IgA Vasculitis Presenting as Pulmonary-Renal Syndrome.

Immunoglobulin A (IgA) vasculitis (IgAV), formerly known as Henoch-Schönlein purpura, is a small-vessel vasculitis characterized by the deposition of IgA-containing immune complexes in vessel walls. While predominantly affecting the pediatric population, adult-onset IgAV often presents with a more severe clinical course and a higher risk of renal complications. Pulmonary-renal syndrome, characterized by diffuse alveolar hemorrhage and glomerulonephritis, is an exceedingly rare manifestation of IgAV and poses substantial diagnostic and therapeutic challenges. We report a case of a 33-year-old male presenting with hemoptysis, fatigue, and diffuse myalgias. The patient had no cutaneous manifestations, such as purpura. Laboratory workup revealed anemia, acute kidney injury with proteinuria, and microscopic hematuria, alongside negative serologies for antineutrophil cytoplasmic antibodies (ANCA), anti-glomerular basement membrane antibodies (anti-GBM), and other autoimmune markers. A chest computed tomography (CT) scan demonstrated bilateral ground-glass opacities, consistent with diffuse alveolar hemorrhage, which was later confirmed by bronchofibroscopy. Renal biopsy confirmed IgA vasculitis nephritis, with mesangial hypercellularity, segmental sclerosis, and dominant IgA deposition. Pulmonary-renal syndrome secondary to IgAV was assumed, and the patient was treated with high-dose intravenous methylprednisolone, followed by oral prednisolone, alongside plasma exchange. This led to the resolution of hemoptysis and the recovery of renal function. Sustained remission was achieved with careful tapering of corticosteroids over the subsequent year. This case underscores the importance of a high index of suspicion and a multidisciplinary approach to managing IgAV, particularly in atypical presentations involving pulmonary-renal syndrome. Early diagnosis and aggressive immunosuppressive therapy are essential to achieving favorable outcomes, even in severe cases.