Case Presentation:

A 45‐year‐old male was transferred from an outside hospital for evaluation of chronic diarrhea of unclear etiology. He had 6 weeks of profuse, painless, watery diarrbea up to 6L/day at its peak, associated with anorexia and a 50‐pound weight loss. Initial evaluation at the outside hospital revealed no explanation for his diarrhea and his course there was complicated by acute renal failure, severe electrolyte abnormalities causing a v‐fib arrest from which he was successfully resuscitated. Antidiarrtieal agents were tried, and he was started on TPN prior to transfer. At our hospital, physical exam was significant for a temperature of 97.4°F, BP of 98/56 mm Hg, HR of 108 bpm, and a nontender abdomen with no hepatosplenomegaly. Extensive tests for infectious etiologies were negative including: HIV, C. difficile, CMV, microsporidium, isospora, cyclospora, giardia, and Cryptosporidium. Laboratory testing showed no evidence of mastocytosis, gastrinoma, vipoma, somatostatinoma, or carcinoid. There was no evidence of inflammatory bowel disease, celiac sprue, hyperthyroidism, alpha 1 antitrypsin deficiency, or laxative abuse. CT scans of the abdomen and pelvis, including CT enterography, revealed thickening of the terminal ileum. EGD, colonoscopy, and push enteroscopy found mucosal congestion of the small bowel with biopsies revealing villous blunting and cryptitis, suggestive of adult autoimmune enteropathy. The patient was started on prednisone 60 mg daily with improvement Antienterocyte antibodies were positive, confirming the diagnosis.


Although primarily considered a disease of children, adult‐onset autoimmune enteropathy is a rare, recently described condition with roughly 30 documented case reports. Clinical manifestations include protracted diarrhea, weight loss, and malnutrition. Its pathophysiology is not completely understood, but a hyperactive immune state caused by a defect in regulatory T‐cell homeostasis has been suggested. Autoimmune enteropathy predominantly, but not exclusively, affects the small bowel and distinguishing it from other small bowel disorders can be challenging. Endoscopic and histological changes can be similar to celiac disease. Both are characterized by crypt hyperplastic villous atrophy. Circulating gut epithelial cell antibodies, specifically antienterocyte and/or antigoblet cell antibodies, may be present. Diarrhea in autoimmune enteropathy does not improve with a gluten‐free diet. Treatment requires aggressive immunosuppression. High‐dose steroids are often necessary to control active disease and refractory cases may necessilate additional immunomodulators.


Chronic diarrhea can be life‐threatening and poses a diagnostic dilemma for hospitalists. When initial evaluation is unrevealing, this condition should be considered.

Author Disclosure:

S. Mohsin, none.