Thyroid hormones play a key role in the growth, development, and differentiation of many tissues. They regulate basal metabolic rate, with the thyroid gland having the strongest effect on BMR out of all the endocrine glands. Hypothyroidism can lead to a 30-40% reduction in basal metabolic rate, while hyperthyroidism can cause an increase of up to 80%. Thyroid hormones also affect the proper functioning of the nervous system and interact with the heart, liver, skeletal muscles, and white and brown adipose tissue.
Hyperthyroidism is the excessive secretion of thyroid hormones beyond what the human body requires. The disease develops over several months to several years. Hormonal tests usually show elevated levels of free fractions of thyroid hormones thyroxine (fT4) and triiodothyronine (fT3), as well as a decrease in thyroid-stimulating hormone (TSH).
There are three main types of hyperthyroidism:
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Subclinical
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Primary
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Secondary
Subclinical hyperthyroidism is the mildest form of hyperthyroidism, indicating the early stages of the disease. TSH levels are lower than the reference range, while free hormones are within range. Subclinical hyperthyroidism may not cause clear symptoms, especially in the early stages, so regular blood tests are crucial. If left undiagnosed, it can have serious consequences, particularly for children and the elderly, such as increased cardiovascular disorders (and even death), more frequent bone fractures, faster dehydration, and dementia.
Subclinical hyperthyroidism is associated with Graves-Basedow disease, the etiopathogenesis of which is not yet fully understood. The disease is characterized by its sudden onset and rapid development, often preceded by traumatic events, psychological or physical shocks, or viral infections that act as triggering factors. The occurrence of these factors leads to autotolerance breakdown and the production of a large amount of TSI immunoglobulins, which bind to TSH and then stimulate the thyroid gland to increase production of fT3 and fT4, as well as its growth.
Primary hyperthyroidism is the most common type of hyperthyroidism. TSH is below the normal range, while free hormones exceed the reference range or are in the upper range. The most common causes of hyperthyroidism among Poles are Graves-Basedow disease and thyroid nodules. Primary hyperthyroidism can also occur during pregnancy, due to strong stress, psychological trauma, menstruation and related disorders, and acute or chronic infections (which are related to hypothalamic activation).
Secondary hyperthyroidism is associated with pituitary or hypothalamic dysfunction and resistance to negative feedback. TSH levels are usually high or normal, while free hormone levels are elevated. The reason for this condition may be a TSH-producing adenoma or resistance to thyroid hormones.
In summary, thyroid disorders are one of the most common endocrinological problems. Both excessive and insufficient function of this gland can lead to serious health consequences. In the case of hyperthyroidism, the most common symptoms include:
- Weight loss
- Excessive activity
- Increased appetite
- Tremors in hands
- Anxiety and agitation
- Vascular disorders (feeling of heat, mild redness on the face and neck)
- Sleep disturbances
- Fatigue
- Heat intolerance
- Excessive sweating
- Increased number of bowel movements, tendency to diarrhea
- Bulging eyes
The most common treatment for hyperthyroidism is pharmacological treatment, which aims to lower the level of thyroid hormones in the blood. There are many other ways to treat hyperthyroidism, such as surgical treatment or radioactive iodine therapy. However, it is important to remember that there is no best therapy, as each method has its own advantages and disadvantages, and the decision on its choice is always made by the doctor, taking into account the causes of the disease, its severity, the patient's age, and any existing comorbidities.
Regardless of the chosen treatment, it is important to remember to supplement vitamin D. Research shows that in cases of hyperthyroidism, a decreased level of the natural metabolite of vitamin D3 - calcitriol, is observed.
