Hydralazine-Induced Lupus Syndrome Manifesting as Large Pericardial Effusion.

Hydralazine-induced lupus syndrome (HILS) is a rare clinical entity with variable manifestations. Pericardial involvement is an uncommon but serious manifestation of the condition. In this report, we present a case of large symptomatic pericardial effusion secondary to HILS. We highlight the important considerations in the evaluation and management of this rare syndrome. HILS should be considered in the differential diagnosis for cardiac tamponade of otherwise unclear etiology in patients taking 100 mg daily or more of hydralazine for longer than three months. A temporal association between the offending drug and presenting symptoms, resolution of symptoms upon discontinuation, and a positive anti-histone antibody test can all support the diagnosis of this syndrome.