A 69-year-old man presented with chronic watery diarrhea that had persisted since the previous September. Colonoscopy performed in December was unremarkable, and treatment for irritable bowel syndrome was ineffective. He was hospitalized for hypokalemia in February and presented to our hospital for evaluation in March. Blood tests, endoscopy, and abdominal CT were unremarkable. In April, small bowel capsule endoscopy (SBCE) revealed diffuse villous atrophy and granular elevation. Olmesartan-associated sprue-like enteropathy (OAE) was diagnosed and his medication regimen was discontinued. Diarrhea decreased within four days and resolved by day 19. Two months later, follow-up SBCE revealed reversal of atrophy, confirming OAE. Although OAE is a malabsorption syndrome that resolves rapidly after drug withdrawal, its diagnosis is often delayed due to low awareness and long latency. We report a case of OAE that was successfully diagnosed using SBCE.
