Introduction: Granulomatosis with polyangiitis (GPA) is a rare small to medium vessel vasculitis. Estimated prevalence within the United Stated for GPA is 3/100,000 patients. The disease classically affects the upper respiratory tract, lungs and kidneys. Rarely, the gastrointestinal system is affected. In such cases, it is important to distinguish GPA from mimics, and diagnosis is guided by clinical judgement taken together with histologic analysis.
Case Description/Methods: A 27- year old male with history of GPA who presented with 2 weeks of bloody and black bowel movements associated with abdominal pain and bloody vomiting. Past history was notable for GPA diagnosed in childhood with presence of nasal inflammation, pulmonary nodules and rapidly progressive crescentic glomerulonephritis.
Initial laboratory analysis demonstrated leukocytosis to 13.6k/uL, elevated CRP to 2.5mg/and elevated Cr to 1.47mg/dL (baseline 1.07mg/dL). Abdominal CT scan revealed mesenteric lymphadenopathy, thickening and edema of the gastric antrum, suggestive of gastritis. Stool testing was positive for fecal calprotectin and lactoferrin, and negative for common bacterial pathogens. Serum C3 and C4 were normal, while testing for ANCA antibodies was negative, both on acute presentation and during routine testing previously.
Endoscopy revealed striking hemorrhagic inflammation of the stomach, and colonoscopy showed pancolitis throughout examined colon. Gastric and colonic biopsies showed acute mucosal inflammation and non-necrotizing vasculitis, without granulomas. He was started on intravenous methylprednisolone, with rapid resolution of his symptoms thereafter. He was discharged on a prednisone taper and later transitioned to azathioprine therapy.
Discussion: Gastrointestinal manifestations of GPA are rare, with estimated prevalence of 6-7% of GPA patients. Gastrointestinal vasculitis causes inflammation with resulting end organ ischemia, leasing to a wide spectrum of clinical presentation. Predominantly intestinal manifestations are described, including mesenteric ischemia and bleeding. Thus, GI manifestations are associated with higher vasculitis severity on scoring indices, higher need for surgery and increased mortality. Interestingly, absence of granulomas on biopsy of the GI tract does not appear to be atypical. An important differential for gastrointestinal GPA is Crohn’s disease. Due to the paucity of data, current guidelines do not provide recommendations on management of GI manifestations on ANCA-associated vasculitis.
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