Hyperthyroidism can be treated in three ways - with medication, radioactive iodine therapy or surgery. The Department of Endocrinology at Singapore General Hospital explains further in detail.
How is hyperthyroidism treated?
Hyperthyroidism is treated in three main ways; with medication, radioactive iodine therapy (RAI) and surgery. "All three forms of treatment are able to decrease the thyroid gland's production of the thyroid hormone," says doctors from the
Department of Endocrinology at
Singapore General Hospital, a member of the
What types of medication are used to treat hyperthyroidism, and how do they work?
The two most common types of medication used are beta-blockers and anti-thyroid drugs. Beta-blockers (e.g. propranolol, atenolol) block the effect of the thyroid hormone on other parts of your body, so many of the symptoms caused by hyperthyroidism improve. However, they do not have an effect on the amount of thyroid hormone being produced and do not cure hyperthyroidism.
Anti-thyroid drugs act directly on the thyroid gland to decrease thyroid hormone production. The commonly used drugs include carbimazole, thiamazole and propylthiouracil ( PTU). When taken daily, these medications are very effective at controlling hyperthyroidism within a few weeks.
What side effects of medication should I look out for?
Beta-blockers should be avoided if you have asthma. Anti-thyroid drugs can have side effects such as rash, itching or joint pain but these are uncommon. Very rarely, patients taking these medications may develop a low white blood cell count, making them prone to serious infection. The main problem with anti-thyroid drugs is that hyperthyroidism often comes back after they are stopped. This is why many patients with hyperthyroidism are advised to consider more permanent treatment for their condition.
What is radioactive iodine treatment (RAI)?
RAI is the most widely recommended permanent treatment of hyperthyroidism. It is based on the fact that only thyroid cells take up iodine in our body. A small dose of radioactive iodine is given which is absorbed by the thyroid cells. The radioactivity destroys the thyroid cells slowly over time. This medication is naturally removed from your body after a few days, but it takes about 2-3 months to achieve its full effect. Most patients only require one dose of RAI, although occasionally more than one dose may be required to completely treat the hyperthyroidism. RAI is not suitable for pregnant women and very young children.
How is RAI given?
RAI is given as a few sips of colourless liquid with no smell or taste. It is taken by mouth with no need for hospitalization.
What are the side effects of RAI?
Since iodine is not taken up significantly by other cells, there are very few side effects on the rest of the body. The only common side effect of radioactive iodine treatment is underactivity of the thyroid gland, or hypothyroidism. This happens because too many thyroid cells are destroyed so that the remaining gland does not produce enough hormone. Hypothyroidism can be easily diagnosed and treated with thyroid hormone replacement. This fully replaces the deficiency, and when given in the correct dose, can be taken safely for the rest of the patient’s life without side effects or complications.
Sometimes, if you have Graves’ disease and your eyes are seriously affected by the disease, RAI may cause a worsening of your eyes. In these cases, your physician may give you a form of medication called steroids to take after the RAI to protect you from worsening eye disease. Some physicians may discuss alternative treatment and avoid RAI completely.
I’ve just taken RAI, is there anything special I should do over the next few days?
Although the amount of radioactivity used to treat hyperthyroidism is extremely small, most physicians will still advise you to avoid close contact with pregnant women or young children for a few days.This would mean maintaining at least a 1 m distance and not sharing food or utensils. Remember to maintain good general hygiene by washing your hands frequently, and flush after using the bathroom. All these precautions are only necessary for a few days since the radioactivity disappears very quickly.
My hormone levels are now controlled with anti-thyroid medication. Why is my doctor recommending RAI?
Although anti-thyroid medication is very effective at controlling your thyroid hormone levels, in more than 50 per cent of patients hyperthyroidism recurs once medication is stopped. If hyperthyroidism has already recurred before, then the chance of another recurrence may be more than 90 per cent. This is because TSH receptor antibodies (TRAb) tend to persist in your bloodstream, and continuously stimulate the thyroid gland to be hyperactive. Long term poorly controlled hyperthyroidism can cause serious damage to the heart and bones.
Most patients will become hypothyroid after RAI. However, this is easily and safely treated with thyroid hormone replacement. Once the appropriate dose of thyroid hormone is chosen, most patients with hypothyroidism feel completely normal, and only need to be seen once or twice a year. This is usually preferable to the frequent follow ups and side effects of uncontrolled hyperthyroidism.
When should I go for surgery?
Thyroid surgery involves removing most of the thyroid gland. This is an effective treatment for hyperthyroidism, and is particularly recommended if the goitre is very big and cosmetically unattractive to you. It is also used if there is a concern about cancer in the thyroid, and in certain women considering pregnancy who do not want to be on anti-thyroid medication. Your thyroid hormone levels need to be normalized with anti-thyroid drugs first before this operation can be done.
What are the side effects of surgery?
There is a risk of hypothyroidism if too much thyroid tissue is removed, while a small number of patients may remain hyperthyroid if insufficient tissue is removed. There will also be a scar on your neck, but this usually becomes pale and unnoticeable after a while. Rarely, the parathyroid glands, which lie very close to the thyroid and control calcium levels in the blood, may be damaged. In this case, long term treatment with calcium and vitamin D tablets may be necessary. Uncommonly, the nerves supplying the voice box may be damaged during surgery, resulting in a hoarse voice.
Radioactive iodine therapy: Do you know?
- Radioactive iodine therapy for hyperthyroidism has been used for more than 50 years.
- Former US president George Bush and his wife had radioactive iodine therapy for Graves’ disease.
- There is no evidence that it causes cancer of the thyroid gland or other parts of the body.
- It does not affect a woman’s chances of becoming pregnant or delivering a healthy baby in the future.