A 41-year-old woman presents with fever, delirium, atrial fibrillation at 160/min, and free T4 four times the upper limit. Which drug sequence is CORRECT in thyroid storm?
- A Propylthiouracil first, iodine at least one hour later, with propranolol and hydrocortisone ✓
- B Lugol iodine first, then propylthiouracil one hour later
- C Radioiodine ablation within 24 hours along with propranolol
- D Propranolol and methimazole, with iodine withheld entirely
Correct answer: A. Propylthiouracil first, iodine at least one hour later, with propranolol and hydrocortisone
Explanation
Thionamides must be given before iodine. If iodine is administered first, it provides substrate for fresh hormone synthesis and can worsen thyrotoxicosis (Jod-Basedow effect). Propylthiouracil is preferred in storm because it also blocks peripheral T4 to T3 conversion. Propranolol controls adrenergic features and hydrocortisone treats possible coexisting adrenal insufficiency while reducing T4 to T3 conversion. Radioiodine is contraindicated during the storm.
Reference: Williams Textbook of Endocrinology, 14th ed.
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Written and medically reviewed by the StethoPrep medical team.