Abstract
Thyroid hormones and the cardiovascular system are strongly intertwined with known risk of coronary disease, atrial fibrillation, and cardiomyopathy. Pericardial effusions are commonly seen in cases of severe hypothyroidism, however large to massive pericardial effusions with cardiac tamponade are exceptionally rare. We report a case of a patient presenting with hypertensive emergency and a concomitant diagnosis of primary hypothyroidism with a large pericardial effusion and early echocardiographic features of tamponade. Following pericardiocentesis, hypertension management, and thyroid replacement therapy the patient's symptoms improved with no recurrence of pericardial effusion. .