Hyperthyroidism. Current treatment guidelines.

Abstract

Hyperthyroidism is common and affects approximately 2% of women and 0.2% of men. The most common cause of hyperthyroidism is Graves' disease, an autoimmune disorder associated with circulating immunoglobulins that bind to and stimulate the thyrotropin (TSH) receptor, resulting in sustained thyroid overactivity. Toxic nodular goitres cause hyperthyroidism due to autonomous hyperfunctioning of localised areas of the thyroid. There are 3 recognised modalities of treatment for hyperthyroidism: antithyroid drugs, surgery and radioiodine. All are effective but no single method offers an absolute cure. Patients with Graves' disease may be prescribed antithyroid drugs over a period of 12 to 18 months with a view to inducing a long term remission. These drugs are also often given for a short period to render the patient euthyroid before definitive therapy with radioiodine or thyroidectomy. However, antithyroid drugs will not 'cure' hyperthyroidism associated with a toxic nodular goitre. The use of radioiodine as a first-line therapy for hyperthyroidism is growing. It is well tolerated, with the only long term sequelae being the risk of developing radioiodine-induced hypothyroidism. Radioiodine can be used in all age groups other than children, although it should also be avoided in pregnancy and during lactation. Pregnancy should be avoided for 4 months following its administration. Radioiodine may cause a deterioration in Graves' ophthalmopathy and corticosteroid cover may reduce the risk of this complication. The treatment of choice for toxic nodular goitre hyperthyroidism is radioiodine. Surgery, either subtotal or near-total thyroidectomy, has limited but specific roles to play in the treatment of hyperthyroidism: this approach is rarely used in patients with Graves' disease unless radioiodine has been refused or there is a large goitre causing symptoms of compression in the neck. The goal of surgery is to cure the underlying pathology while leaving residual thyroid tissue to maintain postoperative euthyroidism.