A Case of Olmesartan-induced Enteritis Mimicking Small Bowel Crohn’s Disease
Background:
A 79-year-old female with history of hypertension presented to clinic for evaluation of chronic diarrhea and weight loss. Two years prior, she was seen in the emergency department for abdominal pain and diarrhea with CT abdomen revealing diffuse enteritis. She was treated supportively for suspected viral enteritis. She returned one year later with severe non-bloody diarrhea and a 20-pound weight loss. Labs were remarkable for albumin 2.4 g/dL and hemoglobin 11 g/dL.
Methods:
CT demonstrated dilated small bowel with pneumatosis without vascular disease, leading to an exploratory laparotomy which was unremarkable. Infectious studies were unrevealing. She subsequently underwent an upper endoscopy and colonoscopy revealing severe ulcerative duodenitis with a cobblestoned appearance. Biopsies revealed chronic duodenitis with moderate activity, without evidence of viral, fungal or bacterial organisms. Colonoscopy to the terminal ileum was unremarkable with normal biopsies. Treatment was initiated with anti-diarrheal and proton pump inhibitor therapy. At discharge her home medication, olmesartan, was held due to hypotension. She returned two weeks later with persistent diarrhea, abdominal pain and development of anasarca. She underwent push enteroscopy revealing continued duodenitis with erosions with marked healing of deep ulcerations and the remainder of small bowel appeared endoscopically normal. Duodenal and jejunal biopsies showed chronic enteritis with crypt depletion with mild activity, without evidence of granulomas. She was initiated on steroids for suspected Crohn’s disease with complete resolution of symptoms.
Results:
She remained well until five months later when her primary care doctor resumed olmesartan for hypertension. Two weeks after initiation, she was admitted to the ICU for hypotension and metabolic encephalopathy, with labs demonstrating severe electrolyte derangements with ketosis. Olmesartan was held and she was reinitiated on steroids with rapid improvement in symptoms. EGD revealed moderate erosive duodenitis, with granular appearing mucosa. Biopsies revealed acute duodenitis. She completed another steroid taper and was advised to stop olmesartan indefinitely. Repeat endoscopy 6 months off steroids was endoscopically and histologically normal, patient has remained without gastrointestinal symptoms.
Conclusions:
Olmesartan is an antihypertensive medication belonging to the angiotensin II receptor blocker class and has been reported to cause a sprue-like enteropathy mimicking celiac disease with over 100 cases reported in the literature. Olmesartan associated enteropathy (OAE) presents an average of 3 years after medication initiation with profound non-bloody diarrhea and weight loss, often requiring hospitalization. Endoscopy typically reveals scalloped or atrophic duodenal mucosa with villous atrophy and intraepithelial lymphocytes on pathology. Celiac serologies are negative and patients do not respond to gluten free diet. There are a few reports of ulcerative enteritis linked to olmesartan in the literature. However, to our knowledge, this is the first case to be described with pathology showing chronic active enteritis in the absence of villous atrophy. While the mechanism of OAE is poorly understood, it is thought to be an immune-mediated drug injury and therefore the spectrum of immune pathology may be broader than originally recognized. This case highlights an unusual pathologic presentation of OAE mimicking Crohn’s disease and reinforces the importance of a good medication history in the management of patients with enteritis.
