It is a condition characterized by decrease in oxygen ( O2 ) carrying capacity of blood.

When haemoglobin concentration or hematocrit is below the lower limit of (95%) reference interval for individual’s age, sex, geographical location ( attitude ), it is called Anemia.

( A ) PATHOPHYSIOLOGIC :-

(a) UNDERPRODUCTION : Decreased reticulocyte count

-Bone marrow failure

-Deficiency of hematinic factors

-Bone marrow suppression

(b) INCREASED LOSS OR DESTRUCTION: Increased reticulocyte count

-Hemorrhage-Hemolysis

(B) MORPHOLOGIC :

Type

Normocytic normochromic

Macrocytic normochromic

Microcytic hypochromic

Normocytic hyperchromic

(A) Pathophysiologic classification :

( I ) Underproduction (Impaired erythrocyte production )

1. Hematopoietic stem cell proliferation and differentiation abnormality:

-Aplastic anemia

- Myelodysplasia

2. Erythroid commited stem cell proliferation and differentiation abnormality:

- Pure red cell aplasia.

- Anemia of chronic renal disease.

- Anemia of endocrine disorders

- Congenital dyserythropoietic

anemia

3. Erythroblast proliferation and maturation abnormality:

(a) Defective DNA synthesis-

- B12 deficiency or impaired utilization

- Folate deficiency or impaired utilization

- Inborn errors

(b) Defective haemoglobin synthesis-

1. Heme synthesis abnormality : Iron deficiency.

2. Globin synthesis abnormality : Thalassemias.

HYPERSEGMENTED NEUTROPHIL

MANY TARGET CELLS

3. Unknown or multiple mechanisms :

- Anemia of chronic disease

- Sideroblastic anemia

- Myelophthisic anemia

( II ) Increasesd loss or destruction :

1. Hemorrhage :

- Acute blood loss anemia

- Chronic blood loss anemia

2. Hemolysis :

(a) Intrinsic (intracorpuscular)abnormalities :-

*Hereditary-

(i) Membrane disorders :

Hereditary spherocytosis

Hereditary elliptocytosis

Hereditary stomatocytosis

Acanthocytosis ( abetalipoproteinemia )

(ii) Enzyme deficiency :

- Glycolytic ( embden-meyerhof ) pathway eg. Pyruvate kinase deficiency

- Hexose monophosphate shunt pathway eg. G6PD deficiency

(iii)Structurally abnormal globin chain :

- Sickle cell anemia

- Hemoglobin C disease

- Unstable hemoglobins

- Hemoglobins with abnormal oxygen affinity

- Methemoglobinemia

Thalassemia Major, Microangiopathic

Hemolytic anaemia,

Cardiac Hemolytic anaemia

Sickle cell anemia

Thalassemia disorder, Sickle cell anaemia,

Hb E & Hb C

disease,Liver disease, after splenectomy

* Acquired-

- Membrane complement sensitivity

- Paroxysmal nocturnal hemoglobinuria

(b) Extrinsic ( extracorpuscular ) abnormalities :-

1.Immune Mediated-

a. Isohemagglutinins

- Erythroblastosis fetalis

- Blood transfusion reaction

b. Autoantibodies

- Warm antibody autoimmume hemoloytic anemia

- Cold antibody autoimmune hemolytic anemia

c. Drug induced immunologic injury to erythrocyte.

2. Mechanical trauma to erythrocyte-

- Traumatic cardiac hemolytic anemia

- March hemoglobinuria

- Microangiopathic hemolytic

anemia

3. Hypersplenism ( hyperactivity of mononuclear

phagocyte system ).

4. Hemolytic anemia due to chemical or physical agents.

5. Hemolytic anemia due to infection.

C. Multifactorial : Alcohol induced anemia.

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