A 30-year-old woman with uncontrolled Graves disease presents for emergency subtotal thyroidectomy. On the operating table she develops fever of 40 degrees Celsius, atrial fibrillation at 150 beats per minute, agitation, and vomiting. Which drug should be given FIRST?

• A Potassium iodide
• B Hydrocortisone intravenously
• C Propylthiouracil orally or by nasogastric tube
• D Propranolol intravenously ✓

Explanation

Thyroid storm is life threatening, and the fastest way to block the adrenergic surge driving tachycardia, fever and agitation is a beta blocker such as propranolol, given immediately. Propylthiouracil follows to block new hormone synthesis, iodine is given only AFTER the thionamide to prevent iodine serving as substrate for more hormone, and hydrocortisone blocks peripheral conversion of T4 to T3 and treats possible adrenal insufficiency. Giving iodine first is the classic sequencing error tested in this scenario.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

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Written and medically reviewed by the StethoPrep medical team.