Progression of ANCA-Associated Vasculitis with Multiorgan Involvement Despite Immunosuppressive Therapy

Introduction: Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a rare group of autoimmune disorders characterized by necrotizing inflammation of small to medium-sized blood vessels. Despite the availability of robust immunosuppressive regimens—including corticosteroids, cyclophosphamide, and rituximab—management remains challenging due to the potential for disease progression and multi-organ involvement. Case Description: A 69-year-old male with a history of benign prostatic hyperplasia (BPH) and obstructive sleep apnea (OSA) on CPAP was diagnosed two months ago with ANCA-associated vasculitis. His initial presentation was renal-limited, with acute kidney injury (AKI), hematuria, and non-nephrotic range proteinuria. Kidney biopsy confirmed the diagnosis of vasculitis. He was started on pulse intravenous corticosteroids, followed by oral prednisone 60 mg daily, and received induction immunosuppression with rituximab 1000 mg along with oral cyclophosphamide 75 mg daily, which was later discontinued. At the time of deterioration, he was on prednisone 25 mg daily. He developed new-onset hemoptysis and progressive hypoxic respiratory failure. Imaging revealed bilateral interstitial infiltrates, and bronchoalveolar lavage (BAL) confirmed diffuse alveolar hemorrhage (DAH). His respiratory status worsened, necessitating mechanical ventilation. He was repulsed with intravenous methylprednisolone and started on daily plasmapheresis (PLEX). Concurrently, he developed mononeuritis multiplex, myocarditis, and hemodynamic instability, prompting the initiation of continuous renal replacement therapy (CRRT). He was later transitioned to intermittent hemodialysis (iHD). The patient was eventually extubated and demonstrated improvement in pulmonary infiltrates. However, he remains dialysis-dependent. Discussion: This case illustrates the complexity of ANCA-associated vasculitis, particularly in the setting of multi-organ involvement. While the treatment of AAV has evolved to include targeted biologic agents for both induction and maintenance, this case underscores that disease progression can still occur despite appropriate therapy. Plasmapheresis was used effectively to manage both DAH and myocarditis.