased surface area may be produced by two different mechanisms: 1) Defects of spectrin, ankyrin (most commonly), or protein 4.2 lead to reduced density of the membrane skeleton, destabilizing the overlying lipid bilayer and releasing band 3-containing microvesicles. 2) Defects of band 3 lead to band 3 deficiency and loss of its lipid-stabilizing effect. This results in the loss of band 3-free microvesicles. Both pathways result in membrane loss, decreased surface area, and formation of spherocytes with decreased deformability.

As the spleen normally targets abnormally shaped red cells (which are typically older), it also destroys spherocytes. In the spleen, the passage from the cords of Billroth into the sinusoids may be seen as a bottleneck, where red blood cells need to be flexible in order to pass through. In hereditary spherocytosis, red blood cells fail

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to pass through and get phagocytosed, causing extravascular hemolysis.

Complications Hemolytic crisis, with more pronounced jaundice due

to accelerated hemolysis (may be precipitated by infection).

Aplastic crisis with dramatic fall in hemoglobin level and (reticulocyte count)-decompensation, usually due to maturation arrest and often associated with megaloblastic changes; may be precipitated by infection, such as influenza, notably with parvovirus B19.[13][14][15]

Folate deficiency caused by increased bone marrow requirement.

Pigmented gallstones occur in approximately half of untreated patients. Increased hemolysis of red blood cells leads to increased bilirubin levels, because bilirubin is a breakdown product of heme. The high levels of bilirubin must be excreted into the bile by the liver, which may cause the formation of a pigmented gallstone, which is composed of calcium bilirubinate.

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Since these stones contain high levels of calcium carbonates and phosphate, they are radiopaque and are visible on x-ray.

Leg ulcer. Abnormally low hemoglobin A1C levels.[16]

Hemoglobin A1C (glycated hemoglobin) is a test for determining the average blood glucose levels over an extended period of time, and is often used to evaluate glucose control in diabetics. The hemoglobin A1C levels are abnormally low because the life span of the red blood cells is decreased, providing less time for the non-enzymatic glycosylation of hemoglobin. Thus, even with high overall blood sugar, the A1C will be lower than expected.

Treatment At this point, there exists no cure for the genetic

defect that causes hereditary spherocytosis.[11] Current management focuses on interventions that limit the severity of the disease. Treatment options include:

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Splenectomy: As in non-hereditary spherocytosis, acute symptoms of anemia and hyperbilirubinemia indicate treatment with blood transfusions or exchanges and chronic symptoms of anemia and an enlarged spleen indicate dietary supplementation of folic acid and splenectomy,[17] the surgical removal of the spleen. Splenectomy is indicated for moderate to severe cases, but not mild cases.[2] To decrease the risk of sepsis, post-splenectomy spherocytosis patients require immunization against the influenza virus, encapsulated bacteria such as Streptococcus pneumoniae and meningococcus, and prophylactic antibiotic treatment. However, the use of prophylactic antibiotics, such as penicillin, remains controversial.[11]

Partial splenectomy: Since the spleen is important for protecting against encapsulated organisms, sepsis caused by encapsulated organisms is a possible complication of splenectomy.[2] The option of partial splenectomy may be considered in the interest of preserving immune function. Research on outcomes is currently limited,[2] but favorable.[18]

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Surgical removal of the gallbladder may be necessary.

EpidemiologyHereditary spherocytosis is the most common disorder of the red cell membrane and affects 1 in 2,000 people of Northern European ancestry.[citation needed] According to Harrison's Principles of Internal Medicine, the frequency is at least 1 in 5,000.

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Hereditary elliptocytosisHereditary elliptocytosis, also known as ovalocytosis, is an inherited blood disorder in which an abnormally large number of the patient's erythrocytes (i.e. red blood cells) are elliptical rather than the typical biconcave disc shape. Such morphologically distinctive erythrocytes are sometimes referred to as elliptocytes or ovalocytes. It is one of many red-cell membrane defects. In its severe forms, this disorder predisposes to haemolytic anaemia. Although pathological in humans, elliptocytosis is normal in camelids.

Hereditary elliptocytosis

Peripheral blood smear showing an abundant number of

elliptocytes.

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Historical perspectiveElliptocytosis was first described in 1904,[1] and was first recognised as a hereditary condition in 1932.[2] More recently it has become clear that the severity of the condition is highly variable,[3] and there is much genetic variability amongst those affected.

Genetic prevalenceThe incidence of hereditary elliptocytosis is hard to determine, as many sufferers of the milder forms of the disorder are asymptomatic and their condition never comes to medical attention.[5] Around 90% of those with this disorder are thought to fall into the asymptomatic population. It is estimated that its incidence is between 3 and 5 per 10,000 in the United States,[6] and that those of African and Mediterranean descent are of higher risk. Because it can confer resistance to malaria, some subtypes of hereditary elliptocytosis are significantly more prevalent in regions where malaria is endemic. For example, in equatorial Africa its incidence is estimated at 60-160 per 10,000,[7]

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and in Malayan natives its incidence is 1500-2000 per 10,000.[8] Almost all forms of hereditary elliptocytosis are autosomal dominant, and both sexes are therefore at equal risk of having the condition. The most important exception to this rule of autosomal dominance is for a subtype of hereditary elliptocytosis called hereditary pyropoikilocytosis (HPP), which is autosomal recessive.[9]

There are three major forms of hereditary elliptocytosis: common hereditary elliptocytosis, spherocytic elliptocytosis and southeast Asian ovalocytosis.

Common hereditary elliptocytosis is the most common form of elliptocytosis, and the form most extensively researched. Even when looking only at this form of elliptocytosis, there is a high degree of variability in the clinical severity of its subtypes. A clinically significant haemolytic anaemia occurs only in 5-10% of sufferers, with a strong bias towards those with more severe subtypes of the disorder.

Southeast Asian ovalocytosis and spherocytic elliptocytosis are less common subtypes predominantly

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affecting those of south-east Asian and European ethnic groups, respectively.

The following categorisation of the disorder demonstrates its heterogeneity: Common hereditary elliptocytosis (in approximate

order from least severe to most severe) With asymptomatic carrier status - individuals have no

symptoms of disease and diagnosis is only able to be made on blood film

With mild disease - individuals have no symptoms, with a mild and compensated haemolytic anaemia

With sporadic haemolysis - individuals are at risk of haemolysis in the presence of particular comorbidities, including infections, and vitamin B12 deficiency

With neonatal poikilocytosis - individuals have a symptomatic haemolytic anaemia with poikilocytosis that resolves in the first year of life

With chronic haemolysis - individual has a moderate to severe symptomatic haemolytic anaemia (this subtype has variable penetrance in some pedigrees)

With homozygosity or compound heterozygosity - depending on the exact mutations involved,

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individuals may lie anywhere in the spectrum between having a mild haemolytic anaemia and having a life-threatening haemolytic anaemia with symptoms mimicking those of HPP (see below)

With pyropoikilocytosis (HPP) - individuals are typically of African descent and have a life-threateningly severe haemolytic anaemia with micropoikilocytosis (small and misshapen erythrocytes) that is compounded by a marked instability of erythrocytes in even mildly elevated temperatures (pyropoikilocytosis is often found in burns victims and is the term is commonly used in reference to such people)

South-east Asian ovalocytosis (SAO) (also called stomatocytic elliptocytosis) - individuals are of South-East Asian descent (typically Malaysian, Indonesian, Melanesian, New Guinean or Filipino, have a mild haemolytic anaemia, and has increased resistance to malaria

Spherocytic elliptocytosis (also called hereditary haemolytic ovalocytosis) - individuals are of European descent and elliptocytes and spherocytes are

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simultaneously present in their blood

PathophysiologyCommon hereditary elliptocytosis EditA number of genes have been linked to common hereditary elliptocytosis (many involve the same gene as forms of Hereditary spherocytosis, or HS).

These mutations have a common end result; they destabilise the cytoskeletal scaffold of cells. This stability is especially important in erythrocytes as they are constantly under the influence of deforming shear forces. As disc-shaped erythrocytes pass through capillaries, which can be 2-3 micrometres wide, they are forced to assume an elliptical shape in order to fit through. Normally, this deformation lasts only as long as a cell is present in a capillary, but in hereditary elliptocytosis the instability of the cytoskeleton means that erythrocytes deformed by passing through a capillary are forever rendered elliptical. These elliptical cells are taken up by the spleen and removed from circulation when they are younger than they would normally be, meaning that the erythrocytes of people

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with hereditary elliptocytosis have a shorter than average

life-span (a normal person's erythrocytes average 120 days or more).

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Figure 2 - A schematic diagram representing the relationships between cytoskeletal molecules as relevant to hereditary elliptocytosis.EL2 and EL3: The most common genetic defects (present in two-thirds of all cases of hereditary elliptocytosis) are in genes for the polypeptides α-spectrin or β-spectrin. These two polypeptides combine with one another in vivo to form an αβ heterodimer. These αβ heterodimers then combine to form spectrin tetramers. These spectrin tetramers are among the basic structural subunits of the cytoskeleton of all cells in the body. Although there is much interindividual variability, it is generally true that α-spectrin mutations result in an inability of α-spectrin to interact properly with β-spectrin to form a heterodimer. In contrast, it is generally true that β-spectrin mutations lead to αβ heterodimers being incapable of combining to form spectrin tetramers.[11] In both cases the end result is a weakness in the cytoskeleton of the cell. Individuals with a single mutation in one of the spectrin genes are usually asymptomatic, but those who are homozygotes or are compound heterozygotes (i.e. they are heterozygous for two different elliptocytosis-causing mutations) have sufficient cell membrane instability to have a

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clinically significant haemolytic anaemia.EL1: Less common than spectrin mutations are band 4.1 mutations. Spectrin tetramers must bind to actin in order to create a proper cytoskeleton scaffold, and band 4.1 is an important protein involved in the stabilisation of the link between spectrin and actin. Similarly to the spectrin mutations, band 4.1 mutations cause a mild haemolytic anaemia in the heterozygous state, and a severe haemolytic disease in the homozygous state.EL4: Southeast Asian ovalocytosis is associated with the Band 3 protein.Another group of mutations that lead to elliptocytosis are those that cause glycophorin C deficiencies. There are three phenotypes caused by abnormal glycophorin C, these are named Gerbich, Yus and Leach (see glycophorin C for more information). Only the rarest of the three, the Leach phenotype, causes elliptocytosis. Glycophorin C has the function of holding band 4.1 to the cell membrane. It is thought that elliptocytosis in glycophorin C deficiency is actually the consequence of a band 4.1 deficit, as glycophorin C deficient individuals also have reduced intracellular band 4.1 (probably due to the reduced number of binding sites for

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band 4.1 in the absence of glycoprotein C).Inheritance of multiple mutations tends to infer more serious disease. For instance, the most common genotype responsible for HPP occurs when the affected individual inherits an α-spectrin mutation from one parent (i.e. one parent has hereditary elliptocytosis) and the other parent passes on an as-yet-undefined defect that causes the affected individual's cells to preferentially produce the defective α-spectrin rather than normal α-spectrin.

DiagnosisThe diagnosis of hereditary elliptocytosis is usually made by coupling a family history of the condition with an appropriate clinical presentation and confirmation on a blood smear. In general it requires that at least 25% of erythrocytes in the specimen are abnormally elliptical in shape, though the observed percentage of elliptocytes can be 100%. This is in contrast to the rest of the population, in which it is common for up to 15% of erythrocytes to be elliptical.[12]

If some doubt remains regarding the diagnosis, definitive diagnosis can involve osmotic fragility testing, an autohaemolysis test, and direct protein assaying by gel

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electrophoresis.

TreatmentThe vast majority of those with hereditary elliptocytosis require no treatment whatsoever. They have a mildly increased risk of developing gallstones, which is treated surgically with a cholecystectomy if pain becomes problematic.

Folate helps to reduce the extent of haemolysis in those with significant haemolysis due to hereditary elliptocytosis.

Because the spleen breaks down old and worn-out blood cells, those individuals with more severe forms of hereditary elliptocytosis can have a splenomegaly, splenectomy can be performed in case that their situation may cause a worsening of the signs and symptoms of their anaemia. These can include:

Vague, poorly localised abdominal painFatigue and dyspnoeaGrowth failureLeg ulcersGallstones.

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Removal of the spleen (splenectomy) is effective in reducing the severity of these complications, but is associated with an increased risk of overwhelming bacterial septicaemia, and is only performed on those with significant complications. Because many neonates with severe elliptocytosis progress to have only a mild disease, and because this age group is particularly susceptible to pneumococcal infections, a splenectomy is only performed on those under 5 years old when it is absolutely necessary.

Because chronic haemolysis increases an individual's risk of gallstones, people with elliptocytosis have an increased risk of suffering from gallstones. This risk is relative to the severity of the disease, and those with symptomatic elliptocytosis should have regular abdominal ultrasounds to monitor the progression of their gall bladder disease.

PrognosisThose with hereditary elliptocytosis have a good prognosis, only those with very severe disease have a shortened life expectancy.

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Hereditary pyropoikilocytosisHereditary pyropoikilocytosis (HPP) is an autosomal recessive form of hemolytic anemia characterized by an abnormal sensitivity of red blood cells to heat and

erythrocyte morphology similar to that seen in thermal burns.

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Patients with HPP tend to experience severe haemolysis and anaemia in infancy that gradually improves, evolving toward typical elliptocytosis later in life. However, the hemolysis can lead to rapid sequestration and destruction of red cells. Splenectomy is curative when this occurs.HPP has been associated with a defect of the erythrocyte membrane protein spectrin and with spectrin deficiency.It was characterized in 1975.[1]It is considered a severe form of hereditary elliptocytosis.[2]

CausesMutations of the alphaspectrin gene causes this disease.[3] HPP can be considered as a subset of hereditary elliptocytosis to homozygous and it leads to severe disruption.

DiagnosisGenetic testing for the presence of mutations in protein molecules is considered to be a confirmatory testing technique. It is important to know the risks regarding the transmission and dangers of HPP.

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Acquired hemolytic anemiaAcquired hemolytic anemia can be divided into immune and non-immune mediated forms of hemolytic anemia.

Immune Immune mediated hemolytic anaemia (direct Coombs

test is positive)

Autoimmune hemolytic anemia Warm antibody autoimmune hemolytic anemia Idiopathic Systemic lupus erythematosus (SLE) Evans' syndrome (antiplatelet antibodies and hemolytic

antibodies) Cold antibody autoimmune hemolytic anemia Idiopathic cold hemagglutinin syndrome Infectious mononucleosis and mycoplasma (atypical)

pneumonia Paroxysmal cold hemoglobinuria (rare) Alloimmune hemolytic anemia Hemolytic disease of the newborn (HDN) Rh disease (Rh D)

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ABO hemolytic disease of the newborn Anti-Kell hemolytic disease of the newborn Rhesus c hemolytic disease of the newborn Rhesus E hemolytic disease of the newborn Other blood group incompatibility (RhC, Rhe, Kidd,

Duffy, MN, P and others)Alloimmune hemolytic blood transfusion reactions (i.e., from a non-compatible blood type)

Drug induced immune mediated hemolytic anemia Penicillin (high dose) Methyldopa

Non-immuneNon-immune mediated hemolytic anemia (direct Coombs test is negative)

Drugs (i.e., some drugs and other ingested substances lead to hemolysis by direct action on RBCs, e.g., ribavirin )

Toxins (e.g., snake venom; plant poisons such as aesculin)

Trauma

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Mechanical (from heart valves, extensive vascular surgery, microvascular disease, repeated mechanical vascular trauma)

Microangiopathic hemolytic anemia (a specific subtype with causes such as TTP, HUS, DIC and HELLP syndrome)

Infections (Note: Direct Coombs test is sometimes positive in hemolytic anemia due to infection)

Malaria Babesiosis Septicemia Membrane disorders Paroxysmal nocturnal hemoglobinuria (rare acquired

clonal disorder of red blood cell surface proteins) Liver disease's

Drug induced hemolysis Drug induced hemolysis has large clinical relevance. It

occurs when drugs actively provoke red blood cell destruction. It can be divided in the following manner:

Drug-induced autoimmune hemolytic anemia

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Drug-induced nonautoimmune hemolytic anemiaA total of four mechanisms are usually described, but there is some evidence that these mechanisms may overlap.

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Cold agglutinin diseaseCold agglutinin disease is an autoimmune disease characterized by the presence of high concentrations of circulating antibodies, usually IgM, directed against red blood cells. [1] It is a form of autoimmune hemolytic anemia, specifically one in which antibodies only bind red blood cells at low body temperatures, typically 28–31 °C.

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Cold agglutinin disease was first described in 1957.[2][3]

CauseCold agglutinin disease can be either primary (arising spontaneously) or secondary (a result of another pathology).

The primary form is caused by excessive cell proliferation[4] of B lymphocytes.[5]

Secondary cold agglutinin disease is a result of an underlying condition.

In adults, this is typically due to a lymphoproliferative disease such as lymphoma and chronic lymphoid leukemia, or infection. Waldenström's macroglobulinemia may also be positive for cold agglutinins.

In children, cold agglutinin disease is often secondary to an infection, such as Mycoplasma pneumonia, mononucleosis, and HIV.

Pathophysiology

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All individuals have circulating antibodies directed against red blood cells, but their concentrations are often too low to trigger disease (titers under 64 at 4 °C). In individuals with cold agglutinin disease, these antibodies are in much higher concentrations (titers over 1000 at 4 °C).

At body temperatures of 28–31 °C, such as those encountered during winter months, and occasionally at body temperatures of 37 °C, antibodies (generally IgM) bind to the polysaccharide region of glycoproteins on the surface of red blood cells (typically the I antigen, i antigen, and Pr antigens). Binding of antibodies to red blood cells activates the classical pathway of the complement system. If the complement response is sufficient, red blood cells are damaged by the membrane attack complex, an effector of the complement cascade. In the formation of the membrane attack complex, several complement proteins are inserted into the red blood cell membrane, forming pores that lead to membrane instability and intravascular hemolysis (destruction of the red blood cell within the blood vessels).

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If the complement response is insufficient to form membrane attack complexes, then extravascular lysis will be favored over intravascular red blood cell lysis. In lieu of the membrane attack complex, complement proteins (particularly C3b and C4b) are deposited on red blood cells. This opsonization enhances the clearance of red blood cell by phagocytes in the liver, spleen, and lungs, a process termed extravascular hemolysis.

Individuals with cold agglutinin disease present with signs and symptoms of hemolytic anemia. Those with secondary agglutinin disease may also present with an underlying disease, often autoimmune.

Treatment Avoid cold weather. Treat the underlying lymphoma. No cold drinks; all drinks should be at room

temperature (or above). Requires heater to maintain temperature in cold

places. Treatment with rituximab has been described.

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Paroxysmal cold hemoglobinuria

Paroxysmal cold hemoglobinuria (PCH), also known as Donath-Landsteiner syndrome, is a disease of humans that is characterized by the sudden presence of hemoglobin in the urine (called hemoglobinuria), typically after exposure to cold temperatures. It carries the name of the Austrian internists Julius Donath (1870–1950) and Karl Landsteiner (1868–1943) who described it in 1904; it was the first condition recognized as an autoimmune disease.

PresentationPeople with PCH, a polyclonal IgG anti-P autoantibody binds to red blood cell surface antigens in the cold. This can occur in a susceptible individual as blood passes through cold extremities in cold weather. When the blood returns to the warmer central circulation, the red blood cells are lysed with complement, causing intravascular hemolysis. Hemoglobinuria and anemia can then occur. The anemia may be mild or severe.

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CausesPCH is a rare autoimmune haemolytic anaemia that can occur following an infection, when a microorganism triggers the formation of antibodies that cross-react with the P antigen on the red blood cell membrane (see article on the P antigen system). Viral infections that can cause PCH include measles, mumps, influenza, adenovirus, chickenpox, cytomegalovirus, and Epstein-Barr virus. Bacterial infections that can cause PCH include syphilis, Haemophilus influenzae and Mycoplasma pneumoniae. PCH can also be a side effect of some vaccinations. Chronic idiopathic (of unknown cause) PCH also occurs, but it is rare.

Treatment and prognosisAcute PCH tends to be transient and self-limited,[2] particularly in children. Chronic PCH associated with syphilis resolves after the syphilis is treated with appropriate antibiotics. Chronic idiopathic PCH is usually mild.

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Risk factorsPeople with PCH are sometimes advised to avoid exposure to cold temperatures.[3] If anemia is severe, blood transfusion may be needed. Careful compatibility testing by the blood bank is necessary because autoantibodies may interfere with blood typing. Prednisone may be used in individuals with PCH and severe anemia.

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Hemolytic-uremic syndromeHemolytic-uremic syndrome (or haemolytic-uraemic syndrome), abbreviated HUS, is a disease characterized by a triad of hemolytic anemia (anemia caused by destruction of red blood cells), acute kidney failure (uremia), and a low platelet count (thrombocytopenia). It predominantly, but not exclusively, affects children. Most cases are preceded by an episode of infectious, sometimes bloody, diarrhea acquired as a foodborne illness or from a contaminated water supply caused by E. coli O157:H7, other non-o157:H7 E. coli serotypes, Shigella, and Campylobacter. A variety of viruses have also been implicated as a causative agent. It is now the most common cause of acquired acute renal failure in childhood. It is a medical emergency and carries a 5–10% mortality rate; of the remainder, the majority recover without major consequences, approximately 30% suffer residual renal injury. The primary target appears to be the vascular endothelial cell. This may explain the pathogenesis of HUS, in which a characteristic renal lesion is capillary microangiopathy.

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[1]

Hemolytic-uremic syndrome

Schistocytes as seen in a person with hemolytic-uremic syndrome.HUS was first defined as a syndrome in 1955.[2][3] The

more common form of the disease, Shiga-like toxin-producing E. coli HUS (STEC-HUS), is triggered by the infectious agent E. coli O157:H7, and several other non-

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O157:H7 E. coli serotypes. Certain Shiga toxin-secreting strains of Shigella dysenteriae can also cause HUS.[4] Approximately 5% of cases are classified as pneumococcal HUS, which results from infection by Streptococcus pneumoniae, the agent that causes traditional lobar pneumonia.[5] There is also a rare, chronic, and severe form known as atypical hemolytic uremic syndrome (aHUS), which is caused by genetic defects resulting in chronic, uncontrolled complement activation.[6] Both STEC-HUS and aHUS cause endothelial damage, leukocyte activation, platelet activation, and widespread inflammation and multiple thromboses in the small blood vessels, a condition known as systemic thrombotic microangiopathy (TMA), which leads to thrombotic events as well as organ damage/failure and death.

Signs and symptomsSTEC-HUS occurs after ingestion of a strain of bacteria expressing Shiga toxin(s), usually types of E. coli, that expresses verotoxin (also called Shiga-like toxin). E. coli can produce stx1 and/or stx2 Shiga toxins, the latter

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being more dangerous and a combination of both toxins in certain ratios is usually associated with HUS. These Shiga toxins bind GB3 receptors, globotriaosylceramide, which are present in renal tissue more than any other tissue and are also found in central nervous system neurons and other tissue. Children have more GB3 receptors than adults which may be why children are more susceptible to HUS. Cattle, swine, deer, and other mammals do not have GB3 receptors, but can be asymptomatic carriers of Shiga toxin-producing bacteria. Some humans can also be asymptomatic carriers. Once the bacteria colonizes, diarrhea followed by bloody diarrhea, hemorrhagic colitis, typically follows. HUS develops about 5–10 days after onset of diarrhea, with decreased urine output (oliguria), blood in the urine (hematuria), kidney failure, thrombocytopenia (low levels of platelets) and destruction of red blood cells (microangiopathic hemolytic anemia). Hypertension is common. In some cases, there are prominent neurologic changes.[9][10][11]

Patients with HUS commonly exhibit the signs and symptoms of thrombotic microangiopathy (TMA),

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which can include abdominal pain,[12] low platelet count,[13] elevated lactate dehydrogenase LDH, a chemical released from damaged cells, and which is therefore a marker of cellular damage)[14] decreased haptoglobin (indicative of the breakdown of red blood cells)[14] anemia (low red blood cell count)/schistocytes (damaged red blood cells),[13][14] elevated creatinine (a protein waste product generated by muscle metabolism and eliminated renally,[15] proteinuria (indicative of kidney injury),[16] confusion,[12] fatigue,[17] edema (swelling),[18] nausea/vomiting,[19] and diarrhea.[20] Additionally, patients with aHUS typically present with an abrupt onset of systemic signs and symptoms such as acute kidney failure,[13] hypertension (high blood pressure),[17] myocardial infarction (heart attack),[21] stroke,[12] lung complications,[21] pancreatitis (inflammation of the pancreas),[19] liver necrosis (death of liver cells or tissue),[13][17] encephalopathy (brain dysfunction),[17] seizure,[22] and coma.[23] Failure of neurologic, cardiac, renal, and gastrointestinal (GI) organs, as well as death, can occur unpredictably at any time, either very quickly or following prolonged

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symptomatic or asymptomatic disease progression.

Atypical HUSMain article: Atypical hemolytic uremic syndromeAtypical HUS (aHUS) represents 5–10% of HUS cases[6] and is largely due to one or several genetic mutations that cause chronic, uncontrolled, and excessive activation of complement.[6] This results in platelet activation endothelial cell damage, and white blood cell activation, leading to systemic TMA, which manifests as decreased platelet count, hemolysis (breakdown of red blood cells), damage to multiple organs, and ultimately death.[7][16][25] Early signs of systemic complement-mediated TMA include thrombocytopenia (platelet count below 150,000 or a decrease from baseline of at least 25%)[14] and evidence of microangiopathic hemolysis, which is characterized by elevated LDH levels, decreased haptoglobin, decreased hemoglobin (the oxygen-containing component of blood), and/or the presence of schistocytes.[7][8][14] Despite the use of supportive care, an estimated 33–40% of patients will die or have

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end-stage renal disease (ESRD) with the first clinical manifestation of aHUS,[20][21] and 65% of patients will die, require dialysis, or have permanent renal damage within the first year after diagnosis despite plasma exchange or plasma infusion (PE/PI) therapy.[20] Patients who survive the presenting signs and symptoms of aHUS endure a chronic thrombotic and inflammatory state, which puts them at lifelong elevated risk of sudden blood clotting, kidney failure, other severe complications and premature death.[8][18]

Historically, treatment options for aHUS were limited to plasma exchange or plasma infusion (PE/PI) therapy, which carries significant safety risks[26][27] and has not been proven effective in any controlled clinical trials. Patients with aHUS and ESRD have also had to undergo lifelong dialysis, which has a 5-year survival rate of 34–38%.[28][29] In recent years the monoclonal antibody eculizumab (INN and USAN, trade name Soliris), a first-in-class terminal complement inhibitor, has been shown in clinical studies to block terminal complement activity in children and adults with aHUS, and to eliminate the need for PE/PI and new dialysis. In these studies

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eculizumab was associated with reduced TMA activity, as shown by improvement in platelet counts and kidney function, as well as hematologic normalization, complete TMA response, and TMA event-free status in a majority of patients.

PathogenesisHUS is one of the thrombotic microangiopathies, a category of disorders that includes STEC-HUS, aHUS, and thrombotic thrombocytopenic purpura (TTP). STEC-HUS is usually preceded by a prodrome of diarrhea, which is often bloody, and is caused by Shiga-like toxin-producing bacteria such as enterohemorrhagic Escherichia coli (EHEC), of which E. coli O157:H7 is the most common serotype.[31] Other serotypes also cause disease and can emerge as new causes of STEC-HUS, as occurred with E. coli O104:H4, which triggered a 2011 epidemic of STEC-HUS in Germany.[32]

The typical pathophysiology of HUS involves the binding of Shiga-toxin to the globotriaosylceramide (Gb3; also called ceramide trihexoside which accumulates in Fabry disease) receptor on the surface of

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the glomerular endothelium.[33] This action includes a cascade of signaling events leading to apoptosis and binding of leukocytes to endothelial cells. The Shiga-toxin-activated endothelial cells then become thrombogenic (clot-producing) by mechanism that is not fully understood,[34] though they have been shown to induce the release of cytokines and chemokines that are implicated in platelet activation.[35] Additionally, the binding action of Shiga-toxin inactivates a metalloproteinase called ADAMTS13, the deficiency of which causes the closely related TTP. Once ADAMTS13 is disabled, multimers of von Willebrand Factor (vWF) form and initiate platelet activation, causing microthrombus formation. The activation of platelets resulting from inhibition of ADAMTS13 is due to the hyperactivity of large multimers of uncleaved vWF. The arterioles and capillaries of the body become obstructed by the resulting complexes of activated platelets, which have adhered to the endothelium via large multimeric vWF. Through a mechanism known as microangiopathic hemolysis, the growing thrombi lodged in smaller vessels destroy red blood cells (RBCs) as they squeeze

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through the narrowed blood vessels, forming schistocytes, or fragments of sheared RBCs.[25] The presence of schistocytes is a key finding that helps to diagnose HUS. Typically, this hemolysis results in a hemoglobin level of less than 80 g/L.

Shiga-toxin directly activates the alternative complement pathway and also interferes with complement regulation by binding to complement factor H, an inhibitor of the complement cascade. Shiga-toxin causes complement-mediated platelet, leukocyte, and endothelial cell activation, resulting in systemic hemolysis, inflammation and thrombosis.[36][37][38] Severe clinical complications of TMA have been reported in patients from 2 weeks to more than 44 days after presentation with STEC-HUS, with improvements in clinical condition extending beyond this time frame, suggesting that complement activation persists beyond the acute clinical presentation and for at least 4 months.[39]

The consumption of platelets as they adhere to the thrombi lodged in the small vessels typically leads to mild or moderate thrombocytopenia with a platelet count

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of less than 60,000 per microliter.[40] As in the related condition TTP, reduced blood flow through the narrowed blood vessels of the microvasculature leads to reduced blood flow to vital organs, and ischemia may develop.[9] The kidneys and the central nervous system (brain and spinal cord) are the parts of the body most critically dependent on high blood flow, and are thus the most likely organs to be affected. However, in comparison to TTP, the kidneys tend to be more severely affected in HUS, and the central nervous system is less commonly affected.[41]

In contrast with typical disseminated intravascular coagulation seen with other causes of septicemia and occasionally with advanced cancer, coagulation factors are not consumed in HUS (or TTP) and the coagulation screen, fibrinogen level, and assays for fibrin degradation products such as "D-Dimers", are generally normal despite the low platelet count (thrombocytopenia).HUS occurs after 3–7% of all sporadic E. coli O157:H7 infections and up to approximately 20% or more of epidemic infections.[42] Children and adolescents are

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commonly affected.[43] Grossly, the kidneys may show patchy or diffuse renal cortical necrosis. Histologically, the glomeruli show thickened and sometimes split capillary walls due largely to endothelial swelling. Large deposits of fibrin-related materials in the capillary lumens, subendothelially, and in the mesangium are also found along with mesangiolysis. Interlobular and afferent arterioles show fibrinoid necrosis and intimal hyperplasia and are often occluded by thrombi.[10]

STEC-HUS most often affects infants and young children, but also occurs in adults. The most common form of transmission is ingestion of undercooked meat, unpasteurized fruits and juices, contaminated produce, contact with unchlorinated water, and person-to-person transmission in daycare or long-term care facilities.[23]

Unlike typical HUS, aHUS does not follow STEC infection and is thought to result from one or several genetic mutations that cause chronic, uncontrolled, and excessive activation of complement.[6] This leads to platelet activation, endothelial cell damage, and white blood cell activation, leading to systemic TMA, which

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manifests as decreased platelet count, hemolysis, damage to multiple organs, and ultimately, death.[7][16][25] Early signs of systemic complement-mediated TMA include thrombocytopenia (platelet count below 150,000 or a decrease from baseline of at least 25%)[14] and evidence of microangiopathic hemolysis, which is characterized by elevated LDH levels, decreased haptoglobin, decreased hemoglobin, and/or the presence of schistocytes.

DiagnosisThe similarities between HUS, aHUS, and TTP make differential diagnosis essential.[7][8] All three of these systemic TMA-causing diseases are characterized by thrombocytopenia[14] and microangiopathic hemolysis,[6][14] plus one or more of the following: neurological symptoms (e.g., confusion,[6][22] cerebral convulsions,[22] seizures[19]); renal impairment[14] (e.g., elevated creatinine,[15] decreased estimated glomerular filtration rate [eGFR],[15] abnormal urinalysis[44]); and gastrointestinal (GI) symptoms (e.g., diarrhea,[17][20] nausea/vomiting,[19] abdominal pain,[19] gastroenteritis[14][17]).The presence of diarrhea does

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not exclude aHUS as the cause of TMA, as 28% of patients with aHUS present with diarrhea and/or gastroenteritis.[16][17] First diagnosis of aHUS is often made in the context of an initial, complement-triggering infection, and Shiga-toxin has also been implicated as a trigger that identifies patients with aHUS.[39] Additionally, in one study, mutations of genes encoding several complement regulatory proteins were detected in 8 of 36 (22%) patients diagnosed with STEC-HUS.[45] However, the absence of an identified complement regulatory gene mutation does not preclude aHUS as the cause of the TMA, as approximately 50% of patients with aHUS lack an identifiable mutation in complement regulatory genes.[17]

Diagnostic work-up supports the differential diagnosis of TMA-causing diseases. A positive Shiga-toxin/EHEC test confirms a cause for STEC-HUS,[23][31] and severe ADAMTS13 deficiency (i.e., ≤5% of normal ADAMTS13 levels) confirms a diagnosis of TTP.

Treatment

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The effect of antibiotics in E. coli O157:H7 colitis is controversial. Certain antibiotics may stimulate further verotoxin production and thereby increase the risk of HUS.[40][47] However, there is also tentative evidence that some antibiotics like quinolones may decrease the risk of hemolytic uremic syndrome.[47] In the 1990s a group of pediatricians from the University of Washington used a network of 47 cooperating laboratories in Washington, Oregon, Idaho, and Wyoming to prospectively identify 73 children younger than 10 years of age who had diarrhea caused by E. coli O157:H7 The hemolytic–uremic syndrome developed in 5 of the 9 children given antibiotics (56 percent), and in 5 of the 62 children who were not given antibiotics (8 percent, P<0.001).[48]

Treatment of HUS is generally supportive, with dialysis as needed. Platelet transfusion may actually worsen the outcome.

In most children with postdiarrheal HUS, there is a good chance of spontaneous resolution, so observation in a hospital is often all that is necessary, with supportive

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care such as hemodialysis where indicated. If a diagnosis of STEC-HUS is confirmed, plasmapheresis (plasma exchange) is contraindicated. However, plasmapheresis may be indicated when there is diagnostic uncertainty between HUS and TTP.

There are case reports of experimental treatments with eculizumab, a monoclonal antibody against CD5 that blocks part of the complement system, being used to treat congenital atypical hemolytic uremic syndrome,[49] as well as severe shiga-toxin associated hemolytic uremic syndrome.[50] These have shown promising results.[citation needed] Eculizeumab was approved by the U.S. Food and Drug Administration (FDA) on March 13, 2007 for the treatment of paroxysmal nocturnal hemoglobinuria (PNH), a rare, progressive, and sometimes life-threatening disease characterized by excessive hemolysis; and on September 23, 2011 for the treatment of atypical hemolytic uremic syndrome (aHUS) It was approved by the European Medicines Agency for the treatment of PNH on June 20, 2007, and on November 29, 2011 for the treatment of aHUS. However, of note is the exceedingly high cost of

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treatment, with one year of the drug costing over $500,000.[citation needed]

PrognosisAcute renal failure occurs in 55–70% of patients with STEC-HUS, although up to 70–85% recover renal function.[51] Patients with aHUS generally have poor outcomes, with up to 50% progressing to ESRD or irreversible brain damage; as many as 25% die during the acute phase.[51] However, with aggressive treatment, more than 90% of patients survive the acute phase of HUS, and only about 9% may develop ESRD. Roughly one-third of persons with HUS have abnormal kidney function many years later, and a few require long-term dialysis. Another 8% of persons with HUS have other lifelong complications, such as high blood pressure, seizures, blindness, paralysis, and the effects of having part of their colon removed. The overall mortality rate from HUS is 5–15%. Children and the elderly have a worse prognosis.[52]

Epidemiology

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The country with the highest incidence of HUS is Argentina[53][54][55][56] and it performs a key role in the research of this condition.

In the United States, the overall incidence of HUS is estimated at 2.1 cases per 100,000 persons/year, with a peak incidence between six months and four years of age.[1]

HUS and the E. coli infections that cause it have been the source of much negative publicity for the FDA, meat industries, and fast-food restaurants since the 1990s, especially in the contaminations linked to Jack in the Box restaurants. The disease was also featured in the Robin Cook novel Toxin. In 2006, an epidemic of harmful E. coli emerged in the United States due to contaminated spinach. In June, 2009, Nestle Toll House cookie dough was linked to an outbreak of E. coli O157:H7 in the United States, which sickened 70 people in 30 states.[1]

In May, 2011 an epidemic of bloody diarrhea caused by E. coli O104:H4-contaminated fenugreek seeds hit Germany. Tracing the epidemic revealed more than

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3,800 cases, with HUS developing in more than 800 of the cases, including 36 fatal cases. Nearly 90% of the HUS cases were in adults.[57][58] In response to the crisis, Alexion Pharmaceuticals, Inc., the makers of Soliris (eculizumab), initiated of an open-label clinical trial to investigate eculizumab as a treatment for patients with Shiga-toxin-producing E. coli hemolytic uremic syndrome (STEC-HUS). Alexion also initiated an eculizumab access program whereby the company provided eculizumab free of charge throughout the crisis. The study was designed to include all patients treated with eculizumab during the 2011 STEC-HUS outbreak.

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Hereditary persistence of fetal hemoglobin

Hereditary persistence of fetal hemoglobin (HPFH, BrE: Hereditary persistence of foetal haemoglobin) is a benign condition in which significant fetal hemoglobin (hemoglobin F) production continues well into adulthood, disregarding the normal shutoff point after which only adult-type hemoglobin should be produced.

CausesThis is usually caused by mutations in the β or α globin gene cluster, or the γ promoter gene region. .[citation needed] The percentage of incorrect expression might be as low as 10-15% or as high as 100% of the total hemoglobin, usually higher in homozygotes than in heterozygotes.[2]

EpidemiologyHPFH may alleviate the severity of certain hemoglobinopathies and thalassemias, and is selected for

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in populations with a high prevalence of these conditions (which in turn are often selected for in areas where malaria is endemic). Thus, it has been found to affect Americans of African and Greek descent.[3]

PresentationThe condition is usually asymptomatic, and is only noticed when screening for other hemoglobin disorders.

Benefit to persons with sickle cell diseaseIn persons with sickle cell disease, high levels of fetal hemoglobin as found in a newborn or as found abnormally in persons with hereditary persistence of fetal hemoglobin, the HbF causes the sickle cell disease to be less severe. In essence the HbF inhibits polymerization of HbS. A similar mechanism occurs with persons who have sickle cell trait. Approximately 40% of the hemoglobin is in the HbS form while the rest is in normal HbA form. The HbA form interferes with HbS polymerization.

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Hereditary stomatocytosisHereditary stomatocytosis describes a number of inherited autosomal dominant human conditions which affect the red blood cell, in which the membrane or outer coating of the cell 'leaks' sodium and potassium ions.

Hereditary stomatocytosis

Stomatocytes

Pathophysiology

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Osmosis leads to the red blood cell having a constant tendency to swell and burst. This tendency is countered by manipulating the flow of sodium and potassium ions. A 'pump' forces sodium out of the cell and potassium in, and this action is balanced by a process called 'the passive leak'. In the hereditary stomatocytoses, the passive leak is increased and the cell becomes swamped with salt and water. The cell lyses and a haemolytic anaemia results. For as yet unknown reasons, the cells take on the shape of a cup, with a 'mouth-shaped' (stoma) area of central pallor. The two varieties of stomatocytosis classified with respect to hydration status are overhydrated (hydrocytosis) and dehydrated (xerocytosis).

VariantsHaematologists have identified a number of variants. These can be classified as below.

Overhydrated hereditary stomatocytosis Dehydrated HSt (hereditary xerocytosis; hereditary

hyperphosphatidylcholine haemolytic anaemia) Dehydrated with perinatal ascites

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Cryohydrocytosis 'Blackburn' variant. Familial pseudohyperkalaemiaThere are other families that do not fall neatly into any of these classifications.[1]

Stomatocytosis is also found as a hereditary disease in Alaskan malamute and miniature schnauzer dogs.

TreatmentAt present there is no specific treatment. Many patients with haemolytic anaemia take folic acid (vitamin B9) since the greater turnover of cells consumes this vitamin. During crises transfusion may be required. Clotting problems can occur for which anticoagulation may be needed. Unlike hereditary spherocytosis, splenectomy is contraindicated.

CausesThe cause for these hereditary conditions is now understood to be various mutations in the erythrocyte membrane protein, band 3. It is this protein which mediates the cation leaks which are characteristic of this

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disease.

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Hexokinase deficiencyHexokinase deficiency is an anemia-causing condition associated with inadequate hexokinase.[1][2] Specifically, the HK1 isozyme is involved.[3]

An acronym for Hexokinase deficiency is HK deficiency, and it is a genetic disease. The person must be homozygous for the trait, as being heterozygous would just make the person a carrier of that mutated gene. [4]

The cause of hexokinase deficiency is linked to mutations of the HK gene and the encoding of the HK enzyme. The result of the mutations lead to reduction in HK activity.

Ineffective erythropoiesisIneffective erythropoiesis is active erythropoiesis with premature death of red blood cells, a decreased output of RBCs from the bone marrow, and, consequently, anemia. It is a condition characterised by the presence or

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abundance of dysfunctional progenitor cells

Rh deficiency syndromeRh deficiency syndrome is a type of hemolytic anemia that involves erythrocytes whom membranes are deficient in Rh antigens. It is considered a rare condition.

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Sickle-cell disease

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Sickle-cell disease (SCD) is a group of blood disorders

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typically inherited from a person's parents.[2] The most common type is known as sickle-cell anaemia (SCA). It results in an abnormality in the oxygen-carrying protein haemoglobin (hemoglobin S) found in red blood cells. This leads to a rigid, sickle-like shape under certain circumstances.[2] Problems in sickle cell disease typically begin around 5 to 6 months of age. A number of health problems may develop, such as attacks of pain ("sickle-cell crisis"), anemia, swelling in the hands and feet, bacterial infections, and stroke.[1] Long term pain may develop as people get older. The average life expectancy in the developed world is 40 to 60 years.Figure (A) shows normal red blood cells flowing freely through veins. The inset shows a cross section of a normal red blood cell with normal haemoglobin. Figure (B) shows abnormal, sickled red blood cells sticking at the branching point in a vein. The inset image shows a cross-section of a sickle cell with long polymerized sickle haemoglobin(HbS) strands stretching and distorting the cell shape.

Sickle-cell disease occurs when a person inherits two abnormal copies of the haemoglobin gene, one from

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each parent.[3] This gene occurs in chromosome 11.[9] Several subtypes exist, depending on the exact mutation in each haemoglobin gene.[2] An attack can be set off by temperature changes, stress, dehydration, and high altitude.[1] A person with a single abnormal copy does not usually have symptoms and is said to have sickle-cell trait.[3] Such people are also referred to as carriers.[5] Diagnosis is by a blood test and some countries test all babies at birth for the disease. Diagnosis is also possible during pregnancy.[4]

The care of people with sickle-cell disease may include infection prevention with vaccination and antibiotics, high fluid intake, folic acid supplementation, and pain medication.[5][6] Other measures may include blood transfusion, and the medication hydroxycarbamide (hydroxyurea).[6] A small proportion of people can be cured by a transplant of bone marrow cells.[2]

As of 2015 about 4.4 million people have sickle-cell disease while an additional 43 million have sickle-cell trait.[7][10] About 80% of sickle-cell disease cases are believed to occur in sub-Saharan Africa.[11] It also

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occurs relatively frequently in parts of India, the Arabian peninsula, and among people of African origin living in other parts of the world.[12] In 2015, it resulted in about 114,800 deaths.[8] The condition was first described in the medical literature by the American physician James B. Herrick in 1910.[13][14] In 1949 the genetic transmission was determined by E. A. Beet and J. V. Neel. In 1954 the protective effect against malaria of sickle-cell trait was described.

Signs and symptoms

Sickle-cell anemia.

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Sickle-cells in human blood: both normal red blood cells

and sickle-shaped cells are present.

Normal blood cells next to a sickle-blood cell, colored scanning electron microscope imageSigns of sickle cell disease usually begin in early childhood. The severity of symptoms can vary from person to person.[15] Sickle-cell disease may lead to various acute and chronic complications, several of which have a high mortality rate.[16]

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Sickle-cell crisisThe terms "sickle-cell crisis" or "sickling crisis" may be used to describe several independent acute conditions occurring in patients with SCD. SCD results in anemia and crises that could be of many types including the vaso-occlusive crisis, aplastic crisis, sequestration crisis, haemolytic crisis, and others. Most episodes of sickle-cell crises last between five and seven days.[17] "Although infection, dehydration, and acidosis (all of which favor sickling) can act as triggers, in most instances, no predisposing cause is identified."

Vaso-occlusive crisisThe vaso-occlusive crisis is caused by sickle-shaped red blood cells that obstruct capillaries and restrict blood flow to an organ resulting in ischaemia, pain, necrosis, and often organ damage. The frequency, severity, and duration of these crises vary considerably. Painful crises are treated with hydration, analgesics, and blood transfusion; pain management requires opioid administration at regular intervals until the crisis has settled. For milder crises, a subgroup of patients manage on nonsteroidal anti-inflammatory drugs (NSAIDs) such

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as diclofenac or naproxen. For more severe crises, most patients require inpatient management for intravenous opioids; patient-controlled analgesia devices are commonly used in this setting. Vaso-occlusive crisis involving organs such as the penis[19] or lungs are considered an emergency and treated with red-blood cell transfusions. Incentive spirometry, a technique to encourage deep breathing to minimise the development of atelectasis, is recommended.[20]

Splenic sequestration crisisBecause of its narrow vessels and function in clearing defective red blood cells, the spleen is frequently affected.[21][needs update] It is usually infarcted before the end of childhood in individuals suffering from sickle-cell anemia. This spleen damage increases the risk of infection from encapsulated organisms;[22][23] preventive antibiotics and vaccinations are recommended for those lacking proper spleen function.

Splenic sequestration crises are acute, painful enlargements of the spleen, caused by intrasplenic trapping of red cells and resulting in a precipitous fall in

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haemoglobin levels with the potential for hypovolemic shock. Sequestration crises are considered an emergency. If not treated, patients may die within 1–2 hours due to circulatory failure. Management is supportive, sometimes with blood transfusion. These crises are transient, they continue for 3–4 hours and may last for one day.[24]

Acute chest syndromeAcute chest syndrome (ACS) is defined by at least two of the following signs or symptoms: chest pain, fever, pulmonary infiltrate or focal abnormality, respiratory symptoms, or hypoxemia.[25] It is the second-most common complication and it accounts for about 25% of deaths in patients with SCD, majority of cases present with vaso-occlusive crises then they develop ACS.[26][27] Nevertheless, about 80% of patients have vaso-occlusive crises during ACS.

Aplastic crisisAplastic crises are acute worsenings of the patient's baseline anaemia, producing pale appearance, fast heart rate, and fatigue. This crisis is normally triggered by

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parvovirus B19, which directly affects production of red blood cells by invading the red cell precursors and multiplying in and destroying them.[28] Parvovirus infection almost completely prevents red blood cell production for two to three days. In normal individuals, this is of little consequence, but the shortened red cell life of SCD patients results in an abrupt, life-threatening situation. Reticulocyte counts drop dramatically during the disease (causing reticulocytopenia), and the rapid turnover of red cells leads to the drop in haemoglobin. This crisis takes 4 days to one week to disappear. Most patients can be managed supportively; some need blood transfusion.[29]

Haemolytic crisisHaemolytic crises are acute accelerated drops in haemoglobin level. The red blood cells break down at a faster rate. This is particularly common in patients with coexistent G6PD deficiency.[30] Management is supportive, sometimes with blood transfusions.[20]

OtherOne of the earliest clinical manifestations is dactylitis,

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presenting as early as six months of age, and may occur in children with sickle-cell trait.[31] The crisis can last up to a month.[32] Another recognised type of sickle crisis, acute chest syndrome, is characterised by fever, chest pain, difficulty breathing, and pulmonary infiltrate on a chest X-ray. Given that pneumonia and sickling in the lung can both produce these symptoms, the patient is treated for both conditions.[33] It can be triggered by painful crisis, respiratory infection, bone-marrow embolisation, or possibly by atelectasis, opiate administration, or surgery.[citation needed] Hematopoietic ulcers may also occur.

GeneticNormally, humans have haemoglobin A, which consists of two alpha and two beta chains, haemoglobin A2, which consists of two alpha and two delta chains, and haemoglobin F, consisting of two alpha and two gamma chains in their bodies. Of these, haemoglobin F dominates until about 6 weeks of age. Afterwards, haemoglobin A dominates throughout life.[citation needed] In people diagnosed with sickle cell disease, at least one of the beta-globin subunits in hemoglobin is

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replaced with hemoglobin S. In sickle cell anemia, a common form of sickle cell disease, hemoglobin S replaces both beta-globin subunits in hemoglobin.[15]

Sickle-cell conditions have an autosomal recessive pattern of inheritance from parents. The types of haemoglobin a person makes in the red blood cells depend on what haemoglobin genes are inherited from her or his parents. If one parent has sickle-cell anaemia and the other has sickle-cell trait, then the child has a 50% chance of having sickle-cell disease and a 50% chance of having sickle-cell trait. When both parents have sickle-cell trait, a child has a 25% chance of sickle-cell disease, 25% do not carry any sickle-cell alleles, and 50% have the heterozygous condition.[35]

Sickle-cell gene mutation probably arose spontaneously in different geographic areas, as suggested by restriction endonuclease analysis. These variants are known as Cameroon, Senegal, Benin, Bantu, and Saudi-Asian. Their clinical importance is because some are associated with higher HbF levels, e.g., Senegal and Saudi-Asian variants, and tend to have milder disease.[36]

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In people heterozygous for HgbS (carriers of sickling haemoglobin), the polymerisation problems are minor, because the normal allele is able to produce over 50% of the haemoglobin. In people homozygous for HgbS, the presence of long-chain polymers of HbS distort the shape of the red blood cell from a smooth doughnut-like shape to ragged and full of spikes, making it fragile and susceptible to breaking within capillaries. Carriers have symptoms only if they are deprived of oxygen (for example, while climbing a mountain) or while severely dehydrated. The sickle-cell disease occurs when the sixth amino acid, glutamic acid, is replaced by valine to change its structure and function; as such, sickle-cell anemia is also known as E6V. Valine is hydrophobic, causing the haemoglobin to collapse on itself occasionally. The structure is not changed otherwise. When enough haemoglobin collapses on itself the red blood cells become sickle-shaped.[citation needed]

The gene defect is a known mutation of a single nucleotide (see single-nucleotide polymorphism - SNP) (A to T) of the β-globin gene, which results in glutamic acid (E/Glu) being substituted by valine (V/Val) at

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position 6.[note 1] Haemoglobin S with this mutation is referred to as HbS, as opposed to the normal adult HbA. This is normally a benign mutation, causing no apparent effects on the secondary, tertiary, or quaternary structures of haemoglobin in conditions of normal oxygen concentration. What it does allow for, under conditions of low oxygen concentration, is the polymerization of the HbS itself. The deoxy form of haemoglobin exposes a hydrophobic patch on the protein between the E and F helices. The hydrophobic side chain of the valine residue at position 6 of the beta chain in haemoglobin is able to associate with the hydrophobic patch, causing HbS molecules to aggregate and form fibrous precipitates.

The allele responsible for sickle-cell anaemia can be found on the short arm of chromosome 11, more specifically 11p15.5. A person who receives the defective gene from both father and mother develops the disease; a person who receives one defective and one healthy allele remains healthy, but can pass on the disease and is known as a carrier or heterozygote. Heterozygotes are still able to contract malaria, but their symptoms are generally less severe.[37]

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Due to the adaptive advantage of the heterozygote, the disease is still prevalent, especially among people with recent ancestry in malaria-stricken areas, such as Africa, the Mediterranean, India, and the Middle East.[38] Malaria was historically endemic to southern Europe, but it was declared eradicated in the mid-20th century, with the exception of rare sporadic cases.[39]

The malaria parasite has a complex lifecycle and spends part of it in red blood cells. In a carrier, the presence of the malaria parasite causes the red blood cells with defective haemoglobin to rupture prematurely, making the Plasmodium parasite unable to reproduce. Further, the polymerization of Hb affects the ability of the parasite to digest Hb in the first place. Therefore, in areas where malaria is a problem, people's chances of survival actually increase if they carry sickle-cell trait (selection for the heterozygote).

In the USA, with no endemic malaria, the prevalence of sickle-cell anaemia among African Americans is lower (about 0.25%) than in West Africa (about 4.0%) and is falling. Without endemic malaria, the sickle-cell

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mutation is purely disadvantageous and tends to decline in the affected population by natural selection, and now artificially through prenatal genetic screening. However, the African American community descends from a significant admixture of several African and non-African ethnic groups and also represents the descendants of survivors of slavery and the slave trade. Thus, a lower degree of endogamy and, particularly, abnormally high health-selective pressure through slavery may be the most plausible explanations for the lower prevalence of sickle-cell anaemia (and, possibly, other genetic diseases) among African Americans compared to West Africans. Another factor that limits the spread of sickle-cell genes in North America is the absence of cultural proclivities to polygamy, which allows affected males to continue to seek unaffected children with multiple partners.

Pathophysiology

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Scanning electron micrograph showing a mixture of red blood cells, some with round normal morphology, some with mild sickling showing elongation and bendingThe loss of red blood cell elasticity is central to the pathophysiology of sickle-cell disease. Normal red blood cells are quite elastic, which allows the cells to deform to pass through capillaries. In sickle-cell disease, low oxygen tension promotes red blood cell sickling and repeated episodes of sickling damage the cell membrane and decrease the cell's elasticity. These cells fail to return to normal shape when normal oxygen tension is restored.

As a

consequence, these rigid blood cells are unable to deform as they pass through narrow capillaries, leading

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to vessel occlusion and ischaemia.

The actual anaemia of the illness is caused by haemolysis, the destruction of the red cells, because of their shape. Although the bone marrow attempts to compensate by creating new red cells, it does not match the rate of destruction.[41] Healthy red blood cells typically function for 90–120 days, but sickled cells only last 10–20 days.

DiagnosisIn HbSS, the complete blood count reveals haemoglobin levels in the range of 6–8 g/dl with a high reticulocyte count (as the bone marrow compensates for the destruction of sickled cells by producing more red blood cells). In other forms of sickle-cell disease, Hb levels tend to be higher. A blood film may show features of hyposplenism (target cells and Howell-Jolly bodies).

Sickling of the red blood cells, on a blood film, can be induced by the addition of sodium metabisulfite. The presence of sickle haemoglobin can also be demonstrated with the "sickle solubility test". A mixture

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of haemoglobin S (Hb S) in a reducing solution (such as sodium dithionite) gives a turbid appearance, whereas normal Hb gives a clear solution.

Abnormal haemoglobin forms can be detected on haemoglobin electrophoresis, a form of gel electrophoresis on which the various types of haemoglobin move at varying speeds. Sickle-cell haemoglobin (HgbS) and haemoglobin C with sickling (HgbSC)—the two most common forms—can be identified from there. The diagnosis can be confirmed with high-performance liquid chromatography. Genetic testing is rarely performed, as other investigations are highly specific for HbS and HbC.[43]

An acute sickle-cell crisis is often precipitated by infection. Therefore, a urinalysis to detect an occult urinary tract infection, and chest X-ray to look for occult pneumonia should be routinely performed.[44]

People who are known carriers of the disease often undergo genetic counseling before they have a child. A test to see if an unborn child has the disease takes either a blood sample from the fetus or a sample of amniotic

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fluid. Since taking a blood sample from a fetus has greater risks, the latter test is usually used. Neonatal screening provides not only a method of early detection for individuals with sickle-cell disease, but also allows for identification of the groups of people that carry the sickle cell trait.

ManagementFolic acid and penicillinFolic acid daily for life is recommended. From birth to five years of age, penicillin daily due to the immature immune system that makes them more prone to early childhood illnesses is also recommended.

Malaria preventionThe protective effect of sickle-cell trait does not apply to people with sickle cell disease; in fact, they are more vulnerable to malaria, since the most common cause of painful crises in malarial countries is infection with malaria. It has therefore been recommended that people with sickle-cell disease living in malarial countries should receive anti-malarial chemoprophylaxis for life.

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[46]

Vaso-occlusive crisisMost people with sickle-cell disease have intensely painful episodes called vaso-occlusive crises. However, the frequency, severity, and duration of these crises vary tremendously. Painful crises are treated symptomatically with pain medications; pain management requires opioid administration at regular intervals until the crisis has settled. For milder crises, a subgroup of patients manage on NSAIDs (such as diclofenac or naproxen). For more severe crises, most patients require inpatient management for intravenous opioids; patient-controlled analgesia (PCA) devices are commonly used in this setting. Diphenhydramine is also an effective agent that doctors frequently prescribe to help control itching associated with the use of opioids.[citation needed]

Acute chest crisisManagement is similar to vaso-occlusive crisis, with the addition of antibiotics (usually a quinolone or macrolide, since cell wall-deficient ["atypical"] bacteria are thought to contribute to the syndrome),[47] oxygen

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supplementation for hypoxia, and close observation. Should the pulmonary infiltrate worsen or the oxygen requirements increase, simple blood transfusion or exchange transfusion is indicated. The latter involves the exchange of a significant portion of the person's red cell mass for normal red cells, which decreases the percent of haemoglobin S in the patient's blood. The patient with suspected acute chest syndrome should be admitted to the hospital with worsening A-a gradient an indication for ICU admission.[25]

HydroxyureaThe first approved drug for the causative treatment of sickle-cell anaemia, hydroxyurea, was shown to decrease the number and severity of attacks in a study in 1995[48] and shown to possibly increase survival time in a study in 2003.[49] This is achieved, in part, by reactivating fetal haemoglobin production in place of the haemoglobin S that causes sickle-cell anaemia. Hydroxyurea had previously been used as a chemotherapy agent, and there is some concern that long-term use may be harmful, but this risk has been shown to be either absent or very small and it is likely

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that the benefits outweigh the risks.[16][50]

Blood transfusionBlood transfusions are often used in the management of sickle-cell disease in acute cases and to prevent complications by decreasing the number of red blood cells (RBC) that can sickle by adding normal red blood cells.[51] In children preventative red blood cell (RBC) transfusion therapy has been shown to reduce the risk of first stroke or silent stroke when transcranial Doppler (TCD) ultrasonography shows abnormal cerebral blood flow.[6] In those who have sustained a prior stroke event it also reduces the risk of recurrent stroke and additional silent strokes.[52][53]

Bone marrow transplantBone marrow transplants have proven effective in children. Bone marrow transplants are the only known cure for SCD.[54] However, bone marrow transplants are difficult to obtain because of the specific HLA typing necessary. Ideally, a close relative (allogeneic) would donate the bone marrow necessary for transplantation.

Prognosis505

About 90% of people survive to age 20, and close to 50% survive beyond the fifth decade.[55] In 2001, according to one study performed in Jamaica, the estimated mean survival for people with sickle-cell was 53 years old for men and 58 years old for women with homozygous SCD.[56] The specific life expectancy in much of the developing world is unknown.[57]

ComplicationsSickle-cell anaemia can lead to various complications, including:

Increased risk of severe bacterial infections due to loss of functioning spleen tissue (and comparable to the risk of infections after having the spleen removed surgically). These infections are typically caused by encapsulated organisms such as Streptococcus pneumoniae and Haemophilus influenzae. Daily penicillin prophylaxis is the most commonly used treatment during childhood, with some haematologists continuing treatment indefinitely. Patients benefit today from routine vaccination for S. pneumoniae.[58]

Stroke, which can result from a progressive narrowing

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of blood vessels, prevents oxygen from reaching the brain. Cerebral infarction occurs in children and cerebral haemorrhage in adults.[citation needed]

Silent stroke causes no immediate symptoms, but is associated with damage to the brain. Silent stroke is probably five times as common as symptomatic stroke. About 10–15% of children with SCD suffer strokes, with silent strokes predominating in the younger patients.[59][60]

Cholelithiasis (gallstones) and cholecystitis may result from excessive bilirubin production and precipitation due to prolonged haemolysis.

Avascular necrosis (aseptic bone necrosis) of the hip and other major joints may occur as a result of ischaemia.[61][needs update]

Decreased immune reactions due to hyposplenism (malfunctioning of the spleen)[62]

Priapism and infarction of the penis[63] Osteomyelitis (bacterial bone infection), the most

common cause of osteomyelitis in SCD is Salmonella (especially the atypical serotypes Salmonella typhimurium, Salmonella enteritidis, Salmonella

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choleraesuis and Salmonella paratyphi B), followed by Staphylococcus aureus and Gram-negative enteric bacilli perhaps because intravascular sickling of the bowel leads to patchy ischaemic infarction.[64]

Acute papillary necrosis in the kidneys Leg ulcers[65] In eyes, background retinopathy, proliferative

retinopathy, vitreous haemorrhages, and retinal detachments can result in blindness.[66] Regular annual eye checks are recommended.

During pregnancy, intrauterine growth retardation, spontaneous abortion, and pre-eclampsia

Chronic pain: Even in the absence of acute vaso-occlusive pain, many patients have unreported chronic pain.[67]

Pulmonary hypertension (increased pressure on the pulmonary artery) can lead to strain on the right ventricle and a risk of heart failure; typical symptoms are shortness of breath, decreased exercise tolerance, and episodes of syncope.[citation needed] 21% of children and 30% of adults have evidence of pulmonary hypertension when tested; this is associated

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with reduced walking distance and increased mortality.[68]

Chronic kidney failure due to sickle-cell nephropathy manifests itself with hypertension, protein loss in the urine, loss of red blood cells in urine and worsened anaemia. If it progresses to end-stage renal failure, it carries a poor prognosis

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Sideroblastic anemiaSideroblastic anemia or sideroachrestic anemia is a form of anemia in which the bone marrow produces ringed sideroblasts rather than healthy red blood cells (erythrocytes).[1] In sideroblastic anemia, the body has iron available but cannot incorporate it into hemoglobin, which red blood cells need in order to transport oxygen efficiently. The disorder may be caused either by a genetic disorder or indirectly as part of myelodysplastic syndrome,[2] which can evolve into hematological malignancies (especially acute myelogenous leukemia).

Sideroblastic anemia

A ring sideroblast visualized by Prussian blue stainSideroblasts (sidero- + -blast) are atypical, abnormal nucleated erythroblasts (precursors to mature

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red blood cells) with granules of iron accumulated in the mitochondria surrounding the nucleus.[3] Normally, sideroblasts are present in the bone marrow, and enter the circulation after maturing into a normal erythrocyte.

Ring sideroblasts are named so because iron-laden mitochondria form a ring around the nucleus. To count a cell as a ring sideroblast, the ring must encircle a third or more of the nucleus and contain five or more iron granules, according to the 2008 WHO classification of the tumors of the hematopoietic and lymphoid tissues.[4]

The WHO International Working Group on Morphology of MDS (IWGM-MDS) defined three types of sideroblasts:Type 1 sideroblasts: fewer than 5 siderotic granules in the cytoplasmType 2 sideroblasts: 5 or more siderotic granules, but not in a perinuclear distributionType 3 or ring sideroblasts: 5 or more granules in a perinuclear position, surrounding the nucleus or encompassing at least one third of the nuclear circumference.

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SymptomsSymptoms of sideroblastic anemia include skin paleness, fatigue, dizziness, and enlarged spleen and liver. Heart disease, liver damage, and kidney failure can result from iron buildup in these organs.[7]

CausesCauses of sideroblastic anemia can be categorized into three groups: congenital sideroblastic anemia, acquired clonal sideroblastic anemia, and acquired reversible sideroblastic anemia. All cases involve dysfunctional heme synthesis or processing. This leads to granular deposition of iron in the mitochondria that form a ring around the nucleus of the developing red blood cell. Congenital forms often present with normocytic or microcytic anemia while acquired forms of sideroblastic anemia are often normocytic or macrocytic.

Congenital sideroblastic anemia X-linked sideroblastic anemia: This is the most

common congenital cause of sideroblastic anemia and involves a defect in ALAS2,[8] which is involved in

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the first step of heme synthesis. Although X-linked, approximately one third of patients are women due to skewed X-inactivation.

Autosomal recessive sideroblastic anemia involves mutations in the SLC25A38 gene. The function of this protein is not fully understood, but it is involved in mitochondrial transport of glycine. Glycine is a substrate for ALAS2 and necessary for heme synthesis. The autosomal recessive form is typically severe in presentation.

Genetic syndromes: Rarely, sideroblastic anemia may be part of a congenital syndrome and present with associated findings, such as ataxia, myopathy, and pancreatic insufficiency.

Acquired clonal sideroblastic anemia Clonal sideroblastic anemias fall under the broader

category of myelodysplastic syndromes (MDS). Three forms exist and include refractory anemia with ringed sideroblasts (RARS), refractory anemia with ringed sideroblasts and thrombocytosis (RARS-T), and refractory cytopenia with multilineage dysplasia and ringed sideroblasts

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(RCMD-RS). These anemias are associated with increased risk for leukemic evolution.

Acquired reversible sideroblastic anemia Causes include excessive alcohol use (the most

common cause of sideroblastic anemia), pyridoxine deficiency, lead poisoning, and copper deficiency. Excess zinc[9] can indirectly cause sideroblastic anemia by decreasing absorption and increasing excretion of copper. Antimicrobials that may lead to sideroblastic anemia include isoniazid, chloramphenicol, cycloserine, and linezolid.

Diagnosis

Bone marrow aspirate: ring sideroblastsRinged sideroblasts are seen in the bone marrow.

The anemia is moderate to severe and dimorphic. Microscopic viewing of the red blood cells will reveal marked unequal cell size and abnormal cell shape. Basophilic stippling is marked and target cells are common. Pappenheimer bodies are present in the red blood cells. The mean cell volume is commonly decreased (i.e., a microcytic

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anemia), but MCV may also be normal or even high. The RDW is increased with the red blood cell histogram shifted to the left. Leukocytes and platelets are normal. Bone marrow shows erythroid hyperplasia with a maturation arrest.

In excess of 40% of the developing erythrocytes are ringed sideroblasts. Serum iron, percentage saturation and ferritin are increased. The total iron-binding capacity of the cells is normal to decreased. Stainable marrow hemosiderin is increased.

Laboratory findings Serum Iron: High Increased ferritin levels Normal total iron-binding capacity High transferrin saturation Hematocrit of about 20-30% The mean corpuscular volume or MCV is usually normal

or low for congenital causes of sideroblastic anemia but normal or high for acquired forms.

With lead poisoning, see coarse basophilic stippling of red blood cells on peripheral blood smear

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Specific test: Prussian blue stain of RBC in marrow shows ringed sideroblasts. Prussian blue staining involves a non-enzymatic reaction of ferrous iron with ferrocyanide forming ferric-ferrocyanide, which is blue in color. A counterstain may be used to provide better visualization.

TreatmentOccasionally, the anemia is so severe that support with transfusion is required. These patients usually do not respond to erythropoietin therapy.[11] Some cases have been reported that the anemia is reversed or heme level is improved through use of moderate to high doses of pyrodoxine (vitamin B6). In severe cases of SBA, bone marrow transplant is also an option with limited information about the success rate. Some cases are listed on MedLine and various other medical sites. In the case of isoniazid-induced sideroblastic anemia, the addition of B6 is sufficient to correct the anemia. Desferrioxamine, a chelating agent, is used to treat iron overload from transfusions. Therapeutic phlebotomy can be used to manage iron overload.[12]

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Course and prognosisSideroblastic anemias are often described as responsive or non-responsive in terms of increased hemoglobin levels to pharmacological doses of vitamin B6.

1- Congenital: 80% are responsive, though the anemia does not completely resolve.

2- Acquired clonal: 40% are responsive, but the response may be minimal.

3- Acquired reversible: 60% are responsive, but course depends on treatment of the underlying cause.

Severe refractory sideroblastic anemias requiring regular transfusions and/or that undergo leukemic transformation (5-10%) significantly reduce life expectancy.

Spur cell hemolytic anemiaSpur cell hemolytic anemia, is a form of hemolytic anemia that results secondary to severe impaired liver function or cirrhosis. Chronic liver disease impairs the liver's ability to esterify cholesterol, causing free cholesterol to bind to the

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red cell membrane, increasing its surface area. This condition also creates rough or thorny projections on the erythrocyte named acanthocytes.

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ThalassemiaThalassemias are inherited blood disorders characterized by abnormal hemoglobin production.[7] Symptoms depend on the type and can vary from none to severe.[1] Often there is mild to severe anemia (low red blood cells). Anemia can result in feeling tired and pale skin. There may also be bone problems, an enlarged spleen, yellowish skin, dark urine, and among children slow growth.[1]

ThalassemiaSynonyms Thalassaemia, Mediterranean anemia

Peripheral blood film from a person with Delta Beta

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thalassemia.Thalassemias are genetic disorders inherited from a person's parents.[2] There are two main types, alpha thalassemia and beta thalassemia.[7] The severity of alpha and beta thalassemia depends on how many of the four genes for alpha globin or two genes for beta globin are missing.[2] Diagnosis is typically by blood tests including a complete blood count, special hemoglobin tests, and genetic tests.[3] Diagnosis may occur before birth through prenatal testing.[8]

Treatment depends on the type and severity. Treatment for those with more severe disease often includes regular blood transfusions, iron chelation, and folic acid. Iron chelation may be done with deferoxamine or deferasirox. Occasionally, a bone marrow transplant may be an option.[4] Complications may include iron overload from the transfusions with resulting heart or liver disease, infections, and osteoporosis. If the spleen becomes overly enlarged, surgical removal may be required.[1]

As of 2013, thalassemia occurs in about 280 million people, with about 439,000 having severe disease.[9] It is

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most common among people of Italian, Greek, Middle Eastern, South Asian, and African descent.[7] Males and females have similar rates of disease.[10] It resulted in 16,800 deaths in 2015, down from 36,000 deaths in 1990.[11][6] Those who have minor degrees of thalassemia, similar to those with sickle-cell trait, have some protection against malaria, explaining why they are more common in regions of the world where malaria exists

Signs and symptoms

The hand of a person with severe anemia (left) compared to one without (right)Iron overload: People with thalassemia can get an overload of iron in their bodies, either from the disease itself or from frequent blood transfusions. Too much iron can result in damage to the heart, liver, and endocrine system, which

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includes glands that produce hormones that regulate processes throughout the body. The damage is characterized by excessive deposits of iron. Without adequate iron chelation therapy, almost all patients with beta-thalassemia accumulate potentially fatal iron levels.[13]Infection: People with thalassemia have an increased risk of infection. This is especially true if the spleen has been removed.[14]Bone deformities: Thalassemia can make the bone marrow expand, which causes bones to widen. This can result in abnormal bone structure, especially in the face and skull. Bone marrow expansion also makes bones thin and brittle, increasing the risk of broken bones.[15]Enlarged spleen: The spleen aids in fighting infection and filters unwanted material, such as old or damaged blood cells. Thalassemia is often accompanied by the destruction of a large number of red blood cells and the task of removing these cells causes the spleen to enlarge. Splenomegaly can make anemia worse, and it can reduce the life of transfused red blood cells. Severe enlargement of the spleen may necessitate its removal.[16]

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Slowed growth rates: anemia can cause a child's growth to slow. Puberty also may be delayed in children with thalassemia.[17]Heart problems: Diseases, such as congestive heart failure and abnormal heart rhythms, may be associated with severe thalassemia.

Cause

Thalassemia has an autosomal recessive pattern of inheritance.

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Both α- and β-thalassemias are often inherited in an autosomal recessive manner. Cases of dominantly inherited α- and β-thalassemias have been reported, the first of which was in an Irish family with two deletions of 4 and 11 bp in exon 3 interrupted by an insertion of 5 bp in the β-globin gene. For the autosomal recessive forms of the disease, both parents must be carriers for a child to be

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affected. If both parents carry a hemoglobinopathy trait, the risk is 25% for each pregnancy for an affected child.

Estimates suggest that approximately 1.5% of the global population (80 - 90 million people) are β-thalassemia carriers.[19] However, exact data on carrier rates in many populations are lacking, particularly in developing areas of the world known or expected to be heavily affected.[20][21] Because of the prevalence of the disease in countries with little knowledge of thalassemia, access to proper treatment and diagnosis can be difficult.[22] While there are some diagnostic and treatment facilities in developing countries, in most cases these are not provided by government services, and are available only to patients that can afford them. In general, poorer populations only have access to limited diagnostic facilities together with blood transfusions. In some developing countries, there are virtually no facilities for diagnosis or management of thalassemia.[22]

EvolutionHaving a single genetic variant for thalassemia may protect against malaria and thus be an advantage.[23]

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People diagnosed with heterozygous (carrier) β-thalassemia have some protection against coronary heart disease.

PathophysiologyNormally, the majority of adult hemoglobin (HbA) is composed of four protein chains, two α and two β globin chains arranged into a heterotetramer. In thalassemia, patients have defects in either the α or β globin chain, causing production of abnormal red blood cells (In sickle-cell disease, the mutation is specific to β globin).

The thalassemias are classified according to which chain of the hemoglobin molecule is affected. In α-thalassemias, production of the α globin chain is affected, while in β-thalassemia, production of the β globin chain is affected.

The β globin chains are encoded by a single gene on chromosome 11; α globin chains are encoded by two closely linked genes on chromosome 16.[25] Thus, in a normal person with two copies of each chromosome, two loci encode the β chain, and four loci encode the α chain. Deletion of one of the α loci has a high prevalence in

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people of African or Asian descent, making them more likely to develop α-thalassemia. β-Thalassemias are not only common in Africans, but also in Greeks and Italians.

Alpha-thalassemiasMain article: Alpha-thalassemiaThe α-thalassemias involve the genes HBA1[26] and HBA2,[27] inherited in a Mendelian recessive fashion. Two gene loci and so four alleles exist. It is also connected to the deletion of the 16p chromosome. α Thalassemias result in decreased alpha-globin production, therefore fewer alpha-globin chains are produced, resulting in an excess of β chains in adults and excess γ chains in newborns. The excess β chains form unstable tetramers (called hemoglobin H or HbH of 4 beta chains), which have abnormal oxygen dissociation curves.

Beta-thalassemiaMain article: Beta-thalassemiaBeta thalassemias are due to mutations in the HBB gene on chromosome 11,[28] also inherited in an autosomal, recessive fashion. The severity of the disease depends on the nature of the mutation and on the presence of mutations

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in one or both alleles.Mutated alleles are called β+ when partial function is conserved (either the protein has a reduced function, or it functions normally but is produced in reduced quantity) or βo, when no functioning protein is produced.The situation of both alleles determines the clinical picture:

β thalassemia major (Mediterranean anemia or Cooley anemia) is caused by a βo/βo genotype. No functional β chains are produced, and thus no hemoglobin A can be assembled. This is the most severe form of β-thalassemia;β thalassemia intermedia is caused by a β+/βo or β+/β+ genotype. In this form, some hemoglobin A is produced;β thalassemia minor is caused by a β/βo or β/β+ genotype. Only one of the two β globin alleles contains a mutation, so β chain production is not terribly compromised and patients may be relatively asymptomatic.

Delta-thalassemiaMain article: Delta-thalassemiaAs well as alpha and beta chains present in hemoglobin, about 3% of adult hemoglobin is made of alpha and delta chains. Just as with beta thalassemia, mutations that affect

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the ability of this gene to produce delta chains can occur.

Combination hemoglobinopathiesThalassemia can coexist with other hemoglobinopathies. The most common of these are:

Hemoglobin E/thalassemia: common in Cambodia, Thailand, and parts of India, it is clinically similar to β thalassemia major or thalassemia intermedia.[citation needed]

Hemoglobin S/thalassemia: common in African and Mediterranean populations, is clinically similar to sickle-cell anemia, with the additional feature of splenomegaly.[citation needed]

Hemoglobin C/thalassemia: common in Mediterranean and African populations, hemoglobin C/βo thalassemia causes a moderately severe hemolytic anemia with splenomegaly; hemoglobin C/β+ thalassemia produces a milder disease.[citation needed]

Hemoglobin D/thalassemia: common in the northwestern parts of India and Pakistan (Punjab region).

Prevention

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The American College of Obstetricians and Gynecologists recommends all people thinking of becoming pregnant be tested to see if they have thalassemia.[29] Genetic counseling and genetic testing are recommended for families who carry a thalassemia trait.

A screening policy exists in Cyprus to reduce the rate of thalassemia, which, since the program's implementation in the 1970s (which also includes prenatal screening and abortion), has reduced the number of children born with the disease from one of every 158 births to almost zero.[30]

In Iran as a premarital screening, the man's red cell indices are checked first, if he has microcytosis (mean cell hemoglobin < 27 pg or mean red cell volume < 80 fl), the woman is tested. When both are microcytic, their hemoglobin A2 concentrations are measured. If both have a concentration above 3.5% (diagnostic of thalassemia trait) they are referred to the local designated health post for genetic counseling.[31]

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Large scale awareness campaigns are being organized in India[32] both by government and non-government organizations in favor of voluntary premarital screening to detect carriers of thalassemia and marriage between both carriers are strongly discouraged.

ManagementMain article: Management of thalassemiaMild thalassemia: people with thalassemia traits do not require medical or follow-up care after the initial diagnosis is made.[33] People with β-thalassemia trait should be warned that their condition can be misdiagnosed as the more common iron deficiency anemia. They should avoid routine use of iron supplements; iron deficiency can develop, though, during pregnancy or from chronic bleeding.[34] Counseling is indicated in all persons with genetic disorders, especially when the family is at risk of a severe form of disease that may be prevented.[35]

Blood transfusions with severe thalassemia require medical treatment. A blood transfusion regimen was the first measure effective

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in prolonging life.[33]

MedicationsMultiple blood transfusions can result in iron overload. The iron overload related to thalassemia may be treated by chelation therapy with the medications deferoxamine, deferiprone, or deferasirox.[36] These treatments have resulted in improving life expectancy in those with thalassemia major.[36]

Deferoxamine is only effective via daily injections which makes its long-term use more difficult. It has the benefit of being inexpensive and decent long-term safety. Adverse effects are primary skin reactions around the injection site and hearing loss.[36]

Deferasirox has the benefit of being an oral medication. Common side effects include: nausea, vomiting and diarrhea. It however is not effective in everyone and is probably not suitable in those with significant cardiac issues related to iron overload. The cost is also significant.[36]

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Deferiprone is a medication that is given by mouth. Nausea, vomiting, and diarrhea are relatively common with its use.[36] It is available in both Europe and the United States.[36][37] It appears to be the most effective agent when the heart is significantly involved.[36]

There is no evidence from randomized controlled trial to support zinc supplementation in thalassemia.[38]

Bone marrow transplantBone marrow transplantation may offer the possibility of a cure in young people who have an HLA-matched donor.[39] Success rates have been in the 80–90% range.[39] Mortality from the procedure is about 3%.[40] There are no randomized controlled trials which have tested the safety and efficacy of non-identical donor bone marrow transplantation in persons with β- thalassemia who are dependent on blood transfusion.[41][needs update]

If the person does not have an HLA-matched compatible donor, another method called bone marrow transplantation (BMT) from haploidentical mother to child (mismatched donor) may be used. In a study of 31 people, the thalassemia-free survival rate 70%, rejection 23%, and

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mortality 7%. The best results are with very young people.

EpidemiologyThe beta form of thalassemia is particularly prevalent among Mediterranean peoples, and this geographical association is responsible for its naming.[43] Thalassemia resulted in 25,000 deaths in 2013 down from 36,000 deaths in 1990.[11]

In Europe, the highest concentrations of the disease are found in Greece, coastal regions in Turkey (particularly the Aegean Region such as Izmir, Balikesir, Aydin, Mugla, and Mediterranean Region such as Antalya, Adana, Mersin), in parts of Italy, particularly southern Italy and the lower Po valley. The major Mediterranean islands (except the Balearics) such as Sicily, Sardinia, Malta, Corsica, Cyprus, and Crete are heavily affected in particular. Other Mediterranean people, as well as those in the vicinity of the Mediterranean, also have high rates of thalassemia, including people from West Asia and North Africa. Far from the Mediterranean, South Asians are also affected, with the world's highest concentration of carriers (30% of the population) being in the Maldives.

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Nowadays, it is found in populations living in Africa, the Americas, and in Tharu people in the Terai region of Nepal and India.[44] It is believed to account for much lower malaria sicknesses and deaths,[45] accounting for the historic ability of Tharus to survive in areas with heavy malaria infestation, where others could not. Thalassemias are particularly associated with people of Mediterranean origin, Arabs (especially Palestinians and people of Palestinian descent), and Asians.[46] The Maldives has the highest incidence of thalassemia in the world with a carrier rate of 18% of the population. The estimated prevalence is 16% in people from Cyprus, 1%[47] in Thailand, and 3–8% in populations from Bangladesh, China, India, Malaysia and Pakistan. Thalassemias also occur in descendants of people from Mediterranean countries (e.g. Greece, Italy, Spain, and others), in Latin America.

Etymology and pronunciationThe word thalassemia (/θælᵻˈsiːmiə/) derives from the Greek thalassa (θάλασσα), "sea", and New Latin -emia (from Greek haema (αἷμα), "blood"). It was coined because the condition called "Mediterranean anemia" was first

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described in people of Mediterranean ethnicities. "Mediterranean anemia" was renamed thalassemia major once the genetics were better understood. The word thalassemia was first used in 1932.[43]:877[48]

Society and cultureIn 2008, in Spain, a baby was selectively implanted to be a cure for his brother's thalassemia. The child was born from an embryo screened to be free of the disease before implantation with in vitro fertilization. The baby's supply of immunologically compatible cord blood was saved for transplantation to his brother. The transplantation was considered successful.[49] In 2009, a group of doctors and specialists in Chennai and Coimbatore registered the successful treatment of thalassemia in a child using an unaffected sibling's umbilical cord blood.

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Triosephosphate isomerase deficiency

Triosephosphate isomerase deficiency is a rare autosomal recessive[1] metabolic disorder which was initially described in 1965.

It is a unique glycolytic enzymopathy that is characterized by chronic haemolytic anaemia, cardiomyopathy, susceptibility to infections, severe neurological dysfunction, and, in most cases, death in early childhood.[3] The disease is exceptionally rare with fewer than 100 patients diagnosed worldwide.

Cause, pathophysiology and genetics

Triosephosphate isomerase deficiency has an autosomal recessive pattern of inheritance.Thirteen different mutations in the respective gene,

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which is located at chromosome 12p13 and encodes the ubiquitous housekeeping enzyme triosephosphate isomerase (TPI), have been discovered so far.[3] TPI is a crucial enzyme of glycolysis and catalyzes the

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interconversion of dihydroxyacetone phosphate and glyceraldehyde-3-phosphate. A marked decrease in TPI activity and an accumulation of dihydroxyacetone phosphate have been detected in erythrocyte extracts of homozygous (two identical mutant alleles) and compound heterozygous (two different mutant alleles) TPI deficiency patients. Heterozygous individuals are clinically unaffected, even if their residual TPI activity is reduced. Recent work suggests that not a direct inactivation, but an alteration in TPI dimerization might underlie the pathology.[1] This might explain why the disease is rare, but inactive TPI alleles have been detected at higher frequency implicating a heterozygote advantage of inactive TPI alleles.

The most common mutation causing TPI deficiency is TPI Glu104Asp. All carriers of the mutation are descendants of a common ancestor, a person that lived in what is today France or England more than 1000 years ago.

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Warm antibody autoimmune hemolytic anemia

Warm antibody autoimmune hemolytic anemia (WAIHA) is the most common form of autoimmune hemolytic anemia.[1] About half of the cases are of unknown cause, with the other half attributable to a predisposing condition or medications being taken. Contrary to cold autoimmune hemolytic anemia (e.g., cold agglutinin disease and paroxysmal cold hemoglobinuria) which happens in cold temperature (28–31 °C), WAIHA happens in body temperature.

PathophysiologyThe most common antibody involved in warm antibody AIHA is IgG, though sometimes IgA is found. The IgG antibodies attach to a red blood cell, leaving their FC portion exposed with maximal reactivity at 37 °C (versus cold antibody induced hemolytic anemia whose antibodies only bind red blood cells at low body temperatures, typically 28-31 °C). The FC region is recognized and

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grabbed onto by FC receptors found on monocytes and macrophages in the spleen. These cells will pick off portions of the red cell membrane, almost as if they are taking a bite. The loss of membrane causes the red blood cells to become spherocytes. Spherocytes are not as flexible as normal RBCs and will be singled-out for destruction in the red pulp of the spleen as well as other portions of the reticuloendothelial system. The red blood cells trapped in the spleen cause the spleen to enlarge, leading to the splenomegaly often seen in these patients.

There are two models for this: the hapten model and the autoantibody model. The hapten model proposes that certain drugs, especially penicillin and cephalosporins, will bind to certain proteins on the red cell membrane and act as haptens (small molecules that can elicit an immune response only when attached to a large carrier such as a protein; the carrier may be one that also does not elicit an immune response by itself). Antibodies are created against the protein-drug complex, leading to the destructive sequence described above. The autoantibody model proposes that, through a mechanism not yet understood, certain drugs will cause antibodies to be made against red

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blood cells which again leads to the same destructive sequence.

It is possible for it to occur in an immunocompromised patient.

CausesAIHA may be:

Idiopathic, that is, without any known cause[3] to another disease, such as an antecedent upper

respiratory tract infection, systemic lupus erythematosus or rheumatoid arthritis[4] or a malignancy, such as chronic lymphocytic leukemia (CLL)[3]

MedicationsSeveral medications have been associated with the development of warm AIHA. These medications include quinidine, nonsteroidal anti-inflammatory drugs (NSAIDs), alpha methyldopa, and antibiotics such as penicillins, cephalosporins (such as ceftriaxone and cefotetan), and ciprofloxacin.

Clinical findings

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Laboratory findings include severe anemia, increased mean corpuscular volume (MCV, due to the presence of a large number of reticulocytes), and hyperbilirubinemia (from increased red cell destruction) that can be of the conjugated or unconjugated type.

DiagnosisDiagnosis is made by a positive direct Coombs test, other lab tests, and clinical examination and history. The direct Coombs test looks for antibodies attached to the surface of red blood cells.

TreatmentCorticosteroids and immunoglobulins are two commonly used treatments for warm antibody AIHA. Initial medical treatment consists of prednisone. If ineffective, splenectomy should be considered.

If refractory to both these therapies, other options include rituximab,[5][6] danazol, cyclosphosphamide, azathioprine, or ciclosporin.

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High-dose intravenous immune globulin may be effective in controlling hemolysis, but the benefit is short lived (1–4 weeks), and the therapy is very expensive.

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-: Second-:Blood cancers :-

Seven-year-

old

Nigerian boy with Burkitt's lymphoma presenting with a severely ulcerated and swollen jaw

A blood cancer or hematological malignancy is a type of malignant cancer that originates, affects, or involves the blood, bone marrow, or lymph nodes.[63] These cancers

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include leukemias, lymphomas, and myelomas. These particular types of cancers can arise as defected mature cell types that have differentiated from hematopoietic precursor cells (often in the bone marrow) and begin to quickly proliferate through the bloodstream where it can then often infiltrate other organs and tissues. Others can involve the formation of tumors from lymphoblasts from within the lymphoid tissue.[64] Incidence of affected people with a form of blood cancer has been steady increasing over recent years; however, due in part to early detection methods and subsequent advancements in the treatment of the diseases, mortality rates have continued to decrease.[65]

LymphomaHodgkin's lymphoma

Hodgkin's lymphoma (HL) is a type of lymphoma, which is generally believed to result from white blood cells of the lymphocyte kind.[8] Symptoms may include fever, night sweats, and weight loss. Often there will be non-painful

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enlarged lymph nodes in the neck, under the arm, or in the groin. Those affected may feel tired or be itchy.[2]

Hodgkin's lymphomaSynonyms Hodgkin lymphoma, Hodgkin's disease[1]

Micrograph showing Hodgkin lymphoma (Field stain)About half of cases of Hodgkin's lymphoma are due to Epstein–Barr virus (EBV).[3] Other risk factors include a

family history of the condition and having HIV/AIDS.[2]

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[3] There are two major types of Hodgkin lymphoma: classical Hodgkin lymphoma and nodular lymphocyte-predominant Hodgkin lymphoma.[5] Diagnosis is by finding Hodgkin's cells such as multinucleated Reed–Sternberg cells (RS cells) in lymph nodes.[2]

Hodgkin lymphoma may be treated with chemotherapy, radiation therapy, and stem cell transplant. The choice of treatment often depends on how advanced the cancer is and whether or not it has favorable features.[4] In early disease a cure is often possible.[9] The percentage of people who survive five years in the United States is 86%.[5] For those under the age of 20 rates of survival are 97%.[10] Radiation and some chemotherapy drugs, however, increase the risk of other cancers, heart disease, or lung disease over the subsequent decades.[9]

In 2015 about 574,000 people had Hodgkin's lymphoma and 23,900 died.[6][7] In the United States 0.2% of people are affected at some point in their life. The most common age of diagnosis is between 20 and 40 years old.[5] It was named after the English physician Thomas Hodgkin, who first described the condition in 1832.

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Signs and symptomsPatients with Hodgkin's lymphoma may present with the following symptoms:

Lymph nodes: the most common symptom of Hodgkin's is the painless enlargement of one or more lymph nodes, or lymphadenopathy. The nodes may also feel rubbery and swollen when examined. The nodes of the neck and shoulders (cervical and supraclavicular) are most frequently involved (80–90% of the time, on average). The lymph nodes of the chest are often affected, and these may be noticed on a chest radiograph.

Itchy skinNight sweatsUnexplained weight lossSplenomegaly: enlargement of the spleen occurs in about

30% of people with Hodgkin's lymphoma. The enlargement, however, is seldom massive and the size of the spleen may fluctuate during the course of treatment.

Hepatomegaly: enlargement of the liver, due to liver involvement, is present in about 5% of cases.

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Hepatosplenomegaly: the enlargement of both the liver and spleen caused by the same disease.

Pain following alcohol consumption: classically, involved nodes are painful after alcohol consumption, though this phenomenon is very uncommon,[12] occurring in only two to three percent of people with Hodgkin's lymphoma,[13] thus having a low sensitivity. On the other hand, its positive predictive value is high enough for it to be regarded as a pathognomonic sign of Hodgkin lymphoma.[13] The pain typically has an onset within minutes after ingesting alcohol, and is usually felt as coming from the vicinity where there is an involved lymph node.[13] The pain has been described as either sharp and stabbing or dull and aching.[13]

Back pain: nonspecific back pain (pain that cannot be localised or its cause determined by examination or scanning techniques) has been reported in some cases of Hodgkin's lymphoma. The lower back is most often affected.[citation needed]

Red-coloured patches on the skin, easy bleeding and petechiae due to low platelet count (as a result of bone marrow infiltration, increased trapping in the spleen etc.

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—i.e. decreased production, increased removal)Systemic symptoms: about one-third of patients with

Hodgkin's disease may also present with systemic symptoms, including low-grade fever; night sweats; unexplained weight loss of at least 10% of the patient's total body mass in six months or less, itchy skin (pruritus) due to increased levels of eosinophils in the bloodstream; or fatigue (lassitude). Systemic symptoms such as fever, night sweats, and weight loss are known as B symptoms; thus, presence of fever, weight loss, and night sweats indicate that the patient's stage is, for example, 2B instead of 2A.[14]

Cyclical fever: patients may also present with a cyclical high-grade fever known as the Pel-Ebstein fever,[15] or more simply "P-E fever". However, there is debate as to whether the P-E fever truly exists.[16]

Nephrotic syndrome can occur in individuals with Hodgkin's lymphoma and is most commonly caused by minimal change disease.

Diagnosis

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Hodgkin's lymphoma must be distinguished from non-cancerous causes of lymph node swelling (such as various infections) and from other types of cancer. Definitive diagnosis is by lymph node biopsy (usually excisional biopsy with microscopic examination). Blood tests are also performed to assess function of major organs and to assess safety for chemotherapy. Positron emission tomography (PET) is used to detect small deposits that do not show on CT scanning. PET scans are also useful in functional imaging (by using a radiolabeled glucose to image tissues of high metabolism). In some cases a Gallium Scan may be used instead of a PET scan.

TypesClassical Hodgkin lymphoma (excluding nodular lymphocyte predominant Hodgkin's lymphoma) can be subclassified into four pathologic subtypes based upon Reed–Sternberg cell morphology and the composition of the reactive cell infiltrate seen in the lymph node biopsy specimen (the cell composition around the Reed–Sternberg cell(s)).

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Lymph node biopsy showing Hodgkin's lymphoma, mixed-

cellularity type

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CT image of a 46-year-old patient with Hodgkin's lymphoma, image at neck height. On the left side of the patient's neck enlarged lymph nodes are visible (marked in red).

Nodular lymphocyte predominant Hodgkin's lymphoma expresses CD20, and is not currently considered a form of classical Hodgkin's lymphoma.

For the other forms, although the traditional B-cell markers (such as CD20) are not expressed on all cells,[18] Reed–Sternberg cells are usually of B cell origin.[19][20] Although Hodgkin's is now frequently grouped with other B-cell malignancies, some T-cell markers (such as CD2 and CD4) are occasionally expressed.[21] However, this may be an artifact of the ambiguity inherent in the diagnosis.

Hodgkin cells produce interleukin-21 (IL-21), which was once thought to be exclusive to T-cells. This feature may explain the behavior of classical Hodgkin's lymphoma, including clusters of other immune cells gathered around HL cells (infiltrate) in cultures.

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StagingThe staging is the same for both Hodgkin's and non-Hodgkin's lymphomas.

After Hodgkin lymphoma is diagnosed, a patient will be staged: that is, they will undergo a series of tests and procedures that will determine what areas of the body are affected. These procedures may include documentation of their histology, a physical examination, blood tests, chest X-ray radiographs, computed tomography (CT)/Positron emission tomography (PET)/magnetic resonance imaging (MRI) scans of the chest, abdomen and pelvis, and usually a bone marrow biopsy. Positron emission tomography (PET) scan is now used instead of the gallium scan for staging. On the PET scan, sites involved with lymphoma light up very brightly enabling accurate and reproducible imaging.[23] In the past, a lymphangiogram or surgical laparotomy (which involves opening the abdominal cavity and visually inspecting for tumors) were performed. Lymphangiograms or laparotomies are very rarely performed, having been supplanted by improvements in imaging with the CT scan and PET scan.

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On the basis of this staging, the patient will be classified according to a staging classification (the Ann Arbor staging classification scheme is a common one):

Stage I is involvement of a single lymph node region (I) (mostly the cervical region) or single extralymphatic site (Ie);Stage II is involvement of two or more lymph node regions on the same side of the diaphragm (II) or of one lymph node region and a contiguous extralymphatic site (IIe);Stage III is involvement of lymph node regions on both sides of the diaphragm, which may include the spleen (IIIs) or limited contiguous extralymphatic organ or site (IIIe, IIIes);Stage IV is disseminated involvement of one or more extralymphatic organs.The absence of systemic symptoms is signified by adding "A" to the stage; the presence of systemic symptoms is signified by adding "B" to the stage. For localised extranodal extension from mass of nodes that does not advance the stage, subscript "E" is added. Splenic involvement is signified by adding "S" to the stage. The inclusion of "bulky disease" is signified by "X".

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PathologyMacroscopyAffected lymph nodes (most often, laterocervical lymph nodes) are enlarged, but their shape is preserved because the capsule is not invaded. Usually, the cut surface is white-grey and uniform; in some histological subtypes (e.g. nodular sclerosis) a nodular aspect may appear.

A fibrin ring granuloma may be seen.

Microscopy

Micrograph of a classic Reed–Sternberg cell

Micrograph showing a "popcorn cell", the Reed–Sternberg

cell variant seen in nodular lymphocyte predominant

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Hodgkin lymphoma. H&E stainMicroscopic examination of the lymph node biopsy reveals complete or partial effacement of the lymph node architecture by scattered large malignant cells known as Reed-Sternberg cells (RSC) (typical and variants) admixed within a reactive cell infiltrate composed of variable proportions of lymphocytes, histiocytes, eosinophils, and plasma cells. The Reed–Sternberg cells are identified as large often bi-nucleated cells with prominent nucleoli and an unusual CD45-, CD30+, CD15+/- immunophenotype. In approximately 50% of cases, the Reed–Sternberg cells are infected by the Epstein–Barr virus.[citation needed]

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Characteristics of classic Reed–Sternberg cells include large size (20–50 micrometres), abundant, amphophilic, finely granular/homogeneous cytoplasm; two mirror-image nuclei (owl eyes) each with an eosinophilic nucleolus and a thick nuclear membrane (chromatin is distributed close to the nuclear membrane).

Variants:

Hodgkin cell (atypical mononuclear RSC) is a variant of RS cell, which has the same characteristics, but is mononucleated.

Lacunar RSC is large, with a single hyperlobulated nucleus, multiple, small nucleoli and eosinophilic cytoplasm which is retracted around the nucleus, creating an empty space ("lacunae").

Pleomorphic RSC has multiple irregular nuclei. "Popcorn" RSC (lympho-histiocytic variant) is a small

cell, with a very lobulated nucleus, small nucleoli. "Mummy" RSC has a compact nucleus with no

nucleolus and basophilic cytoplasm. Hodgkin's lymphoma can be sub-classified by

histological type. The cell histology in Hodgkin's

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lymphoma is not as important as it is in non-Hodgkin's lymphoma: the treatment and prognosis in classic Hodgkin's lymphoma usually depends on the stage of disease rather than the histotype.

ManagementPatients with early stage disease (IA or IIA) are effectively treated with radiation therapy or chemotherapy. The choice of treatment depends on the age, sex, bulk and the histological subtype of the disease.[citation needed] Adding localised radiation therapy after the chemotherapy regimen controls the tumors better and provides a better chance for survival than chemotherapy alone.[24] Patients with later disease (III, IVA, or IVB) are treated with combination chemotherapy alone. Patients of any stage with a large mass in the chest are usually treated with combined chemotherapy and radiation therapy.[citation needed]It should be noted that the common non-Hodgkin's treatment, rituximab (which is a monoclonal antibody against CD20) is not routinely used to treat Hodgkin's lymphoma due to the lack of CD20 surface antigens in

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most cases. The use of rituximab in Hodgkin's lymphoma, including the lymphocyte predominant subtype has been reviewed recently.[28]

Although increased age is an adverse risk factor for Hodgkin's lymphoma, in general elderly patients without major comorbidities are sufficiently fit to tolerate standard therapy, and have a treatment outcome comparable to that of younger patients. However, the disease is a different entity in older patients and different considerations enter into treatment decisions.[29]

For Hodgkin's lymphomas, radiation oncologists typically use external beam radiation therapy (sometimes shortened to EBRT or XRT). Radiation oncologists deliver external beam radiation therapy to the lymphoma from a machine called linear accelerator which produces high energy X Rays and Electrons. Patients usually describe treatments as painless and similar to getting an X-ray. Treatments last less than 30 minutes each.

For lymphomas, there are a few different ways radiation oncologists target the cancer cells. Involved field radiation is when the radiation oncologists give radiation only to

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those parts of the patient's body known to have the cancer. Very often, this is combined with chemotherapy. Radiation therapy directed above the diaphragm to the neck, chest or underarms is called mantle field radiation. Radiation to below the diaphragm to the abdomen, spleen or pelvis is called inverted-Y field radiation. Total nodal irradiation is when the therapist gives radiation to all the lymph nodes in the body to destroy cells that may have spread.

Adverse effectsThe high cure rates and long survival of many patients with Hodgkin's lymphoma has led to a high concern with late adverse effects of treatment, including cardiovascular disease and second malignancies such as acute leukemias, lymphomas, and solid tumors within the radiation therapy field. Most patients with early-stage disease are now treated with abbreviated chemotherapy and involved-field radiation therapy rather than with radiation therapy alone. Clinical research strategies are exploring reduction of the duration of chemotherapy and dose and volume of radiation therapy in an attempt to reduce late morbidity and mortality of treatment while maintaining high cure rates. Hospitals are also treating those who respond quickly to

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chemotherapy with no radiation.

In childhood cases of Hodgkin's lymphoma, long-term endocrine adverse effects are a major concern, mainly gonadal dysfunction and growth retardation. Gonadal dysfunction seems to be the most severe endocrine long-term effect, especially after treatment with alkylating agents or pelvic radiotherapy.

PrognosisTreatment of Hodgkin's disease has been improving over the past few decades. Recent trials that have made use of new types of chemotherapy have indicated higher survival rates than have previously been seen. In one recent European trial, the 5-year survival rate for those patients with a favorable prognosis (FFP) was 98%, while that for patients with worse outlooks was at least 85%.[32]

In 1998, an international effort[33] identified seven prognostic factors that accurately predict the success rate of conventional treatment in patients with locally extensive or advanced stage Hodgkin's lymphoma. Freedom from progression (FFP) at 5 years was directly related to the

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number of factors present in a patient. The 5-year FFP for patients with zero factors is 84%. Each additional factor lowers the 5-year FFP rate by 7%, such that the 5-year FFP for a patient with 5 or more factors is 42%.

The adverse prognostic factors identified in the international study are:

Age ≥ 45 years Stage IV disease Hemoglobin < 10.5 g/dl Lymphocyte count < 600/µl or < 8% Male Albumin < 4.0 g/dl White blood count ≥ 15,000/µlOther studies have reported the following to be the most important adverse prognostic factors: mixed-cellularity or lymphocyte-depleted histologies, male sex, large number of involved nodal sites, advanced stage, age of 40 years or more, the presence of B symptoms, high erythrocyte sedimentation rate, and bulky disease (widening of the mediastinum by more than one third, or the presence of a nodal mass measuring more than 10 cm in any dimension.)

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More recently, use of positron emission tomography (PET) early after commencing chemotherapy has demonstrated to have powerful prognostic ability.[34] This enables assessment of an individual's response to chemotherapy as the PET activity switches off rapidly in patients who are responding. In this study,[34] after two cycles of ABVD chemotherapy, 83% of patients were free of disease at 3 years if they had a negative PET versus only 28% in those with positive PET scans. This prognostic power exceeds conventional factors discussed above. Several trials are underway to see if PET-based risk adapted response can be used to improve patient outcomes by changing chemotherapy early in patients who are not responding.

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Non-Hodgkin lymphomaNon-Hodgkin lymphoma (NHL) is a group of blood cancers that includes all types of lymphoma except Hodgkin's lymphomas.[1] Symptoms include enlarged lymph nodes, fever, night sweats, weight loss, and tiredness. Other symptoms may include bone pain, chest pain, or itchiness. Some forms are slow growing while others are fast growing.[1]

Non-Hodgkin lymphomaSynonyms Non-Hodgkin disease

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Micrograph of mantle cell lymphoma, a type of non-Hodgkin lymphoma. Terminal ileum. H&E stain.Lymphomas are types of cancer that develop from lymphocytes, a type of white blood cell.[2] Risk factors include poor immune function, autoimmune diseases, Helicobacter pylori infection, hepatitis C, obesity, and Epstein-Barr virus infection.[1][3] The World Health Organization (WHO) classifies lymphomas into five major groups, including one for Hodgkin's lymphoma.[6] Within the four groups for NHL there are over 60 specific types of lymphoma.[7][8] Diagnosis is by examination of a bone marrow or lymph node biopsy. Medical imaging is done to help with cancer staging.[1]

Treatment depends on if the lymphoma is slow or fast growing and if it is in one area or many areas. Treatments may include chemotherapy, radiation, immunotherapy, targeted therapy, stem cell transplantation, surgery, or watchful waiting. If the blood becomes overly thick due to antibodies, plasmapheresis may be used. Radiation and some chemotherapy, however, increase the risk of other cancers, heart disease or nerve problems over the

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subsequent decades.[1]

In 2015 about 4.3 million people had non-Hodgkin lymphoma and 231,400 died.[4][5] In the United States 2.1% of people are affected at some point in their life. The most common age of diagnosis is between 65 to 75 years old. The percentage of people who survive five years in the United States is 71%.

Signs and symptomsThe signs and symptoms of non-Hodgkin's lymphoma vary depending upon its location within the body. Symptoms include enlarged lymph nodes, fever, night sweats, weight loss, and feeling tired. Other symptoms may include bone pain, chest pain, or itchiness. Some forms are slow growing while others are fast growing.[1] Enlarged lymph nodes may cause lumps to be felt under the skin when they are close to the surface of the body. Lymphomas in the skin may also result in lumps, which are commonly itchy, red or purple. Lymphomas in the brain can cause weakness, seizures, problems with thinking and personality changes.[medical citation needed]

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CausesThe many different forms of lymphoma probably have different causes. These possible causes and associations with at least some forms of NHL include the following: Infectious agents: Epstein-Barr virus: associated with Burkitt's lymphoma,

Hodgkin's lymphoma, follicular dendritic cell sarcoma, extranodal NK-T-cell lymphoma[9]

Human T-cell leukemia virus: associated with adult T-cell lymphoma

Helicobacter pylori: associated with gastric lymphoma HHV-8: associated with primary effusion lymphoma,

multicentric Castleman disease Hepatitis C virus: associated with splenic marginal zone

lymphoma, lymphoplasmacytic lymphoma and diffuse large B-cell lymphoma[10]

HIV infection[11] Some chemicals, like polychlorinated biphenyls (PCBs),

[12][13][14] diphenylhydantoin, dioxin, and phenoxy herbicides.

Medical treatments, like radiation therapy and chemotherapy

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Genetic diseases, like Klinefelter's syndrome, Chédiak-Higashi syndrome, ataxia telangiectasia syndrome

Autoimmune diseases, like Sjögren’s syndrome, celiac disease, rheumatoid arthritis, and systemic lupus erythematosus.

HIV/AIDSThe Center for Disease Control and Prevention (CDC) included certain types of non-Hodgkin's lymphoma as AIDS-defining cancers in 1987.[17] Immune suppression rather than HIV itself is implicated in the pathogenesis of this malignancy, with a clear correlation between the degree of immune suppression and the risk of developing NHL. Additionally, other retroviruses such as HTLV may be spread by the same mechanisms that spread HIV, leading to an increased rate of co-infection.[18] The natural history of HIV infection has been greatly changed over time. As a consequence, the incidence of non-Hodgkin's lymphoma (NHL) in HIV infected patients has significantly declined in recent years.

Treatment

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The most common chemotherapy used is CHOP-R for non-Hodgkin lymphoma.

EpidemiologyIn the US, data from 2007–2011 show that there were about 19.7 cases of NHL per 100,000 adults per year, 6.3 deaths per 100,000 adults per year. About 2.1 percent of men and women are diagnosed with NHL at some point during their lifetime, and there were around 530,919 people living with non-Hodgkin lymphoma.[19]

Globally, as of 2010, there were 210,000 deaths, up from 143,000 in 1990.[20]

AgeNon-Hodgkin lymphoma increases with age steadily.[15]:PPPSexUp to 45 years NHL is more common among males than females.[21]Geography—UKNHL is the sixth most common cancer in the UK (around 12,800 people were diagnosed with the disease in 2011),

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and it is the eleventh most common cause of cancer death (around 4,700 people died in 2012).

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Anaplastic large-cell lymphoma

Anaplastic large-cell lymphoma (ALCL) is a type of non-Hodgkin lymphoma involving aberrant T cells or null lymphocytes. It is described in detail in the "Classification of Tumours of the Haematopoietic and Lymphoid Tissues" edited by experts of the World Health Organisation (WHO). The term anaplastic large cell lymphoma (ALCL) encompasses at least 4 different clinical entities, all sharing the same name, and histologically have also in common the presence of large pleomorphic cells that express CD30 and T-cell markers. Two types of ALCL present as systemic disease and are considered as aggressive lymphomas, while two types present as localized disease and may progress

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locally.Figure:Micrograph of an anaplastic large cell lymphoma. H&E stain.Its name derives from anaplasia and large-cell lymphoma.

Signs and symptomsThe clinical presentation varies according to the type of ALCL. Two of the ALCL subtypes are systemic lymphomas, in that they usually present with enlarged lymph nodes in multiple regions of the body, or with tumors outside the lymph nodes (extranodal) such as bone, intestine, muscle, liver, or spleen. These 2 subtypes usually associate with weight loss, fevers and night sweats, and can be lethal if left untreated without chemotherapy.[1] The third type of ALCL is so-called cutaneous ALCL, and is a tumor that presents in the skin as ulcers that may persist, or occasionally may involute spontaneously, and commonly recur. This type of ALCL usually manifests in different regions of the body and may extend to regional lymph nodes, i.e., an axillary lymph node if the ALCL presents in the arm.[2]

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A rare subtype of ALCL has been identified in a few women who have silicone breast implants (protheses) as a result of breast reconstruction after a diagnosis of breast cancer.[3] The tumor initially manifests with swelling of the breast due to fluid accumulation around the implant. The disease may progress to invade the tissue surrounding the capsule, and if left untreated may progress to the axillary lymph nodes.[4]

It typically presents at a late stage and is often associated with systemic symptoms ("B symptoms").

DiagnosisThe diagnosis of ALCL requires the examination by a pathologist of any enlarged lymph node, or any affected extranodal tissue where there the tumor is found, such as the intestine, the liver or bone in the case of systemic ALCL. For the case of cutaneous ALCL, a skin excision is recommended, and for the diagnosis of ALCL associated with breast implants, a cytologic specimen of the effusion around the breast implant or complete examination of the breast capsule surrounding the implant is required.[5]

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To make this diagnosis under its present system of classification, the WHO emphasizes the identification of "hallmark" cells and immunopositivity for CD30. Integration of this information with clinical presentation is crucial for final classification and management of patients.

The classification acknowledges the recognition of large cells with pleomorphic nuclei and abundant cytoplasm. Also required in the diagnosis is immunophenotypic evidence that cells are T lymphocytes, such as the expression of immunologic markers CD3 or CD4, but CD30 expression must be present in all neoplastic cells. Out of the 4 types of ALCL, one subtype of systemic ALCL expresses the protein anaplastic lymphoma kinase (ALK); the other types of ALCL do not express ALK.

The hallmark cells are of medium size and feature abundant cytoplasm (which may be clear, amphophilic or eosinophilic), kidney shaped nuclei, and a paranuclear eosinophilic region. Occasional cells may be identified in which the plane of section passes through the nucleus in such a way that it appears to enclose a region of cytoplasm within a ring; such cells are called "doughnut" cells.

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By definition, on histological examination, hallmark cells are always present. Where they are not present in large numbers, they are usually located around blood vessels. Morphologic variants include the following types:

Common (featuring a predominance of hallmark cells) Small-cell (featuring smaller cells with the same

immunophenotype as the hallmark cells) Lymphohistiocytic Sarcomatoid Signet ring

ImmunophenotypeThe hallmark cells (and variants) show immunopositivity for CD30[6][7] (also known as Ki-1). True positivity requires localisation of signal to the cell membrane and/or paranuclear region (cytoplasmic positivity is considered non-specific and non-informative). Another useful marker which helps to differentiate this lesion from Hodgkin lymphoma is Clusterin. The neoplastic cells have a golgi staining pattern (hence paranuclear staining), which is characteristic of this lymphoma. The cells are also typically positive for a subset of markers of T-cell lineage. However, as with other T-cell

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lymphomas, they are usually negative for the pan T-cell marker CD3. Occasional examples are of null (neither T nor B) cell type. These lymphomas show immunopositivity for ALK protein in 70% of cases. They are also typically positive for EMA. In contrast to many B-cell anaplastic CD30 positive lymphomas, they are negative for markers of Epstein–Barr virus (EBV).

Molecular biologyThe majority of cases, greater than 90%, contain a clonal rearrangement of the T-cell receptor. This may be identified using PCR techniques, such as T-gamma multiplex PCR. Oncogeneic potential is conferred by upregulation of a tyrosine kinase gene on chromosome 2. Several different translocations involving this gene have been identified in different cases of this lymphoma. The most common is a chromosomal translocation involving the nucleophosmin gene on chromosome 5. The translocation may be identified by analysis of giemsa-banded metaphase spreads of tumour cells and is characterised by t(2;5)(p23;q35). The product of this fusion gene may be identified by immunohistochemistry using antiserum to ALK protein. Probes are available to identify the translocation by fluorescent in situ hybridization.

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The nucleophosmin component associated with the commonest translocation results in nuclear positivity as well as cytoplasmic positivity. Positivity with the other translocations may be confined to the cytoplasm. Mutagenesis and functional studies have identified a plethora of NPM1–ALK interacting molecules which ultimately lead to the activation of key pathways including RAS/Erk, PLC-γ, PI3K, and Jak/signal transducers and activators of transcription (STAT) path- ways, which in turn control cell proliferation and survival and cytoskeletal rearrangements.[8] It has been demonstrated that NPM-ALK oncogenic effects is sustained by STAT3 activation. Activation of STAT3 is associated with a specific signature, which includes several transcription factors (i.e., CEBP/β), cell cycle (i.e., Cyclin D, c-myc etc.), survival/apoptosis molecules (Bcl-A2, Bcl-XL, Survivin, MCL-1) and cell adhesion, and mobility proteins.[9]

Differential diagnosis and diagnostic pitfallsEditAs the appearance of the hallmark cells, pattern of growth (nesting within lymph nodes) and positivity for EMA may mimic metastatic carcinoma, it is important to include markers for cytokeratin in any diagnostic panel (these will be

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negative in the case of anaplastic lymphoma). Other mimics include CD30 positive B-cell lymphomas with anaplastic cells (including Hodgkin lymphomas). These are identified by their positivity for markers of B-cell lineage and frequent presence of markers of EBV. Primary cutaneous T-cell lymphomas may also be positive for CD30; these are excluded by their anatomic distribution. ALK positivity may also be seen in some large-cell B-cell lymphomas and occasionally in rhabdomyosarcomas.

TreatmentFor the cases of systemic ALCL, the recommendation is to Manage under "Aggressive Lymphoma" guidelines.CHOP is first line of treatment, CHOP-Rituximab in the unlikely scenario that CD20 is positive, given that CD20 is a B-cell marker.Radiation therapy as per institutional preference (based on ECOG, SWOG, and GELA trials), but usually added for bulky diseaseLocalized primary cutaneous ALCL[10]Breast implant-associated ALCL is a recently recognized lymphoma and definitive management and therapy is under

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evaluation. However, it appears that removal of the implant, and resection of the capsule around the implant as well as evaluation by medical and surgical oncologists are cornerstones. Still under evaluation is the extent of capsulectomy: partial versus complete capsulectomy; similarly it is not defined the significance of replacement of the implant in the affected breast, or the removal of contralateral implant. Similarly, the value of radiation therapy and chemotherapy are under evaluation.

Radiation therapy aloneSurgical excision aloneSurgically excision with adjuvant radiation.Currently, there is a drug, LDK378, undergoing Phase III clinical trials at Vanderbilt University that targets ALK positive small cell lung cancer,[11] and has showed clinical promise in its previous clinical trials.[12] Because approximately 70% of ALCL neoplasms are also ALK positive, there is hope that similar highly selective and potent ALK inhibitors may be used in the future to treat ALK positive cases of ALCL.[13][14]

Prognosis

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The prognosis varies according with the type of ALCL. During treatment, relapses may occur but these typically remain sensitive to chemotherapy.

Those with ALK positivity have better prognosis than ALK negative ALCL. It has been suggested that ALK-negative anaplastic large-cell lymphomas derive from other T-cell lymphomas that are morphologic mimics of ALCL in a final common pathway of disease progression. Whereas ALK-positive ALCLs are molecularly characterized and can be readily diagnosed, specific immunophenotypic or genetic features to define ALK-negative ALCL are missing and their distinction from other T-cell non-Hodgkin lymphomas (T-NHLs) remains controversial, although promising diagnostic tools for their recognition have been developed and might be helpful to drive appropriate therapeutic protocols.[15]

Systemic ALK+ ALCL 5-year survival: 70–80%.[10] Systemic ALK- ALCL 5-year survival: 15–45%.[10] Primary Cutaneous ALCL: Prognosis is good if there is not extensive involvement regardless of whether or not ALK is positive with an approximately 90% 5-year survival rate.[10] Breast implant-associated ALCL has an excellent prognosis when

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the lymphoma is confined to the fluid or to the capsule surrounding the breast implant. This tumor can be recurrent and grow as a mass around the implant capsule or can extend to regional lymph nodes if not properly treated.[5]

EpidemiologyThe lymphoma is more common in the young and in males.

A 2008 study found an increased risk of ALCL of the breast in women with silicone breast implants (protheses), although the overall risk remained exceedingly low due to the rare occurrence of the tumor.

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Angioimmunoblastic T-cell lymphoma

Angioimmunoblastic T-cell lymphoma (AITL, sometimes misspelled AILT) (formerly known as "angioimmunoblastic lymphadenopathy with dysproteinemia"[2]:747) is a mature T-cell lymphoma of blood or lymph vessel immunoblasts characterized by a polymorphous lymph node infiltrate showing a marked increase in follicular dendritic cells (FDCs) and high endothelial venules (HEVs) and systemic involvement.

Signs and symptomsPatients with this disease usually present at an advanced stage and show systemic involvement. The clinical findings typically include a pruritic skin rash and possibly edema, ascites, pleural effusions, and arthritis.[3][4]

Sites of involvementDue to the systemic nature of this disease, neoplastic cells can be found in lymph nodes, liver, spleen, skin, and bone marrow.

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CausesThis disease was originally thought to be a premalignant condition, termed angioimmunoblastic lymphadenopathy, and this atypical reactive lymphadenopathy carried a risk for transformation into a lymphoma. Currently, it is postulated that the originating cell for this disease is a mature (post-thymic) CD4+ T-cell that arises de novo,[1] although some researchers argue that there is a premalignant subtype of this disease.[5][6] The Epstein–Barr virus (EBV) is observed in the majority of cases,[1] and the virus has been found in the reactive B-cells that comprise part of the polymorphous infiltrate of this disease[7] and in the neoplastic T-cells.[8] Immunodeficiency is also seen with this disease, but it is a sequela to the condition and not a predisposing factor.

DiagnosisLaboratory findingsThe classical laboratory finding is polyclonal hypergammaglobulinemia, and other immunoglobulin derangements are also seen, including hemolytic anemia with cold agglutinins, circulating immune complexes, anti-smooth muscle antibodies, and positive rheumatoid factor.[1][3]

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Lymph nodeThe normal architecture of a lymph node is partially effaced by a polymorphous infiltrate and residual follicles are commonly seen. The polymorphous infiltrate consists of lymphocytes of moderate size with pale/clear cytoplasm and smaller reactive lymphocytes, eosinophils, histiocytes, plasma cells, and follicular dendritic cells. In addition, blast-like B-cells are occasionally seen. A classic morphological finding is the aborization and proliferation of high endothelial venules.[1] Hyperplastic germinal centers and Reed-Sternberg-like cells can also be seen.[9][10]

ImmunophenotypeAITL typically has the phenotype of a mixture of CD4+ and CD8+ T-cells, with a CD4:CD8 ratio greater than unity. Polyclonal plasma cells and CD21+ follicular dendritic cells are also seen.[1]

Molecular findingsClonal T-cell receptor gene rearrangements are detected in 75% of cases,[11] and immunoglobin gene rearrangements are seen in 10% of cases, and these cases are believed to be due to expanded EBV-driven B-cell populations.[12]

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Similarly, EBV-related sequences can be detected in most cases, usually in B-cells but occasionally in T-cells.[7][8] Trisomy 3, trisomy 5, and +X are the most frequent chromosomal abnormalities found in AITL cases.

TreatmentThere is no proven or standard first-line chemotherapy that works for the majority of AITL patients. There are several clinical trials that offer treatment options that can fight the disease. Stem cell transplantation is the treatment of choice, with the allogeneic one being the preference because AITL tends to recur after autologous transplants.

EpidemiologyThe typical patient with angioimmunoblastic T-cell lymphoma (AITL) is either middle-aged or elderly, and no gender preference for this disease has been observed.[1] AITL comprises 15–20% of peripheral T-cell lymphomas and 1–2% of all non-Hodgkin lymphomas.

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Hepatosplenic T-cell lymphoma

DefinitionHepatosplenic T-cell lymphoma is a systemic neoplasm comprising medium-sized cytotoxic T-cells that show a significant sinusoidal infiltration in the liver, spleen, and bone marrow.[1]

Signs and symptomsThe typical clinical finding in a patient with hepatosplenic T-cell lymphoma is hepatosplenomegaly.[3]

Sites of involvementThe spleen and liver are always involved, with bone marrow involvement frequently present. Nodal involvement is exceedingly rare.[1][4]

CauseThe cell of origin for this disease is an immature cytotoxic T-cell clonally expressing the γδ T-cell receptor. This disease is seen more often in immunosuppressed solid organ transplant

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recipients, an association that has led to the hypothesis that long-term immune stimulation in the setting of immunosuppression is the causative agent.

Cases of hepatosplenic T-cell lymphoma (HSTCL) have been reported in patients treated with the immunosuppressants azathioprine, infliximab and adalimumab. The majority occurred in patients with inflammatory bowel disease. Adolescents and young adult males were the major cohort of cases. They presented with a very aggressive disease course and, with one exception, died of the lymphoma. The FDA has required changes to the labeling to inform users and clinicians of the issue.

DiagnosisThe neoplastic cells in this disorder show a monotonous appearance, with a small amount of cytoplasm and inconspicuous nucleoli.[4]

Laboratory findingsThe constellation of thrombocytopenia, anemia, and leukopenia is common in patients with hepatosplenic T-cell lymphoma.[8]

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Spleen and liverThis disease shows a distinct sinusoidal pattern of infiltration which spares the splenic white pulp and hepatic portal triads.[1]

Bone marrowWhile the bone marrow is commonly involved, the detection of the neoplastic infiltrate may be difficult due to diffuse, interstitial pattern. Immunohistochemistry can aid in the detection of this lymphoma.[1]

Peripheral bloodCells of a similar morphology observed in solid organs are observed in peripheral blood.[1]

ImmunophenotypeThe immunophenotype for hepatosplenic T-cell lymphoma is a post-thymic, immature T-cell.

EpidemiologyThis lymphoma is rare, comprising less than 5% of all cases, and is most common in young adults and adolescents. A distinct male gender preference has been described.

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B-cell lymphomaThe B-cell lymphomas are types of lymphoma affecting B cells. Lymphomas are "blood cancers" in the lymph nodes. They develop more frequently in older adults and in immunocompromised individuals.B-cell lymphomas include both Hodgkin's lymphomas and most non-Hodgkin lymphomas. They are typically divided into low and high grade, typically corresponding to indolent (slow-growing) lymphomas and aggressive lymphomas, respectively. As a generalisation, indolent lymphomas respond to treatment and are kept under control (in remission) with long-term survival of many years, but are not cured. Aggressive lymphomas usually require intensive treatments, with some having a good prospect for a permanent cure.[1]

Prognosis and treatment depends on the specific type of lymphoma as well as the stage and grade. Treatment includes radiation and chemotherapy. Early-stage indolent B-cell lymphomas can often be treated with radiation alone, with long-term non-recurrence. Early-stage aggressive disease is treated with chemotherapy and often radiation, with a 70-

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90% cure rate.[1] Late-stage indolent lymphomas are sometimes left untreated and monitored until they progress. Late-stage aggressive disease is treated with chemotherapy, with cure rates of over 70%.

Types

Micrograph showing Hodgkin's lymphoma, a type of B cell lymphoma that is usually considered separate from other B cell lymphomas. Field stain.There are numerous kinds of lymphomas involving B cells. The most commonly used classification system is the WHO classification, a convergence of more than one, older classification systems.

Common

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Five account for nearly three out of four patients with non-Hodgkin lymphoma:

Diffuse large B-cell lymphoma (DLBCL)[3] Follicular lymphoma Marginal zone B-cell lymphoma (MZL) or Mucosa-

Associated Lymphatic Tissue lymphoma (MALT) Small lymphocytic lymphoma (also known as chronic

lymphocytic leukemia, CLL) Mantle cell lymphoma (MCL)

RareThe remaining forms are much less common:[2]

DLBCL variants or sub-types of Primary mediastinal (thymic) large B cell lymphoma T cell/histiocyte-rich large B-cell lymphoma Primary cutaneous diffuse large B-cell lymphoma, leg

type (Primary cutaneous DLBCL, leg type) EBV positive diffuse large B-cell lymphoma of the

elderly Diffuse large B-cell lymphoma associated with

inflammation Burkitt's lymphoma

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Lymphoplasmacytic lymphoma, which may manifest as Waldenström's macroglobulinemia

Nodal marginal zone B cell lymphoma (NMZL) Splenic marginal zone lymphoma (SMZL) Intravascular large B-cell lymphoma Primary effusion lymphoma Lymphomatoid granulomatosis Primary central nervous system lymphoma ALK-positive large B-cell lymphoma Plasmablastic lymphoma Large B-cell lymphoma arising in HHV8-associated

multicentric Castleman's disease B-cell lymphoma, unclassifiable with features

intermediate between diffuse large B-cell lymphoma and Burkitt lymphoma

B-cell lymphoma, unclassifiable with features intermediate between diffuse large B-cell lymphoma and classical Hodgkin lymphoma

OtherAdditionally, some researchers separate out lymphomas that appear to result from other immune system disorders, such as AIDS-related lymphoma.

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Classic Hodgkin's lymphoma and nodular lymphocyte predominant Hodgkin's lymphoma are now considered forms of B-cell lymphoma.

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HistoplasmosisHistoplasmosis (also known as "Cave disease,"[1] "Darling's disease,"[1] "Ohio valley disease,"[1] "reticuloendotheliosis,"[1] "spelunker's lung" and "caver's disease") is a disease caused by the fungus Histoplasma capsulatum. Symptoms of this infection vary greatly, but the disease affects primarily the lungs.[2] Occasionally, other organs are affected; this is called disseminated histoplasmosis, and it can be fatal if left untreated.Histoplasma capsulatum. Methenamine silver stain showing histopathologic changes in histoplasmosis.

Histoplasmosis is common among AIDS patients because of their suppressed immunity.[3] In immunocompetent

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individuals, past infection results in partial protection against ill effects if reinfected.

Histoplasma capsulatum is found in soil, often associated with decaying bat guano or bird droppings. Disruption of soil from excavation or construction can release infectious elements that are inhaled and settle into the lung.

Signs and symptoms

Skin lesion on the upper lip due to Histoplasma capsulatum infection.If symptoms of histoplasmosis infection occur, they will start within 3 to 17 days after exposure; the average is 12–14 days. Most affected individuals have clinically silent manifestations and show no apparent ill effects.[4] The acute phase of histoplasmosis is characterized by non-specific

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respiratory symptoms, often cough or flu-like. Chest X-ray findings are normal in 40–70% of cases.[4] Chronic histoplasmosis cases can resemble tuberculosis;[5][6] disseminated histoplasmosis affects multiple organ systems and is fatal unless treated.[7]

While histoplasmosis is the most common cause of mediastinitis, this remains a relatively rare disease. Severe infections can cause hepatosplenomegaly, lymphadenopathy, and adrenal enlargement.[2] Lesions have a tendency to calcify as they heal.

Presumed ocular histoplasmosis syndrome (POHS) causes chorioretinitis, where the choroid and retina of the eyes are scarred, resulting in a loss of vision not unlike macular degeneration. Despite its name, the relationship to Histoplasma is controversial.[8][9] Distinct from POHS, acute ocular histoplasmosis may rarely occur in immunodeficiency.

MechanismsH. capsulatum grows in soil and material contaminated with bird or bat droppings (guano). The fungus has been found in

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poultry house litter, caves, areas harboring bats, and in bird roosts (particularly those of starlings). The fungus is thermally dimorphic: in the environment it grows as a brownish mycelium, and at body temperature (37 °C in humans) it morphs into a yeast. Histoplasmosis is not contagious, but is contracted by inhalation of the spores from disturbed soil or guano.[2] The inoculum is represented principally by microconidia. These are inhaled and reach the alveoli.

In the alveoli, macrophages ingest these microconidia. They survive inside the phagosome. As the fungus is thermally dimorphic, these microconidia are transformed into yeast. They grow and multiply inside the phagosome. The macrophages travel in lymphatic circulation and spread the disease to different organs.

Within the phagosome the fungus has an absolute requirement for thiamine.[12] Cell-mediated immunity for histoplasmosis develops within 2 weeks. If the patient has strong cellular immunity, macrophages, epithelial cells and lymphocytes surround the organisms and contain them, and eventually calcify. In immunocompromised individuals, the

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organisms disseminate to different organs such as bone, spleen, liver, adrenal glands and mucocutaneous membranes, resulting in progressive disseminated histoplasmosis. Chronic lung disease can manifest.

Diagnosis

Chest X-ray of a patient with acute pulmonary histoplasmosis.Clinically, there is a wide spectrum of disease manifestation, making diagnosis somewhat difficult. More severe forms include: (1) the chronic pulmonary form, often occurring in the presence of underlying pulmonary disease; and (2) a disseminated form, which is characterized by the progressive spread of infection to extra-pulmonary sites. Oral manifestations have been reported as the main complaint of the disseminated forms, leading the patient to seek treatment, whereas pulmonary symptoms

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in disseminated disease may be mild or even misinterpreted as flu.[13] Histoplasmosis can be diagnosed by samples containing the fungus taken from sputum (via bronchoalveolar lavage), blood, or infected organs. It can also be diagnosed by detection of antigens in blood or urine samples by ELISA or PCR. Antigens can cross-react with antigens of African histoplasmosis (caused by Histoplasma duboisii), blastomycosis, coccidioidomycosis, paracoccidioidomycosis, and Penicillium marneffei infection. Histoplasmosis can also be diagnosed by a test for antibodies against Histoplasma in the blood. Histoplasma skin tests indicate whether a person has been exposed, but do not indicate whether they have the disease.[2] Formal histoplasmosis diagnoses are often confirmed only by culturing the fungus directly.[3] Sabouraud agar is one type of agar growth media on which the fungus can be cultured. Cutaneous manifestations of disseminated disease are diverse and often present as a nondescript rash with systemic complaints. Diagnosis is best established by urine antigen testing, as blood cultures may take up to 6 weeks for diagnostic growth to occur and serum antigen testing often comes back with a false negative before 4 weeks of

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disseminated infection.

TypesHistoplasmosis may be divided into the following types:

1. Primary pulmonary histoplasmosis2. Progressive disseminated histoplasmosis3. Primary cutaneous histoplasmosis4. African histoplasmosis

PreventionIt is not practical to test or decontaminate most sites that may be contaminated with H. capsulatum, but the following sources list environments where histoplasmosis is common, and precautions to reduce a person's risk of exposure, in the three parts of the world where the disease is prevalent. Precautions common to all geographical locations would be to avoid accumulations of bird or bat droppings.

The US National Institute for Occupational Safety and Health (NIOSH) provides information on work practices and personal protective equipment that may reduce the risk of infection.[16] This document is available in English and

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Spanish.

Authors at the University of Nigeria have published a review which includes information on locations in which histoplasmosis has been found in Africa (in chicken runs, bats and the caves bats infest, and in soil), and a thorough reference list including English, French, and Spanish language references.

TreatmentIn the majority of immunocompetent individuals, histoplasmosis resolves without any treatment. Antifungal medications are used to treat severe cases of acute histoplasmosis and all cases of chronic and disseminated disease. Typical treatment of severe disease first involves treatment with amphotericin B, followed by oral itraconazole.[18][19]

Liposomal preparations of amphotericin B are more effective than deoxycholate preparations. The liposomal preparation is preferred in patients that might be at risk of nephrotoxicity, although all preparations of amphotericin B have risk of nephrotoxicity. Individuals taking amphotericin B are monitored for renal function.[20]

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Treatment with itraconazole will need to continue for at least a year in severe cases,[21] while in acute pulmonary histoplasmosis, 6 to 12 weeks treatment is sufficient. Alternatives to itraconazole are posaconazole, voriconazole, and fluconazole. Individuals taking itraconazole are monitored for hepatic function.

ComplicationsIn absence of proper treatment and especially in immunocompromised individuals, complications can arise. These include recurrent pneumonia, respiratory failure, fibrosing mediastinitis, superior vena cava syndrome, pulmonary vessel obstruction, progressive fibrosis of lymph nodes. Fibrosing mediastinitis is a serious complication and can be fatal. Smokers with structural lung disease have higher probability of developing chronic cavitary histoplasmosis.

After healing of lesions, hard calcified lymph nodes can erode the walls of airway causing hemoptysis.

Epidemiology

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Histoplasmosis capsulatum is found throughout the world. It is endemic in certain areas of the United States, particularly in states bordering the Ohio River valley and the lower Mississippi River. The humidity and acidity patterns of soil are associated with endemicity. Bird and bat droppings in soil promote growth of Histoplasma. Contact with such soil aerosolizes the microconidia, which can infect humans. It is also common in caves in southern and East Africa. Positive histoplasmin skin tests occur in as many as 90% of the people living in areas where H. capsulatum is common, such as the eastern and central United States.[2]

In Canada, the St. Lawrence River Valley is the site of the most frequent infections, with 20-30 percent of the population testing positive.[22]

In India, the Gangetic West Bengal is the site of most frequent infections, with 9.4 percent of the population testing positive.[23] Histoplasma capsulatum capsulatum was isolated from the local soil proving endemicity of histoplasmosis in West Bengal.

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Letterer–Siwe diseaseLetterer–Siwe disease is one of the four recognized clinical syndromes of Langerhans cell histiocytosis (LCH). It causes approximately 10% of LCH disease and is the most severe form.[1] Prevalence is estimated at 1:500,000 and the disease almost exclusively occurs in children less than three years old.[2] The name is derived from the names of Erich Letterer and Sture Siwe.

Clinical Presentation.Letterer-Siwe is characterized by skin lesions, ear drainage, lymphadenopathy, osteolytic lesions, and hepatosplenomegaly. The skin lesions are scaly and may involve the scalp, ear canals, and abdomen.[3]

PrognosisThe disease is often rapidly fatal, with a five year survival rate of 50%. The development of thrombocytopenia is a poor prognostic sign.

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Primary central nervous system lymphoma

A primary central nervous system lymphoma (PCNSL), also known as microglioma and primary brain lymphoma,[1] is a primary intracranial tumor appearing mostly in patients with severe immunodeficiency (typically patients with AIDS). PCNSLs represent around 20% of all cases of lymphomas in HIV infections (other types are Burkitt's lymphomas and immunoblastic lymphomas). Primary CNS lymphoma is highly associated with Epstein-Barr virus (EBV) infection (> 90%) in immunodeficient patients (such as those with AIDS and those immunosuppressed),[2] and does not have a predilection for any particular age group. Mean CD4+ count at time of diagnosis is ~50/uL. In immunocompromised patients, prognosis is usually poor. In immunocompetent patients (that is, patients who do not have AIDS or some other immunodeficiency), there is rarely an association with EBV infection or other DNA viruses. In the immunocompetent population, PCNSLs typically appear in older patients in their 50's and 60's. Importantly, the

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incidence of PCNSL in the immunocompetent population has been reported to have increased more than 10-fold from 2.5 cases to 30 cases per 10 million population.[3][4] The cause for the increase in incidence of this disease in the immunocompetent population is unknown.

Brain magnetic resonance imaging showing primary central nervous system B-cell non-Hodgkin lymphoma of the sella turcica and

hypothalamus, continuing to the tectum (intensely white areas in the middle).

Classification

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Most PCNSLs are diffuse large B cell non-Hodgkin lymphomas.[5][6]

Signs and symptoms

A primary CNS lymphoma usually presents with seizure, headache, cranial nerve findings, altered mental status, or other focal neurological deficits typical of a mass effect.[7][8] Systemic symptoms may include fever, night sweats, or weight loss.Other symptoms include

diplopia dysphagia vertigo monocular vision loss progressive dementia or stupor in patients with a

nonfocal neurologic exam and minimal abnormalities on MRI (more common in AIDS patients)

facial hypoesthesia

Diagnosis

Micrograph showing a primary CNS lymphoma with the

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characteristic perivascular distribution composed of large cells with prominent nucleoli. Brain biopsy. HPS stain.The definitive diagnosis is arrived at from tissue, i.e. a biopsy, by a pathologist.

MRI or contrast enhanced CT classically shows multiple ring-enhancing lesions in the deep white matter. The major differential diagnosis (based on imaging) is cerebral toxoplasmosis, which is also prevalent in AIDS patients and also presents with a ring-enhanced lesion, although toxoplasmosis generally presents with more lesions and the contrast enhancement is typically more pronounced. Imaging techniques cannot distinguish the two conditions with certainty, and cannot exclude other diagnoses. Thus, patients undergo a brain biopsy.

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TreatmentSurgical resection is usually ineffective because of the depth of the tumour. Treatment with irradiation and corticosteroids often only produces a partial response and tumour recurs in more than 90% of patients. Median survival is 10 to 18 months in immunocompetent patients, and less in those with AIDS. The addition of IV methotrexate and folinic acid (leucovorin) may extend survival to a median of 3.5 years. If radiation is added to methotrexate, median survival time may increase beyond 4 years. However, radiation is not recommended in conjunction with methotrexate because of an increased risk of leukoencephalopathy and dementia in patients older than 60.[10] In AIDS patients, perhaps the most important factor with respect to treatment is the use of highly active anti-retroviral therapy (HAART), which affects the CD4+ lymphocyte population and the level of immunosuppression.[11] The optimal treatment plan for patients with PCNSL has not been determined. Combination chemotherapy and radiotherapy at least doubles survival time, but causes dementia and leukoencephalopathy in at least 50% of patients who undergo it. The most studied chemotheraputic agent in PCNSL is methotrexate (a folate

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analogue that interferes with DNA repair). Methotrexate therapy in patients with PCNSL typically requires hospitalization for close monitoring and intravenous fluids. Leucovorin is often given for the duration of the therapy. Standard chemotherapeutic regimens for lymphoma such as CHOP are ineffective in PCNSL, probably due to poor penetration of the agents through the blood brain barrier.[11]

Newer treatments, such as high dose chemotherapy combined with stem cell transplant are proving to increase survival by years.

A phase 1 clinical trial of ibrutinib - an inhibitor of Bruton's tyrosine kinase - in 13 patients reported responses in 10 (77%).[12] Five of the responses were complete.

PrognosisIn immunocompetent patientsThe initial response to radiotherapy is often excellent, and may result in a complete remission. However, the duration of response with radiotherapy alone remains short, with median survival after treatment with radiotherapy just 18 months. Methotrexate based chemotherapy markedly improves

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survival, with some studies showing median survival after methotrexate chemotherapy reaching 48 months.[13]

In AIDS patientsPatients with AIDS and PCNSL have a median survival of only 4 months with radiotherapy alone. Untreated, median survival is only 2.5 months, sometimes due to concurrent opportunistic infections rather than the lymphoma itself. Extended survival has been seen, however, in a subgroup of AIDS patients with CD4 counts of more than 200 and no concurrent opportunistic infections, who can tolerate aggressive therapy consisting of either methotrexate monotherapy or vincristine, procarbazine, or whole brain radiotherapy. These patients have a median survival of 10–18 months. Of course, highly active antiretroviral therapy (HAART) is critical for prolonged survival in any AIDS patient, so compliance with HAART may play a role in survival in patients with concurrent AIDS and PCNSL.

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Diffuse large B-cell lymphomaDiffuse large B-cell lymphoma (DLBCL or DLBL) is a cancer of B cells, a type of white blood cell responsible for producing antibodies. It is the most common type of non-Hodgkin lymphoma among adults,[1] with an annual incidence of 7–8 cases per 100,000 people per year.[2][3] This cancer occurs primarily in older individuals, with a median age of diagnosis at approximately 70 years of age,[3] though it can also occur in children and young adults in rare cases.[4] DLBCL is an aggressive tumor which can arise in virtually any part of the body,[5] and the first sign of this illness is typically the observation of a rapidly growing mass, sometimes associated with B symptoms—fever, weight loss, and night sweats.The causes of diffuse large B-cell lymphoma are not well understood. Usually DLBCL arises from normal B cells, but it can also represent a malignant transformation of other types of lymphoma or leukemia. An underlying immunodeficiency is a significant risk factor.[7] Infection with Epstein–Barr virus has also been found to contribute to the development of some subgroups of DLBCL.[8]

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Diagnosis of DLBCL is made by removing a portion of the tumor through a biopsy, and then examining this tissue using a microscope. Usually a hematopathologist makes this diagnosis.[9] Several subtypes of DLBCL have been identified, each having a different clinical presentation and prognosis. However, the usual treatment for each of these is chemotherapy, often in combination with an antibody targeted at the tumor cells.[10] Through these treatments, more than half of patients with DLBCL can be cured,[11] and the overall five-year survival rate for older adults is around 58%.

ClassificationDiffuse large B-cell lymphoma encompasses a biologically and clinically diverse set of diseases,[13] many of which cannot be separated from one another by well-defined and widely accepted criteria. The World Health Organization (WHO) classification system defines more than a dozen subtypes,[14] each of which can be differentiated based on the location of the tumor, the presence of other cells within the tumor (such as T cells), and whether the patient has certain other illnesses related to DLBCL. One of these well-

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defined groupings of particular note is "primary mediastinal (thymic) large B cell lymphoma", which arises within the thymus or mediastinal lymph nodes.[15]

In some cases, a tumor may share many features with both DLBCL and Burkitt's lymphoma. In these situations, the tumor is classified as simply “B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and Burkitt lymphoma”. A similar situation can arise between DLBCL and Hodgkin's lymphoma; the tumor is then classified as “B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and Hodgkin’s lymphoma”.[citation needed]

When a case of DLBCL does not conform to any of these subtypes, and is also not considered unclassifiable, then it is classified as “diffuse large B-cell lymphoma, not otherwise specified” (DLBCL, NOS). The majority of DLBCL cases fall into this category. Much research has been devoted to separating this still-heterogeneous group; such distinctions are usually made along lines of cellular morphology, gene expression, and immunohistochemical properties.[citation

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needed]

MorphologyWithin cellular morphology, three variants are most commonly seen: centroblastic, immunoblastic, and anaplastic.

Most cases of DLBCL are centroblastic, having the appearance of medium-to-large-sized lymphocytes with scanty cytoplasm. Oval or round nuclei containing fine chromatin are prominently visible, having two to four nucleoli within each nucleus. Sometimes the tumor may be monomorphic, composed almost entirely of centroblasts. However, most cases are polymorphic, with a mixture of centroblastic and immunoblastic cells.[16]

Immunoblasts have significant basophilic cytoplasm and a central nucleolus. A tumor can be classified as immunoblastic if greater than 90% of its cells are immunoblasts.[16]This distinction can be problematic, however, because hematopathologists reviewing the microscope slides may often disagree on whether a collection of cells is best characterized as centroblasts or immunoblasts.[17] Such disagreement indicates poor inter-rater reliability.

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The third morphologic variant, anaplastic, consists of tumor cells which appear very differently from their normal B cell counterparts. The cells are generally very large with a round, oval, or polygonal shape and pleomorphic nuclei, and may resemble Reed-Sternberg cells.Gene and microRNA expressionGene expression profiling studies have also attempted to distinguish heterogeneous groups of DLBCL from each other. These studies examine thousands of genes simultaneously using a DNA microarray, looking for patterns which may help in grouping cases of DLBCL. Many studies now suggest that cases of DLBCL, NOS can be separated into two groups on the basis of their gene expression profiles; these groups are known as germinal center B-cell-like (GCB) and activated B-cell-like (ABC).[13][18][19][20] Tumor cells in the germinal center B-cell-like subgroup resemble normal B cells in the germinal center closely, and are generally associated with a favorable prognosis.[21][22] Activated B-cell-like tumor cells are associated with a poorer prognosis,[22] and derive their name from studies which show the continuous activation of certain pathways normally activated when B cells interact with an antigen. The NF-κB pathway,

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which is normally involved in transforming B cells into plasma cells, is an important example of one such pathway.[23]

Another notable finding of recent gene expression studies is the importance of the cells and microscopic structures interspersed between the malignant B cells within the DLBCL tumor, an area commonly known as the tumor microenvironment. The presence of gene expression signatures commonly associated with macrophages, T cells, and remodelling of the extracellular matrix seems to be associated with an improved prognosis and better overall survival.[22][24] Alternatively, expression of genes coding for pro-angiogenic factors is correlated with poorer survival.[22]

Recently, it was described that short non-coding RNAs named microRNAs (miRNAs) have important functions in lymphoma biology. In malignant B cells miRNAs participate in pathways fundamental to B cell development like B cell receptor (BCR) signalling, B cell migration/adhesion, cell-cell interactions in immune niches, and the production and class-switching of immunoglobulins.[25] MiRNAs influence

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B cell maturation, generation of pre-, marginal zone, follicular, B1, plasma and memory B cells.[25]

ImmunohistochemistryWith the apparent success of gene expression profiling in separating biologically distinct cases of DLBCL, NOS, some researchers examined whether a similar distinction could be made using immunohistochemical staining (IHC), a widely used method for characterizing tissue samples. This technique uses highly specific antibody-based stains to detect proteins on a microscope slide, and since microarrays are not widely available for routine clinical use, IHC is a desirable alternative.[26][27] Many of these studies focused on stains against the products of prognostically significant genes which had been implicated in DLBCL gene expression studies. Examples of such genes include BCL2, BCL6, MUM1, LMO2, MYC, and p21. Several algorithms for separating DLBCL cases by IHC arose out of this research, categorizing tissue samples into groups most commonly known as GCB and non-GCB.[27][28][29][30] The correlation between these GCB/non-GCB immunohistochemical groupings and the GCB/ABC groupings used in gene expression profiling studies is

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uncertain,[21][29] as is their prognostic value.[21] This uncertainty may arise in part due to poor inter-rater reliability in performing common immunohistochemical stains.

Signs and symptomsThe most typical symptom at the time of diagnosis is a mass that is rapidly enlarging and located in a part of the body with multiple lymph nodes.[31]

TreatmentChemotherapyCurrent treatment typically includes R-CHOP, which consists of the traditional CHOP, to which rituximab has been added.[32][33] This regimen has increased the rate of complete response for DLBCL patients, particularly in elderly patients.[34]R-CHOP is a combination of one monoclonal antibody (rituximab), three chemotherapy agents (cyclophosphamide, doxorubicin, vincristine), and one steroid (prednisone).[35] These drugs are administered intravenously, and the regimen is most effective when it is administered multiple times over a period of months. People often receive this type of chemotherapy through a PICC line (peripherally inserted

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central catheter) in their arm near the elbow or a surgically implanted venous access port. The number of cycles of chemotherapy given depends on the stage of the disease — patients with limited disease typically receive three cycles of chemotherapy, while patients with extensive disease may need to undergo six to eight cycles. A recent approach involves obtaining a PET scan after the completion of two cycles of chemotherapy, to assist the treatment team in making further decisions about the future course of treatment.[citation needed]Older people often have more difficulty tolerating therapy than younger people. Lower intensity regimens have been attempted in this age group.[36]

Radiation therapyRadiation therapy is often part of the treatment for DLBCL. It is commonly used after the completion of chemotherapy. Radiation therapy alone is not an effective treatment for this disease.

PrognosisThe germinal center subtype has the best prognosis,[34]with 66.6% of treated patients surviving more than five years. The IPI score is used in prognosis in clinical practice.[37]

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Lenalidomide has been recently shown to improve outcomes in the non-germinal center subtype.[38] Ratios of immune effectors such as CD4 and CD8 to immune checkpoints such as PD-L1 and M2 macrophages are independent of and additive to the cell of origin and IPI in DLBCL, and are applicable to paraffin-embedded biopsy specimens. These findings might have potential implications for selection of patients for checkpoint blockade and/or lenalidomide within clinical trials.[39]

For children with diffuse large B-cell lymphomas, most studies have found 5-year survival rates ranging from about 70% to more than 90%.

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Follicular lymphomaFollicular lymphoma is a type of blood cancer. It is the most common of the indolent (slow-growing) non-Hodgkin's lymphomas, and the second-most-common form of non-Hodgkin's lymphomas overall. It is defined as a lymphoma of follicle center B-cells (centrocytes and centroblasts), which has at least a partially follicular pattern. It is positive for the B-cell markers CD10, CD19, CD22, and usually CD20,[1] but almost always negative for CD5.There are several synonymous and obsolete terms for this disease, such as CB/CC lymphoma (Centroblastic and Centrocytic lymphoma), nodular lymphoma[3] and Brill-Symmers Disease.

CausesA translocation between chromosome 14 and 18 results in the overexpression of the bcl-2 gene.[4] As the bcl-2 protein is normally involved in preventing apoptosis, cells with an overexpression of this protein are basically immortal. The bcl-2 gene is normally found on chromosome 18, and the translocation moves the gene near to the site of the

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immunoglobulin heavy chain enhancer element on chromosome 14.

Translocations of BCL6 at 3q27 can also be involved.[5]

microRNA expressionIn 2014, it was described that short non-coding RNAs named microRNAs (miRNAs) have important functions in lymphoma biology, including follicular lymphoma. In malignant B cells, miRNAs participate in pathways fundamental to the cells' development, such as receptor signalling, migration/adhesion, cell-cell interactions in immune niches, and the production and class-switching of immunoglobulins.[6] MiRNAs influence B cell maturation, generation of pre-, marginal zone, follicular, B1, plasma and memory B cells.[6]

Morphology

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Follicular lymphoma replacing a lymph node.The tumor is composed of follicles containing a mixture of centrocytes (Kiel nomenclature adopted by WHO experts) or cleaved follicle center cells (older American nomenclature), "small cells", and centroblasts (Kiel nomenclature adopted by WHO experts) or large noncleaved follicle center cells (older American nomenclature), "large cells". These follicles are surrounded by non-malignant cells, mostly T-cells. In the follicles, centrocytes typically predominate; centroblasts are usually in minority. Peripheral smear will also reveal buttock cells.

Diagnosis626

Grading

Classic appearance of spleen involved by follicular lymphoma, namely the presence of discrete, miliary, small, white "pearly" nodules throughout the whole parenchyma.According to the WHO criteria, the disease is

morphologically graded into:[8]

grade 1 (<5 centroblasts per high-power field (hpf)) grade 2 (6–15 centroblasts/hpf) grade 3 (>15 centroblasts/hpf). Grade 3 is further subdivided into:

grade 3A (centrocytes still present)

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grade 3B (the follicles consist almost entirely of centroblasts)

The WHO 2008 update classifies grades 1 and 2 now as low grade follicular lymphoma, grade 3A as high grade follicular lymphoma, and grade 3B as Diffuse Large B Cell Lymphoma (DLBCL).

TreatmentThere is no consensus regarding the best treatment protocol. Several considerations should be taken into account including age, stage, and prognostic scores (see International Prognostic Index). Patients with advanced disease who are asymptomatic might benefit from a watch and wait approach, as early treatment does not provide survival benefit.[9][10] When patients are symptomatic, specific treatment is required, which might include various combinations of alkylators, nucleoside analogues, anthracycline-containing chemotherapy regimens (e.g., CHOP), monoclonal antibodies (e.g. rituximab), radioimmunotherapy, autologous (self) and allogeneic (donor) hematopoietic stem cell transplantation. Follicular lymphoma is regarded as incurable, unless the disease is localized, in which case it can be cured by local

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irradiation. Although allogeneic stem cell transplantation may be curative, the mortality from the procedure is too high to be a first line option.

In 2010 rituximab was approved by the European Commission for first-line maintenance treatment of follicular lymphoma.[11] Pre-clinical evidence suggests that rituximab could be also used in combination with integrin inhibitors to overcome the resistance to rituximab mediated by stromal cells .[12] However, follicular lymphoma which is CD20 negative will not benefit from Rituximab, which targets CD20.

Trial results released in June 2012 show that bendamustine, a drug first developed in East Germany in the 1960s, more than doubled disease progression-free survival when given along with rituximab. This combination therapy also left patients with fewer side effects than the older treatment (a combination of five drugs—rituximab, cyclophosphamide (Cytoxan), doxorubicin (Adriamycin), vincristine and prednisone, collectively called R-CHOP).[13]

There are many recent and current clinical trials for follicular lymphoma.[14] For example, personalised idiotype vaccines

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have shown promise, particularly as upfront therapy,[15] but have still to prove their efficacy in randomized clinical trials.[16]

PrognosisMedian survival is around 10 years, but the range is wide, from less than one year, to more than 20 years. Some patients may never need treatment. The overall survival rate at five years is 72–77%.[17] Recent advances and addition of Rituximab, improved median survival. Recent reports for the period 1986 and 2012 estimates median survival of over 20 years.[18]

EpidemiologyOf all cancers involving the same class of blood cell (lymphoproliferative disorders), 22% of cases are follicular lymphomas.

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B-cell chronic lymphocytic leukemia

"B-cell CLL" redirects here. For the gene family, see B-cell CLL/lymphoma.B-cell chronic lymphocytic leukemia (B-CLL), also known as chronic lymphoid leukemia (CLL), is the most common type of leukemia (a type of cancer of the white blood cells) in adults.[1] CLL affects B cell lymphocytes, which originate in the bone marrow, develop in the lymph nodes, and normally fight infection by producing antibodies.Peripheral blood smear showing CLL cells.In CLL, B cells grow in an uncontrolled manner and accumulate in the bone marrow and blood, where they crowd out healthy blood cells. CLL is a stage of small lymphocytic lymphoma (SLL), a type of B-cell lymphoma, which presents primarily in the lymph nodes.[2][dubious ] CLL and SLL are

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considered the same underlying disease, just with different appearances.[3]:1441

CLL is a disease of the elderly;[4] however, in rare cases, it can occur in teenagers and occasionally in children. Some of these may relate to an inherited predisposition.[citation needed] CLL is more common in men than women, with 63% of new cases occurring in men (UK, 2014).[5]

Most people are diagnosed without symptoms as the result of a routine blood test that shows a high white blood cell count. As it advances, CLL results in swollen lymph nodes, spleen, and liver, and eventually anemia and infections. Early CLL is not treated, and late CLL is treated with chemotherapy and monoclonal antibodies.

DNA analysis has distinguished two major types of CLL, with different survival times. People with CLL that is positive for the marker ZAP-70 have an average survival of 8 years, while those negative for ZAP-70 have an average survival of more than 25 years.[citation needed] Many patients, especially older ones with slowly progressing disease, can be reassured and may not need any treatment in their lifetimes.

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Signs and symptomsMost people are diagnosed without symptoms as the result of a routine blood test that shows a high white blood cell count. Less commonly, CLL may present with enlarged lymph nodes without a high white blood cell count or no evidence of the disease in the blood. This is referred to as small lymphocytic lymphoma. In some individuals, the disease comes to light only after the cancerous cells overwhelm the bone marrow resulting in anemia producing tiredness or weakness.

Diagnosis

Micrograph of a lymph node affected by B-CLL showing a

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characteristic proliferation center (right of image), composed of larger, lighter-staining, cells, H&E stainCLL is usually first suspected by a diagnosis of lymphocytosis, an increase in a type of white blood cell, on a complete blood count test. This frequently is an incidental finding on a routine physician visit. Most often the lymphocyte count is greater than 4000 cells per microliter (µl) of blood, but can be much higher. The presence of lymphocytosis in an elderly individual should raise strong suspicion for CLL, and a confirmatory diagnostic test, in particular flow cytometry, should be performed unless clinically unnecessary.

The diagnosis of CLL is based on the demonstration of an abnormal population of B lymphocytes in the blood, bone marrow, or tissues that display an unusual but characteristic pattern of molecules on the cell surface. This atypical molecular pattern includes the coexpression of cell surface markers clusters of differentiation 5 (CD5) and 23. In addition, all the CLL cells within one individual are clonal, that is, genetically identical. In practice, this is inferred by the detection of only one of the mutually exclusive antibody light chains, kappa or lambda, on the entire population of the

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abnormal B cells. Normal B lymphocytes consist of a stew of different antibody-producing cells, resulting in a mixture of both kappa- and lambda-expressing cells. The lack of the normal distribution of these B cells is one basis for demonstrating clonality, the key element for establishing a diagnosis of any B cell malignancy (B cell non-Hodgkin lymphoma).

The combination of the microscopic examination of the peripheral blood and analysis of the lymphocytes by flow cytometry to confirm clonality and marker molecule expression is needed to establish the diagnosis of CLL. Both are easily accomplished on a small amount of blood. A flow cytometer instrument can examine the expression of molecules on individual cells in fluids. This requires the use of specific antibodies to marker molecules with fluorescent tags recognized by the instrument. In CLL, the lymphocytes are genetically clonal, of the B cell lineage (expressing marker molecules clusters of differentiation 19 and 20), and characteristically express the marker molecules CD5 and CD23. These B cells resemble normal lymphocytes under the microscope, although slightly smaller, and are fragile when smeared onto a glass slide, giving rise to many broken cells,

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which are called "smudge" or "smear" cells.Smudge cells in peripheral bloodThe Matutes's CLL score allows the identification of a homogeneous subgroup of classical CLL, that differs from atypical/mixed CLL for the five markers' expression (CD5, CD23, FMC7, CD22, and immunoglobulin light chain) Matutes's CLL scoring system is very helpful for the differential diagnosis between classical CLL and the other B cell chronic lymphoproliferative disorders, but not for the immunological distinction between mixed/atypical CLL and mantle cell lymphoma (MCL malignant B cells).[8] Discrimination between CLL and MCL can be improved by adding non-routine markers such as CD54[9] and CD200.[10] Among routine markers, the most discriminating feature is the CD20/CD23 mean fluorescence intensity ratio. In contrast, FMC7 expression can surprisingly be misleading for borderline cases.[11]

Clinical stagingStaging, determining the extent of the disease, is done with the Rai staging

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system or the Binet classification (see details[12]) and is based primarily on the presence of a low platelet or red cell count. Early-stage disease does not need to be treated.

Rai staging system[13][14]

Stage 0: characterized by absolute lymphocytosis (>15,000/mm3) without adenopathy, hepatosplenomegaly, anemia, or thrombocytopeniaStage I: characterized by absolute lymphocytosis with lymphadenopathy without hepatosplenomegaly, anemia, or thrombocytopeniaStage II: characterized by absolute lymphocytosis with either hepatomegaly or splenomegaly with or without lymphadenopathyStage III: characterized by absolute lymphocytosis and anemia (hemoglobin <11 g/dL) with or without lymphadenopathy, hepatomegaly, or splenomegalyStage IV: characterized by absolute lymphocytosis and thrombocytopenia (<100,000/mm3) with or without lymphadenopathy, hepatomegaly, splenomegaly, or anemiaBinet classification[15]

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Clinical stage A: characterized by no anemia or thrombocytopenia and fewer than three areas of lymphoid involvement (Rai stages 0, I, and II)Clinical stage B: characterized by no anemia or thrombocytopenia with three or more areas of lymphoid involvement (Rai stages I and II)Clinical stage C: characterized by anemia and/or thrombocytopenia regardless of the number of areas of lymphoid enlargement (Rai stages III and IV).Gene mutation statusIgVH mutation statusPrognosis varies greatly depending on into which diagnostic group CLL falls. The two[16] or three[17] prognostic groups are based on the maturational state of the cell. This distinction is based on the maturity of the lymphocytes as discerned by the immunoglobulin variable-region heavy chain (IgVH) gene mutation status.[18] High-risk patients have an immature cell pattern with few mutations in the DNA in the IgVH antibody gene region, whereas low-risk patients show considerable mutations of the DNA in the antibody gene region indicating mature lymphocytes.[19] Moreover, usage of specific subgenes (i.e. V3-21) for variable segment

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of immunoglobulin is a marker for more severe prognosis.[20] It is believed that the structure of variable subgenes of Ig and the whole surface immunoglobulin determines the propensity of chronic or tonic BCR signalling in CLL.[21] Additionally, the usage of certain variable segments (i.e. V2 family) is also connected to the activation of microRNA miR-650, which further influences the biology of CLL.[22][23]

Since assessment of the IgVH antibody DNA changes is difficult to perform, the presence of either CD38 or Z-chain–associated protein kinase-70 (ZAP-70) may be surrogate markers of high-risk subtype of CLL.[18] Their expression correlates positively with a more immature cellular state and a more rapid disease course.

Chromosomal abnormalitiesIn addition to the immunoglobulin variable-region heavy chain (IgVH) gene mutation status, the prognosis of patients with CLL is dependent on the genetic changes within the neoplastic cell population. These genetic changes can be identified in about 80% of patients by array-CGH or fluorescent in situ hybridization (FISH).[18][23]

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Deletions of part of the short arm of chromosome 17 (del 17p), which target the cell cycle regulating protein p53 are particularly deleterious. The deletion of p53 leads to deregulation of numerous genes including microRNAs (miR-34a).[24] Patients with this abnormality have significantly short interval before they require therapy and a shorter survival. This abnormality is found in 5–10% of patients with CLL.Deletions of the long arm on chromosome 11 (del 11q) are also unfavorable although not to the degree seen with del 17p. The abnormality targets the ATM gene and occurs infrequently in CLL (5–10%).Trisomy 12, an additional chromosome 12, is a relatively frequent finding occurring in 20–25% of patients and imparts an intermediate prognosis.Deletion of the long arm of chromosome 13 (del 13q) is the most common abnormality in CLL with roughly 50% of patients with cells containing this defect. These patients have the best prognosis and most live many years, even decades, without the need for therapy. The gene targeted by this deletion is a segment coding for microRNAs miR-15a and miR-16-1.[25][26] Studies have found the miR-15a/16-1

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microRNA cluster to function as a tumour suppressor, with the oncogene BCL2 as its target.[27]It was described that in malignant B cells miRNAs participate in pathways fundamental to B cell development like B cell receptor (BCR) signalling, B cell migration/adhesion, cell-cell interactions in immune niches, and the production and class-switching of immunoglobulins. MiRNAs influence B cell maturation, generation of pre-, marginal zone, follicular, B1, plasma and memory B cells.[25]

Array-based karyotypingMain article: Virtual karyotypeArray-based karyotyping is a cost-effective alternative to FISH for detecting chromosomal abnormalities in CLL. Several clinical validation studies have shown >95% concordance with the standard CLL FISH panel.[28][29][30][31][32]

Related diseasesIn the past, cases with similar microscopic appearance in the blood but with a T cell phenotype were referred to as T-cell CLL. However, these are now recognized as a separate

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disease group and are currently classified as T-cell prolymphocytic leukemias.CLL should not be confused with acute lymphoblastic leukemia, a highly aggressive leukemia most commonly diagnosed in children, and highly treatable in the pediatric setting.

Differential diagnosisLymphoid disorders that can present as chronic leukemia and can be confused with typical B-cell chronic lymphoid leukemia[35]Follicular lymphomaSplenic marginal zone lymphomaNodal marginal zone lymphomaMantle cell lymphomaHairy cell leukemiaProlymphocytic leukemia (B cell or T cell)Lymphoplasmacytic lymphomaSézary syndromeSmoldering adult T cell leukemia/lymphoma

Hematologic disorders that may resemble CLL in their clinical presentation, behavior, and microscopic appearance

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include mantle cell lymphoma, marginal zone lymphoma, B cell prolymphocytic leukemia, and lymphoplasmacytic lymphoma.

B cell prolymphocytic leukemia, a related, but more aggressive disorder, has cells with similar phenotype, but are significantly larger than normal lymphocytes and have a prominent nucleolus. The distinction is important as the prognosis and therapy differ from CLL.Hairy cell leukemia is also a neoplasm of B lymphocytes, but the neoplastic cells have a distinct morphology under the microscope (hairy cell leukemia cells have delicate, hair-like projections on their surfaces) and unique marker molecule expression.All the B cell malignancies of the blood and bone marrow can be differentiated from one another by the combination of cellular microscopic morphology, marker molecule expression, and specific tumor-associated gene defects. This is best accomplished by evaluation of the patient's blood, bone marrow, and occasionally lymph node cells by a pathologist with specific training in blood disorders. A flow cytometer is necessary for cell marker analysis, and the detection of genetic problems in the cells may require

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visualizing the DNA changes with fluorescent probes by FISH.

TreatmentCLL treatment focuses on controlling the disease and its symptoms rather than on an outright cure. CLL is treated by chemotherapy, radiation therapy, biological therapy, or bone marrow transplantation. Symptoms are sometimes treated surgically (splenectomy - removal of enlarged spleen) or by radiation therapy ("de-bulking" swollen lymph nodes).

Initial CLL treatments vary depending on the exact diagnosis and the progression of the disease, and even with the preference and experience of the health care practitioner. Any of dozens of agents may be used for CLL therapy.[36] An initial treatment regimen that contains fludarabine, cyclophosphamide, and rituximab (known as FCR) has demonstrated higher overall response rates and complete response rates.[37]

During pregnancyLeukemia is rarely associated with pregnancy, affecting only about one in 10,000 pregnant women.[38] Treatment for

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chronic lymphocytic leukemias can often be postponed until after the end of the pregnancy. If treatment is necessary, then giving chemotherapy during the second or third trimesters is less likely to result in pregnancy loss or birth defects than treatment during the first trimester.[38]

Decision to treatWhile generally considered incurable, CLL progresses slowly in most cases. Many people with CLL lead normal and active lives for many years—in some cases for decades. Because of its slow onset, early-stage CLL is, in general, not treated since it is believed that early CLL intervention does not improve survival time or quality of life. Instead, the condition is monitored over time to detect any change in the disease pattern.[37]

The decision to start CLL treatment is taken when the patient's clinical symptoms or blood counts indicate that the disease has progressed to a point where it may affect the patient's quality of life.

Clinical "staging systems" such as the Rai four-stage system and the Binet classification can help to determine when and how to treat the patient.[12]

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Determining when to start treatment and by what means is often difficult; no survival advantage is seen in treating the disease very early. The National Cancer Institute Working Group has issued guidelines for treatment, with specific markers that should be met before it is initiated.

ChemotherapyCombination chemotherapy regimens are effective in both newly diagnosed and relapsed CLL. Combinations of fludarabine with alkylating agents (cyclophosphamide) produce higher response rates and a longer progression-free survival than single agents:

FC (fludarabine with cyclophosphamide)[40] FR (fludarabine with rituximab)[41] FCR (fludarabine, cyclophosphamide, and rituximab)

[42] CHOP (cyclophosphamide, doxorubicin, vincristine, and

prednisolone)Although the purine analogue fludarabine was shown to give superior response rates to chlorambucil as primary therapy,[43][44] no evidence shows early use of fludarabine improves overall survival, and some clinicians prefer to

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reserve fludarabine for relapsed disease.

Chemoimmunotherapy with FCR has shown to improve response rates, progression-free survival, and overall survival in a large randomized trial in CLL patients selected for good physical fitness.[45] This has been the first clinical trial demonstrating that the choice of a first-line therapy can improve the overall survival of patients with CLL.

Alkylating agents approved for CLL include bendamustine and cyclophosphamide.

Targeted therapyTargeted therapy attacks cancer cells at a specific target, with the aim of not harming normal cells.

Alemtuzumab is a mAb directed against CD52 used in CLL.[37]

Rituximab, ofatumumab, and obinutuzumab are antibodies against CD20 used to treat CLL.[37][46]

Ibrutinib, a Bruton's tyrosine kinase (BTK) inhibitor, is used to treat CLL.

Idelalisib is a PI3K inhibitor.[47][48] and is taken orally.[49][50]

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Venetoclax is a Bcl-2 inhibitor used to treat people with CLL who have 17p deletion (deletion located on the chromosome 17 short arm) and who have been treated with at least one prior therapy.[51]

Stem cell transplantationAutologous stem cell transplantation, using the recipient's own cells, is not curative.[3]:1458 Younger individuals, if at high risk for dying from CLL, may consider allogeneic hematopoietic stem cell transplantation (HSCT). Myeloablative (bone marrow killing) forms of allogeneic stem cell transplantation, a high-risk treatment using blood cells from a healthy donor, may be curative, but treatment-related toxicity is significant.[3]:1458 An intermediate level, called reduced-intensity conditioning allogeneic stem cell transplantation, may be better tolerated by older or frail patients.[52][53]

Refractory CLL"Refractory" CLL is a disease that no longer responds favorably to treatment. In this case, more aggressive therapies, including lenalidomide, flavopiridol, and bone marrow (stem cell) transplantation, are considered.[54] The

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monoclonal antibody alemtuzumab (directed against CD52) may be used in patients with refractory, bone marrow-based disease.

ComplicationsComplications include Richter's syndrome, hypogammaglobulinemia leading to recurrent infection, warm autoimmune hemolytic anemia in 10–15% of patients, and transformation to high-grade lymphoma.

Chronic lymphocytic leukemia may transform into Richter's syndrome, the development of fast-growing diffuse large B cell lymphoma, prolymphocytic leukemia, Hodgkin's lymphoma, or acute leukemia in some patients. Its incidence is estimated to be around 5% in patients with CLL.[56]

Gastrointestinal (GI) involvement can rarely occur with chronic lymphocytic leukemia. Some of the reported manifestations include intussusception, small intestinal bacterial contamination, colitis, and others. Usually, GI complications with CLL occur after Richter transformation. Two case to date have been reported of GI involvement in chronic lymphocytic leukemia without Richter's

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transformation.[57]

PrognosisPrognosis depends on the subtype. Some subtypes have a median survival of 6–8 years, while others have a median survival of 22 years (which is a normal lifespan for older patients).[citation needed] Telomere length has been suggested to be a valuable prognostic indicator of survival.

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Mantle cell lymphomaMantle cell lymphoma (MCL) is a type of non-Hodgkin's lymphoma (NHL), comprising about 6% of NHL cases.[1][2] There are only about 15,000 patients presently in the U.S.MCL is a subtype of B-cell lymphoma, due to CD5 positive antigen-naive pregerminal center B-cell within the mantle zone that surrounds normal germinal center follicles. MCL cells generally over-express cyclin D1 due to a t(11:14)[3] chromosomal translocation in the DNA. Specifically, the translocation is at t(11;14)(q13;q32).

SymptomsAt diagnosis, patients typically are in their 60s and present to their physician with advanced disease. About half have either fever, night sweats, or unexplained weight loss (over 10% of body weight). Enlarged lymph nodes (for example, a "bump" on the neck, armpits or groin) or splenomegaly are usually present. Bone marrow, liver and GI tract involvement occurs relatively early in the course of the disease.[6]

Pathogenesis

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MCL, like most malignancies, results from the acquisition of a combination of (non-inherited) genetic mutations in somatic cells. This leads to a clonal expansion of malignant B lymphocytes. The factors that initiate the genetic alterations are typically not identifiable, and usually occur in people with no particular risk factors for lymphoma development. Because it is an acquired genetic disorder, MCL is neither communicable nor inheritable. A defining characteristic of MCL is mutation and overexpression of cyclin D1, a cell cycle gene, that contributes to the abnormal proliferation of the malignant cells. MCL cells may also be resistant to drug-induced apoptosis, making them harder to cure with chemotherapy or radiation. Cells affected by MCL proliferate in a nodular or diffuse pattern with two main cytologic variants, typical or blastic. Typical cases are small to intermediate-sized cells with irregular nuclei. Blastic (aka blastoid) variants have intermediate to large-sized cells with finely dispersed chromatin, and are more aggressive in nature.[7] The tumor cells accumulate in the lymphoid system, including lymph nodes and the spleen, with non-useful cells eventually rendering the system dysfunctional. MCL may also replace normal cells in the bone marrow,

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which impairs normal blood cell production.

Diagnosis

Lymph node with mantle cell lymphoma (low power view, H&E)

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Mantle cell lymphoma. Notice the irregular nuclear contours of the medium-sized lymphoma cells and the presence of a pink histiocyte. By

immunohistochemistry the lymphoma cells expressed CD20, CD5 and Cyclin D1 (high power view, H&E)

Micrograph of terminal ileum with mantle cell lymphoma

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(bottom of image). H&E stain.

Micrograph of terminal ileum with mantle cell lymphoma (bottom of image - brown colour). Cyclin D1 immunostain.

Diagnosis generally requires stained slides of a surgically removed part of a lymph node. Other methods are also commonly used, including cytogenetics and fluorescence in situ hybridization (FISH). Polymerase chain reaction (PCR) and CER3 clonotypic primers are additional methods, but are less often used.[citation needed]

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The immunophenotype profile consists of CD5+ (in about 80%),[8] CD10-/+, and it is usually CD5+ and CD10-.[9] CD20+, CD23-/+ (though plus in rare cases). Generally, cyclin D1 is expressed but it may not be required. The workup for Mantle cell lymphoma is similar to the workup for many indolent lymphomas and certain aggressive lymphomas.

Mantle cell lymphoma is a systemic disease with frequent involvement of the bone marrow and gastrointestinal tract (generally showing polyposis in the lining). There is also a not-uncommon leukemic phase, marked by presence in the blood. For this reason, both the peripheral blood and bone marrow are evaluated for the presence of malignant cells. Chest, abdominal, and pelvic CT scans are routinely performed.[citation needed]

Since mantle cell lymphoma may present a lymphomatous polyposis coli and colon involvement is common, colonoscopy is now considered a routine part of the evaluation. Upper endoscopy and neck CT scan may be helpful in selected cases. In some patients with the blastic variant, lumbar puncture is done to evaluate the spinal fluid

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for involvement.CT scan - Computerized tomography scan yields images of part or whole body. Gives a large number of slices on X-ray image.[citation needed]

PET scan - Generally of the whole body, shows a three-dimensional image of where previously injected radioactive glucose is metabolized at a rapid rate. Faster-than-average metabolism indicates that cancer is likely present. Metabolism of radioactive glucose may give a false positive, particularly if the patient has exercised before the test.[citation needed]

PET scans are much more effective when the information from them is integrated with that from a CT scan to show more precisely where the cancer activity is located and to more accurately measure the size of tumors.

PrognosisThe overall 5-year survival rate for MCL is generally 50%[10] (advanced stage MCL) to 70%[11] (for limited-stage MCL).

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Prognosis for individuals with MCL is problematic and indexes do not work as well due to patients presenting with advanced stage disease. Staging is used but is not very informative, since the malignant B-cells can travel freely though the lymphatic system and therefore most patients are at stage III or IV at diagnosis. Prognosis is not strongly affected by staging in MCL and the concept of metastasis does not really apply.[citation needed]

The Mantle Cell Lymphoma International Prognostic Index (MIPI) was derived from a data set of 455 advanced stage MCL patients treated in series of clinical trials in Germany/Europe. Of the evaluable population, approximately 18% were treated with high-dose therapy and stem cell transplantation in first remission. The MIPI is able to classify patients into three risk groups: low risk (median survival not reached after median 32 months follow-up and 5-year OS rate of 60%), intermediate risk (median survival 51 months) and high risk (median survival 29 months). In addition to the 4 independent prognostic factors included in the model, the cell proliferation index (Ki-67) was also shown to have additional prognostic relevance. When the Ki67 is available, a biologic MIPI can be calculated.[12]

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MCL is one of the few NHLs that can cross the boundary into the brain, yet it can be treated in that event.[citation needed]

There are a number of prognostic indicators that have been studied. There is not universal agreement on their importance or usefulness in prognosis.[citation needed]

Ki-67 is an indicator of how fast cells mature and is expressed in a range from about 10% to 90%. The lower the percentage, the lower the speed of maturity, and the more indolent the disease. Katzenberger et al. Blood 2006;107:3407 graphs survival versus time for subsets of patients with varying Ki-67 indices. He shows median survival times of about one year for 61-90% Ki-67 and nearly 4 years for 5-20% Ki-67 index.

MCL cell types can aid in prognosis in a subjective way. Blastic is a larger cell type. Diffuse is spread through the node. Nodular are small groups of collected cells spread through the node. Diffuse and nodular are similar in behavior. Blastic is faster growing and it is harder to get long remissions. Some thought is that given a long time, some non-blastic MCL transforms to blastic. Although survival of

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most blastic patients is shorter, some data shows that 25% of blastic MCL patients survive to 5 years. That is longer than diffuse type and almost as long as nodular (almost 7 yrs).[citation needed]

Beta-2 microglobulin is another risk factor in MCL used primarily for transplant patients. Values less than 3 have yielded 95% overall survival to 6 yrs for auto SCT where over 3 yields a median of 44 most overall survival for auto SCT (Khouri 03). This is not yet fully validated.[citation needed]

Testing for high levels of LDH in NHL patients is useful because LDH is released when body tissues break down for any reason. While it cannot be used as a sole means of diagnosing NHL, it is a surrogate for tracking tumor burden in those diagnosed by other means. The normal range is approximately 100-190.

TreatmentsThere are no proven standards of treatment for MCL, and there is no consensus among specialists on how to treat it optimally.[13] Many regimens are available and often get

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good response rates, but patients almost always get disease progression after chemotherapy. Each relapse is typically more difficult to treat, and relapse is generally faster. Fortunately, regimens are available that will treat relapse, and new approaches are under test. Because of the aforementioned factors, many MCL patients enroll in clinical trials to get the latest treatments.[citation needed]

There are four classes of treatments currently in general use: chemotherapy, immune based therapy, radioimmunotherapy and new biologic agents. The phases of treatment are generally: frontline, following diagnosis, consolidation, after frontline response (to prolong remissions), and relapse. Relapse is usually experienced multiple times.[citation needed]

ChemotherapyChemotherapy is widely used as frontline treatment, and often is not repeated in relapse due to side effects. Alternate chemotherapy is sometimes used at first relapse. For frontline treatment, CHOP with rituximab is the most common chemotherapy, and often given as outpatient by IV. A stronger chemotherapy with greater side effects (mostly hematologic)

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is HyperCVAD, often given as in-patient, with rituximab and generally to fitter patients (some of which are over 65). HyperCVAD is becoming popular and showing promising results, especially with rituximab. It can be used on some elderly (over 65) patients, but seems only beneficial when the baseline Beta-2-MG blood test was normal. It is showing better complete remissions (CR) and progression free survival (PFS) than CHOP regimens. A less intensive option is bendamustine with rituximab.[14]

Second line treatment may include fludarabine, combined with cyclophosphamide and/or mitoxantrone, usually with rituximab. Cladribine and clofarabine are two other drugs being investigated in MCL. A relatively new regimen that uses old drugs is PEP-C, which includes relatively small, daily doses of prednisone, etoposide, procarbazine, and cyclophosphamide, taken orally, has proven effective for relapsed patients. According to John Leonard, PEP-C may have anti-angiogenetic properties,[15][16] something that he and his colleagues are testing through an ongoing drug trial.[17]

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Another approach involves using very high doses of chemotherapy, sometimes combined with total body irradiation (TBI), in an attempt to destroy all evidence of the disease. The downside to this is the destruction of the patients' entire immune system as well, requiring rescue by transplantation of a new immune system (hematopoietic stem cell transplantation), using either autologous stem cell transplantation, or those from a matched donor (an allogeneic stem cell transplant). A presentation at the December 2007 American Society of Hematology (ASH) conference by Christian Geisler, chairman of the Nordic Lymphoma Group[18] claimed that according to trial results, mantle cell lymphoma is potentially curable with very intensive chemo-immunotherapy followed by a stem cell transplant, when treated upon first presentation of the disease.[19][20]

These results seem to be confirmed by a large trial of the European Mantle Cell Lymphoma Network indicating that induction regimens containing monoclonal antibodies and high dose ARA-C (Cytarabine) followed by ASCT should become the new standard of care of MCL patients up to approximately 65 years.[21]

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A study released in April 2013 showed that patients with previously untreated indolent lymphoma, bendamustine plus rituximab can be considered as a preferred first-line treatment approach to R-CHOP because of increased progression-free survival and fewer toxic effects.ImmunotherapyImmune-based therapy is dominated by the use of the rituximab monoclonal antibody, sold under the trade name Rituxan (or as Mabthera in Europe and Australia). Rituximab may have good activity against MCL as a single agent, but it is typically given in combination with chemotherapies, which prolongs response duration. There are newer variations on monoclonal antibodies combined with radioactive molecules known as Radioimmunotherapy (RIT). These include Zevalin and Bexxar. Rituximab has also been used in small numbers of patients in combination with thalidomide with some effect.[23] In contrast to these antibody-based 'passive' immunotherapies, the field of 'active' immunotherapy tries to activate a patient's immune system to specifically eliminate their own tumor cells. Examples of active immunotherapy include cancer vaccines, adoptive cell transfer, and immunotransplant, which combines vaccination and

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autologous stem cell transplant. Though no active immunotherapies are currently a standard of care, numerous clinical trials are ongoing.[24][25][26]

Targeted therapyIn November 2013, ibrutinib was approved by the US FDA for treating MCL.[27] Other targeted agents include the proteasome inhibitor bortezomib, mTOR inhibitors such as temsirolimus, and the P110δ inhibitor GS-1101.

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