Pericardial Effusion as a Complication of Severe Primary Hypothyroidism

Large pericardial effusions with associated cardiac tamponade are a rare manifestation of hypothyroidism. We present the case of a 63-year-old female with chronic heart failure and newly diagnosed hypothyroidism, who presented to her primary care physician complaining of progressively worsening dyspnea. Chest radiography showed cardiomegaly and transthoracic echocardiography (TTE) revealed a large pericardial effusion with tamponade physiology. An emergent pericardial window was performed, resulting in an improvement in left ventricular systolic function. Pericardial tissue biopsy was normal. Thyroid function tests were consistent with severe primary hypothyroidism. After inpatient treatment with intravenous levothyroxine and interval resolution of symptoms without recurrence of effusion, the patient was discharged home on oral levothyroxine therapy. Close follow up with surveillance echocardiography was planned. While metabolic disorders are seldom thought of as an etiology, it is imperative for clinicians to recognize hypothyroidism as a cause of the pericardial effusion. It is one of the few reversible causes and delay in treatment can result in fatal sequelae.