USMLE Step 1 Question 291

Question:

A 65 year old man undergoes a subtotal gastrectomy for gastric carcinoma. During the procedure, most of the body of the stomach was resected. There were no intra-operative complications and the immediate post-operative course was uneventful. What is the most likely long-term post-operative complication that this patient will develop?

Correct Answer: D.  Iron deficiency

The body of the stomach is the primary location for parietal cells, and a subtotal gastrectomy that involves the majority of the body of the stomach will greatly reduce the number of parietal cells in the stomach. Parietal cells produce gastric acid and intrinsic factor. Intrinsic factor is necessary in the absorption of vitamin B12. Gastric acid has numerous functions, one of which is to aid the absorption of iron. Ingested iron comes in different forms: heme, ferrous (Fe++), and ferric (Fe+++). Ferrous iron is soluble and can be easily absorbed in the duodenum/jejunum while ferric iron is insoluble. Stomach acid is needed to decrease the pH to allow reduction of ferric iron to ferrous iron. Without adequate number parietal cells, stomach pH will not be low enough to facilitate ferric iron absorption, potentially leading to iron deficiency (choice D).

Vitamin B6 deficiency (choice A) is most commonly induced by INH and certain oral contraceptives.

Vitamin C (choice B), folate (choice C), and zinc (choice E) deficiencies are not associated with loss of parietal cells or stomach size.