A Case of Anti-neutrophil Cytoplasmic Antibody-Associated Vasculitis Presenting With Diffuse Alveolar Hemorrhage and Renal Sparing

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a necrotizing vasculitis disease that traditionally includes three variants classified based on their clinical and pathological appearance: microscopic polyangiitis (MPA), granulomatosis with polyangiitis, and eosinophilic granulomatosis with polyangiitis (alternatively, Churg-Strauss syndrome). The mainstay of AAV treatment is immunosuppressive treatments, which improve survival and lower rates of end-stage kidney disease. Here we describe a patient with MPA ANCA who presented with diffuse alveolar hemorrhage and, six months later, recurrent pulmonary hemorrhage with renal sparing while off therapy.