Myxedema Coma

  • Myxedema coma is an extreme complication of hypothyroidism in which patients exhibit multiple organ abnormalities and progressive mental deterioration
  • Precipitating factors include poor adherence to daily thyroid hormone replacement therapy, stroke, heart failure, myocardial infarction, infection, metabolic disturbances, cold exposure, trauma, gastrointestinal bleeding, acidosis, and hypoglycemia
  • Multiple organ systems are affected:
    • Hypoventilation leading to hypercapnia and hypoxemia
    • Bradycardia and hypotension
    • Hyponatremia
    • Hypoglycemia
  • Two most common findings are hypothermia and mental status changes
  • Mortality rate of myxedema coma is over 20%
  • Physical exam findings: altered mentation, bradycardia, delayed reflex relaxation, dry/cool skin, myxedematous face, constipation, abdominal distension
  • If myxedema coma is suspected, the TSH and free T4 levels should be checked promptly, but is a clinical diagnosis
  • Intravenous levothyroxine has traditionally been administered, with an initial bolus of 200 to 500 micrograms followed by daily doses between 50 and 100 micrograms until transition to oral administration is feasible
  • May consider lower doses in patients with significant cardiac history to avoid cardiac irregularities
  • Concurrent treatment with high-dose glucocorticoids (such as hydrocortisone) is recommended until adrenal insufficiency is excluded and appropriate adrenal function is confirmed
  • Also treat underlying condition that may have contributed to this: infection, bleeding, hypoglycemia