Overview Immune complex-mediated transmural vasculitis with fibrinoid necrosis Affects small and medium arteries Typically involves renal and visceral vessels, NOT pulmonary arteries Lesions are of different ages Presentation fever weight loss malaise abdominal pain melena headache myalgia hypertension neurologic dysfunction cutaneous eruptions Evaluation Hepatitis B seropositivity in 30% of patients Multiple aneurysms and constrictions on arteriogram Treatment Corticosteroids Cyclophosphamide