Renal Limited Anti-Neutrophil Cytoplasmic Antibody Associated Vasculitis: A Case Report

Abstract

Background: Renal Limited Vasculitis (RLV) is a localized autoimmune vascular inflammatory disorder that is part of the Pauci Immune Glomerulonephritis (PIGN) spectrum. Over 90% of PIGN patients have circulating Anti-Neutrophil Cytoplasmic Antibodies (ANCA Ab). Anti-Neutrophil Cytoplasmic Antibody (ANCA) associated vasculitides are a heterogeneous group of multisystemic autoimmune disorders with distinct pathological findings. They are characterized by widespread inflammation of vessels according to their size, their location, and their serotypes based on the presence or absence of ANCA antibodies, namely Myeloperoxidase (MPO-ANCA), Proteinase-3 (PR3-ANCA) or simply ANCA negative, if no antibodies are found. RLV is characterized by antibody positivity to myeloperoxidase in the majority of cases. Case Report: A 77-year-old Caucasian female was admitted with altered mental status and laboratory evidence of renal function compromise consistent with non-oliguric acute renal failure. Imaging and renal biopsy resulted in a diagnosis of pauci-immune glomerulonephritis consistent with MPO-ANCA vasculitis with a subtype that was associated with necrotizing arteritis, a severe form of the disease. She was placed on hemodialysis, intravenous cyclophosphamide, and oral prednisone, and entered remission. Conclusion: A high level of suspicion and familiarity with clinical signs and symptoms are critical in distinguishing primary RPGN subtypes from other types of ANCA-associated small vessel vasculitis. If left untreated, renal limited vasculitis can progress to widespread systemic involvement and become fatal.