If you came to the clinic complaining of excessive irritability and anxiety, unreasonable weight gain or loss of fatigue, fatigue, and the doctor appoints you tests for antibodies to TSH receptors, then he wants to check the status of your thyroid gland. What is the relationship here? The fact is that TSH receptors “live” in the thyroid gland and are responsible for the synthesis of the most important hormones in it. Any violations of this process can cause the problems mentioned above, and many other troubles. So, first things first.
What is TTG
TSH stands for thyrotropin, or thyroid-stimulating hormone. It is produced by a small pituitary gland located near the brain. By acting on special receptors located on the surface of the thyroid gland, TSH hormones have a stimulating effect on the production of thyroxine (T4), which, in turn, affects the increase in thyroid iodine intake. In the future, TSH affect the synthesis of T4 and T3 (triiodothyronine). These two hormones are very important for the growth and development of human cells, for the proper functioning of the digestive tract, heart, blood vessels, reproductive and nervous systems. When an “Antibody to TSH Receptor Antibody” assay is scheduled, there is a suspicion of impaired hormone production, which can lead to serious diseases, such as:
- hyperthyroidism (Graves or Bazedov disease);
- hypothyroidism;
- thyrotoxicosis.
Antibodies and receptors
Receptors are such formations in which nerve endings, sensitive neurons, other particles of intercellular substance are intertwined, transforming the action of the stimulus into a nerve impulse. There are a lot of them in the body. In particular, TSH receptors respond to hormones of the same name and stimulate their production, which is necessary for the normal functioning of many human systems.
Antibodies are a specific type of protein (glycoproteins) that unusually selectively bind to specific types of molecules. This property is used by the human immune system. In case of failures, antibodies to TSH receptors begin to be produced in it. They come in several forms, differing in their functions.
- They block the activity of TSH and themselves begin to imitate their effect on the thyroid gland (stimulate its work). As a result, the levels of T3 and T4 increase, and hyperthyroidism develops.
- More strongly than TSH hormones bind to receptors. In this case, the levels of T3 and T4 increase over a long period, since thyroid cells are stimulated continuously.
- They do not block, but reduce the activity of TSH hormones, as a result, the thyroid gland becomes insensitive to them (atrophies). There is hypothyroidism.
When you need to be tested for antibodies to TSH receptors
Such tests are prescribed for the following indications:
- Symptoms of hyperthyroidism, which include irritability, hypersensitivity to heat, anxiety, causeless weight loss, heart problems, oligoamenorrhea.
- Symptoms of hypothyroidism: lack of appetite with an increase in body weight, apathy, drowsiness, fatigue, hypersensitivity to cold.
- Graves' disease (diagnosis, treatment monitoring).
- Pregnant or planning a pregnancy who have suspected Graves' disease or other deviations from TSH.
Sometimes the need for an analysis arises with viral infections, as certain groups of viruses can bind to receptors.
How to pass the analysis
It is known that the concentration of thyrotropin in the blood is not the same during the day. It has the highest rates at 3-4 a.m., the lowest - at about 5-7 a.m. As a rule, an analysis of antibodies to TSH receptors is given in the morning. Before this, you can not drink (the exception is water), eat, smoke. Since the last meal, at least 8 hours should pass, and the use of fatty foods is highly undesirable. If analyzes are carried out in order to determine the dynamics of changes in the number of antibodies, they must be taken every time at the same time. Blood is taken from a vein. The answer should be ready the next day.
Why carry out this analysis
The antibodies in the blood serum sought for TSH receptors have a characteristic feature - they appear if a person has diffuse toxic goiter (Graves disease). Their presence in the blood serum is a kind of marker proving the presence of the disease. In 85-100% of patients, stimulating antibodies are detected and approximately 96% have blocking antibodies. That is, most patients have two forms of antibodies, which requires adjustment of the prescribed treatment.
In addition to DTZ, a test for antibodies to TSH receptors is positive in 15% of patients with Hashimoto (Hashimoto) thyroiditis autoimmune.
The dynamics of changes in the number of antibodies is revealed when the patient is already receiving treatment. So, after taking antithyroid drugs, the concentration of antibodies drops, which may serve as a reason for the complete withdrawal of drugs.
However, in a number of cases, DTZ and Hashimoto's thyroiditis are combined with lupus erythematosus, rheumatoid arthritis and some other conditions. Therefore, with a positive analysis, it is desirable to conduct other tests to exclude concomitant diseases.
Antibodies in pregnant women
Not all pregnant women are prescribed tests for antibodies to TSH receptors. It must be completed if:
- a woman was treated with radioactive iodine;
- surgical treatment of DTZ was performed;
- there are signs of hyperthyroidism;
- takes thyreostatic drugs.
Antibodies to the TSH receptor are able to pass through the placenta to the fetus and cause hyperthyroidism in it. In addition to a blood test, patients with suspected DTZ undergo scintigraphy, which is contraindicated for pregnant women. For them, perhaps, the only way to protect the child from the disease is to do an analysis for antibodies to TSH receptors. The norm for different categories of people is not the same, but on average it is from 0 to 0.99 Me / l.
This should not be confused with TSH assays. Their rate during pregnancy can increase or decrease and reach a level of 0.2-3.5 Me / L. It is important to carry out tests for antibodies and hormones in the early stages of pregnancy, while the fetus does not function on its own.
results
After analyzing the antibodies, the level of protein of interest is determined:
- less than 1.5 Me / l - negative;
- from 1.5 to 1.75 Me / l - doubtful;
- more than 1.75 Me / l - positive.
If the result of the test for antibodies to TSH receptors is negative, this may mean the absence of problems with the thyroid gland, a successful treatment result or mistakes made by the laboratory assistant during blood collection. Unfortunately, a negative result is not always an indicator of a normal thyroid gland. In cases of doubt, the doctor may prescribe additional studies.
A positive result means that a person has DTZ or autoimmune thyroiditis.
Treatment
When the analysis revealed that antibodies to the TSH receptor are elevated, only the doctor prescribes treatment, since the reasons for the deviation can be different. If it is DTZ, the therapy is carried out with the “Merkazolil” or “Methylthiouracil” preparations. In recent years, excellent results have been achieved with radioiodine therapy. However, it is contraindicated for pregnant women. In this case, only Propylthiouracil is ascribed. Monitoring the concentration of antibodies is required.
In some cases, surgical treatment is prescribed.
If it is Hashimoto's thyroiditis autoimmune, the treatment is carried out with the following hormonal agents: “Thyroxine”, “Thyroidin”, “L-thyroxine” and others, as well as glucocorticoids. Quite good results are shown with white cinquefoil therapy.
In any case, self-medication without the supervision of a doctor is contraindicated.