S6170 Microscopic Colitis and Celiac Disease

Introduction: Symptoms associated with celiac disease should resolve with strict adherence to a gluten-free diet. If symptoms are still present despite dietary compliance, clinicians must consider the possibility of multiple concurrent causes. We will discuss a case in which microscopic colitis was found to be a contributing factor to persistent symptoms of celiac disease despite dietary compliance. Case Description/Methods: A 67-year-old woman presented with iron deficiency anemia. A bidirectional endoscopy was performed with biopsies revealing small bowel mucosal villous blunting. Follow up serology was confirmatory for celiac disease with a tTg-IgA of 62 U/mL. After 4 months of strict compliance with a gluten free diet, her tTg-IgA levels improved to 5 U/mL. Despite this, the patient revealed chronic diarrhea at a follow-up visit. An enteric panel testing for parasites and bacteria was unremarkable and pancreatic elastase levels were within normal limits. A repeat colonoscopy was performed with biopsies revealing microscopic collagenous colitis. She responded exceptionally well to a 12-week tapered course of 9 mg budesonide with near resolution of symptoms. However, upon completion of the budesonide course, all symptoms returned. She subsequently resumed budesonide at 3 mg which was later discontinued due to patient intolerance. The patient was then trialed on cholestyramine with minimal symptom improvement before transitioning to vedolizumab. We will continue to closely follow this patient in order to gauge her response to immunotherapy. Throughout the treatment course, she remained adherent to a strict gluten-free diet and her celiac disease remained well-controlled as indicated by maintenance of a normal tTg-IgA level and improvement in iron deficiency anemia. Discussion: Initial work-up for iron deficiency anemia should include small bowel biopsies to assess for celiac sprue. Refractory symptoms of celiac disease are commonly attributed to accidental ingestion of gluten. However, other concurrent conditions including microscopic colitis must be considered particularly in cases with noted serological improvements in tTg-IgA levels and iron deficiency. Given the generalized symptoms of microscopic colitis as well as benign appearing mucosa with endoscopic evaluation, diagnosing this disorder is often delayed. Our case emphasizes the need to check for microscopic colitis in cases of persistent symptoms of celiac disease despite strict dietary compliance.