Hyperthyroidism is a disorder of the thyroid gland in which it produces an excess of thyroid hormones. What are the causes? What are the symptoms associated with hyperthyroidism? Can hyperthyroidism be prevented? What treatments are available to treat this disease? Here are our explanations.
What is hyperthyroidism?
Hyperthyroidism refers to the abnormally high production of hormones by the thyroid gland, the butterfly-shaped organ located at the base of the neck, under Adam’s apple. It is not a swelling of the thyroid, as is sometimes believed.
The disease usually occurs in adults between the ages of 20 and 40. However, it can occur at any age, such as in children and the elderly. It is less common than hypothyroidism.
The influence of the thyroid gland on the body is major: its main role is to regulate the metabolism of the cells of our body. It, therefore, determines the speed of the “engine” of our cells and organs and the rate at which the “fuels” will be used:
- lipids or fats;
- carbohydrates or sugars.
In people with hyperthyroidism, the engine works in accelerated mode. As a result, they can:
- feeling nervous;
- have frequent bowel movements;
- lose weight;
At rest, the body consumes energy to maintain its vital functions:
- blood circulation;
- brain function;
- maintenance of body temperature;
This is called basal metabolism, which is partly controlled by thyroid hormones. The amount of energy expended varies from one individual to another, depending on:
- the activity of the thyroid gland.
What causes hyperthyroidism?
There are different disorders responsible for hyperthyroidism.
Graves’ disease or Graves’ disease
Graves’ disease is by far the most common cause of hyperthyroidism, occurring in about 90% of cases. It is an autoimmune disease: antibodies excessively stimulate the thyroid to produce more hormones. The disease also sometimes attacks other tissues, such as those in the eyes. This disease affects about 1% of the population in Canada7.
Thyroid nodules are small masses that form in the thyroid gland, either alone or in groups. Not all nodules produce hormones, but those that do are called “toxic” and can lead to hyperthyroidism.
Thyroiditis is an inflammation that affects the thyroid and can also cause excess thyroid hormones in the blood. Often, the cause of inflammation is not known. It can:
- be infectious in nature;
- occur after pregnancy.
Usually, thyroiditis causes short-term hyperthyroidism, with the thyroid returning to normal functioning after a few months, without intervention.
Medications can help relieve symptoms while waiting for the disease to pass. Thyroiditis progresses to permanent hypothyroidism in about 1 in 10 cases.
|Note: Some medications, such as those high in iodine, can cause temporary hyperthyroidism. This is the case, for example, of amiodarone, prescribed in some cases of cardiac arrhythmia, and iodinated contrast agents sometimes injected during a radiology examination.|
Hyperthyroidism: possible complications
Hyperthyroidism causes an acceleration of metabolism, therefore an increased expenditure of energy.
In the long term, untreated hyperthyroidism increases the risk of:
- to have osteoporosis, because the absorption of calcium by the bones is affected;
- develop a type of cardiac arrhythmia called atrial fibrillation
- Have a thyrotoxic crisis: During such an attack, all the signs of hyperthyroidism come together and are expressed at their peak, which can lead to serious complications, such as heart failure or coma. The person is confused and agitated. This situation requires emergency medical attention.
How to diagnose hyperthyroidism?
Symptoms of hyperthyroidism can be subtle, especially in older people. Only a blood test will confirm the diagnosis by showing both:
- low levels of the hormone TSH
- elevated levels of thyroid hormones T4 and T3.
The appearance of the symptoms listed below should prompt consulting a doctor in order to obtain a reliable diagnosis.
TSH and thyroid hormones T3 and T4
The two main hormones secreted by the thyroid are:
- T3 or triiodothyronine;
- T4 or tetra-iodothyronine or thyroxine.
Both include the term “iodo” because iodine is essential for their production. The amount of hormones produced depends on other glands, such as the hypothalamus which instructs the pituitary gland to produce the thyroid-stimulating hormone TSH. In turn, the hormone TSH stimulates the thyroid to produce its hormones.
Hypoactivity or overactivity of the thyroid gland can be detected by measuring the level of TSH in the blood.
High TSH level in hypothyroidism
In hypothyroidism, TSH levels are elevated because the pituitary gland reacts to the lack of thyroid hormones T4 and T3 by secreting more TSH. By this means, the pituitary gland tries to stimulate the thyroid to produce more hormones;
Low TSH levels in hyperthyroidism
In a situation of hyperthyroidism, when there is too much thyroid hormone, the opposite happens: the TSH level is low because the pituitary gland perceives excess thyroid hormone in the blood and stops stimulating the thyroid gland.
Even at the very beginning of a thyroid problem, TSH levels are often abnormal.
The symptoms of hyperthyroidism are numerous. If the hyperthyroidism is mild, it may go unnoticed. Moreover, in the elderly, the symptoms are often less pronounced.
Symptoms of hyperthyroidism include:
- a rapid heart rate that often exceeds 100 beats per minute at rest;
- heart palpitations
- excessive sweating
- hot flashes;
- fine tremors of the hands;
- difficulty falling asleep
- mood swings
- frequent bowel movements
- muscle weakness
- shortness of breath;
- weight loss despite normal or even increased appetite;
- a change in the menstrual cycle
- the appearance of a goiter at the base of the neck;
- abnormal protrusion of the eyes out of their sockets or exophthalmos
- irritated or dry eyes, in case of Graves’ disease;
- exceptionally, redness and swelling of the skin of the legs, in case of Graves’ disease.
Who is at risk for hyperthyroidism? Do we know the risk factors that promote the onset of this thyroid disease?
Hyperthyroidism: people at risk
People at risk for hyperthyroidism are:
- women who are more at risk than men: hyperthyroidism affects 8 women for 1 man;
- the frequency of Graves’ disease is higher in families previously diagnosed with a thyroid disorder.
What are the risk factors for hyperthyroidism?
Medicine does not recognize a specific risk factor for hyperthyroidism. In most cases, it is an autoimmune disease, called Graves’ disease, whose exact cause is not known.
Some experts believe that the systematic addition of iodine to table salt would contribute to a significant increase in the incidence of hyperthyroidism, but only for a minority of people already at risk1.
The addition of iodine to table salt is aimed at preventing iodine deficiency, which was the main cause of hypothyroidism in the early twentieth century.
Can hyperthyroidism be prevented? What are the effective measures that people suffering from this disease can put in place?
Hyperthyroidism: prevention measures
Can hyperthyroidism be prevented?
There is currently no way to prevent hyperthyroidism.
Measures to prevent complications
To prevent complications of hyperthyroidism, it is necessary to:
- get a good night’s sleep;
- If necessary, take naps in the early afternoon.
To prevent complications of hyperthyroidism, it is also important to:
- Make sure you have a good intake of calcium because hyperthyroidism contributes to depleting bones of minerals;
- eat smaller but more frequent meals;
- avoid consuming caffeine, which stimulates the body, even more, contained in the following beverages: coffee, tea, energy drinks, cola-type soft drinks, and chocolate that contain it in varying quantities;
- Do not take natural iodine supplements or multivitamins that contain it;
- Avoid very salty foods and seaweed, as they contain high doses of iodine, which can impair the synthesis of thyroid hormones. Seafood is not contraindicated for people with hyperthyroidism, even if it contains a little iodine.
If there has been weight loss, treating hyperthyroidism, without increasing food intake, is usually sufficient to regain the lost weight.
However, in rare cases, a diet a little richer in calories and protein is indicated, until the treatments take effect and the thyroid returns to its normal activity. Ask your doctor or nutritionist before changing your eating habits.
|Note: Some foods make iodine unusable by the thyroid, this is the case for all cabbage-related plants such as cauliflower, broccoli, turnip, rutabaga, mustard and rapeseed, soybeans, millet, peanuts, and pine nuts. This effect is due to the isothiocyanates they contain. This property may seem interesting for people with hyperthyroidism. However, the isothiocyanate content of these foods is too low to contribute to the treatment of hyperthyroidism.2. It would be necessary to eat in disproportionate quantities to obtain a therapeutic effect. In addition, cooking inactivates isothiocyanates.|
In times of hyperthyroidism, intense physical exercise for the heart should be avoided, as the body is already in a state of “hyperactivity”. For example, the following should be avoided:
- racquet sports;
- training on the fitness equipment.
Moderate-intensity walking and swimming are usually well tolerated.
Once the problem is treated, regular exercise is especially important, as it helps prevent or limit bone demineralization, say experts at the Mayo Clinic in the United States.
Prevention and relief of eye problems
Here are some tips to reduce eye irritation, which is common in people who have autoimmune hyperthyroidism such as Graves’ disease:
- do not smoke, as smoking also increases the risk of exophthalmos;
- avoid direct wind in the eyes;
- avoid bright light when wearing sunglasses, since the eyes are more sensitive to ultraviolet rays;
- use lubricating eye drops in the form of “tears” during the day, and “gel” at bedtime;
- apply cold compresses to the eyes to calm irritation;
- elevate the head at night with a cushion to reduce pressure in the eye area;
- Consult your doctor if symptoms remain bothersome.
It is important, as a priority, to recover euthyroidism, that is to say, the normal functioning of the thyroid as soon as possible in order to relieve the affected person and avoid complications. Treatment with antithyroid drugs or radioactive iodine can usually achieve this goal within a few months, depending on the severity of the hyperthyroidism.
If these treatments fail, surgical removal of the thyroid is sometimes considered.
Each of these solutions has advantages and disadvantages and the person concerned will have to inquire with his doctor in order to make the decision best suited to his case.
Hyperthyroidism: what treatment?
Antithyroid drugs, such as propylthiouracil or methimazole, prevent the production of new thyroid hormones, without causing permanent damage. They restore normal hormone levels after 2 to 4 months of treatment.
Often, the medication must be continued for half a year. Sometimes hyperthyroidism reappears.
Treatment with radioactive iodine
Radioactive iodine, at low levels, permanently destroys part of the thyroid cells, so that the thyroid gland produces fewer hormones. Radioactive iodine not absorbed by the thyroid gland will be eliminated by the body within a few days. Treatment allows a return to normal after about 3 to 6 months. In more than 90% of cases, a single dose of radioactive iodine is sufficient. Otherwise, a second dose is sometimes offered.
This treatment usually causes a permanent state of hypothyroidism. This is much easier to treat than hyperthyroidism. Synthetic thyroid hormones in tablet form, such as Eltroxin®, Levothyroid®, or Synthroid®, taken daily and for life, can correct hypothyroidism, without causing adverse effects.
Pregnant or breastfeeding women cannot receive such treatment, as radioactive iodine can interfere with the functioning of the thyroid gland of the fetus or newborn.
Pregnancy after radioactive iodine treatment
It is recommended that a woman who wants to get pregnant wait 6 to 12 months after radioactive iodine treatment before conceiving a child. Indeed, radioactive iodine can harm the development of the fetus.
In addition, it is preferable that the thyroid hormone levels of the future mother are well controlled before pregnancy. Thyroid hormone requirements usually increase as early as the first trimester of pregnancy, from weeks 1 to 13.
For pregnant women who take synthetic hormones, monitoring the level of TSH hormone in the blood every quarter, with a family doctor or endocrinologist, is necessary. After childbirth, the dosage is often revised downwards.
For his part, a man who receives radioactive iodine treatment should wait 3 months before conception.
Removal of the thyroid
Total or partial removal of the thyroid gland by surgery or thyroidectomy may be considered but is rarely used.
To relieve specific symptoms, other medications are sometimes used as needed:
- To relieve heart palpitations and reduce heart rate and tremors, beta-blocker drugs are sometimes prescribed, such as propranolol;
- the eye disorders that accompany Graves’ disease, when severe, may require treatment with corticosteroids to decrease inflammation behind the eye or surgery to reduce pressure on the eye. Smokers may respond less well to these treatments. Moreover, it is strongly recommended not to smoke in case of eye symptoms caused by Graves’ disease.
Hyperthyroidism requires follow-up and medical treatment. Some herbs traditionally used to treat hyperthyroidism can nevertheless be used as adjuvant therapy.2. However, they have not been the subject of clinical trials.
Hyperthyroidism: complementary approaches
Gremil or Lithospermun officinale, lycope or Lycopus ssp, lemon balm or Melissa officinalis
These 3 plants belonging to the Lamiaceae family have been used, traditionally, to help treat hyperthyroidism. However, their effectiveness has not been tested in clinical trials.
However, according to in Vitro and animal tests conducted during the 1980s, these plants could inhibit the stimulating effects of the hormone TSH on the thyroid.
- infuse 1 to 3 g of the aerial parts of the dried plant in 150 ml of boiling water;
- drink 3 cups daily of this hot infusion;
- Instead of infusion, one can take 2 to 6 ml of tincture (1:5) or 1 to 3 ml of a fluid extract (1:1), 3 times a day.
According to traditional Chinese medicine, symptoms of hyperthyroidism result from a Liver Fire, which may be accompanied by a deficiency in Qi or yin. The acupuncturist will therefore treat the liver.
Calming baths are recommended before going to bed, to help find a restful sleep2. A cold compress applied 15 minutes a day to goiter or eyes when suffering from exophthalmos will provide relief.
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