A196 DIARRHEA AS A PRESENTING SYMPTOM OF RELAPSED GRANULOMATOSIS WITH POLYANGIITIS

Abstract Background Granulomatosis with polyangiitis (GPA) is a rare, small-to-medium sized-vessel vasculitis that typically involves the sinus, respiratory, and renal systems. The gastrointestinal (GI) tract is rarely involved, but its exact frequency is poorly characterized. GI symptoms have been reported to occur in up to 10% of acute presentations, and a historic series of 56 autopsies of GPA patients found 24% to have focal necrotizing arteriolitis of the intestine (Storesund, 1998). There are few case reports of colitis associated with GPA. They commonly describe abdominal pain, rectal bleeding, and less frequently, perforation, early in the disease course in conjunction with other classic systems involvement which aid in the diagnosis of GPA. Aims We present the case of a 77 year-old woman with lung biopsy-proven cANCA-positive GPA who was found to have colonic vasculitis after she had been in remission for several years. Methods Case report and literature review Results The patient presented with a 1-month history of progressive back pain, followed by 1 week of severe abdominal pain and watery diarrhea. She was afebrile, with a leukocyte count of 13.8x109/L, C-reactive protein of 213 mg/L, and fecal calprotectin of 669mg/kg. cANCA was strongly positive at 5.4 AI. Computed tomography scan revealed focal inflammatory change at the cecum and terminal ileum. Stool cultures were negative. Colonoscopy showed a polypoid, inflammatory-appearing hard mass at the ileocecal valve with surrounding fragile mucosa. Ileocecal valve biopsies described fibropurulent material and granulation tissue consistent with ulcer bed with surrounding mucosa showing chronic ischemic colitis with various degrees of acute cryptitis. The most likely etiology was speculated by the pathologist to be involvement of the colon by vasculitis, as other etiologies appeared to be ruled out. The patient had mild kidney injury, but no additional lung findings, in contrast to her initial presentation of GPA. She was started on prednisone 50mg/day. Her back pain, abdominal pain, and diarrhea resolved within 1 week, and renal function improved. Currently, there is a plan to start Rituximab for chronic treatment. Conclusions Our case of GPA-associated colitis is unique for several reasons. First, most case reports describe rectal bleeding as the presenting symptom of GPA colitis, whereas our patient presented with non-hemorrhagic diarrhea. Second, where available, reports of colitis correlated endoscopically with colonic ulcerations, whereas our patient had an ileocecal mass. Third, most reports present colitis associated with a new diagnosis of GPA, whereas our patient presented with colitis as new GI system involvement with likely inflammatory back pain as the presenting feature of GPA relapse. While a rare feature, colitis secondary to GPA can be considered in the appropriate context. Funding Agencies None

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