P69 | Collagenous colitis: an unfamiliar but treatable disease

Introduction: Microscopic colitis is part of the differential diagnosis of chronic watery diarrhea. Colonoscopy is normal, its diagnosis is based on histology and encompasses two entities: collagenous colitis end lymphocytic colitis. In case of suspected drug-induced microscopic colitis, identification of the responsible drug is a key to management. After discontinuation of the suspected drug, treatment is budesonide. Here, we report a patient with collagenous colitis of drug origin.Case report: A 75 year old woman with a 2 weeks watery diarrhea, and weight loss. History of arterial hypertension being treated with olmesartan. Laboratory tests were normal, except hypokalemia and moderate CRP. Stool culture, and Clostridium difficile toxin testing were negative. Abdominal TC scan was normal. We started her on piperacillin/tazobactam without response. The workup was completed by endoscopic examination which was negative: randomly biopsies revelated collagenous colitis. The patient had started olmesartan 1 month before the onset of diarrhea. Suspecting enteropathy caused by olmesartan, which was discontinued and started budesonide 6 mg daily for 8 weeks. Within 2 weeks her clinical symptoms improved. Three months later, diarrhea resolved.Conclusions: In unexplained cases of diarrhea, medication history should be reconfirmed. Olmesartan reportedly causes sprue like enteropathy and collagenous colitis. To exclude microscopic colitis a colonoscopy with multiple biopsies is mandatory. Nowadays, there is sufficient evidence to recommend budesonide as the first-choice treatment.