What is the relation between pernicious anemia and megaloplastic anemia?

Answer 1

the two terms are more or less interchangeable but they are not exactly the same.

Pernicious anaemia refers specifically to a condition where B12 fails to absorb in the gut: intrinsic factor is necessary for this absorption and is secreted by gastric pareital cells. Failure to secrete this substance can be due to atrophy of the cells, their absence due to total or partial gasrectomy or from circulating autoimmune pareital cell antibodies. There are other causes of failure to absorb B12 such as Blind Loop Syndrome but this is not known as Pernicious Anaemia. Nor is folate deficiency however all these conditions are known as megaloblastic anaemias. The diagnostic features of all this group of anaemias include megaloblasts in the bone marrow and are morphologically indistinguishable whether caused by B12 deficiency (for whatever reason) or folate deficiency.

As far as I know, the two terms are more or less interchangeable. Both apply to a kind of anaemia caused by a deficiency of either B vitamins B12 or B9 (folic acid). It is characterised by big red blood cells i.e. a raised MCV (mean cell volume). If one looks at the developing red cells in the bone marrow they have a characteristic appearance and are known as MEGALOBLASTS. Poor diet can be the cause of folic acid (folate) deficiency but the most likely cause of B12 deficiency is a failure to absorb the vitamin due to a problem in the gut. Both are easily treated. Injections of vitamin B12 will cause a remarkably quick recovery. Oral folate supplements will remedy this deficiency quickly too.