hyperthyroidism symptoms and treatments

The hyperthyroidism means an abnormally high output of hormones by the gland thyroid , the butterfly-shaped member located at the base of the neck under the Adam's apple (see diagram). It is not a swelling of the thyroid, as is sometimes believed.

The disease usually starts in adults between the ages of 20 and 40. However, it can occur at any age, and it is also seen in children and the elderly. It is less common than hypothyroidism.

The influence of the thyroid gland on the organism 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 “fuels” will be used: lipids (fat), proteins and carbohydrates (sugars). In people with hyperthyroidism , the motor runs faster. They may feel nervous, have frequent bowel movements, shake and lose weight, for example.

Basic metabolism

"At rest, the body consumes energy to keep its vital functions active: blood circulation, brain function, breathing, digestion, maintaining body temperature, etc. This is called the basal metabolism, which is partly controlled by thyroid hormones. The amount of energy expended varies from individual to individual, depending on the size, weight, age, gender, and activity of the thyroid gland".

Causes

The main causes

• Graves 'disease (or Graves' disease ). It is by far the most common cause of hyperthyroidism (around 90% of cases 7 ). This is an autoimmune disease  : antibodies over- stimulate the thyroid to produce more hormones. The disease also sometimes attacks other tissues, such as the eyes. This disease affects approximately 1% of the population in Canada 7 .
• Thyroid nodules . Nodules are small masses that form in the thyroid gland, alone or in groups (see our Thyroid Nodule sheet). Not all nodules produce hormones, but the ones that do (called “toxic”) can lead to hyperthyroidism.
• Thyroiditis . If inflammation affects the thyroid, it can also cause excess thyroid hormones in the blood. Often, the cause of the inflammation is not known. It can be infectious in nature or occur after pregnancy. Usually, thyroiditis causes short-lived hyperthyroidism, with the thyroid returning to normal function after a few months, without intervention. Medication can help relieve symptoms while you wait for the disease to pass. Thyroiditis progresses to permanent hypothyroidism in about 1 in 10 cases.

Remark. Some medications , such as those high in iodine , can cause temporary hyperthyroidism. This is the case, for example, with amiodarone, prescribed in certain cases of cardiac arrhythmia, and iodinated contrast agents sometimes injected during a radiology examination.

Possible complications

The hyperthyroidism causes an increased metabolism , thus increasing energy expenditure. In the long term, untreated hyperthyroidism increases the risk of developing osteoporosis because the absorption of calcium from the bones is affected. The risk of developing a type of heart arrhythmia called atrial fibrillation also increases.

Untreated major hyperthyroidism can lead to 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 urgent medical attention.

Diagnostic

The symptoms of hyperthyroidism may be subtle, especially in older people. Only a blood test (see box below) showing both a drop in TSH hormone levels and an increase in thyroid hormone levels (T4 and T3) will confirm the diagnosis. The onset of the symptoms listed below should prompt you to seek medical attention in order to obtain a sure diagnosis.

TSH, thyroid hormones T3 and T4 and Co

The 2 main hormones secreted by the thyroid are T3 (triiodothyronine) and T4 (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. It is the hypothalamus which controls the pituitary gland to produce the hormone TSH (for thyroid stimulating hormone ). In turn, the hormone TSH stimulates the thyroid to produce its hormones.

You can detect an underactive or overactive thyroid gland by measuring the level of TSH in the blood. In hypothyroidism , the TSH level is high because the pituitary gland responds to the lack of thyroid hormones (T4 and T3) by secreting more TSH. In this way, the pituitary gland tries to stimulate the thyroid to produce more hormones. In a situation of hyperthyroidism (when there is too much thyroid hormone), the reverse happens: the TSH level is low because the pituitary gland perceives the excess thyroid hormones in the blood and stops stimulating. the thyroid gland. Even at the very beginning of a thyroid problem, TSH levels are often abnormal.

Symptoms of hyperthyroidism

Here are the main symptoms of hyperthyroidism . If the hyperthyroidism is mild, it may go unnoticed. In addition, in the elderly, the symptoms are often less pronounced.

• A rapid heart rate (which often exceeds 100 beats per minute at rest) and heart palpitations ;
• Excessive sweating, and sometimes hot flashes;
• Fine hand tremors;
• Difficulty falling asleep;
• Mood swings;
• Nervousness;
• Frequent bowel movements;
• Muscle weakness;
• Shortness of breath;
• Weight loss despite a 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 (exophthalmos) and irritated or dry eyes, in Graves' disease;
• Exceptionally, redness and swelling of the skin of the legs, in Graves' disease.

People at risk and risk factors for hyperthyroidism

People at risk

• The women are more at risk: Hyperthyroidism affects 8 women to 1 man;
• The frequency of Graves' disease is higher in families who have previously been diagnosed with a thyroid disorder.

Risk factors

Medicine does not recognize a specific risk factor for hyperthyroidism. In most cases, it is an autoimmune disease (Graves' disease), the exact cause of which is not known.

Some experts believe that the systematic addition of iodine to table salt would significantly increase the incidence of hyperthyroidism, but only for a minority of people already at risk 1 . The addition of iodine to table salt is to prevent iodine deficiency, which was the main cause of hypothyroidism in the early XX th  century.

Prevention of hyperthyroidism

Can we prevent?

There is currently no way to prevent hyperthyroidism.

Measures to prevent complications

•  Adequate rest

Get a good nights sleep. If necessary, take naps in the early afternoon.

• Food

- Make sure you have a good intake of calcium , because hyperthyroidism contributes to depleting the bones of minerals. See which foods are the best sources of calcium: Calcium - Nutrient chart .

- Eat smaller, but more frequent meals .

- Avoid consuming caffeine , which would stimulate the body even more: coffee, tea, energy drinks, cola-type soft drinks and chocolate contain it in varying amounts. Consult our Caffeine file to find out more.

- Do not take any natural iodine supplement or multivitamin that contains it.

- Also avoid very salty foods and seaweed, as they contain high doses of iodine, which can interfere with the synthesis of thyroid hormones. The seafood is not against-indicated for people with hyperthyroidism, even if they contain some iodine.

- If there has been weight loss , treatment of the 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, while the treatments take effect and the thyroid returns to its normal activity. Check with your doctor or a nutritionist before changing your eating habits.

Remark. Certain foods make iodine unusable by the thyroid: this is the case with all plants related to cabbage (cauliflower, broccoli, turnip, rutabaga, mustard and rapeseed), soybeans (soybeans) , millet, peanuts and pine nuts. This effect is attributable 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 inordinate amounts to obtain a therapeutic effect. In addition, cooking inactivates isothiocyanates.

• Physical exercise

- In times of hyperthyroidism, intense physical exercise for the heart (for example, running, racket sports, cardio-cycling, and training on fitness equipment) should be avoided because the body is already in a state of "hyperactivity". Walking and swimming (moderate intensity) are usually well tolerated.

- Once the problem is treated, regular exercise is especially important because it helps prevent or limit bone demineralization , say experts at the Mayo Clinic in the United States.

•  Prevention and relief of eye problems

- Some tips for reducing eye irritation, common in people with autoimmune hyperthyroidism (Graves' disease):

- do not smoke , because smoking also increases the risk of exophthalmos ;

- avoid direct wind in the eyes;

- avoid bright light by 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 on the eyes, to calm the irritation;

- elevate the head during the night with a cushion in order to reduce the pressure in the eye region;

- consult your doctor if the symptoms remain bothersome.

Medical treatments for hyperthyroidism

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 usually achieves 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 should check with their doctor in order to make the decision best suited to their case.

•  Antithyroid drugs

These drugs (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 1 ½ years. Sometimes hyperthyroidism reoccurs.

• Radioactive iodine treatment

The radioactive iodine (at low levels) is used to permanently destroy a part of thyroid cells, so that the thyroid gland produces less hormones. Radioactive iodine not absorbed by the thyroid gland will be eliminated by the body within a few days. The treatment allows a return to normal after about 3 to 6 months. In over 90% of cases, a single dose of radioactive iodine is sufficient (otherwise, a second dose is sometimes offered).

This treatment often causes a permanent state of hypothyroidism. Hypothyroidism is much easier to treat than hyperthyroidism. Synthetic thyroid hormones in the form of tablets taken daily and for life can correct hypothyroidism (Eltroxin®, Levothyroid® or Synthroid®), without causing undesirable effects.

The pregnant women or nursing mothers can not receive such treatment because radioactive iodine can impair the function of the thyroid gland of the fetus or newborn.

Pregnancy after radioactive iodine treatment

"It is recommended that a woman who wishes to become pregnant wait 6 to 12 months after treatment with radioactive iodine before conceiving a child. Indeed, radioactive iodine can harm the development of the fetus.

In addition, it is best if the mother-to-be's thyroid hormone levels are well controlled before pregnancy. The need for thyroid hormones generally increases from the first trimester of pregnancy (weeks 1 to 13). For pregnant women taking synthetic hormones, monitoring the TSH hormone level in the blood quarterly with a family doctor or endocrinologist is necessary. After childbirth, the dosage is often lowered.

For his part, a man who receives radioactive iodine treatment should wait 3 months before conception".

• Thyroid removal

Total or partial removal of the thyroid gland by surgery (thyroidectomy) may be considered, but is rarely done.

• Specific treatments

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 (eg, propranolol).

The eye disorders that accompany Graves' disease, when severe, may require treatment with corticosteroids (to reduce inflammation behind the eye) or surgery (to reduce pressure in the eye). Smokers may respond less well to these treatments 3 . Moreover, it is strongly recommended not to smoke in the event of eye symptoms caused by Graves' disease.

Opinion of a doctor

"Hyperthyroidism is a very troublesome disease because its symptoms greatly affect the quality of life. In addition, it can have serious consequences on health, especially on the heart and bones. This is why the person who has it is usually referred to an endocrinologist, the specialist in the thyroid gland.

If you have it, you should know that hyperthyroidism is usually treated fairly well. The key to success is to follow your doctor's recommendations to the letter. This means, for example, going for your blood tests at the required time, even though these can be frequent, taking your medications as prescribed and going to your follow-up appointments. This way, you will get the maximum benefit from medical care. It is also very important not to smoke".

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