American Board of Internal Medicine (ABIM) Certification Practice Exam

What is the role of thionamide drugs in treating Graves disease?

1. To increase thyroid hormone production

2. To reduce autoantibody titers

3. To induce remission through surgery

4. To enhance radioactive iodine uptake

The correct answer is: To reduce autoantibody titers

Thionamide drugs, such as methimazole and propylthiouracil, play a significant role in the management of Graves' disease by reducing the synthesis of thyroid hormones. They achieve this by inhibiting the enzyme thyroid peroxidase, which is crucial in the production of thyroxine (T4) and triiodothyronine (T3). This action leads to a decrease in the levels of circulating thyroid hormones, alleviating symptoms of hyperthyroidism associated with Graves' disease. While thionamides may indirectly influence the immune response by lowering thyroid hormone levels, their primary function does not involve directly reducing autoantibody titers, which are associated with the autoimmune aspect of Graves' disease. Instead, the reduction of hormone production can lead to a subsequent decline in the stimulation of the thyroid gland and potentially allow the immune system to recalibrate. However, the primary mechanism by which thionamides exert their effect is through the inhibition of hormone synthesis rather than directly influencing autoantibody levels. In summary, the use of thionamide drugs in treating Graves' disease is centered around their role in decreasing the synthesis of thyroid hormones, which helps manage hyperthyroid symptoms and can contribute to the long-term management strategies for