A Rare Case of Pulmonary Renal Syndrome Diagnosed as Microscopic Polyangiitis

Microscopic Polyangiitis (MPA) is a systemic pauci-immune vasculitis primarily affecting glomerular capillaries, leading to necrotizing glomerulonephritis and often involving the kidneys and lungs. MPA is a significant cause of Pulmonary-renal syndrome, with a male predominance and typically presenting in individuals aged 50-60 years. Clinical manifestations include rapidly progressive glomerulonephritis characterized by a rapid decline in glomerular filtration rate, microscopic hematuria, erythrocyte casts, proteinuria, and hypertension, along with lung involvement such as diffuse alveolar hemorrhage. Although the pathogenesis remains unclear, environmental factors and genetic predisposition are believed to play roles. Diagnosis is confirmed histologically, and treatment involves remission induction and maintenance strategies using immunosuppressive therapies. A clinical case of a 45-year-old male with MPA presenting with shortness of breath, hemoptysis, and renal involvement highlights the disease's complexity and the importance of prompt, accurate diagnosis and treatment to improve patient outcomes.