Myxedema coma with reversible pulmonary arrest accompanied with massive pericardial effusion: A case report

Myxedema coma (MC) is a rare life-threatening endocrine emergency with a high mortality rate, frequently triggered by factors, including infection in untreated hypothyroidism. Early diagnosis and treatment are crucial, but frequently delayed owing to nonspecific symptoms and slow turnaround of laboratory results. We here report a case of a 68-year-old female with previously undiagnosed thyroid disorders who presented with impaired consciousness, hypothermia, bradycardia, and severe anasarca. The patient developed massive pericardial effusion, causing cardiac tamponade and respiratory arrest. Lifesaving measures encompassed emergency pericardial window and mechanical ventilation in the intensive care unit. It was 6 days delay that MC diagnosis was made and levothyroxine (LT4) was initiated because the thyroid function test was temporarily unobtainable due to year-end and New Year period. After confirming hypothyroidism (thyroid-stimulating hormone, 20.22 mIU/L; free thyroxine, <0.3 ng/dL), LT4 200 μg via nasogastric tube was promptly initiated and subsequently continued at 100 μg starting the following day. Intravenous hydrocortisone 100 mg was simultaneously administered, which led to a favorable outcome. This patient recovered without neurologic deficits, highlighting that timely intervention can reverse severe organ dysfunction. This case underscores the significance of high clinical suspicion for MC, even without immediate laboratory confirmation.