American Board of Internal Medicine (ABIM) Certification Practice Exam

What is one potential adverse effect of radioiodine therapy in patients with Graves ophthalmopathy?

1. Hypothyroidism

2. Acute elevation of thyroid autoantibody titers

3. Increased blood pressure

4. Decreased insulin sensitivity

The correct answer is: Acute elevation of thyroid autoantibody titers

Radioiodine therapy is a common treatment for hyperthyroidism, particularly in conditions like Graves' disease. While this therapy is effective in reducing thyroid hormone levels, it can also lead to a range of adverse effects, especially in patients who have Graves ophthalmopathy, an autoimmune condition linked to hyperthyroidism that affects the eyes. One notable potential adverse effect of radioiodine therapy in these patients is the acute elevation of thyroid autoantibody titers. This increase occurs because the therapy can trigger changes in the immune system, leading to a temporary rise in the autoantibodies that are involved in the autoimmune response associated with Graves' disease. An elevation in these antibody levels can exacerbate the ophthalmopathy, potentially worsening the symptoms or leading to increased ocular inflammation and edema. In contrast, while hypothyroidism can indeed occur as a long-term consequence of radioiodine therapy, particularly in patients with pre-existing thyroid abnormalities, it is not an immediate effect and is less critical in the context of managing Graves ophthalmopathy acutely. Increased blood pressure and decreased insulin sensitivity are not directly related to the impacts of radioiodine therapy in the context of thyroid treatment and its effects on ocular conditions. Thus, the acute elevation of thyroid autoantibody titers is