Studies suggest a potential role for an intrathyroid dexamethasone injection to prevent relapse (410). Other medical therapies include iodide and lithium, both of which reduce thyroid hormone release and inhibit the organification of iodine. Iodide leads to the secondary coupling of T3 and T4. Iodide inhibition of thyroid metabolism is only transient, and complete escape from inhibition occurs within 1 to 2 weeks of iodide therapy, making this useful only for acute management of severe thyrotoxicosis (394). Lithium may be used when thionamide therapy is contraindicated or in combination with PTU or methimazole (394). To avoid toxicity during treatment, serum lithium levels should be monitored. Lithium has been associated with fetal Ebstein anomaly, and iodide has been associated with congenital goiter; these medications should not be used in pregnant women and should be used with caution in women of reproductive age. Because of the complications related to medical therapy of hyperthyroidism, women desiring pregnancy should be counseled to strongly consider surgical treatment or radioactive iodine treatment prior to pregnancy (402).
Surgery Thyroidectomy was used for the treatment of Graves disease but is now rarely used unless there is a suspicion for coexisting thyroid malignancy (368). Potential candidates for surgical intervention include pregnant women refusing or not tolerating antithyroid medical therapy, pediatric patients presenting with Graves disease, or patients who refuse radioactive iodine therapy. Surgery is the most rapid and consistent method of achieving a euthyroid state in Graves disease and avoids the possible long-term risks of radioactive iodine. Surgical intervention may be considered in severe Graves ophthalmopathy. Patients should be rendered euthyroid before a thyroidectomy. The risks of surgery include postoperative hypoparathyroidism, recurrent laryngeal nerve paralysis, routine anesthetic and surgical risks, hypothyroidism, and failure to relieve thyrotoxicosis.
β-Blockers Propranolol occasionally is used with or without concurrent antithyroid medications before radioactive iodine or surgery to provide relief of symptoms. Larger and more frequent doses may be required because of a relative resistance to β-adrenergic antagonists in the setting of hyperthyroidism.
Thyroid Storm Thyroid storm is an acute, life-threatening exacerbation of hyperthyroidism and should be treated as a medical emergency in an intensive care unit setting. Symptoms include tachycardia, tremor, diarrhea, vomiting, fever, dehydration, and altered mental status that may proceed to coma. Patients with poorly controlled hyperthyroidism are most susceptible. Beta-blocker agents, glucocorticoids, PTU (the action of which includes inhibition of T4-T3 conversion), and iodides are all key elements of therapy.
Because of the weak TSH-like activity of hCG, conditions with high levels of hCG, such as molar pregnancy, may be associated with biochemical and clinical hyperthyroidism. Symptoms regress with removal of the abnormal trophoblastic tissue and resolution of elevated levels of hCG. In a similar fashion, when hyperemesis gravidarum is associated with high levels of hCG, mild biochemical and clinical features of hyperthyroidism may be seen (411,412). Gestational trophoblastic disease is reviewed in Chapter 39.