A 60-year-old man, 15 years after a Polya gastrectomy, develops macrocytic anaemia, hypoalbuminaemia, and steatorrhoea. Aspirate of the stagnant afferent limb grows coliforms. What is the principal mechanism of the anaemia?

• A Competitive consumption of vitamin B12 by proliferating luminal bacteria ✓
• B Autoimmune destruction of gastric parietal cells
• C Deconjugated bile salts damaging the gastric remnant mucosa
• D Pancreatic exocrine insufficiency from ductal compression

Explanation

Blind loop syndrome results from bacterial overgrowth in stagnant segments of small bowel. The organisms bind and consume vitamin A12 before it reaches the ileal receptors, producing megaloblastic anaemia, while deconjugation of bile salts by bacteria causes steatorrhoea by depleting the micellar bile acid pool. Parietal cell autoimmunity defines pernicious anaemia rather than the post-surgical blind loop, and pancreatic insufficiency does not explain the macrocytosis here.

Reference: Bailey and Love's Short Practice of Surgery, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.