USMLE (United States Medical Licensing Examination) Step 1 Practice Exam

What hormone is utilized in the treatment of subacute painless lymphocytic thyroiditis when it progresses to the hypothyroid stage?

1. Corticosteroids

2. Levothyroxine

3. Propranolol

4. Thionamides

The correct answer is: Levothyroxine

In the context of subacute painless lymphocytic thyroiditis, also known as silent thyroiditis, the condition often presents with an initial phase of hyperthyroidism followed by a hypothyroid stage as the thyroid gland becomes depleted of hormone reserves. When this condition progresses to the hypothyroid stage, hormone replacement therapy becomes necessary. This is where levothyroxine, a synthetic thyroid hormone, comes into play. Levothyroxine replaces the deficient thyroid hormone, thereby addressing the symptoms associated with hypothyroidism, such as fatigue, weight gain, and depression. This management is essential not only for symptom control but also for normalizing metabolism and supporting overall physiological functions. Corticosteroids, while they can be effective in reducing inflammation in certain thyroid conditions, are not used for managing hypothyroidism. Propranolol is a beta-blocker that may help alleviate symptoms in the hyperthyroid phase but does not address the underlying hormone deficiency when hypothyroidism develops. Thionamides, which inhibit thyroid hormone synthesis, are utilized primarily in hyperthyroid states, not in hypothyroidism. Thus, levothyroxine is the appropriate choice for treating the hypothyroid phase in patients with subacute painless lymphocytic thyroiditis.