A 33-year-old woman comes to the physician because of palpitations, restlessness, sweating, weight loss, and a tremor for the past 3 weeks

A 33-year-old woman comes to the physician because of palpitations, restlessness, sweating, weight loss, and a tremor for the past 3 weeks. She does not drink coffee, tea, soda, or alcohol, and she does not smoke cigarettes. Her temperature is 37 C (98.6 F), blood pressure is 130/80 mm Hg, and pulse is 90/min. Examination shows a fine tremor, lid lag and stare, and pretibial myxedema. The thyroid gland is diffusely enlarged, asymmetric, and lobular. A bruit is present over the gland. Laboratory studies show an undetectable level of thyroid-stimulating hormone, an increased level of thyroid hormones, and an increased radioactive iodine uptake (RAIU). The diagnosis of Graves’ disease is made and the treatment options are discussed. The patient selects radioactive iodine therapy. This patient is at greatest risk for which of the following conditions?

A. Cholestasis
B. Granulocytopenia
C. Hypothyroidism
D. Recurrent laryngeal nerve damage
E. Thyroid carcinoma

Explanation: The correct answer is C. Hypothyroidism is the main complication of radioactive iodine therapy,
affecting up to 70% of patients in 10 years. Radioactive iodine therapy is a safe and effective treatment for Graves’ disease because it can provide the same ablative effects of surgery without the surgical complications. There is no evidence that this treatment increases the risk for carcinoma (choice E).

Cholestasis (choice A) and granulocytopenia (choice B) are side effects of long-term antithyroid therapy (propylthiouracil).

Recurrent laryngeal nerve damage (choice D) is a complication of subtotal thyroidectomy. Subtotal thyroidectomies provide rapid control of the disease but can lead to nerve damage, hemorrhage, hypothyroidism, and hypoparathyroidism.