2616 Seronegative Adult Autoimmune Enteropathy

Abstract

INTRODUCTION: Autoimmune enteropathy (AIE) is a rare disorder of the immune system characterized by 6 or more weeks of severe diarrhea with malabsorption and histologic changes on small intestinal biopsy. This condition is primarily seen in neonates and children, but rarely has been reported in adults. CASE DESCRIPTION/METHODS: A 75-year-old woman presented with 4 months of intractable diarrhea, vomiting, and 30-pound weight loss. Prior workup was unrevealing including celiac testing, stool enteric pathogens, Cytomegalovirus, Herpes simplex virus, Helicobacter Pyloritesting, and colonoscopy without biopsies. Non-specific acute and chronic inflammation without villous blunting was seen in duodenal biopsies. She was treated supportively but her symptoms progressed requiring admission. She appeared emaciated with stable vital signs and a benign abdominal exam. She had severe hypoalbuminemia and hypomagnesemia. C-reactive protein, liver and thyroid tests, anti-nuclear antibody, HIV, and immunoglobulin levels were normal or negative. Repeat esophagogastroduodenoscopy (EGD) showed duodenal scalloping and friability with contact (Figure 1). Colonoscopy appeared endoscopically normal to the terminal ileum. Biopsies of the duodenum and terminal ileum showed glandular destruction, epithelial apoptosis, and goblet cell depletion without significant intraepithelial lymphocytosis (Figures 2 and 3). Periodic acid-Schiff stain and random colonic biopsies were negative for Whipple's disease and microscopic colitis. Anti-enterocyte antibodies were negative. She was diagnosed with AIE and started on high-dose steroids with a prolonged taper. At her 2-month follow-up she had gained back 10 pounds with complete resolution of her nausea, vomiting, and diarrhea. DISCUSSION: AIE should be included in the differential diagnosis for adult patients with intractable diarrhea. Diagnostic criteria include partial or complete blunting of small intestinal villi, deep crypt lymphocytosis, increased crypt apoptosis and minimal intraepithelial lymphocytosis. Anti-enterocyte antibodies are positive in approximately 80% of cases. In this case, the small intestinal histopathology was not diagnostic for AIE 2 months into her symptomatology but was diagnostic on EGD 9 weeks later, highlighting the utility of repeat EGD and biopsy in patients with persistent symptoms. This emphasizes that villous blunting may be patchy and chronic inflammatory changes of AIE may evolve over time. More research is needed to better understand this emerging condition.