Large Pericardial Effusion as a Manifestation of Overlapping Hydralazine-Induced Lupus and ANCA Vasculitis.

BACKGROUND: Hydralazine can rarely cause drug-induced lupus erythematosus and antineutrophil cytoplasmic antibody-associated vasculitis. CASE SUMMARY: A 71-year-old man with hypertension and chronic myelomonocytic leukemia developed respiratory failure, kidney failure, bilateral pleural effusions, and a large circumferential pericardial effusion attributed to hydralazine started 4 months before. Rheumatological workup revealed a positive antihistone antibody, p-antineutrophil cytoplasmic antibody, and antinuclear antibody (1:640) with a speckled pattern. After discontinuing hydralazine, he was managed with diuresis, bilevel positive airway pressure ventilation, and pericardiocentesis. His condition improved within days with no return of serositis. DISCUSSION: This case demonstrates a rare overlapping syndrome of drug-induced lupus erythematosus and ANCA-associated vasculitis associated with hydralazine, highlighting the importance of recognizing drug-induced autoimmune syndromes in patients with unexplained multiorgan failure. TAKE-HOME MESSAGES: Hydralazine at doses >200 mg qd can cause severe overlapping autoimmune syndromes. Clinicians should maintain a high suspicion for drug-induced disease in patients with pericardial effusions and multiorgan failure in the setting of chronic hydralazine use.