Content
Subclinical hyperthyroidism is a change in the thyroid in which the person does not show signs or symptoms of hyperthyroidism, but has changes in the tests that assess thyroid function, and the need for treatment should be investigated and verified.
Thus, as it does not lead to the appearance of symptoms, the identification of the alteration is only possible by checking the levels of TSH, T3 and T4 in the blood, which are hormones related to the thyroid. It is important that subclinical hyperthyroidism is identified, because even if there are no signs or symptoms, this situation can favor the development of cardiac and bone changes.
Main causes
Subclinical hyperthyroidism can be classified according to the cause into:
- Endogenous, which is related to the production and secretion of hormone by the gland, which is what happens when the person makes inappropriate use of thyroid drugs, such as Levothyroxine, for example;
- Exogenous, in which the changes are not directly linked to the thyroid gland, as in the case of goiter, thyroiditis, toxic adenoma and Graves' disease, which is an autoimmune disease in which the cells of the immune system attack the thyroid itself, leading to deregulation in hormone production.
Subclinical hyperthyroidism does not normally lead to the appearance of signs or symptoms, being identified only through blood tests that assess thyroid function. Thus, conducting tests is important so that the cause is identified and the need to initiate appropriate treatment is assessed.
Despite not leading to the appearance of signs and symptoms, subclinical hyperthyroidism can increase the risk of cardiovascular changes, osteoporosis and osteopenia, especially in menopausal women or people over 60 years of age. So it is important that it is diagnosed. See how to identify hyperthyroidism.
How the diagnosis is made
The diagnosis of subclinical hyperthyroidism is made mainly through tests that evaluate the thyroid, mainly the blood levels of TSH, T3 and T4 and of antithyroid antibodies, in which case the levels of T3 and T4 are normal and the level of TSH is below the reference value, which for people over 18 is between 0.3 and 4.0 μUI / mL, which may vary between laboratories. Learn more about the TSH test.
Thus, according to TSH values, subclinical hyperthyroidism can be classified into:
- Moderate, where blood TSH levels are between 0.1 and 0.3 μUI / mL;
- Severe, where blood TSH levels are below 0.1 μUI / mL.
In addition, it is important that other tests are performed to confirm the diagnosis of subclinical hyperthyroidism, identify the cause and assess the need for treatment. For this, ultrasound and thyroid scintigraphy are usually performed.
It is also important that people who have been diagnosed with subclinical hyperthyroidism are monitored regularly so that hormone levels can be assessed over time and, thus, it can be identified if there has been an evolution to hyperthyroidism, for example.
Treatment for subclinical hyperthyroidism
Treatment for subclinical hyperthyroidism is defined by the general practitioner or endocrinologist based on the assessment of the person's general health status, presence of symptoms or risk factors, such as age equal to or over 60 years, osteoporosis or menopause, in addition to being also taken taking into account the evolution of TSH, T3 and T4 levels in the last 3 months.
In some cases it is not necessary to start treatment, as they may only be transient changes, that is, that due to some situations experienced by the person, there were changes in the concentration of hormones circulating in the blood, but which then return to normal.
However, in other situations, it is possible that hormonal levels may not return to normal, on the contrary, TSH levels may become lower and T3 and T4 levels higher, characterizing hyperthyroidism, and it is necessary to initiate appropriate treatment. , which can be through the use of drugs that regulate the production of hormones, treatment with radioactive iodine or surgery. Understand how the treatment for hyperthyroidism is done.