What is it about ?
The thyroid is a small, butterfly-shaped gland that sits at the base of the neck, just below the Adam’s apple.
It produces thyroid hormones (T3 (triiodothyronine) and T4 (thyroxine)). These hormones play an important role at all stages of life. They allow
- normal growth and development,
- the regulation of many processes, including metabolism (they stimulate the metabolism),
- and that the pregnancy is proceeding normally.
When your thyroid is overactive, it makes too much thyroid hormone (hyperthyroidism). It boosts your metabolism.
The most common cause is Graves ‘or Graves’ disease. In this case, you are making antibodies against your own thyroid (anti-thyroid antibodies). This disease often causes severe symptoms and usually affects women between the ages of 30 and 40.
Another possible cause is the development of small balls (nodules) in the thyroid. These nodules can produce extra thyroid hormones (“hot nodule”). When there is only one nodule, it is called adenoma or isolated nodule. When there are several nodules or an overall swelling of the thyroid, it is called a “goiter”. Sometimes the goiter is so large that it extends all the way behind the breastbone (dipping goiter). The presence of nodules is not always synonymous with hyperthyroidism. The “cold nodules” in this case do not produce thyroid hormones and therefore do not cause hyperthyroidism.
Hyperthyroidism can be temporary, such as an inflammation of the thyroid (thyroiditis). But an overactive thyroid can also be a temporary reaction that precedes an underactive thyroid (hypothyroidism).
Finally, hyperthyroidism can be caused by drugs or contrast agents used for certain imaging tests, such as a CT scan.
What is its frequency?
Hyperthyroidism is less common than hypothyroidism. It is estimated that about 1 in 100 people have an overactive thyroid. Hyperthyroidism is more common in women (1.7%) than in men (0.5%).
How to recognize it?
In some cases, the disease begins with very marked symptoms; in other cases, only localized or generalized swelling is observed in the neck.
Common signs of hyperthyroidism are:
- General symptoms: hypersensitivity to heat, sweating, fatigue, muscle weakness, reduced general condition, hand tremors, weight loss (even with a good appetite), excessive thirst and
frequent need to urinate, menstrual cycle disturbances. - Skin symptoms: hot, damp skin.
- Gastrointestinal symptoms: diarrhea, increased bowel function, difficulty swallowing due to the pressure exerted by the thyroid on the esophagus.
- Cardiac symptoms: mainly arrhythmias and rapid heartbeat.
- Psychological symptoms: irritability, nervousness, insomnia.
- Eye symptoms, especially protruding eyes (only in Graves’ disease).
These symptoms do not necessarily appear all together. Older people, in particular, often have only one symptom, such as palpitations or weight loss.
How is the diagnosis made?
It is often difficult to make a diagnosis on the basis of symptoms alone, as many of these symptoms are also present in other diseases. And it’s even more difficult if you have few symptoms. In addition, a swelling of the thyroid is not always accompanied by an increase in hormone production. The doctor will therefore always take a blood test in addition to the clinical examination.
Three hormones can be measured in the blood: TSH, T4 and T3. TSH is the first hormone monitored when it comes to detecting thyroid disease. If (and only if) TSH is not normal, T4 and possibly T3 are measured. If the doctor suspects Graves’ disease, he will also order a test for thyroid antibodies.
In addition, an ultrasound and a scintigraphy (examination requiring the injection of a contrast product) can also be performed to measure the size of the thyroid and visualize one or more hyperactive (hot) nodules.
What can you do ?
When you are on treatment for hyperthyroidism, there is not much you can do other than take your medication and follow the instructions carefully.
However, it is important to remain vigilant for possible side effects of medication: a fever and sore throat may indicate abnormal destruction of white blood cells, which means that your immune system is no longer functioning properly.
If you are planning to have a child, it is important to discuss this with your doctor, as too little or too much thyroid hormone can harm the fetus. Also, if you are taking certain thyroid medications or radioactive iodine treatment, pregnancy is not recommended until at least 6 months after the end of treatment.
What can your doctor do?
Your GP will initiate medication for the treatment of hyperthyroidism and refer you to a hormone specialist (endocrinologist) for follow-up.
For drug treatment, the first choice is an antithyroid drug. This is a drug that slows down thyroid function. A medicine that slows the heart rate (beta blocker) may also be prescribed.
Your doctor will monitor your treatment closely with blood tests. He can thus monitor the effectiveness of the treatment and quickly detect any side effects. Once the thyroid hormones are normalized by the drugs, he can decide what to do next: whether to continue the current treatment, to treat with radioactive iodine or to have surgery. This choice depends on the size of the thyroid, the severity of the symptoms, the presence of pregnancy or breastfeeding, the age and the presence of other possible serious illnesses.
If treatment is continued, the doctor will give you an antithyroid drug for a longer period. The duration of this treatment is generally from 1 year to 1 year and a half. Drug treatment does not always slow down the thyroid permanently. The disease can recur when the drug is stopped, as is always the case with a goiter. Medicines must therefore be taken for life.
If you have Graves’ disease, you have a 1 in 2 chance of having the disease again. The risk of it having recurrence is also greater if you have a very large thyroid and high thyroid values that are difficult to normalize.
Treatment with radioactive iodine is a kind of local radiation therapy. The method is safe. Iodine is only absorbed from the thyroid and destroys thyroid tissue in a very localized manner. Treatment may alternate between taking medication and administering iodine until thyroid hormone levels decrease. One of the disadvantages of treatment is that the thyroid is often not functional enough afterwards and it is therefore necessary to take thyroid hormones for chronic treatment. The advantage of this treatment is that it can reduce the size of the thyroid when it is swollen. The method is therefore often used in the treatment of goiter.
If you have eye symptoms, treatment with radioactive iodine is usually not chosen, as it may make eye symptoms worse.
The choice is rather on surgery when the thyroid is very large and, for example, it puts pressure on the trachea. During this procedure, the thyroid can be removed in part or in whole. As with radioactive iodine treatment, you will then need to take thyroid hormones. As in any operation, there is a risk of complications: paralysis of the vocal cords if a nerve is affected during the operation or hypoparathyroidism if the parathyroid glands are affected. This happens between 2 and 4 times in 100. This is why thyroid surgery is preferably performed in a specialized center.
Want to know more?
- Ultrasound here Where to find on this page of Cliniques St Luc UCL
- The scintigraphy, here, Where to find on this page of Cliniques St Luc UCL
- Antithyroid drugs – CBIP – Belgian Center for Pharmacotherapeutic Information
- Surgical treatment of the thyroid (thyroid image) – Hôpital Erasme ULB
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