Granulomatosis with Polyangiitis Presenting Primarily With Gastrointestinal Bleeding

Abstract

Introduction Granulomatosis with Polyangiitis (GPA) is characterized by vasculitis of small vessels. Gastrointestinal (GI) involvement in GPA is uncommon. We describe a case of a young male with GPA and initial findings indistinguishable from ulcerative colitis. Case description A 16 year old African American male presented with bloody diarrhea for two days. History was significant for abdominal pain, melena and weight loss. Exam was remarkable for mild generalized abdominal tenderness and bloody stool on rectal exam. Initial blood work revealed low hemoglobin and elevated inflammatory markers. Findings were concerning for GI bleed. Upper endoscopy showed no active bleeding. Colonoscopy revealed pancolitis without involvement of terminal ileum and illeocecal valve, suggestive for inflammatory bowel disease (IBD). Colon biopsy showed pancolitis with mucosal architectural distortion and ulceration, suggestive for ulcerative colitis. Despite systemic steroid treatment patient continued to have bloody stool. He also developed painless gross hematuria with normal renal function panel which raised concern for autoimmune vasculitis. Serologic tests showed elevated neutrophil proteinase-3 antibody (PR-3 AB or C-ANCA) concerning for GPA. Renal biopsy revealed crescentic necrotizing glomerulonephritis which confirmed the diagnosis. The patient was started on cyclophosphamide therapy. Discussion GPA predominantly involves upper airways, lungs and kidneys. GI manifestations are rare. Infrequently GPA might present primarily with GI symptoms. GI involvement might mimic IBD or infectious colitis and extraintestinal manifestations of IBD and GPA may overlap. Our patient presented primarily with rectal bleeding without sinopulmonary signs or symptoms. Colonoscopic findings of pancolitis without involvement of terminal ileum in conjunction with biopsy findings of mucosal architectural changes and ulceration were suggestive for IBD. However patient's inappropriate response to steroids and development of gross hematuria raised further concern regarding alternative etiologies. Elevated C-ANCA and renal biopsy finding of necrotizing glomerulonephritis confirmed the diagnosis of GPA. GPA may present primarily with symptoms mimicking IBD, thus a high index of suspicion is required for diagnosis. It is important to differentiate these two conditions as early initiation of cyclophosphamide therapy appears to improve the long-term outcome in patients with GPA. 1.2045_A Figure 1 No Caption available.2045_B Figure 2 No Caption available.2045_C Figure 3 No Caption available.