Hyperthyroidism: Overactivity of the Thyroid Gland
Part 4: Treatment Options for Hyperthyroidism
There are readily available and effective treatments for all common types of hyperthyroidism. Some of the symptoms of hyperthyroidism (such as tremor and palpitations, which are caused by excess thyroid hormone acting on the cardiac and nervous system) can be improved within a number of hours by medications called beta-blockers (eg, propranolol; Inderal).
These drugs block the effect of the thyroid hormone but don't have an effect on the thyroid itself, thus beta blockers do not cure the hyperthyroidism and do not decrease the amount of thyroid hormone being produced; they just prevent some of the symptoms. For patients with temporary forms of hyperthyroidism (thyroiditis or taking excess thyroid medications), beta blockers may be the only treatment required. Once the thyroiditis (inflammation of the thyroid gland) resolves and goes away, the patient can be taken off these drugs.
For patients with sustained forms of hyperthyroidism, such as Graves' disease or toxic nodular goiter, anti-thyroid medications are often used. The goal with this form of drug therapy is to prevent the thyroid from producing hormones.
Two common drugs in this category are methimazole and propylthiouracil (PTU), both of which actually interfere with the thyroid gland's ability to make its hormones. The illustration shows that some hormone is made, but the thyroid becomes much less efficient. When taken faithfully, these drugs are usually very effective in controlling hyperthyroidism within a few weeks.
Anti-thyroid drugs can have side effects such as rash, itching, or fever, but these are uncommon. Very rarely, patients treated with these medications can develop liver inflammation or a deficiency of white blood cells therefore, patients taking antithyroid drugs should be aware that they must stop their medication and call their doctor promptly if they develop yellowing of the skin, a high fever, or severe sore throat. The main shortcoming of antithyroid drugs is that the underlying hyperthyroidism often comes back after they are discontinued. For this reason, many patients with hyperthyroidism are advised to consider a treatment that permanently prevents the thyroid gland from producing too much thyroid hormone.
Radioactive Iodine Treatment
Radioactive iodine is the most widely-recommended permanent treatment of hyperthyroidism. This treatment takes advantage of the fact that thyroid cells are the only cells in the body which have the ability to absorb iodine. In fact, thyroid hormones are experts at doing just that.
By giving a radioactive form of iodine, the thyroid cells which absorb it will be damaged or killed. Because iodine is not absorbed by any other cells in the body, there is very little radiation exposure (or side effects) for the rest of the body. Radioiodine can be taken by mouth without the need to be hospitalized. This form of therapy often takes one to two months before the thyroid has been killed, but the radioactivity medicine is completely gone from the body within a few days. The majority of patients are cured with a single dose of radioactive iodine.
The only common side effect of radioactive iodine treatment is underactivity of the thyroid gland. The problem here is that the amount of radioactive iodine given kills too many of the thyroid cells so that the remaining thyroid does not produce enough hormone, a condition called hypothyroidism.There is no evidence that radioactive iodine treatment of hyperthyroidism causes cancer of the thyroid gland or other parts of the body, or that it interferes with a woman's chances of becoming pregnant and delivering a healthy baby in the future. It is also important to realize that there are different types of radioactive iodine (isotopes). The type used for thyroid scans (iodine scans) as shown in the picture below give up a much milder type of radioactivity which does not kill thyroid cells.
Surgical Removal of the Gland or Nodule
Another permanent cure for hyperthyroidism is to surgically remove all or part. Surgery is not used as frequently as the other treatments for this disease. The biggest reason for this is that the most common forms of hyperthyroidism are a result of overproduction from the entire gland (Graves' disease) and the methods described above work quite well in the vast majority of cases.
Although there are some Graves' disease patients who will need to have surgical removal of their thyroid (cannot tolerate medicines for one reason or another, or who refuse radioactive iodine), other causes of hyperthyroidism are better suited for surgical treatment earlier in the disease.
One such case is illustrated here where a patient has hyperthyroidism due to a hot nodule in the lower aspect of the right thyroid lobe. Depending on the location of the nodule, the surgeon can remove the lower portion of the lobe as illustrated on the left, or he/she may need to remove the entire lobe which contains the hot nodule as shown in the second picture. This should provide a long term cure.
Concerns about long hospitalizations following thyroid surgery have been all but alleviated over the past few years since many surgeons are now sending their patients home the morning following surgery (23 hour stay). This, of course, depends on the underlying health of the patient and their age, among other factors. Some are even treating partial thyroidectomy as an out-patient procedure where healthy patients can be sent home a few hours after the surgery. Although most surgeons require that the patient be put to sleep for operations on the thyroid gland, a some are even removing one side of the gland under local anesthesia with the aid of IV sedation. These smaller operations tend to be associated with fewer complaints.
A potential down side of the surgical approach is that there is a small risk of injury to structures near the thyroid gland in the neck including the nerve to the voice box (the recurrent laryngeal nerve). The incidence of this is about 1%. Like radioactive iodine treatment, surgery often results in hypothyroidism. This fact is obvious when the entire gland is removed, but it may occur following a lobectomy as well.
Whenever hypothyroidism occurs after treatment of an overactive thyroid gland, it can be easily diagnosed and effectively treated with levothyroxine. Levothyroxine fully replaces thyroid hormones deficiency and, when used in the correct dose , can be safely taken for the remainder of a patient's life without side effects or complications. Just one small pill per day.