A challenging twist in pulmonary renal syndrome.

Case. We report a rare case of hydralazine-induced anti-neutrophil cytoplasmic antibody-associated vasculitis. A 75-year-old African American woman with history of high blood pressure on hydralazine for 3 years presented with acute onset of shortness of breath and hemoptysis. Lab workup revealed a severe normocytic anemia and a serum creatinine of 5.09 mg/dL (baseline 0.9). Bronchoscopy demonstrated active pulmonary hemorrhage. A urine sample revealed red cell casts and a renal biopsy demonstrated pauci-immune, focally necrotizing glomerulonephritis with small crescents consistent with possible anti-neutrophil cytoplasmic antibody-positive renal vasculitis. Serologies showed high-titer MPO-ANCA and high-titer anti-histone antibodies. She was treated with intravenous steroids and subsequently with immunosuppression after cessation of hydralazine. The patient was subsequently discharged from hospital after a rapid clinical improvement. Conclusion. Hydralazine-induced anti-neutrophil cytoplasmic antibody-positive renal vasculitis is a rare adverse effect and can present as a severe vasculitic syndrome with multiple organ involvement. Features of this association include the presence of high titer of anti-myeloperoxidase anti-neutrophil cytoplasmic antibody with multiantigenicity, positive anti-histone antibodies, and the lack of immunoglobulin and complement deposition. Prompt cessation of hydralazine may be sufficient to reverse disease activity but immunosuppression may be needed.