The causes of the appearance of varieties of hypothyroidism
In hypothyroidism, there is a disruption in the process and a decrease in the production of thyroid hormones, which are responsible for the growth, development, metabolism and many other processes in the body. Clinically hypothyroidism manifests itself as a violation of the functions of almost all organs and systems - cardiovascular, nervous, digestive, excretory and others.
For a disease of hypothyroidism, the consequences can be unpredictable and very dangerous. So, for example, in severe cases, myxedema occurs in adults, and in children, there are signs of mental underdevelopment or cretinism. Moreover, without timely treatment, the patients always have signs of heart failure. Therefore, for disease prevention measures, it is important to know what causes the disease can cause.
Why does hypothyroidism occur?
The main cause of the disease is that the thyroid gland is unable to produce the necessary hormones( T3 and T4).And the condition can be primary, when the sign of the lack of hormones becomes the gland itself, as well as secondary, when the failure occurs in the hypothalamic-pituitary system. At the same time, the thyroid gland, being in a single endocrine system with these organs, responds with a decreased production of hormones in response to hormonal failure.
In addition, with the disease of hypothyroidism, symptoms may appear even during the formation of the fetus in the womb, and in this case they speak of the congenital form of the disease, when the child is already born with signs of the disease. If the disease develops during life for several years, then talk about the acquired form of the disease.
Consider separately each type of disease and possible types of appearance of one form or another of the disease.
Causes of the congenital form of
In the diagnosis of congenital hypothyroidism, the causes of the onset can occur both in the period of the formation of the organs and systems of the child( at the time of 8-12 weeks of pregnancy) and throughout the entire pregnancy, after the formation of the systems.
The main causes of congenital hypothyroidism:
- Thyroid dysfunction.
- Disturbance of hypothalamic and pituitary structures.
- The presence of antibodies in the mother with various autoimmune diseases.
- Taking medication during pregnancy( thyreostatics).
- Viral, fungal and bacterial processes during pregnancy.
- Congenital deficiency of enzymes that participate in the synthesis of thyroid hormones.
- Birth of a child before the due date and immaturity of the thyroid gland.
During the formation of the nervous system of the child, the deficiency of thyroid hormones is the main cause of mental underdevelopment of the fetus, which is not determined at birth, but reveals much later when the child begins to interact with surrounding people.
Reasons for acquired hypothyroidism
In contrast to the causes of congenital hypothyroidism, 99% of all cases occur during the life of the patient due to various problems, including:
- Damage to thyroid cells by lymphocytes of the immune system when autoimmune hypothyroidism occurs. The disease due to this cause does not occur instantaneously, but develops over several years, acquiring the status of chronic hypothyroidism.
- Partial resection or complete removal of the thyroid gland. In these cases, talk about the so-called iatrogenic hypothyroidism.
- Atrophy of the gland tissue due to radioactive irradiation with ionization, X-rays or radioactive iodine.
- Hypothyroidism may occur as a result of prolonged use of thyreostatics in the treatment of diffuse goiter with the phenomena of intoxication of the body( diffuse toxic goiter).
- Prolonged and uncontrolled administration of drugs that can disrupt the synthesis of thyroid hormones( lithium carbonate, amiodarone, propylthiouracil).
- Iodine deficiency in foods and drinking water. This cause most often has its negative impact on children and pregnant women. Restoring the balance of iodine in the body quickly removes all the symptoms of the disease. Prolonged deficiency of iodine causes hypothyroidism in children with signs of mental underdevelopment.
Causes of primary type
For the disease, primary hypothyroidism causes the following:
- Inflammatory processes( viral, fungal, bacterial) of the thyroid parenchyma.
- Aplasia( underdevelopment) or hypoplasia of the gland tissue
- A heredity factor that affects the synthesis of hormones.
- Partial or complete removal of the gland. Iodine deficiency in food and drinking water.
Sometimes the problem of the onset of the disease remains unclear, then they talk about idiopathic hypothyroidism.
Causes of secondary hypothyroidism
In the secondary process, the causes of the illness lie in a disruption of the connection between the organs of the endocrine system:
- Benign or malignant tumors of the pituitary or hypothalamus.
- Surgery on the brain in tumors, when the result of surgical intervention affected the tissue of the hypothalamus or pituitary gland.
- Long-term radioactive effects on the body.
- Brain Injuries( including hemorrhagic stroke).
In case of subclinical hypothyroidism, the causes of the appearance are the same, but the clinical picture differs when the symptoms are not expressed, and the blood determines the deficiency of thyroid hormones.
How is the diagnosis of the disease carried out?
For differential diagnosis, the following examination methods are performed:
- ultrasound and thyroid scintigraphy.
- Puncture followed by a biopsy of the thyroid gland.
- If there is a suspicion of an autoimmune process, the determination of antibodies in the blood.
Computed tomography and MRI of the hypothalamus, pituitary gland and thyroid gland.