Granulomatosis With Polyangiitis Complicated by Diffuse Alveolar Hemorrhage and Mitral Valve Chordal Rupture: An Uncommon Cardiopulmonary Manifestation.

Granulomatosis with polyangiitis (GPA) is an anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis that typically affects the upper and lower respiratory tract and kidneys. Cardiac complications, particularly those involving the valvular or subvalvular structures, are rare. We present the case of a 59-year-old woman with known anti-proteinase 3 (PR3)-ANCA-positive GPA who developed a severe disease flare characterized by diffuse alveolar hemorrhage (DAH) and mitral valve insufficiency due to chordae tendineae rupture. The diagnosis was confirmed by high-resolution computed tomography demonstrating ground-glass opacities consistent with DAH, markedly elevated PR3-ANCA titers, and echocardiography showing severe mitral regurgitation with ruptured chordae. She was treated with high-dose corticosteroids, rituximab, and avacopan, which resulted in marked clinical and radiological improvements. This case highlights the need for increased awareness of rare GPA manifestations, importance of multidisciplinary evaluation, and potential benefits of early immunosuppressive therapy.