Syndrome of congenital thyroid insufficiency. Symptoms and treatment of congenital hypothyroidism. Symptoms of hypothyroidism in babies

Congenital hypothyroidism is a chronic pathology characterized by impaired thyroid function in a newborn along with insufficient production of thyroid-stimulating hormones (TSH) by this organ, or a complete cessation of their production. According to medical statistics, hypothyroidism occurs on average in 1-2 babies out of five thousand, but recently there has been a tendency to increase cases of the disease.

The thyroid gland plays an important role in the harmonious development of the baby. This organ is involved in the formation of the nervous system, intelligence and bones of the child's skeleton, and is also responsible for regulating body temperature and normalizing metabolic processes in the body.

• dryness and peeling of the skin;
• brittle hair;
• persistent constipation;
• poor appetite;
• low body temperature;
• late closure of the fontanel.

In children with congenital hypothyroidism at the age of 4 months, in addition to developmental delay and other signs characteristic of this pathology, delayed teething is noted.

Timely provision of therapeutic assistance to the baby in most cases allows you to successfully compensate for the lack of hormones, providing the child with full development in the future.

Without timely treatment, hypothyroidism entails the development of cretinism. This disease is characterized by such manifestations as puffiness of the face, deformities of the bones of the skull and limbs, short stature, a weak level of intellectual development, and a predisposition to chronic diseases.

Diagnosis of congenital hypothyroidism is carried out in the maternity hospital for each newborn. For these purposes, use:

• neonatal screening.

Allows you to detect an increased level of TSH in an infant by analyzing a sample of his blood taken from the heel on the 3-4th day of life.

• Apgar scale.

It is a test that allows you to assess the condition of the baby by five indicators: pulse, respiration, muscle tone, reflex excitability and skin color. Congenital hypothyroidism may be suspected if the test score is greater than 5.

Early detection of pathology is essential for successful therapy. Congenital hypothyroidism in a baby should begin to be treated no later than one month of age.

Treatment of the congenital form of hypothyroidism in children is carried out through replacement therapy with thyroid drugs used in doses corresponding to the individual characteristics of the body of each infant. Therapeutic measures are aimed at replenishing the missing thyroid hormones and normalizing metabolic processes.

One of the most effective drugs for hormone replacement therapy is synthetic thyroxine (levothyroxine sodium), which is most identical to the natural hormone. The drug is stored in the patient's blood, and is consumed as needed by conversion to T3.

Properly organized treatment allows you to achieve hormonal balance in the body and maintain an optimal level of hormones in the future.

For preventive purposes, pregnant women are prescribed iodine preparations (the lack of this element in the body of a future mother is one of the most common causes of developmental delays in babies).

To prevent congenital hypothyroidism in a future baby, his parents are also recommended to visit a geneticist, especially if any of the parents or relatives had thyroid pathologies.

congenital hypothyroidism- a condition in which, for various reasons, from birth, the thyroid gland cannot perform its functions.

It is noteworthy that with timely detection and proper treatment, instead of a severely disabled child, a completely healthy person grows up from a child with congenital hypothyroidism.

Thyroid functions

• Regulation of the rate of metabolic processes in the body.
• Regulation of growth and development processes.
• Participation in providing the body with energy.
• Acceleration of the processes of oxidation of nutrients.
• Strengthening of heat exchange processes.
• Activation of the activity of some endocrine glands (for example, sex glands, adrenal glands).
• Stimulation of the activity of the nervous system.

With violations at any of the stages of the synthesis of thyroid hormones, it ceases to perform these functions, and hypothyroidism develops.

Causes of Congenital Hypothyroidism

The reasons leading to congenital hypothyroidism are very diverse, but in general they come down either to hereditary pathology, or to spontaneous genetic mutations, or to the effect on the mother of factors that cause impaired development of the child in the prenatal period.

These factors include:

• toxic damage (exposure to alcohol, nicotine, pesticides, etc.);
• taking certain medications by the mother;
• infections;
• exposure to radiation,
• living in a region unfavorable for iodine content.

Can maternal hypothyroidism cause congenital hypothyroidism in a child?

First of all, it must be remembered that hypothyroidism is not a specific disease, but a condition that is caused by completely different reasons.

In older children, adolescents, and adults, most commonly girls and women, the main cause of hypothyroidism is autoimmune thyroiditis. This is a disease caused by an autoimmune inflammation of the thyroid gland. It destroys the structure of her cells, and they cannot perform their functions of producing hormones. By itself, autoimmune thyroiditis is not transmitted to a newborn child, but uncompensated increases the likelihood of developing congenital hypothyroidism in an infant.

In iodine-deficient regions, women often have a condition called latent hypothyroidism, caused by a constant lack of iodine in the diet. This affects the condition of the child in the same way - it slightly increases the likelihood of developing hypothyroidism in the child, but does not directly lead to it.

There are single hereditary diseases and mutations that can be passed from parent to child through genes. It occurs extremely rarely, usually in parents with mild hypothyroidism.

In the vast majority of cases (85-90%), the appearance of hypothyroidism in a newborn child is unpredictable and is due to random, newly emerging mutations.

Hypothyroidism in children: symptoms

The appearance of a detailed picture of hypothyroidism indicates that the disease was not diagnosed in time. Provided that this condition is detected early and treatment is started immediately (the optimal time is up to 3 weeks of life), no symptoms will develop, the child will not differ from his peers, will grow and develop normally.

Previously, when the disease was not studied, and there were no opportunities for early diagnosis, the classic picture of congenital hypothyroidism, appearing at about 2-3 years of age, included the following manifestations:

• Severe mental retardation.
• Delayed physical development.
• Violation of the proportions of the skeleton.
• Features of appearance: wide sunken bridge of the nose, large tongue, constantly open mouth.
• An increase in the size and disruption of the heart, changes in the ECG, bradycardia (decreased heart rate).
• Signs of heart failure.
• Difficulties in breathing.
• Rough, low voice.

Congenital hypothyroidism: symptoms in newborns

Only 10-20% of children with congenital hypothyroidism have any of its manifestations at the time of birth:

• (birth after 41 weeks).
• Large birth weight (3500 grams or more).
• Puffiness, puffiness primarily of the face, lips and eyelids.
• Edema of the hands, stop.
• Large tongue, half-open mouth.
• Rough voice, hoarseness when crying.
• Protracted.

Symptoms of congenital hypothyroidism in infants

The rest of the newborns, despite the latent development of the disease, look perfectly healthy until the gradual appearance of the following symptoms:

• Loss of appetite, low weight gain.
• Constipation, flatulence (flatulence).
• Dryness and peeling of the skin.
• Hypotension (decreased muscle tone).
• Difficulty breathing.
• Delay in the timing of teething, closing.
• Approximately from the fifth or sixth month of life, a lag in physical and mental development can be noted.

There are children who have a congenital dysfunction of the thyroid gland, not complete, but partial. Then a certain amount of hormones needed by the body is still produced, and mental retardation and other symptoms will not be expressed.

Diagnosis of hypothyroidism

The main method for diagnosing hypothyroidism is the analysis of the level of thyroid hormones in the blood. It is almost impossible to detect the first symptoms of congenital hypothyroidism in a newborn child, and timely diagnosis of the disease is very important, therefore, not so long ago in Russia, as earlier in other countries, a special screening in the hospital. All newborns take a small amount of blood and determine the content of TSH (thyroid-stimulating hormone). With increased and borderline numbers, the child is carefully examined in order to start treatment in a timely manner if a disease is detected.

In Russia, TSH is determined during screening, and TSH and T4 hormones are used for the final diagnosis.

In 70-90% of cases, in a child, during examination, in addition to changes in the concentration of hormones in the blood, one can detect either the absence of the thyroid gland, or a pronounced decrease in its size, which can be combined with an incorrect location. The size and location of the thyroid gland, or its absence, can be determined using ultrasound.

Treatment of hypothyroidism

As already mentioned, with timely diagnosis and early treatment (up to 3 weeks of life), the disease is completely amenable to correction. If for any reason the diagnosis is not made in time, the brain is damaged irreversibly! At that moment, when visible symptoms of hypothyroidism appear, the work of the brain is no longer subject to restoration, the child will be deeply disabled.

Children who are treated in the first months of life grow and develop normally.

The drug for treatment and its dosage is chosen by the doctor under the constant control of blood tests.

An important feature is the strict rules for taking the drug, with which the doctor must introduce parents.

Congenital hypothyroidism is a clinical syndrome that manifests itself in the neonatal period and is associated with a deficiency of thyroid hormones or insensitivity of body tissues to them. According to statistics, it is considered one of the most common among all congenital diseases of the endocrine glands. The average frequency of its occurrence is 1:3500-4000. Moreover, in girls this pathology is detected more often than in boys.

The reasons

In most cases, congenital hypothyroidism is primary and is caused by damage to the thyroid rudiment during fetal development (at 4-9 weeks) due to exposure, treatment of the expectant mother with radioactive iodine or thyreostatic drugs. However, cases of secondary and even tertiary congenital hypothyroidism associated with pathology of the hypothalamic-pituitary system are possible.

The main causes of congenital forms of hypothyroidism are:

• malformations of the thyroid gland (complete absence of an organ or its underdevelopment, a combination of the latter with a dystopic location, when the glandular tissue is detected in the root of the tongue, trachea);
• hereditary dis- or agenesis of the gland;
• genetic defects in synthesis (impaired capture and metabolism of iodine), secretion and metabolism of thyroid hormones;
• insensitivity of tissue receptors to thyroid hormones;
• hereditary resistance to thyroid-stimulating hormone;
• in a woman's body during pregnancy;
• malformations of the nervous system in the fetus;
• damage to the pituitary gland as a result of trauma during childbirth;
• aplasia of the pituitary gland;
• congenital deficiency of thyroid-stimulating hormone or thyreoliberin, etc.

In some cases, hypothyroidism in a newborn can be transient if the pregnant woman has thyroid diseases of an autoimmune nature and the transfer of thyroid-blocking antibodies through the placenta. Sometimes transient dysfunction of the gland is observed in premature or low birth weight newborns as a result of intrauterine growth retardation.

Fundamentals of pathogenesis

All pathological changes in the body that occur during hypothyroidism are due to a lack of thyroid hormones. Since the latter perform many important functions and participate in all types of metabolism, this significantly affects the development of the child. First of all, the functioning of the nervous system is disrupted:

• the total number of neurons decreases;
• the amount of biologically active substances (neurotransmitters, peptides) in the nervous tissue decreases, which leads to a pronounced depression of the central nervous system;
• the differentiation of brain tissue cells suffers;
• the process of myelination of nerve fibers slows down.

It should be noted that after reaching 4-6 weeks of age, these changes become almost irreversible.

With hypothyroidism, there is a decrease in protein synthesis and a violation of energy processes, resulting in:

• the growth and differentiation of the bones of the skeleton slows down;
• muscle performance decreases;
• hematopoiesis is inhibited;
• immunity is weakened;
• enzymatic activity decreases (in the gastrointestinal tract, liver, kidneys).

In addition, in the body of patients, lipolysis slows down and the exchange of mucopolysaccharides is disturbed. A special substance, mucin, accumulates in the tissues, as a result of which they become edematous. That is why such children, despite poor appetite, never look emaciated.

Clinical manifestations

The clinical picture of congenital hypothyroidism is characterized by a variety of symptoms. However, their severity varies from a latent course to manifest forms with pronounced symptoms. It is not so easy to identify this pathology immediately after birth, because its manifestations increase by 3-6 months. But this question is fundamental, since the prognosis depends on the timeliness of the diagnosis and the start of treatment. It is possible to suspect the presence of hypothyroidism in a newborn by a combination of signs:

• large body weight at birth;
• late passage of meconium;
• protracted (up to 10 days);
• dry skin;
• low physical activity;
• muscle hypotension;
• sluggish sucking and poor appetite;
• respiratory disorders (noisy breathing, difficulty breathing through the nose, periods);
• gastrointestinal problems (bloating and its increase in size,);
• decrease in body temperature;
• early (poorly treatable).

Each of these symptoms individually is not pathognomonic, but their combination should alert the doctor and parents.

As the child develops, the clinical picture of hypothyroidism becomes more pronounced. The child lags behind peers both in physical and neuropsychic development. Him:

• lethargy, adynamia increases;
• growth slows down;
• body proportions are violated (relative shortening of the limbs and fingers, thick neck, narrow palpebral fissures, wide bridge of the nose);
• teeth erupt late
• edema appears (on the trunk, face, feet);
• eyelids, lips, nostrils, tongue thicken (does not fit in the mouth);
• voice becomes low;
• the fontanel does not close for a long time;
• there is a pathology of the cardiovascular system (the boundaries of cardiac dullness expand, heart sounds become deaf, blood pressure decreases, systolic murmur can be heard);
• often comes to light.

In this case, the thyroid gland may not be determined (with underdevelopment) or increase in size (with pathology of hormone synthesis).

The manifestation of mild variants of congenital hypothyroidism can occur by 2-5 years of age and even during puberty. Usually, this can reveal growth retardation, sexual development, decreased intelligence and symptoms.

Diagnostics

Early diagnosis of hypothyroidism is very important. In order not to miss this pathology in a newborn, it is customary to use screening methods. To do this, on the 3rd-4th day of life, capillary blood is taken from the child to study the level of thyroid hormones and thyroid-stimulating hormone (TSH) of the pituitary gland. Upon receipt of positive (or doubtful) results of the analysis, it is repeated, but at the same time, venous blood is taken for the study.

In areas where screening is not available, newborns with at least two of the symptoms listed above should be screened.

In general, diagnosis is based on a detailed analysis of clinical data and the results of additional research methods. The list of required examinations includes:

• and TSH;
• (reveals anemia, lipid metabolism disorders);
• ultrasound examination of the gland;
• radiography of the wrist joints (detects a lag behind the age norm of the rate of ossification processes).

It should be noted that changes on the radiograph and obvious metabolic disorders appear after 3-4 months of age.

Differential diagnosis in congenital hypothyroidism is carried out with the following pathological conditions:

• birth injury;
• jaundice and anemia of various origins;
• chondrodysplasia;
• and etc.

Treatment

The mainstay of treatment for congenital hypothyroidism is lifelong replacement therapy. It starts from the moment the diagnosis is established, regardless of the possibility of laboratory confirmation. For this, L-thyroxine is used in a starting dose of 10-15 mcg per day. Gradually increase the dose of the drug, assessing the dynamics of clinical symptoms and hormone levels in the blood plasma.

The purpose of such treatment is to normalize the content of thyroid hormones in the blood and prevent damage to the central nervous system. The effectiveness of such treatment is evidenced by the active behavior of the child and the physiological dynamics of growth.

Additionally, such children may be assigned:

• vitamins;
• neurotrophic drugs (Cerebrolysin, Piracetam);
• massage;
• physical therapy classes.

Forecast and possible consequences

With early diagnosis and timely treatment (in the first month of life), the prognosis for the life and health of the child is favorable. Adequate replacement therapy can achieve good results. The child retains normal intelligence, and he does not lag behind his peers in physical development.

Congenital hypothyroidism is a disease caused by a deficiency of hormones produced by the thyroid gland. The lack of these substances is fraught with a delay in the development of the child, both mental and physical. If treatment is started on time, the prognosis is quite favorable. The lack of professional therapy leads to the progression of the disease, when the child is given even a disability.

The reasons

The thyroid gland is responsible for the production of thyroxine (T4) and triiodothyronine (T3). These hormones contribute to the harmonious development of the child's body. Hypothyroidism develops as a result of a deficiency of one or another substance, leading to developmental delay, both physical and mental.

The disease occurs for many reasons. Congenital hypothyroidism in children is closely related to genetics. Often, genetic mutations negatively affect the formation of the thyroid gland even at the time when the unborn baby is in the mother's womb.

Damage to the hypothalamus also leads to the development of the disease. He is responsible for the work of the endocrine glands in the human body, including the functioning of the thyroid gland. Due to damage to the hypothalamus, various diseases of the endocrine system develop.

Another reason for the development of the disease may be a decrease in the body's sensitivity to thyroid hormones. Most often this happens due to the intake of antithyroid drugs by a pregnant woman. The doctor can prescribe them to the expectant mother if she is diagnosed with a goiter.

If the cells of the thyroid gland lose their sensitivity to iodine, then the thyroid hormones in the body are not produced as expected. The formation of these hormones can be disrupted due to improper iodine metabolism or due to the fact that the necessary substances are not delivered to the thyroid gland in the right amount. All this is the cause of hypothyroidism.

Symptoms

Not all newly born babies show symptoms of hypothyroidism. Only after some time, mom and dad notice some violations in a newborn child. Their suspicions are confirmed by the pediatrician.

But it happens that already in the first month of a baby’s life, obvious symptoms of hypothyroidism are observed:

• newborn weight from 4 kg;
• non-closing mouth;
• swelling all over the face and in the dimples located above the collarbones;
• low voice;
• baby jaundice, difficult to cure with conventional therapeutic methods;
• blueness in the area of ​​the nose and lips.

In babies who have reached 3 months, the signs of congenital hypothyroidism are somewhat different:

• peeling is clearly visible on the skin;
• the baby suffers from constant constipation;
• the child does not eat well (decreased appetite);
• hair painfully brittle;
• hypothermia (low temperature).

In the future, hypothyroidism manifests itself with other symptoms. In a sick child much later than their peers, teeth begin to cut, signs of hypotension appear, weakness in the muscles is observed, the work of the heart muscle is disturbed, the child complains that it is difficult for him to swallow, he is tormented by constant chills.

If sick babies are not treated, they become lethargic and indifferent. They are not interested in games, they do not contact with others. Patients with hypothyroidism often suffer from viral infections and anemia. The latter is difficult to treat with drugs.

Symptoms of hypothyroidism in adolescents are manifested by hearing problems. Sick guys suffer from obesity and short stature. They have no desire to learn. Often their psyche is disturbed.

Pathogenesis

Thyroid hormones are essential for normal fetal development. If for some reason they are not produced by the thyroid gland, then they enter the body of the unborn baby through the placenta from the mother's body. But as soon as the child is born, the level of maternal hormones drops sharply, and the gland does not produce its own. This is dangerous, since hormones are essential for the physical development of a child at such an early age.

The formation of the myelin sheath of nerve fibers responsible for the development of the cerebral cortex depends on the hormones produced by the thyroid gland. If there is a lack of T3 and T4, then the underdevelopment of the cortex occurs. This process is irreversible, leading to mental retardation of the child, and the degree of the disease may be different. Even complete cretinism is possible.

The best time to start replacement therapy is the first week of a baby's life, so every baby in the hospital is tested for hypothyroidism.

For the proper development of the nervous system, it is important to start all therapeutic measures on time. After diagnosis, the baby is assigned an individual course of therapy.

Not only the central nervous system suffers from hypothyroidism. Deficiency of hormones produced by the thyroid gland adversely affects the growth of the skeleton and other organs.

Diagnostics

It is impossible to diagnose hypothyroidism only by the symptoms that appear in children, therefore, in every maternity hospital, there is a rule in accordance with which early screening is mandatory, on the 4th day from the date of birth of the baby. This requires blood sampling from the heel of a small patient.

In the laboratory, the level of thyrotropin, triiodothyronine and thyroxine is determined. If the indicator exceeds 100 mU / l, then primary hypothyroidism is diagnosed. If the result of the analysis shows 20-50 mU / l, then the study is repeated, but only a dry blood spot is already analyzed. If the indicator again exceeds 20 mU / l, then the level of TSH in the blood serum is determined. The disease code according to ICD 10 is E03.

To diagnose hypothyroidism, the Apgar scale has also been developed. It is a test based on the summation of scores for each question about the presence of a particular trait. This table looks like this:

If the total score exceeds 5, then hypothyroidism can be suspected.

Treatment of congenital hypothyroidism

Immediately after the diagnosis of hypothyroidism in infants, treatment begins, which is based on taking hormones, since the thyroid gland will never produce them. This means that medications will have to be taken throughout life.

Only the attending physician selects a regimen for taking medications. Self-treatment is unacceptable. Often, the doctor prescribes levothyroxine to patients with congenital hypothyroidism. The chemical composition of this drug is similar to the hormones that the thyroid gland should produce in children, which is why endocrinologists choose this drug for replacement therapy in small patients.

Hypothyroidism negatively affects the mental activity of the child, therefore, the doctor includes drugs that improve the metabolic processes of the brain in the complex of therapeutic measures.

Since the thyroid gland is responsible for many processes in the body, for example, for the exchange of calcium and other substances, the doctor may prescribe drugs that help improve these processes. Antianemic and laxatives are also prescribed. But the latter may not be needed if hormone therapy is chosen correctly.

Psychologists and defectologists constantly monitor a sick child. They use various methods that can correct the violations of the cognitive activity of the baby. Here, such a method as game therapy is indispensable.

If a child needs treatment in a clinic, then a nurse comes to the aid of the doctor. A whole complex for the care of patients with hypothyroidism, called the nursing process, has been developed. It includes several stages, from collecting an anamnesis to following all the doctor's instructions.

Complications of hypothyroidism

The most common consequence of hypothyroidism is mental retardation, sometimes reaching an extreme degree -. The consequences of the disease are also manifested in physical disabilities, for example, often a child grows much more slowly than his peers, and when he reaches the age of puberty, he lags behind in these indicators. The child also suffers from frequent infectious diseases that last for a long time, turning into a chronic stage. There is also a problem with the stool: it is either unnecessarily difficult or impossible without taking special preparations.

If a pregnant woman suffers from hyperthyroidism, then this can affect the health of the baby. Often these patients have various diseases of the internal organs and even heart defects. It is not uncommon for babies to be born with various problems associated with the thyroid gland.

There is another complication - hypothyroid coma. Fortunately, it is rare and only occurs in older people who do not receive regular treatment and suffer from comorbidities.

Hypothyroidism often leads to infertility in both women and men. The disease weakens the immune system, which leads to frequent infectious processes in the body, cancer.

Prevention

A pregnant woman should make sure that the baby avoids hypothyroidism. To do this, you should lead the right lifestyle while expecting a baby. Bad habits should be completely excluded: they have a detrimental effect on the formation of the thyroid gland of an unborn child.

Hypothyroidism in pregnant women and children

HYPOTHYROISIS - Causes, Symptoms and FOLK TREATMENTS

There are various genetic variants of the causes of the disease.

So, if a pregnant woman suffers from hypothyroidism, then the child is most often born with this disease. But the expectant mother must undergo hormone therapy as prescribed by the doctor, which will help the baby to be born healthy.

Congenital hypothyroidism (CH) is a disease of the thyroid gland that occurs with a frequency of 1 case per 4000-5000 newborns. In girls, the disease is detected 2-2.5 times more often than in boys.

The disease is based on a complete or partial deficiency of thyroid hormones produced by the thyroid gland, which leads to a delay in the development of all organs and systems. First of all, the central nervous system suffers from a lack of thyroid hormones. A direct relationship has been established between the age at which treatment was started and the index of the child's intellectual development in the future. Favorable (adequate) mental development can be expected only if replacement therapy was started in the first month of a child's life.

It is possible to make a diagnosis in a timely manner and, therefore, start treatment on time only if an early (in the first days of life) examination of all newborns is carried out.

Mass examination (screening) for congenital hypothyroidism was first carried out in Canada in 1971. Today, this is a common method of examination in most developed countries. In Russia, a similar screening has been carried out over the past 12 years.

The basic principles of neonatal screening for VH are as follows. All variants of congenital hypothyroidism are accompanied by low levels of thyroid hormones (T 4 , T 3 ), increased levels of thyroid-stimulating hormone (TSH) is characteristic of primary hypothyroidism. But since it is the most common variant of the disease (up to 90% of all cases), in most countries screening is based on the determination of TSH. In the USA and Canada, screening is based on the determination of T 4 . It would be optimal to determine both parameters, but this significantly increases the cost of the survey.

The main goal of screening for congenital hypothyroidism is the early detection of all newborns with elevated TSH levels in the blood. All newborns with abnormally high TSH require an urgent in-depth examination for the final diagnosis of the disease and the immediate start of replacement therapy (optimally - in the first 3 weeks of life).

All newborns on the 4-5th day of life (in premature babies on the 7-14th day of life) take blood (usually from the heel) and 6-8 drops are applied to a special porous filter paper. The obtained and dried blood samples are sent to a specialized laboratory where TSH is determined.

The concentration of TSH depends on the method of determination. The threshold level of TSH is subject to fluctuations and is set separately for each laboratory, depending on the chosen method of determination. Most laboratories work with diagnostic kits "Delphia", for which the threshold level is TSH - 20 mU / l. Thus, all TSH samples up to 20 mU / l are a variant of the norm. All specimens with TSH concentrations above 20 mU/L should be retested, TSH levels above 50 mU/L suggest hypothyroidism, and TSH levels above 100 mU/L are highly suggestive of disease. Therefore, it is necessary to urgently clarify the diagnosis in all newborns with a TSH level above 20 mU / l, this is possible with repeated blood sampling and determination of the levels of TSH and St. T4 in blood serum.

After taking blood, children with a TSH level above 50 mU / l are immediately (without waiting for the results) levothyroxine replacement therapy (euthyrox, L-thyroxine, thyro-4, L-thyroc, L-thyroxine-Acri, L-thyroxine-Farmak) . Treatment can be canceled after receiving normal results of St. T4 and TSH.

The issue of prescribing treatment for children with TSH levels of 20-50 mU / l is decided after re-donating blood and obtaining indicators of TSH and St. T 4 .

Children who were not immediately treated need to be re-examined to determine the levels of TSH, T 4 (in a week, then in a month), and if the TSH level increases, thyroid replacement therapy should be prescribed with further careful monitoring of the child.

Etiology of congenital hypothyroidism

Congenital hypothyroidism is a rather heterogeneous group of diseases in terms of etiology, caused by morphofunctional immaturity of the hypothalamic-pituitary system, thyroid gland or their anatomical damage in the prenatal period.

In recent years, in connection with the development of methods of molecular genetic analysis, views on the etiology of congenital hypothyroidism have largely changed. In the vast majority of cases (85-90%), primary congenital hypothyroidism occurs. Approximately 85% of cases of primary hypothyroidism are sporadic, 15% are hereditary. Most sporadic cases are due to thyroid dysgenesis, with cases of ectopic thyroid being more common than complete absence (agenesis) or hypoplasia of the thyroid gland. According to various authors, thyroid agenesis occurs in 22-42% of cases, thyroid tissue is ectopic in 35-42%, and thyroid hypoplasia occurs in 24-36%.

Probably, both genetic and environmental factors can be the cause of thyroid dysgenesis, but its molecular basis is still poorly understood. To date, 3 transcription factors involved in the initiation and differentiation of the thyroid gland have been identified: PAX-8 (paired domain homeobox), TTF-1, and TTF-2 (thyroid transcription factors 1 and 2). An experiment on mice showed the role of TTF-1 in the presence of thyroid agenesis, severe malformations of the lungs and anterior brain regions. The TTF-1 gene is located in the 14q13 region.

TTF-2 is essential for normal thyroid morphogenesis. The participation of TTF-2 in the migration of the thyroid gland and the overgrowth of the hard palate has been experimentally proven. In addition, TTF-2 regulates the expression of thyroglobulin and thyroid peroxidase in the thyroid gland, as does PAX-8.

Most familial cases of CH are congenital “errors” that impair T4 synthesis or its binding to target organs, this variant of the disease most often manifests itself as congenital goiter. To date, the following congenital disorders of hormonogenesis in the thyroid gland are known: decreased sensitivity to thyroid-stimulating hormone; lack of ability to concentrate iodide; violation of the organization of iodine (due to defects in peroxidase or the system that generates H2O2); violation of deiodinase of iodotyrosines; violation of the synthesis or transport of thyroglobulin.

Mutations in the genes for thyroid peroxidase and thyroglobulin have been described. The absence of thyroid peroxidase activity leads to a decrease in the uptake of iodide by thyrocytes, disruption of the processes of iodide organization, which, in turn, leads to a decrease in the synthesis of thyroid hormones. Newborns with TPO enzymatic defects have very high TSH levels and very low T4 levels at birth and develop a goiter later on.

Much less often (5-10% of cases), secondary congenital hypothyroidism occurs, manifested by an isolated deficiency of TSH synthesis or hypopituitarism. In some cases, secondary hypothyroidism is caused by a defect in the Pit-1 gene, a pituitary-specific transcription factor-1, mutations in which cause a combined deficiency of growth hormone, prolactin, and thyroid-stimulating hormone. The role of a defect in the Prop-1 gene, a transcription factor that causes a deficiency of not only TSH, STH and prolactin, but also gonadotropins, is being studied.

Congenital isolated TSH deficiency is a very rare autosomal recessive disorder caused by mutations in the TSH gene. Here is the most common classification of the causes of congenital hypothyroidism today.

Primary

• Thyroid dysgenesis: agenesis (athyreosis); hypogenesis (hypoplasia); dystopia.
• Disorders of hormonogenesis in the thyroid gland: deficiency (defect) of TSH receptors; iodide transport defect; peroxidase system defect; defect in the synthesis or transport of thyroglobulin; violation of the deiodinase of iodotyrosines.

Secondary

• Panhypopituitarism.
• Isolated deficiency of TSH synthesis.

Resistance to thyroid hormones. Transient hypothyroidism

• Drug-induced hypothyroidism (maternal use of antithyroid drugs).
• Hypothyroidism induced by maternal antibodies blocking TSH receptors.
• Exposure to iodine in the pre- or postnatal period.

Diagnosis of congenital hypothyroidism

Prior to the era of screening for congenital hypothyroidism, the widespread introduction into clinical practice of radioimmunological methods for determining hormones in blood serum, the diagnosis of CH was made on the basis of clinical and anamnestic data, which explained the rather late start of replacement therapy.

A typical clinical picture of congenital hypothyroidism in newborns, children of the first month of life, when it is extremely important to make a diagnosis, is observed in only 10-15% of cases. The most typical signs of the disease in the early postnatal period are: post-term pregnancy (more than 40 weeks); large body weight at birth (more than 3500 g); swollen face, lips, eyelids, half-open mouth with a wide, "flattened" tongue; localized edema in the form of dense "pads" in the supraclavicular fossae, back surfaces of the hands, feet; signs of immaturity in full-term pregnancy; low, rough voice when crying, screaming; late passage of meconium; late discharge of the umbilical cord, poor epithelialization of the umbilical wound; prolonged jaundice.

Later, at the 3-4th month of life, if treatment is not started, other clinical symptoms of the disease appear: reduced appetite, difficulty in swallowing, poor weight gain; flatulence, constipation; dryness, pallor, peeling of the skin; hypothermia (cold hands, feet); brittle, dry, dull hair; muscle hypotension.

In later periods, after the 5-6th month of life, the growing delay in the psychomotor, physical development of the child, late teething comes to the fore.

The proportions of the body in children with hypothyroidism approach chondrodystrophic, the development of the facial skeleton lags behind (wide sunken bridge of the nose, hypertelorism, late closure of the fontanelles). Eruption is delayed, and later the change of teeth. Attention is drawn to cardiomegaly, deafness of heart tones, a decrease in blood pressure, a decrease in pulse pressure, bradycardia (in children of the first months, the pulse rate may be normal). Children with congenital hypothyroidism are characterized by a low, rough voice, they often have cyanosis of the nasolabial triangle, stridor breathing.

Summarizing the above clinical signs of congenital hypothyroidism, we present the Apgar scale, which helps in early clinical screening of CH (Table). However, only screening for congenital hypothyroidism makes it possible to make a diagnosis in the first days of a child's life, before the appearance of a detailed clinical picture of the disease, and thus avoid the serious consequences of the disease, the main of which are a delay in the mental and physical development of the child. Economically, the cost of screening and the cost of treating a disabled child in late-diagnosed cases correlate as 1:4.

Replacement therapy with levothyroxine sodium

Observation of children with CH in the first year of life should be carried out by an endocrinologist, pediatrician, neuropathologist.

Control blood sampling is carried out 2 weeks and 1.5 months after the start of replacement therapy. The possibility of an overdose of levothyroxine sodium must always be kept in mind. The dosage of levothyroxine sodium is selected individually, taking into account clinical and laboratory data.

In children of the first year of life, it is necessary to focus primarily on the level of T4, since in the first months of life, a violation of the regulation of TSH secretion according to the feedback principle is possible. Evaluation of the TSH level alone may lead to the appointment of unnecessarily high doses of levothyroxine sodium. In cases of relatively high levels of TSH and normal levels of total T4 or St. The T4 dose of levothyroxine sodium can be considered adequate. Further control determinations of the concentration of TSH, T4 levels should be carried out in the first year of life every 2-3 months of life, after a year - every 3-4 months.

Thus, immediately after the diagnosis is established, and also in doubtful cases, replacement therapy with levothyroxine sodium preparations (euthyrox, L-thyroxine, thyro-4, L-thyroc, L-thyroxine-Acri, L-thyroxine-Farmak) should be started. Treatment in most countries begins no later than the first month of life, on average at the 2nd week, for example, in Germany, treatment begins on the 8th-9th day of life, in the UK - on the 11th-15th day.

The first-line drug in the treatment of congenital hypothyroidism is levothyroxine sodium. The drug can be produced in various dosages - 25, 50 and 100 mcg in one tablet. The presence of different dosages of drugs should definitely pay the attention of parents and indicate the prescribed dose of levothyroxine in mcg, and not just in parts of the tablet.

Levothyroxine is completely identical to the natural human hormone thyroxin, which is its main advantage over other synthetic drugs. In addition, after taking levothyroxine (euthyrox, L-thyroxine, thyro-4, L-thyroc, L-thyroxine-Acri, L-thyroxine-Farmak), a "depot" of this drug is created in the blood, which is consumed as needed by deiodination of thyroxine and converting it to T 3 . In this way, high, peak levels of triiodothyronine in the blood are avoided.

The entire daily dose should be given in the morning 30 minutes before breakfast, with a small amount of liquid. For young children, the drug should be prescribed during the morning feeding, in crushed form.

The initial dosage of levothyroxine is 12.5-25-50 mcg / day or 10-15 mcg / kg / day. In addition, the child's need for thyroid hormones correlates with the surface of the body. Newborns are recommended to prescribe levothyroxine at a dose of 150-200 mcg / m 2 of body surface, and children older than 100-150 mcg / m 2.

Taking into account the clinical symptoms, it should nevertheless be remembered that the most reliable indicator of the adequacy of the treatment received by the child for hypothyroidism is the normal level of TSH in the blood serum, in children of the first year of life - the levels of thyroxine. It should be borne in mind that the level of T 4 usually normalizes 1-2 weeks after the start of treatment, the level of TSH - 3-4 weeks after the start of replacement therapy. With long-term treatment, indicators of the adequacy of the applied dose of levothyroxine sodium are data on growth dynamics, general development of the child, and indicators of skeletal differentiation.

V. A. Peterkova, professor, doctor of medical sciences
O. B. Bezlepkina, Candidate of Medical Sciences
GU ENTS RAMS, Moscow