Classification of Anaemias Based on Etiology  

Anaemia  can be classified  as  

Impaired Production of Red Blood Cells and Hemoglobin: This can be due to nutritional  deficiency, deficiency of iron, vitamin B6, vitamin B  12, vitamin C, folic acid and amino acids etc. or due to bone marrow failure. 

Excessive Destruction of Red Blood Cells: This can be caused by  hemolytic disease of new born, erythroblastosis fetalis, the effects of toxic drugs, Venoms or lead poisoning, thermal injury or burns, transfusion reactions, certain  infections, such as infectious monoucleosis, and splenic enlargemnt. Other defects which include  abnormalities  in haemoglobin synthesis are sickle cell anaemia and thalassemia. 

Blood loss: This may be due to acute blood  loss from the placenta, umbilical cord, trauma, epistaxis, or circumcision. Anaemia may also be caused by chronic blood loss due  to bleeding in gastronitestnial tract, hookworm  infestation, chronic dysentery, peptic ulcer or oesophageal varices, etc. 

Blood Diseases: Haemorrhagic diseases of the new born; scurvy, haemophilia, purpura, leukaemia may also cause anaemia.