Subclinical Hypothyroidism Presenting as Myxedema Coma: Case Report and Literature Review

Myxedema coma is a medical emergency with a high mortality rate. Patients with hypothyroidism may develop myxedema coma if left untreated, although quite rare nowadays owing to regular TSH (thyroid stimulating hormone) monitoring. We present the case of a patient with a known history of subclinical hypothyroidism, defined by normal free T4 (thyroxine) and high TSH, who was found to be in myxedema coma. Clinically, the patient was found to be lethargic, bradycardic, and hypothermic, and in the background of high TSH, myxedema coma was suspected. The patient was admitted to the ICU (Intensive Care Unit) and initially treated with intravenous (IV) hydrocortisone for possible concomitant adrenal insufficiency. This was followed by treatment with IV levothyroxine.