Hydralazine-Induced Dual ANCA-Positive Crescentic Glomerulonephritis

Abstract

An 80-year-old woman presented with rapidly progressive renal failure following five months of hydralazine therapy at 100 mg daily. She reported dark urine, weight loss, and fatigue. Laboratory studies revealed dual ANCA positivity (MPO 30 IU/mL, PR3 197 IU/mL), positive ANA, low complement C3, and active urinary sediment. Renal biopsy demonstrated pauci-immune necrotising crescentic glomerulonephritis, consistent with ANCA-associated vasculitis. Hydralazine-induced vasculitis was suspected, and the drug was discontinued. She received high-dose intravenous methylprednisolone followed by rituximab, with partial renal recovery at three weeks. Hydralazine-induced ANCA vasculitis is a rare but important cause of rapidly progressive glomerulonephritis that may closely mimic primary AAV. Dual ANCA positivity and ANA seropositivity are characteristic, although atypical serological patterns may occur. Recognition of this association and prompt discontinuation of hydralazine, alongside appropriate immunosuppression, are critical for improving renal outcomes and preventing irreversible kidney injury.