Pericardial effusion as an expression of thyrotoxicosis

Patients who have either hyperthyroidism or hypothyroidism can present with cardiovascular complications. These manifestations of thyroid disease-congestive heart failure, atrial tachyarrhythmias, atrioventricular conduction disorders, and mitral valve dysfunction-are well known to the clinician. Pericardial effusion is considered a complication of hypothyroidism; as an expression of thyrotoxicosis, it is extremely rare.Herein, we present the case of a 76-year-old woman who had pericardial effusion associated with thyrotoxicosis. She was treated with high-dose beta-blockers, methimazole, diuretics, and short-term steroids. She recovered completely, which precluded the need for pericardiocentesis. We suggest that thyrotoxicosis be considered in the differential diagnosis of pericardial effusion.