An 82-year-old woman is found unresponsive with core temperature 31°C, heart rate 38/min, bradycardic ECG with low voltage, dry skin, and periorbital puffiness. TSH is 78 mIU/L and free T4 is undetectable. Along with supportive care, what is the correct immediate hormonal therapy?
- A Oral levothyroxine 100 micrograms daily and fludrocortisone 0.1 mg
- B IV levothyroxine 300 to 400 micrograms loading dose plus IV hydrocortisone 100 mg every 8 hours ✓
- C IV triiodothyronine alone at 20 micrograms every 8 hours without steroids
- D Subcutaneous levothyroxine 200 micrograms once daily with close TSH monitoring
Correct answer: B. IV levothyroxine 300 to 400 micrograms loading dose plus IV hydrocortisone 100 mg every 8 hours
Explanation
Myxedema coma requires large parenteral levothyroxine loading because gastrointestinal absorption is unreliable in shock and hypothermia, and hydrocortisone covers coexisting relative adrenal insufficiency, which untreated thyroid replacement can precipitate. Oral or subcutaneous routes are inadequate, and giving thyroid hormone without steroid cover risks adrenal crisis.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
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Written and medically reviewed by the StethoPrep medical team.