drug therapy
	the use of radioactive iodine, and
	surgery.

Patients with mild to moderate disease can usually then have the dose of antithyroid drug gradually reduced to the smallest that will maintain the euthyroid state. The maintenance dose will need to be continued for at least a year and possibly two. In some cases, therapy may need to be lifelong.

Sometimes the initial higher dose is maintained and supplemental thyroxine given. Some authorities consider that this regime provides a greater chance of lasting remission when the antithyroid drug is finally withdrawn, but the issue is controversial. Either way, therapy needs to be continued for at least one year to 18 months.

If therapy is withdrawn, frequent follow-up is important to make sure that remission is maintained. Relapses following withdrawal of therapy are common and occur in 50 per cent of patients, usually within two years.

Methimazole (available in the US) needs usually to be taken once daily only. Improvement in symptoms is seen in one to three weeks and control of symptoms is achieved in one to two months. Carbimazole (available in the UK) is rapidly and completely metabolized to methimazole in the body and it is this that is responsible for the clinical antithyroid activity. The dosage and use of both drugs is similar.

Both drugs can cause a skin rash. This occurs in about two per cent of cases. A disorder of white blood cells occurs much more rarely, but if a severe sore throat or mouth ulcers develop, patients should consult their doctors immediately.

Although methimazole and carbimazole are the drugs of choice in the treatment of hyperthyroidism, propylthiouracil is often prescribed instead if a patient develops a rash or is contemplating pregnancy. (Methimazole and carbimazole, taken before and during pregnancy, have been associated with abnormal nail growth in the fetus.)

Patients with severe hyperthyroidism or recurrent, relapsing disease may require to be treated with radioactive iodine or surgery.

The thyroid cells are the only cells in the body that are able to absorb iodine. By giving radioactive iodine, cells in the thyroid are damaged or destroyed and are unable to produce further thyroid hormone. There is little risk of radiation exposure to the rest of the body. A single dose of radioactive iodine, taken by mouth, is usually sufficient to provide permanent treatment. An endocrinologist will carefully calculate the dose before administration based on the results of the thyroid function tests. The drug is eliminated from the body within a few days, although it may be several weeks before the effect of the treatment is seen. During this time it is necessary to continue taking antithyroid drugs.

It is difficult to predict exactly the dose of radioactive iodine a patient needs to achieve the euthyroid state and sometimes after treatment the thyroid gland produces too little hormone (becomes hypothyroid). In this case, supplemental thyroid hormone in the form of thyroxine needs to be taken. Lifelong follow-up of thyroid function is needed for patients who receive radioactive iodine.

	In patients with Graves' disease unable to achieve lasting remission from disease with antithyroid drugs.
	As the treatment of choice for patients with toxic nodular goiter. (The incidence of hypothyroidism is much less common than after treatment for Graves' disease.)
	In the treatment of toxic adenoma. This also rarely results in hypothyroidism, as the shriveled cells around the nodule in the gland take up little or no radioactive iodine.
	Increasingly it is being considered as first-line therapy for adults with hyperthyroidism.

Radioactive iodine must not be given to children, or to women during pregnancy or breast-feeding.

Surgery
Surgery is mainly used for the treatment of hyperthyroidism that results from over-production of hormones in a section of the gland (rather than a diffuse over-activity) and it is reserved for a minority of patients with thyrotoxicosis.

However, some medical centers prefer its use to radioactive iodine in the treatment of recurrent Graves' disease. It is otherwise generally indicated in Graves' disease for those patients who:

	have very large goiters
	cannot tolerate antithyroid medicine
	refuse radioactive iodine treatment
	have opthalmopathy (staring/bulging eyes), or
	are young women and contemplating pregnancy.

The operation usually requires only a short stay in hospital. There is a small risk of injury during the procedure to structures lying adjacent to the gland, in particular to the nerve supply to the voice box. As with radioactive iodine treatment, the method can result in hypothyroidism if too much gland is removed, although the risk is less. Thyroid surgery should be undertaken only by an experienced specialist surgeon.

In nodular toxic goiter and toxic adenoma, surgery is commonly employed as an alternative to radioactive iodine treatment. The affected area of the gland or an entire lobe may be removed.

Finally, any nodular enlargement of the thyroid needs to be investigated, preferably by fine-needle aspiration biopsy and ultrasonography, to exclude the possibility of a malignant (cancerous) growth.