RBC DisordersANEMIAS

Antonio Rivas PA-C

Lecture 2. 2009

Objectives

Discuss the etiology, pathogenesis, clinical features, laboratory evaluation, and management of:

Aplastic anemia Iron deficiency anemia Megaloblastic anemia Anemia of chronic disease Hemolytic anemia Sickle cell disease Thalassemias Sideroblastic anemia

Disruption of the normal stem cell development can result in:- Underproduction of mature cells •Aplastic anemia

- Overproduction of mature cells • Myeloproliferative disease

- Failed differentiation with with production of increased immature cells

• Myelodisplasia • Acute leukemia

Disorders of Hematopoiesis

Anemia classification-cell size

Microcytic anemia: Iron deficiency anemia

Macrocytic anemia: Megaloblastic anemia

Normocytic anemia: Anemia of chronic disease

Differential Dx.Anemias - MCV

Low MCV

Thalassemia

Iron def.

Lead Pois.

Sideroblastic

Normal MCV

Acute B. loss

Aplastic A.

Chronic Dis.

Hemoglobinop-athies

Hemolysis

Iron def.

High MCVAlcohol abuseAplastic A.B12 def.Folate defHemolysisHypothyroidismLiver DsMyelodysplastic s

Reticulocyte count vs Retic index Reticulocyte: young circulating Rbc that exhibits

basophilia

Retic count: characterize the bone marrow attempt to compensate, if at all, for the anemia present

The Retic. Index: more useful, corrects for the hematocrit abnormalities

Retic index

Less than 2 found:

Hypoproliferative anemias

Dis. Of heme or globin synthesis Iron deficiency and other metabolic anemias

B12 or folate deficiency

Chronic dis.

Lead poisoning

Thalassemias

Retic index Greater than 2 found:

Hyperproliferative anemias Acute blood loss

Nutrient replacement(B12,folate,Iron) before resolution of the anemia

Hereditary or acquired hemolysis

Polycythemia

Pathophysiology Immune hemolytic anemia

Warm hemolytic anemia(IgG) Cold hemolytic anemia(IgM)

Hemolysis causes extrinsic to RBCs Microangiopathic hemolytic anemia infection

Hemolysis due to disorders RBC membrane Inherited membrane abn.(HS,HE) Acquired membrane abn.(PNH,Spur cell anemia)

Hemolysis due to disorders in RBC enzymes G6PD deficiency

Hemoglobinopathies Sickle cell disease Thalassemia(alpha,beta)

Anemia Reduction of RBC mass or HGB

concentration

Symptoms reflect the rapidity of onset

Pat. with acute hemorrhage/massive hemolysis may exhibit symptoms of hypovolemic shock

Slowly established anemia produce few symptoms

Anemia Symptoms

Fatigue

Decreased exercise tolerance

Dyspnea

Palpitations

Anemia, physical exam

Major sign is pallor of skin, and mucous membranes

May develop tachycardia

Possible audible flow murmurs

Patients with hemolysis could present with jaundice and splenomegaly

Laboratory evaluation Reticulocyte count differentiates between

failure of RBC production (low retic) and increased RBC destruction (increased retic)

Peripheral blood smear provide clues to the cause of the anemia: Spherocytes in immune hemolysis Schistocytes in microangiopathic hemolysis

Laboratory eval. Cont.

Sickle and target cell in hemoglobinopathies Tear drop cells and nucleated RBCs in

myelofibrosis and marrow infiltration Intracellular parasites in Malaria and Babesiosis Pencil shape cells in severe iron deficiency Hypersegmented neutrophils and large plts. In

megaloblastic anemia Immature blasts in leukemias

Laboratory eval.cont. MCV is important in anemia with low retic count, to

differentiate according to cell size Bone marrow analysis helpful in patients with low

retic count, provides information about causes of anemia

If retic count is increased no need for bone marrow analysis, need to determine if decreased RBC mass is due to bleeding or hemolysis

Aplastic anemia(AA) Essentials of Diagnosis

Pancytopenia

No abnormal cells seen

Hypo cellular bone marrow

AA - General considerations Hematopoietic stem cell failure Rare disorder Incidence 1-5 cases per million Affects young adults(20-25yo) and older adults

(60-65yo) Three fold higher incidence in developing

countries (Thailand and China) Most common cause: suspected autoimmune

suppression of hematopoiesis by T-cell mediated cellular mechanism

AA. Acquired causes Drugs : dose related, chemotherapeutic agents,

antibiotics (chloramphenicol , trimethoprim, sulfamethoxazole)

Idiosyncratic(unproven): chloramphenicol, quinacrine, NSAIDS, cimetidine ,penicillamine

Toxins: benzene/hydrocarbons,insecticides Viral infections: hepatitis,EBV,HIV Immune mediated: GVHD ,immuno-

deficiency/SLE, paroxysmal nocturnal hemoglobinuria(PNH) Radiation Pregnancy

AA-Congenital causes

Small proportion of the cases Defective genetic material (DNA ,gene mutations,

etc.) Fanconi’s anemia(most common)

Schwachmann-Diamond syndrome

Dyskeratosis congenita

AA- signs/symptoms

Clinical onset can be insidious or abrupt Early in the disease not all cell lines are

always affected Weakness-fatigue due to anemia Vulnerability to infections if leukopenia is

present Mucosal/skin bleeding associated to

thrombocytopenia

AA-Laboratory findings

Pancytopenia

Anemia may be severe, always associated to decreased reticulocytes

RBC morphology is unremarkable

Hypo cellular marrow analysis

No abnormal cells seen

AA-Differential Diagnosis

From other causes of pancytopenias: Myelodisplasia/acute leukemia: exhibit

morphologic abnormalities in the cells and increased blasts, or abn. Cytogenetics in bone marrow

Hairy cell leukemia: presence of splenomegaly and abnormal Lymphoid cells in bone marrow

SLE, disseminated infection , or hypersplenism: normocellular bone marrow

AA-treatment Current approaches geared to:

Replacing defective marrow: Stem cell transplant

or

Controlling an overactive immune response:

using antithymocyte globulin (ATG) and other

immunesuppresors such as Cyclosporine; Cyclophosphamide

AA-treatment Based on severity of disease:

• mild cytopenias - monitor patient

• severe cases as indicated by blood count results showing:

- anemia, with retic count < 1%

- neutrophil count <500cells/ul

- Plt. count <20,000./ul

- bone marrow cellularity <25%

have poor survival, 2-6 months, without treatment

AA-treatment Supportive care with broad-spectrum antibiotics,

antifungals, and antivirals is warranted in advanced neutropenia

RBC and Plt. Transfusions are helpful for very symptomatic patients

Allogeneic bone marrow transplant offers better outcome (75-90% survival rate) on patients 30 years of age and younger

Immunosuppressive therapy achieve restoration of marrow function in 70-80% of the patients, with a 90% survival rate in 5 years (patients older than 40 years of age)

Hypoproliferative anemias

Microcytic anemia: Iron deficiency anemia

Macrocytic anemia:Megaloblastic anemia

Normocytic anemia:Anemia of chronic disease

Iron deficiency anemia

Essentials of diagnosis Serum ferritin < 12 mcg/L

Caused by bleeding in adults unless proved otherwise

Responds to iron therapy

Iron deficiency anemia

Most common cause of anemia worldwide

Average american diet contains 10-15mg of iron per day (10% is absorbed)

Iron Absorption in proximal small intestine

Balanced daily iron absorption and loss at 1mg/day

Iron deficiency anemia

Iron Bound to transferrin in plasma Serum iron: men 50mg/kg, women 40 mg/kg 60-75% found in Hgb Iron Stored as ferritin in the liver, spleen, BM,and

muscle Pre-menopausal women could loose15mg of iron

per month, and 900mg/pregnancy Investigate GI blood loss in iron deficient men and

postmenopausal women

Iron def.anemia, causes

Most frequent cause of iron def. is blood loss

Decreased iron absorption is rare, occasional after gastric surgery

Hemoglobinuria in traumatic hemolysis due to prosthetic heart valve

Frequent blood donors

Iron deficiency -symptoms

In severe cases, skin and mucosal changes: Smooth tongue

Brittle nails

Cheilosis

Dysphagia-esophageal webs (Plummer-Vinson syndrome

Pica (ice,dirt)

Iron def.anemia laboratory Dx.

Early Iron storage depletion stage - no changes on RBC morphology

Decreased total serum iron concentration Increased total iron binding capacity (TIBC) Decreased ferritin levels Advanced iron deficiency affects RBC

morphology: microcytic - hypochromic cells, target cells, pencil shaped cells

Differential diagnosis

Anemia chronic disease - NL or increased iron stores in bone marrow, NL or elevated ferritin level, low serum iron level, TIBC NL or low.

Thalassemia - greater degree of microcytosis , changes on the RBC morphology occur earlier

Treatment of Iron deficiency Oral Ferrous sulfate (325mg TID)

Improve compliance, gradually escalating the dose, taken with food

Improvement in 3 weeks, return to baseline in 2 months, continue for 3-6 months to replenish stores

Parenteral Iron in case of oral intolerance, possible anaphylactic reaction

Megaloblastic anemia-general Results from block of synthesis of nucleotide

precursors of DNA Maturation of cell nucleus is arrested, maturation

of cytoplasm continues

Most common causes: Vitamin B12 (Cobalamin) deficiency, more

common Folate deficiency Medications that inhibit DNA synthesis / block

folate metabolism Myelodysplasia

B12 deficiency anemia Essentials of diagnosis

Macrocytic anemia

Macro-ovalocytes / hypersegmented neutrophils on peripheral smear

Serum vitamin B12 level < 100 pg/ml

B12 deficiency anemia-general

B12 absorbed from animal protein in the diet

Absorbed in the terminal ileum bound to intrinsic factor, a protein secreted by gastric

parietal cells

B12 stored in the liver 3 years supply

Daily losses 3-5 mcg, daily absorption 5mcg

Dietary B12 deficiency is rare Vegans diet

B12 deficiency anemia- causes

Pernicious anemia: Autoimmune atrophy of gastric parietal cells ( most common) Gastrectomy

Pancreatic insufficiency failure to inactivate competing binding

protein

B12 deficiency anemia- causes

Bacterial overgrowth in the intestine

Inflammatory bowel disease (crohn’s disease)

Tapeworm infection

Congenital Intrinsic Factor or Transcobalamin II deficiency

Megaloblastic anemia symptoms Often severe anemia at presentation

Insidious onset

Yellowish of skin pallor and jaundice

Mucosal changes glossitis, anorexia, diarrhea, cheilosis

B12 deficiency leads to complex neurologic syndrome:

paresthesias - early difficulty with balance - late

Megaloblastic anemia cont.

Pernicious anemia patients present with atrophic gastritis - achlorhydria

associated with increased risk for gastric carcinoma

association with other autoimmune conditions such as: IgA deficiency and endocrine insufficiency

Laboratory findings Variable severity anemia

possible pancytopenia MCV: 110-140 fl

Peripheral smear large ovalocytes, hypersegmented neutrophils, and large platelets

Hyper cellular bone marrow abnormally large precursors

Increased bilirubin and lactate dehydrogenase enzyme (LDH)

intramedullary destruction of RBCs

Laboratory findings Schilling test :

Radioactive B12 given orally

with a large parenteral dose of unlabeled B12.

Oral absorption determine by: measuring radioactivity in the urine;

B12+ IF + different isotope given at the same time,

selective absorption of the B12+IF suggest pernicious anemia

Schilling test cont. If neither isotope is absorbed,

possible bacterial overgrowth, treat with antibiotics and repeat test

Supply pancreatic enzymes and repeat test to rule out pancreatic insufficiency

New antibody tests for Anti-parietal cell AB , and Anti-IF AB now available

Differential diagnosis

Folic Acid deficiency where: RBC folate is low

Vitamin B12 levels in blood are normal

Treatment Intramuscular B12-

100mcg/dose daily for 7days, then weekly for a month, and monthly for life

Accompanied with Folic acid 1-5 mg /day, oral Folate alone will not correct neurological

symptoms of B12 deficiency

Prognosis Rapid response to therapy,

peak within 7-10 days

Increased reticulocyte count 2 days after therapy

Monitor patient Hypo-kalemia,

Hyper-urecemia,

Hypo-phosphatemia

Neurologic manifestations improve slowly,

some are irreversible

Anemia of chronic disease Occur in patients with:

chronic inflammatory conditions (RA) Infections malignant (cancer) autoimmune diseases (SLE)

Usually normocytic-normochromic occasionally microcytic

Common causes: EPO deficiency (chronic renal failure) Direct inhibition of erythropoiesis Poor iron incorporation to developing Rbcs Shortened erythrocyte survival

Symptoms Related to the underlying disease

SLE: increased fatigue, susceptibility to infections

RA: arthritis, Fatigue / decreased endurance

HIV: Fatigue weight loss lymphadenopathy

Laboratory findings Low serum iron level

TIBC is also reduced

Transferrin saturation >10%

Ferritin level normal or increased

MCV normal or slightly reduced

RBC morphology- non diagnostic

Treatment Mainstay

EPO replacement in the case of chronic renal failure

Anemia will improve if the underlying chronic condition is treated

Some other conditions also respond to EPO treatment, good results in

M.Myeloma, R.Arthritis, and HIV infection

EPO-Treatment Purified recombinant

erythropoietin (epo alfa) 30,000 units once weekly, SQ

Very expensive, used when quality of life clearly improve by hematologic response

Hemolytic anemiasGeneral

Premature loss of RBCs by hemolysis either: extrinsic (reticuloendothelial system)

intrinsic ( blood vessels)

Reticulocytosis as a compensatory response of a normal

bone marrow

Only other condition causing reticulocytosis in anemia is blood loss

Classification Hemolytic Anemia Immune hemolytic anemia

IgG mediated - warm AIHA IgM mediated - cold

Causes extrinsic to erythrocytes Micro-angiopathic (DIC,TTP,drugs,eclampsia, valvular

hemolysis)

Erythrocyte membrane disorders Inherited - H.spherocytosis/elliptocytosis Acquired - PNH, Spur cell anemia

Enzymopathies G6PD deficiencyPK

Hemoglobinopathies Sickle cell disease Thalassemia

Sickle cell anemia essential Dx. Sickled cells on blood smear

Positive family history and lifelong history of hemolytic anemia

Recurrent painful episodes

Hemoglobin S, major Hgb

present on Hgb

electrophoresis

Sickle cell disease - general Belongs to the hemoglobinopathies group

Point mutation in DNA that results in substitution of valine for

glutamine in the sixth position on the beta-globin chain of hemoglobin (beta-sickle chain)

Homozygous genotype(SS)

Resulting Hgb is called Hgb S (sickle)

2 alpha chain

2 beta sickle chain

Sickle cell disease - general Found in African and Mediterranean population

One birth out of 400 in american blacks will produce a child with sickle cell anemia

Onset during the first year of life when fetal Hgb is replaced by adult Hgb

Hgb S is less soluble susceptible to polymerization and precipitation

Trigger factors include Dehydration

Hypoxia,

acidosis,

and high altitudes

Sickle cell anemia symptoms Anemia symptoms

Jaundice

Hepatomegaly

Splenomegaly in children

Enlarged heart, systolic murmurs

Poorly healing ulcers over the lower tibia

Increased susceptibility to encapsulated bacteria (strep. pneumoniae infections)

Delayed puberty

Sickle cell anemia - symptoms Acute complications - vaso-occlusion

Painful crises - ischemia (extremities,chest, abdomen, back)

Acute chest syndrome - life threatening Priapism Cerebrovascular events

Thrombotic/hemorrhagic strokes

Aplastic crisis Splenic sequestration osteomyelitis

Sickle cell anemia - symptoms Chronic manifestations

Chronic renal disease

Chronic pulmonary disease

Sickle hepatopathy

Retinopathy

Avascular necrosis

Skin ulcers

Sickle cell anemia- Lab.findings Hematocrit

20-30%

Increased WBC count (12-15000/mcl)

Thrombocytosis Reticulocytosis

(10-25%)

High indirect bilirubin level Peripheral smear:

Sickled cells Nucleated RBCs Howell - Jolly bodies Target cells

Sickle cell anemia Dx. tests Screening tests

Confirmatory test- hemoglobin electrophoresis showing

85-98% Hgb S present

No Hgb A present in homozygous

Variable amount of Hgb F present

Prenatal testing available(fetal cells), counseling should be offered

Sickle cell anemia-treatment None available for primary disease Folic acid supplementation Blood transfusions for aplastic and hemolytic

crisis Pneumococcal vaccine Antibiotics in case of infections In acute painful episodes,

identify trigger and treat if found. hydrate patient oxygen supplementation as needed analgesics

Sickle cell anemia-treatmentExchange blood transfusion indicated to decreased Hgb S to 30-40% in :

Chest syndrome

Bone marrow necrosis

Priapism

New treatments

Hydroxyurea : increases Hgb F concentration, less susceptible to polymerization.

Survival advantage

Decreased in WBC count

Sickle cell trait Patients with heterozygous genotype (AS)

Clinically normal

Acute painful episodes under extreme conditions only

Hematologically normal, no anemia, normal RBCs

May have inability to concentrate urine, and experience episodes of hematuria

Screening test-positive, Hgb electrophoresis will show 40% Hgb S

No treatment is necessary. Genetic counseling

Hgb C disease

From substitution of glutamic acid to lysine in the sixth position of the beta globin chain

Homozygous Hgb C causes very mild disease, almost silent, mild anemia, mild jaundice, and pigment

gallstones

RBC morph.target cells, Hgb C crystals in a few cells (rectangular)

Compound heterozygous for HgbS/HgbC are more symptomatic, possible retinopathy and splenic sequestration crisis

Thalassemia Hemoglobinopathies

Hereditary reduction in the synthesis of globin chain

alpha or beta

Hypochromic -microcytic anemia because of defective hemoglobinization of RBCs

Often confused with iron deficiency, decreased MCV

Thalassemia Most common inherited hemolytic disorder Defective Hgb caused by decreased production of

at least one globin chain Common in persons of Mediterranean, African

and Southeastern ancestry Alpha thalassemia due to:

gene deletion causing decreased alpha globin chain common in persons from Asia and China, less in blacks

Beta thalassemia caused by: point mutations, leading to reduced or absent beta-globin

chain synthesis primarily affects persons of Mediterranean origin, Chinese and

black to a lesser extent

Essentials of diagnosis

Microcytosis out of proportion to the degree of anemia

Positive family Hx or lifelong personal Hx of microcytic anemia

Microcytes, acanthocytes, and target cells in blood smear

In beta-thalassemia elevated levels of Hgb A2 or F

Alpha thalassemia

Three alpha globin gene present-silent carrier Two alpha globin gene present-trait

only mild microcytic anemia

Only one alpha globin chain present, Hgb H disease(thalassemia minor or intermedia) Pallor and splenomegaly present. infections can cause hemolytic crisis

All four alpha globin gene deletion- affected fetus is stillborn (hydrops fetalis)

B-Thalassemia

B-Thalassemia minor clinically

asymptomatic microcytosis, mild anemia

B-thalassemia Intermediate produce moderate hemolysis

severe anemia

main complication iron overload (non transfusion dependent

Signs and Symptoms B-Thalassemia major (Cooley’s anemia)

homozygous normal at birth after 6 months develop severe

anemia(need transfusion) growth failure bony deformities pathologic fractures and hepatosplenomegaly

B-Thalassemia major

Improved with blood transfusion,

but iron overload develops(hemosiderosis), deposits in heart(heart failure),

liver(cirrhosis),

and endocrine glands (endocrinopathies)

Laboratory findings

Alpha thalassemia trait: mild anemia,MCV 60-75fl, RBC count normal, microcytes, hypochromia, occasional target cells and acanthocytes

Hgb H disease: more marked hemolytic anemia, MCV 60-70 fl, RBC morphology includes all trait changes and poikilocytosis, increased retic count

Laboratory findings

Beta thalassemia minor : modest anemia, MCV 55-75 fl , RBC count normal or increased, peripheral smear similar to alpha thalassemia, basophilic stippling present

Beta thalassemia major: severe anemia, hematocrit of 10% without transfusion, bizarre peripheral smear with microcytes, poikilocytosis , hypochromia, basophilic stippling, target cells and nucleated RBCs

Differential Dx

Mild thalassemias similar to Iron deficiency anemia, but with lower MCV and a more normal RBC count. Peripheral blood smear is more striking in thalassemias, iron studies are normal in thalassemias

Thalassemia major is confused with other hemoglobinopathies, Dx by Hgb electrophoresis

Treatment

B-thalassemia minor require no treatment Hgb H disease should take folate supp. B-thalassemia major patients receive transfusions

as needed Splenectomy may help if hypersplenism Deferoxamine given as an iron-chelating agent Allogeneic bone marrow transplantation has been

successful, treatment of choice for beta-thalassemia

G6PD deficiency X-linked recessive disorder in american black

men Episodic hemolysis in response to oxidant

drugs or infection Reduced levels of glucose-6-phosphate

dehydrogenase between hemolytic episodes Commonly found in people of African,

Mediterranean, Sephardic Jews and Chinese descents

G6PD deficiency

Most female carriers are asymptomatic Partially protects the patient from malaria Clinical problems arise only when the affected

individual is exposed to oxidative stress (infections, drugs )

Oxidized Hgb denatures and precipitates forming Heinz-bodies, that damage RBC membrane, cells are removed by spleen

Signs and Symptoms

Patients usually healthy,

episodes of hemolysis self limiting, because damage red cells are removed from circulation and replaced by functionally normal RBCs

Mediterranean variants may have hemolysis with fava beans exposure

Laboratory Test

During hemolytic episodes there is reticulocytosis, and increased indirect bilirubin

Bite-cells in smear: indicates pitting of Hgb aggregates by the spleen

Treatment

Usually self limiting No specific treatment necessary If hemoglobinuria develops maintain

adequate urine output Have patient avoid Fava beans,

antimalarials, sulfonamides, nitrofurantoin, analgesics, vitamin K

Sideroblastic Anemia

Reduced Hgb synthesis because of failure to incorporate heme into protoporphyrin

Iron accumulates in the mitochondria Prussian blue stain reveals ringed sideroblasts in

bone marrow-cells with iron deposits around the nucleus

Acquired disorder, seen in alcoholism, and lead poisoning

Stage in evolution of a bone marrow disorder that terminates in acute leukemia

Sideroblastic Anemia

Signs and Symptoms/ Laboratory

Moderate anemia, Hematocrit 20-30%, transfusion occasionally required

MCV is normal or increased Dimorphic population of RBC in smear one

normal other hypochromic Lead poisoning shows basophilic stippling Bone marrow iron stores are increased with ringed

sideroblasts present Increased serum iron and transferrin