Hydralazine-Induced ANCA-Associated Vasculitis With Lupus Nephritis Features and a Unique Antibody Profile.

Drug-induced antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a condition caused by a few culprit medications, notably hydralazine. Despite the significant morbidity and mortality associated with this condition, its rarity makes timely diagnosis challenging. A 68 year-old female presented to her nephrologist for a routine follow up of her chronic kidney disease stage III secondary to hypertension. Routine lab work noted worsened creatinine and protein to creatinine ratios. Additionally, her hypertension became more difficult to control, and she suffered from malaise, poor appetite, joint aches/pains and lower extremity edema. Given her sudden worsening of renal function, a serologic investigation was performed which revealed an elevated ANA, dsDNA, and anti-PR3. Renal biopsy showed a membranous pattern of immune-complex glomerulonephritis, necrotizing crescentic lesions, and focal acute tubular injury, concerning for SLE membranous nephropathy and overlapping AAV. She was diagnosed with both SLE and AAV and began empiric treatment with prednisone and rituximab as well as hydroxychloroquine. Several months later a medication review noted over 10 years of hydralazine use, with doses up to 125 mg twice daily. Given her presentation, biopsy, auto-antibodies, and hydralazine use, hydralazine-induced AAV was considered, and the medication was discontinued. She was eventually transitioned to mycophenolate and was deemed in remission. However, two years later her disease flared, and she passed away from diffuse alveolar hemorrhage related to AAV. This case illustrates a rare adverse effect of a commonly used medication. Awareness of this disorder is essential in guiding discontinuation of the drug and obtaining appropriate treatment.