Procainamide-induced lupus erythematosus pericarditis encountered during coronary bypass sugery

Procainamide is probably the most common offending drug responsible for the drug-induced lupus erythematosus syndrome today. Pericarditis has been reported to occur in from 14 to 18 per cent of the cases of procainamide-induced lupus erythematosus, and occasional reports of massive pericardial effusion, pericardial tamponade and constrictive pericarditis have appeared in the literature. We describe a patient who presented with features of procainamide-induced lupus erythematosus without any clinical evidence of pericarditis. He underwent coronary bypass surgery 12 days after administration of the drug was stopped and was found to have a significant pericardial effusion at the time of surgery; histologic examination of pericardial tissue and pericardial fluid confirmed that the pericardial effusion was related to the procainamide-induced lupus syndrome. The incidence of pericarditis in procainamide-induced lupus erythematosus may be higher than presently accepted figures would indicate. Symptoms and signs related to procainamide-induced lupus pericarditis may cause diagnostic confusion with common postoperative bypass complications; the full implications of this disease entity to the patient undergoing coronary bypass are unknown.