DIMORPHIC ANAEMIA

Combined deficiency of haemopoietic factors are common particularly when the basic cause is dietary inadequacy or intestinal malabsorption. When iron deficiency is associated with deficiency of folic and/or vitamin B12, the resulting condition has been called dimorphic anaemia. Dimorphic anaemia may therefore occur whenever and wherever causes contributing to the deficiency of iron, folic acid and vitamin B12 are operative. The causative factors will thus include a combination of those discussed under iron deficiency anaemia and nutritional macrocytic anaemia. Common conditions where anaemia is dimorphic are :

(a) Dietary inadequacy, particularly during growing periods and in pregnancy.

(b) Intestinal malabsorption and post-gastrectomy syndrome.

(c) Dietary inadequacy in association with blood loss.

Clinical features will vary depending on the degree of anaemia; the relative proportion of the deficient factors, is also one of the basic cause.

The haematological findings will be determined by the relative contribution of iron on one hand and folic acid and/or vitamin B12 on the other hand. In an average case, evidences of dimorphic anaemia will be evident from the following :

Gross erythrocytic hypochromia and/or hypoferraemia in association with megaloblasts in blood and/or low serum vitamin B12 or serum folate.

When one deficiency is predominating, the expression of other deficiency may be masked. The presence of such a latent minor deficiency may be unmasked when the major deficiency has been corrected with appropriate therapy.