A 42-year-old woman with untreated Graves disease presents with fever of 40 degrees C, pulse 152/min irregular, vomiting, agitation, and confusion following an episode of pneumonia. A diagnosis of thyroid storm is made. Which sequence of drug administration is correct?

• A Lugol iodine first, followed one hour later by propylthiouracil
• B Propylthiouracil first, followed one hour later by iodine ✓
• C Iodine and carbimazole simultaneously as the first dose
• D Radioiodine ablation once the acute phase settles

Explanation

In thyroid storm, a thionamide must be given before iodine. Propylthiouracil is preferred because it also blocks peripheral T4 to T3 conversion. Iodine given first provides substrate for new hormone synthesis and can precipitate worsening thyrotoxicosis, which kills option A. Beta blockers and glucocorticoids are given concurrently, but the thionamide-before-iodine rule is the examined point. Radioiodine is contraindicated in the storm itself.

Reference: Sabiston Textbook of Surgery, 21st ed.

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