SAT-619 Myxedema Coma: A Modern Day Rarity

Background: Myxedema coma is a rare, but severe form of hypothyroidism with a high mortality rate. Case: An eighty-nine-year-old female with a history of hypothyroidism and hypertension presented from a nursing home with lethargy, bradycardia, and hypothermia. She was oriented to self only, minimally verbal requiring assistance for activities of daily life at baseline. Medications included cardizem, lisinopril, and levothyroxine 150 mcg at stable doses for a year. Physical examination was significant for hypothermia (35.4°C) and bradycardia (heart rate of 40); the patient was obtunded. Initial labs were significant for AKI, hyperkalemia, and transaminitis. Echo showed an EF of 60% with impaired LV relaxation. A temporary pacemaker was placed and the patient was started on an isoproterenol drip. TSH was drawn due to the history of hypothyroidism and was elevated at 270 (0.5-5 mU/L). Serum cortisol was drawn and a dose of hydrocortisone 100 mg was given intravenously followed by an IV dose of levothyroxine 100 mcg and liothyronine 20 µg. Serum cortisol level was high at 54.2 µg/dl (0.4-22.6 µg/dl). Her mental status improved the following day, bradycardia resolved and the isoproterenol drip was stopped. She was started on IV levothyroxine 50mcg daily. Subsequently, hyperkalemia and transaminitis resolved, but her renal function continued to deteriorate. Due to her poor baseline functional status, her spouse decided against dialysis and the patient was transitioned to inpatient hospice. Discussion: Myxedema coma is defined as severe hypothyroidism leading to decreased mental status, hypothermia and other symptoms related to slowing of function in multiple organs. Nowadays, due to the wide availability of TSH assays that are performed routinely, hypothyroidism is detected and treated early and rarely leads to myxedema coma. However, it can present itself in hypothyroid patients with poor compliance and comorbid conditions. Since it is associated with a high mortality rate, treatment should be initiated without waiting for lab results. Glucocorticoids are given until the possibility of co-existing adrenal insufficiency has been excluded. A dose of IV T₃ and T₄ is administered followed by maintenance IV T₄ daily until the patient is able to take PO.T₃ is continued until clinical improvement and stabilization of the patient. Clinical and biochemical improvement is usually seen within a week. Despite treatment, it has a 30-50% mortality rate. Conclusion: Myxedema coma is a rare endocrine emergency with a high mortality rate that requires a high index of suspicion and warrants early treatment.