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Difficulty: MediumEndocrinology and Metabolism

A 28-year-old woman is brought to the emergency department by her roommate due to severe agitation, confusion, and palpitations. She has a history of Graves disease but stopped taking her medications three months ago. Temperature is 40.2°C (104.4°F), blood pressure is 160/90 mm Hg, pulse is 150/min and irregular, and respirations are 24/min. Physical examination reveals a diffuse goiter, bilateral exophthalmos, fine tremor, and diaphoresis. An electrocardiogram shows atrial fibrillation with rapid ventricular response. A clinical diagnosis of thyroid storm is made. Arrange the following therapeutic interventions in the most appropriate chronological order for the management of this patient, from the most immediate acute step to long-term definitive therapy.

  1. 1Administration of intravenous propranolol
  2. 2Administration of propylthiouracil
  3. 3Administration of potassium iodide
  4. 4Radioactive iodine ablation

Answer

The correct chronological sequence is: administration of intravenous propranolol, followed by propylthiouracil, then potassium iodide, and finally radioactive iodine ablation.
The treatment of thyroid storm requires a careful, staged approach. First, life-threatening adrenergic symptoms must be controlled, typically with propranolol. Second, thyroid hormone synthesis must be halted using a thionamide like propylthiouracil (PTU). Third, the release of preformed hormone is blocked using iodine solutions (e.g., potassium iodide), which must be given at least an hour after the thionamide to prevent the iodine from being used to create more hormone. Finally, once the patient is completely stabilized and euthyroid (weeks to months later), definitive therapy such as radioactive iodine ablation can be performed.

Step-by-Step Solution

1
Administer intravenous propranolol
Controls adrenergic symptoms and lowers heart rate.
The most immediate life-threatening complications of thyroid storm are cardiovascular. Beta-blockade rapidly stabilizes the patient.
2
Administer propylthiouracil (PTU)
Halts the production of new thyroid hormones.
Blocking synthesis must occur before blocking release to ensure that subsequently administered iodine is not used to synthesize more hormone.
3
Administer potassium iodide
Inhibits the release of preformed thyroid hormones from the gland.
Must be given at least 1 hour after PTU. If given before PTU, the iodine will serve as a substrate and worsen the thyrotoxicosis (Jod-Basedow phenomenon).
4
Perform radioactive iodine ablation
Provides definitive, long-term cure of Graves disease.
Definitive therapy can only be safely pursued after the acute crisis has resolved and the patient has returned to a euthyroid state.

Key Concept

The management of thyroid storm follows a strict sequential protocol: beta-blockers for symptom control, thionamides to block hormone synthesis, iodine solutions (delayed by at least 1 hour) to block hormone release, and eventually definitive therapy once euthyroid.
Estimated Time:1m 0s
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Topics

Endocrinology and Metabolism

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