Hyperthyroidism is a disease, in which the thyroid produces too much thyroid hormone (thyroxine). The thyroid is located at the front of the neck, below the Adam’s apple and releases this hormone into the blood. Thyroid hormone stimulates metabolism in the body. Due to an excess of thyroid hormone in the blood, metabolism is accelerated.
Hyperthyroidism can have various causes. Usually, this is the so-called Graves’ disease (or Basedow), an autoimmune disease, in which immune cells attack the thyroid.
Another cause of hyperthyroidism is Plummer’s disease, in which the thyroid is enlarging in the course of time and is producing too much thyroid hormone. An oversized thyroid is called a goiter (or goitre).
A benign nodule (toxic adenoma) also occurs once in a while as the cause of an overactive thyroid. Finally, an inflammation of the thyroid, using lithium and iodine-including medicines and other autoimmune diseases can cause the condition.
An excess of thyroid hormone can cause various signs and symptoms, including:
- A stressed or irritated feeling.
- Losing weight, while still eating well.
- Eye problems, such as eyes that appear larger than normal or difficulty closing the eyelids.
- The skin may feel warm and humid.
- A swollen thyroid.
- Menstrual changes.
Sometimes, the symptoms are not so clear and the disease is not easily recognized.
The diagnosis of hyperthyroidism is determined by blood tests. In the blood test, the content of thyroid-stimulating hormone (TSH) and thyroid hormone in the blood is measured. The amount of thyroid hormone will be increased and the amount of thyroid-stimulating hormone usually decreased. If a blood test demonstrates that there’s an overactive thyroid, additional tests will be done, such as scintigraphy, to determine the cause. Here, a low dose of radioactive iodine will be given, in order to find out how much of this is absorbed by the thyroid and where in the thyroid it’s located exactly.
There are three ways to treat hyperthyroidism, so that the amount of thyroid hormone in the blood will return to normal:
- Medications. There are medicines that inhibit the operation of the thyroid and slows down hormone production.
- Radioactive iodine. Treatment with radioactive iodine is safe and works quickly. The patient has to drink a liquid with radioactive iodine in the hospital, which passes through the intestines into the blood and via the blood into the thyroid. Due to the radiation of the iodine, the thyroid produces no thyroid hormone anymore. The patient pees out the radioactive substance afterwards. The thyroid will return to normal operation and the symptoms disappear. When the thyroid is swollen, it will shrink back by radioactive iodine.
- Surgery. In some cases, the patient will choose to partially or completely remove the thyroid. When the thyroid is enlarged, surgery has the advantage that it could reduce pressure of the thyroid on the trachea and the swelling in the neck disappears. Surgery also has disadvantages. There are chances that the thyroid will operate too slowly afterwards (hypothyroidism). Then the patient still has to take medications (artificial thyroid hormone) for life. There is also a small risk of permanent hoarseness, caused by damage to a nerve that runs through the thyroid.
With treatment, the prospects are good. Most symptoms disappear after successful treatment. In elderly people, long-term hyperthyroidism can lead to heart failure.
- People can do little to an overactive thyroid by theirselves. It requires medical treatment.
- In women with hyperthyroidism who want to get pregnant, it’s important to postpone pregnancy. Too much thyroid hormone in the blood indicates a risk of growth retardation and skull defects of the unborn child. Once the amount of thyroid hormone in the blood returns to normal, it is safe to get pregnant.
- Patients with hyperthyroidism who smoke have a higher risk of bulging of the eyes. An extra reason to quit.
- The term ‘hyperthyroidism’ is derived from the Greek prefix hupér- (over, beyond, excessive) and the Greek word thyreos/thureos (shield).
- The prevalence of hyperthyroidism is 0.2%.
- The condition is most common in women aged 25 to 50 years.
- Women are eight times more likely to develop a thyroid disease than men.