An elderly woman is brought comatose with hypothermia (32°C), bradycardia, dry skin, and puffy facies. TSH is markedly elevated and free T4 is undetectable. Before starting levothyroxine, which drug must be administered first and why?
- A Hydrocortisone, because coexisting adrenal insufficiency may be unmasked by thyroid hormone ✓
- B Dopamine, to raise the blood pressure
- C Passive rewarming, before any pharmacotherapy
- D Broad-spectrum antibiotics, since infection is always the trigger
Correct answer: A. Hydrocortisone, because coexisting adrenal insufficiency may be unmasked by thyroid hormone
Explanation
Myxedema coma is often accompanied by relative adrenal insufficiency, and giving thyroid hormone accelerates cortisol clearance, which can precipitate vascular collapse. Hydrocortisone (100 mg IV) precedes levothyroxine. Rewarming too rapidly can cause vasodilatory shock; passive warming is preferred but is not the reason to delay hormones. Infection is a common trigger and should be sought, but empiric antibiotics are not universally mandatory.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
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Written and medically reviewed by the StethoPrep medical team.