(278) Under Pressure: Navigating Myxedema Coma With Cardiac Complications

Introduction: Myxedema coma is a life-threatening manifestation of severe hypothyroidism characterized by encephalopathy, hemodynamic instability and multiorgan dysfunction. Alterations in capillary permeability associated with hypothyroidism may also lead to effusions, although complications from these effusions are rare. Here we present a case of a patient with myxedema coma leading to pericardial effusion and cardiac tamponade.

Description: A 50-year-old male with a history of hypertension and pericardial effusion requiring pericardiocentesis presented to our emergency room with subacute onset of altered mental status for 12 hours, associated with three months of generalized malaise and bilateral lower extremity edema. Vitals on presentation showed tachycardia but were otherwise stable. Exam revealed a lethargic patient with bilateral rales, 2+ pitting edema to mid-shin and distant heart sounds. TSH was 594 uIU/mL, free T4 < 0.10 ng/dL.

12-lead electrocardiogram showed sinus tachycardia with low voltage QRS. Chest x-ray indicated an enlarged cardiac silhouette, interstitial opacities and right sided pleural effusion. Transthoracic echocardiogram (TTE) showed an ejection fraction of 55-60% with large pericardial effusion causing diastolic collapse of the right ventricle, concerning for cardiac tamponade. Patient was admitted to the coronary care unit (CCU) for further intervention. APACHE-II score on admission was 11.

An urgent surgical pericardial window was performed with removal of 2.1L of clear fluid from the pericardial and right pleural space. IV thyroid hormone replacement was started upon consultation with endocrinology. Post-operative TTE showed resolution of the pericardial effusion. The pericardial drain was removed on postoperative day (POD) 6 and the patient was discharged home on POD 10 on oral levothyroxine, with resolving hypothyroidism on repeat thyroid function studies.

Discussion: This case highlights the need for heightened awareness of myxedema coma’s potential to cause severe cardiopulmonary complications. Management was multidisciplinary, including urgent surgical pericardial window and IV thyroid hormone replacement. Clinicians should consider this diagnosis in patients presenting with cardiac or pleural effusions to ensure rapid, coordinated, and lasting treatment efforts.