Severe Pulmonary-Renal Syndrome Due to Hydralazine-Induced ANCA-Associated Vasculitis.

Antineutrophilic cytoplasmic antibodies glomerulonephritis (ANCA-GN) is the most common type of crescentic glomerulonephritis in the elderly. It is life-threatening, and early detection is key to facilitating complete remission with treatment. Albeit rare, more reports are implicating hydralazine use in the development of ANCA-associated vasculitis (AAV) and ANCA-GN. Classic treatment involves the use of corticosteroids with cyclophosphamide (+/- plasmapheresis) in ANCA-GN. However, a definite therapeutic approach and duration for drug-induced AAV has yet to be studied in clinical trials. In our case, we aim to provide another approach that would one day improve and structure therapy guidelines for drug-induced AAV. We present a 75-year-old female patient, with medical history of hypertension, atrial fibrillation status post ablation on anticoagulation, pulmonary hypertension, who came to the nephrology clinic with symptoms of fatigue, anorexia, nausea, weight loss, hemoptysis, and rise in serum creatinine to 2.39 mg/dL from baseline of 0.65 mg/dL, and by admission to the hospital in August 2024 was 4.6 mg/dL. Anti-MPO and anti-histone antibodies were positive; complement was normal. Renal biopsy confirmed pauci-immune necrotizing GN with crescents. Therapy included steroids, rituximab, cyclophosphamide, and plasmapheresis with clinical improvement and complete remission of extra-renal disease.