Deciding which treatment is best depends on what caused the hyperthyroidism, its severity, and other conditions present. It is important that you work closely with your endocrinologist to determine your best course of treatment. For a referral to one of Cedars-Sinai's expert team members, please call 310-248-6510. Please click here for more information on hyperthyroidism including symptoms and causes.
Treatment Options for Hyperthyroidism
In the United States, two drugs are available for treating hyperthyroidism: propylthiouracil (PTU) and methimazole (Tapazole). These medications control hyperthyroidism by slowing thyroid hormone production, and are frequently used for several months after the initial diagnosis of hyperthyroidism to normalize the thyroid hormone levels. Some patients with hyperthyroidism caused by Graves' disease experience a spontaneous or natural remission of hyperthyroidism after a 12 to 18 month course of treatment with these drugs, and may sometimes avoid permanent underactivity of the thyroid (hypothyroidism), which often occurs as a result of using the other methods of treating hyperthyroidism. Unfortunately, the remission is frequently only temporary, with the hyperthyroidism recurring after several months or years off medication and requiring additional treatment, so relatively few patients are treated solely with antithyroid medication in the United States.
Antithyroid drugs may cause an allergic reaction in about 15% of patients who use them. This usually occurs during the first six weeks of drug treatment. Such a reaction may include rash or hives, but after discontinuing use of the drug, the symptoms resolve within one to two weeks, and there is no permanent damage.
A more serious effect, but occurring in only about one in 250-500 patients during the first four to eight weeks of treatment, is a rapid decrease of white blood cells in the bloodstream. This could increase susceptibility to serious infection. Symptoms such as a sore throat, infection, or fever should be reported promptly to your physician, and a blood cell count should be done immediately. In nearly every case, when a person stops using the medication, the white blood cell count returns to normal.
Very rarely, antithyroid drugs may cause liver problems, which can be detected by monitoring blood tests or joint problems characterized by joint pain and/or swelling. Your physician should be contacted if there is yellowing of the skin ("jaundice"), fever, loss of appetite, or abdominal pain. Due to a rare complication of acute liver failure requiring liver transplant, PTU is no longer recommended as a first line treatment for Graves' hyperthyroidism. PTU's main use during the first trimester of pregnancy when methmezoli is contraindicated because of its potential for causing aplasia cutis congenita in the fetus.
Radioactive Iodine (RAI) Treatment
Iodine is an essential ingredient in the production of thyroid hormone. Each molecule of thyroid hormone contains either four (T4) or three (T3) molecules of iodine. Since most overactive thyroid glands are quite hungry for iodine, it was discovered in the 1940's that the thyroid could be "tricked" into destroying itself by simply feeding it radioactive iodine. The radioactive iodine, usually in capsule form, is given by mouth and is quickly absorbed from the bowel. It then enters the thyroid cells from the bloodstream and gradually destroys them. Maximal benefit is usually noted within three to six months.
While the goal of RAI treatment is to normalize thyroid hormone production, radioiodine eventually damages all thyroid cells making the patient hypothyroid. Many endocrinologists strive to completely destroy the diseased thyroid gland with a single dose of radioiodine. This results in the intentional development of an underactive thyroid state (hypothyroidism), which is easily, predictably and inexpensively corrected by lifelong daily use of oral thyroid hormone replacement therapy. Although every effort is made to calculate the correct dose of radioiodine for each patient, not every treatment will successfully correct the hyperthyroidism, particularly if the goiter is quite large and a second dose of radioactive iodine is occasionally needed.
Thousands of patients have received radioactive iodine ablation treatment. Since the RAI dose is relatively small, it is a safe, simple, and reliably effective treatment. It is considered by many thyroid specialists to be the treatment of choice for hyperthyroidism cases caused by overproduction of thyroid hormone.
Radioactive iodine treatment should never be given to a pregnant woman. Small amounts of radioactive iodine will also be excreted in breast milk. Since radioiodine could permanently damage the infant's thyroid, breast-feeding is not allowed. If radioiodine is inadvertently administered to a woman who is subsequently discovered to be pregnant, the advisability of terminating the pregnancy should be discussed with the patient's obstetrician and endocrinologist. Therefore, prior to administering diagnostic or therapeutic radioiodine treatment, pregnancy testing is mandatory whenever pregnancy is possible.
Are future pregnancies possible?
For cautionary purposes, males are advised to avoid fathering a child for several months. Females are advised to postpone pregnancy for six months after radioiodine treatment. Women are advised to wait longer to help stabilize their thyroid status before conception. Even though the amount of radioactivity remaining in the body may be small and there is no medical proof of an actual risk from radioiodine treatment, there is a theoretical risk to a developing fetus. Such precautions essentially eliminate direct fetal exposure to radioactivity, and markedly reduce the possibility of conception with sperm that might have been damaged by exposure to radioiodine. You may need to contact your physician for guidance about methods of contraception.
A woman who is breastfeeding should wait 3 months after stopping breastfeeding to be administered RAI since milk ducts readily take up RAI.
Regulations regarding the use of radioiodine therapy are made by the US Nuclear Regulatory Commission (NRC). Physicians and hospitals that administer this therapy must have a license to administer radioiodine, and must adhere to stringent regulations regarding its use. If you have any questions before or after receiving your treatment, please do not hesitate to contact your physician or your hospital radiation safety officer for clarification.
Is hospitalization necessary for treatment with radioiodine?
Treatment for hyperthyroidism is almost always done on an outpatient basis, because the dose required is relatively small in comparison with the doses typically used for treatment of thyroid cancer. If you have to take a larger dose of radioiodine for treatment of thyroid cancer, you may need to be admitted to the hospital for several days depending on the amount of radioiodine administered, your living environment, regulations in your state of residence, or local practice patterns.
If you require hospitalization, your hospital room will have frequently handled items (such as the television control, table, phone, faucet handles, etc), covered with protective material, and the floor will be partially covered. These precautions are designed to prevent the radioactive iodine from contaminating those items that will be reused by other patients after your dismissal from the hospital. To limit the contamination of your personal items, you should bring a minimal amount of belongings for your stay. All items will be monitored at your dismissal. Clothing should be limited to what you wear when you are admitted. You should use hospital gowns during your stay. You may want to bring disposable items, such as magazines or newspapers. Important, valuable or durable items like hardcover books, laptops, glasses and jewelry should be left at home. Check with your endocrinologist if you have any questions.
After treatment, should contact with other people be limited?
The amount of radioactive exposure to other persons during your daily activities will depend on the duration of contact and the distance you are from them. Therefore, the general principle is to avoid prolonged, close contact with other people for several days.
If your daily activities involve contact with small children or pregnant women, it is necessary to wait several days after your treatment to resume these activities. Those patients with infants at home should arrange for care to be provided by another person for the first several days after treatment. It will not be necessary for you personally to stay elsewhere after your treatment, although you will need to sleep alone for several days.
Recommendations for reduction of exposure to others for several days after treatment:
- Use private toilet facilities, if possible; flush twice after each use.
- Bathe daily and wash hands frequently.
- Drink normal amount of fluids.
- Use disposable eating utensils or wash your utensils separately from others.
- Sleep alone and avoid prolonged intimate contact.
- Launder your linens, towels, and clothes daily at home, separately from others. No special cleaning of the washing machine is required between loads. This is because the radioiodine administered is water soluble.
- Do not prepare food for others that requires prolonged handling with bare hands (such as mixing a meatloaf or kneading bread)
- Brief periods of close contact, such as handshaking and hugging, are permitted.
Surgical Removal of the Thyroid
Total thyroidectomy involves the removal of the entire thyroid gland and results in permanent hypothyroidism and the need for lifelong thyroxine replacement. Surgery tends to be a last resort when other treatments for hyperthyroidism, such as antithyroid medication or RAI cannot be used. For example, surgery may be recommended to pregnant women since radioactive iodine is not safe for the baby.
A drug from the class of beta-adrenergic blocking agents such as propranolol, atenolol and metoprolol (which decrease the effects of excess thyroid hormone) may be used temporarily to control hyperthyroid symptoms until other therapies take effect. In cases where hyperthyroidism is caused by thyroiditis or excessive ingestion of either iodine or thyroid hormone, this may be the only type of treatment required.