American Board of Internal Medicine (ABIM) Certification Practice Exam

What should be administered at least 1 hour after the first dose of a thionamide in thyroid storm treatment?

1. Thyroid hormone replacement

2. Iodine drops

3. Calcium supplements

4. Insulin

The correct answer is: Iodine drops

The administration of iodine drops at least 1 hour after the first dose of a thionamide in the treatment of thyroid storm is appropriate because it follows the principle of using the Wolff-Chaikoff effect, where high doses of iodide can lead to a temporary reduction in thyroid hormone synthesis. In the case of a thyroid storm, the initial management often includes thionamides, such as propylthiouracil or methimazole, which inhibit the synthesis of thyroid hormones. Once the thionamide has been given, iodine can then be administered to reduce the release of pre-formed thyroid hormones from the thyroid gland. However, timing is crucial; administering iodine too early, before thionamide action has begun, can actually lead to increased thyroid hormone release instead of its desired effect. This sequenced approach helps to effectively manage the hyperthyroid state by decreasing hormone production and release, thus aiming to stabilize the patient’s condition more quickly. Other options, such as thyroid hormone replacement, calcium supplements, and insulin, are not relevant to the immediate management of thyroid storm in conjunction with thionamides.