MCQ 2 What is the underlying cause of pernicious anemia in untreated gastrectomy patients?

A.lack of vitamin B12 (cobalamin) in the diet
B. lack of intrinsic factor secreted by gastric parietal cells
C. lack of folate (folic acid) in the diet
D. inability to absorb dietary iron
E.reduced circulating levels of erythropoietin



Answer is B : lack of intrinsic factor secreted by gastric parietal cells 

Post-operative effects of Gastrectomy

The most obvious effect of the removal of the stomach is the loss of a storage place for food while it is being digested. Since only a small amount of food can be allowed into the small intestine at a time, the patient will have to eat small amounts of food regularly in order to prevent gastric dumping syndrome.
Another major effect is the loss of the intrinsic factor secreting parietal cells in the stomach lining. Intrinsic factor is essential for the uptake of vitamin B₁₂ and without it the patient will suffer from a vitamin B₁₂ deficiency. This can lead to a type of anemia known as pernicious anemia which severely reduces red-blood cell synthesis (known as erythropoiesis). This can be treated by giving the patient direct injections of vitamin B₁₂.