A 49-year-old man presents with a 6-month history of bloating and loose stools.He has 4 to 7 bowel movements daily, with nocturnal stools.His bloating is relieved after a bowel movement. There has been no hematochezia or melena. He underwent a Roux-en-Y gastric bypass 3 years previously for medically complicated obesity and has lost 54.5 kg since the operation. Although his weight loss has stabilized, he has lost an additional 4.5 kg during the previous month. His mother has Crohn disease.
He takes an iron-containing multivitamin and oral vitamin B12 daily. Findings on examination are unremarkable. Laboratory findings Hemoglobin, 10.8 g/dL Mean corpuscular volume, 104 fL Folate, 43 μg/L (≥3.5 μg/L) Vitamin B12, 194 ng/L (200-650 ng/L) Tissue transglutaminase IgA, normal Stool cultures, including repeated cultures for ova and parasites, were negative. Findings on colonoscopy with random…
