Medium-vessel hemorrhage is a rare occurrence in ANCA-associated vasculitis, and has been previously described in only a few patients with microscopic polyangiitis. We report a case of renal hemorrhage in a patient with microscopic polyangiitis that was successfully managed by transcatheter arterial embolization of the active bleeding sites. The early clinical findings included necrotizing arteritis, as indicated by skin biopsy; rapidly progressive glomerulonephritis; mononeuritis multiplex; positive screening for myeloperoxidase-specific antineutrophil cytoplasmic antibody. Corticosteroid therapy was initiated. The patient's health deteriorated at 1 week, with rapidly progressing anemia. Computerized tomography identified a large, right-sided, perirenal hematoma, with active bleeding. Bleeding was successfully managed via segmental embolization of the renal artery. The patient was treated with steroid therapy and MZR, and subsequently underwent maintenance hemodialysis treatment for end-stage renal disease. Spontaneous renal hemorrhage is a rare but fatal clinical condition. A ruptured renal artery should be considered in a patient with microscopic polyangiitis, even in the absence of previous trauma and renal biopsy, when unexplained anemia or signs of shock occur.
Keywords: Antineutrophil cytoplasmic antibody (ANCA); Artery embolization; Microscopic polyangiitis; Perirenal hematoma; Renal hemorrhage.