Hydralazine-Induced Antineutrophil Cytoplasmic Antibody-Associated Vasculitis: Asymptomatic and Renal-Restricted Presentation.

BACKGROUND Hydralazine, a potent vasodilator widely used to treat hypertension, has been implicated in an increasing number of cases of drug-induced autoimmune diseases in recent years. However, antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis secondary to hydralazine use has rarely been described and most reported cases involved multi-organ-related vasculitis, including skin and lung-kidney manifestations. ANCA-associated vasculitis is an immune-inflammatory condition characterized by necrotizing vasculitis with few or no immune deposits, predominantly affecting small vessels. The fact that the vasculitis is associated with hydralazine use and improves with discontinuation of hydralazine supports the diagnosis of hydralazine-induced disease. The case we report is a hydralazine-induced, ANCA-associated, pauci-immune crescentic glomerulonephritis with a presentation limited to the kidneys. CASE REPORT A 66-year-old woman was admitted to the hospital for worsening renal function over a month with no symptoms. Serology work-up was significantly positive for antinuclear, perinuclear ANCA, anti-histone, anti-double-stranded DNA, anti-cardiolipin, and anti-myeloperoxidase antibodies. The patient ultimately underwent a kidney biopsy, which revealed pauci-immune crescentic glomerulonephritis. Her kidney function improved with cessation of hydralazine as well as therapy with pulse steroids. CONCLUSIONS Hydralazine is commonly prescribed to treat hypertension. Healthcare providers should be aware of potentially severe hydralazine-induced ANCA-associated vasculitis, which can present with various clinical manifestations. Serologic studies have indicated that it has features that overlap with lupus. Biopsy is helpful for making a definitive diagnosis and developing individual treatment plans. Early diagnosis, cessation of the offending drug, and initiation of immunosuppressive therapy are key for favorable prognosis.