Pericardial Effusion with Tamponade in Untreated Hypothyroidism.

BACKGROUND Small pericardial effusions are common with chronic hypothyroidism, but large pericardial effusion with tamponade or pre-tamponade physiology is a rare complication of severe uncontrolled hypothyroidism. Presentation of pericardial effusion of any etiology can range from being asymptomatic to hemodynamic instability with cardiac tamponade, depending on the amount and speed of accumulation of pericardial fluid, but pericardial effusion associated with hypothyroidism are usually small. Protracted medication non-adherence was a key factor in our patient's presentation. CASE REPORT We present a case of a woman in her 40s with a known history of autoimmune hypothyroidism with medication non-adherence for longer than 9 months who presented with fatigue, weight gain, limited physical activity, and exertional dyspnea with bilateral swelling of the upper and lower extremities. Examination revealed muffled heart sounds, positive JVD, and positive pulsus paradoxus. She had an elevated TSH, low free T4, and a high anti-thyroid peroxidase antibody level. Echocardiography revealed a large pericardial effusion with impending tamponade. Pericardiocentesis with pericardial drain was done and the patient's symptoms resolved quickly. The patient was restarted on a prior dose of levothyroxine 175 mcg. She had improved by the 3rd day of hospitalization; the pericardial drain was removed, and she was discharged with access to medication. Follow-up revealed complete resolution of her symptoms. CONCLUSIONS This case emphasizes the importance of recognition of hypothyroidism as the etiology of life-threatening large pericardial effusions, as it is treatable and recurrences are preventable. To prevent recurrence, it is important to achieve euthyroidism after treating an episode of pericardial effusion.