Abstract
Emerging evidence has shed light on non-celiac causes of enteropathy in recent years, presenting a diagnostic challenge for clinicians. This study discusses the diagnostic challenges related to non-celiac enteropathy, specifically focusing on olmesartan-induced enteropathy (OIE). A 73-year-old lady presented to the emergency department with a six-month history of watery diarrhea exacerbated by food intake and significant weight loss. The patient at admission was found to be dehydrated with severe hypokalemia and hypocalcemia. The extensive testing that was performed was unremarkable, including celiac disease panel, enteric panel, ova and parasites, Clostridium difficile, fecal calprotectin, and computed tomography of the abdomen and pelvis. A significant electrolyte imbalance was corrected at admission, and subsequent upper endoscopy investigation with duodenal biopsies revealed moderate to severe villi blunting with a significant intraepithelial infiltrate of CD3+ lymphocytes. A colonoscopy that was performed at the same time was unremarkable, with negative biopsies for microscopic colitis. Given the suspicion of OIE, olmesartan was discontinued. One-month follow-up revealed resolution of malabsorption, with electrolyte normalization and duodenal biopsies showing improved duodenitis. This study emphasizes the importance of considering medication history and ruling out other potential causes of enteropathy. Olmesartan is an angiotensin II receptor antagonist that is commonly prescribed for hypertension. However, in rare cases, it may induce enteropathy, which often remains underdiagnosed. This rare side effect may present as chronic diarrhea, weight loss, and signs of malabsorption. Interestingly, OIE presents with overlapping clinical and histopathological features to celiac disease and, therefore, may mislead physicians to an extensive diagnostic investigation. Greater awareness of medication-related diarrheal syndromes such as OIE should be promoted, given that simple discontinuation of the medication can lead to dramatic clinical improvement.