A Case of End Stage Renal Disease and Diffuse Alveolar Hemorrhage as Initial Presentation of P-ANCA Vasculitis

Introduction: Perinuclear anti-neutrophil cytoplasmic antibodies (P-ANCA) are autoantibodies that target the myeloperoxidase (MPO) antigen within neutrophils. They are associated with a necrotizing vasculitis that predominantly affects capillaries, venules, and arterioles, most commonly presenting with pulmonary and renal manifestations. The renal histologic findings are classically pauci-immune, but there are some reported cases with immune complex deposition that have been associated with increased disease severity. Case Presentation: We present a case of an elderly patient with no prior autoimmune diagnosis who presented with severe anemia, hypoxic respiratory failure, and acute renal failure. She underwent bronchoscopy and was diagnosed with diffuse alveolar hemorrhage. Her renal function rapidly progressed to end stage renal disease requiring regular hemodialysis. Renal biopsy revealed segmental necrosis, scarring and sclerosis with crescent formation, and mesangial hyper-cellularity with immune complex deposits in the mesangium. Immunology workup revealed elevated P-ANCA and low complement. The patient was diagnosed with P-ANCA vasculitis and treated with pulse dose steroids, cyclophosphamide, and plasmapheresis. She responded well to therapy with significant improvement in renal function. Deviation: The patient was initially assumed to have lupus nephritis based on her clinical presentation. However, the renal biopsy revealed both immune complex deposition and necrosis consistent with an ANCA vasculitis. Discussion: This case provides further demonstration of the possible synergistic effect between ANCA and immune complex deposition that leads to clinically more severe disease. Conclusion: The patient’s good response to treatment supports the use of plasmapheresis in severe cases of renal failure suggestive of autoimmune mediated etiology. Grants: None