About the disease
Congenital hypothyroidism is a disease that can be caused by various reasons, but in any case, leading to a decrease or complete loss of thyroid gland (thyroid) function. According to statistics, the ailment is not rare, it occurs in one baby out of 4-5 thousand newborns and is one of the most common diseases of the endocrine system in children.
Female representatives are more susceptible to this pathology, manifestations of the disease are observed in them 2 times more often than in boys. With hypothyroidism, the thyroid gland cannot properly perform its function, which significantly affects the health and development of the baby.
What is the role of the thyroid gland in the body?
This organ of internal secretion is the source of three types of hormones: thyroxine (T4), triiodothyronine (T3), calcitonin. The first two (T3, T4) contain iodine, and their role in the child's body largely depends on the age of the baby.
In the perinatal period and in early childhood, these biologically active substances are necessary for the proper development of the baby, especially his skeletal system and organs of the central nervous system. In adults, thyroid hormones are involved in many metabolic processes, provide mental functions such as memory, speed of reflex reactions, and others.
In addition to iodine-containing biologically active substances, the thyroid gland produces the peptide hormone thyrocalcitonin. This substance is actively involved in mineral metabolism, maintains the required concentration of calcium and phosphorus, contributes to the formation of a normal composition of bone tissue and teeth.
How does congenital hypothyroidism appear in children?
The formation of organs and systems of the fetus, its growth and development occurs mainly due to maternal hormones, which penetrate the body of the crumbs through the placenta. Therefore, newborns with hypothyroidism usually do not differ significantly from other children, do not have signs of significant pathology of internal organs.
The baby's problems arise after birth, when the hormones received from the mother begin to break down, and their own biologically active substances are not synthesized. In healthy children, thanks to these substances, the formation of brain cells occurs, the development of mental functions.
For the normal development of the child's central nervous system, the presence of a sufficient amount of T3 and T4 in the body is mandatory. If in infancy the baby has a lack of thyroid hormones, then mental retardation (cretinism) is formed, which is irreversible, the normal formation of the skeleton is disrupted, and pathologies of other organs arise.
Classification and causes of congenital hypothyroidism
Depending on the factor that caused the disease, the disease are divided into several types.
Primary hypothyroidism (thyrogenic)
Most often (about 90% of all cases of the disease) manifestations of the disease occur due to defects in the formation of the thyroid gland itself during intrauterine development. The share of ectopia (its incorrect location) accounts for about 30 - 45% of ailments. Agenesis (the absence of a part of an organ) accompanies 35 - 45% of cases of pathology, and hypoplasias (a decrease in the total size of the gland) are less common, about 5% of the total number of diseases.
The most common causes of primary hypothyroidism are considered unfavorable environmental factors - exposure to radiation and a lack of iodine in the expectant mother. Some intrauterine infections can also negatively affect the development of thyroid tissue.
It is possible that the toxic effect of some medications that entered the fetus's body in utero - thyreostatics, tranquilizers and other drugs - is possible. In a number of cases, there were autoimmune pathologies in the mother, endemic goiter.
It is believed that a small number of primary hypothyroidism is hereditary and associated with a gene defect in the baby's body. Usually, in such cases, there are signs of congenital pathologies of many organs and systems (for example, heart disease, anomalies in the structure of the palate and upper lip, and others).
Secondary (pituitary)
The disease is associated with the pathology of the brain, more precisely the adenohypophysis, where thyroid-stimulating hormone is synthesized. This substance normally regulates the formation of thyroid hormones, maintains their normal concentration in the body.
Usually, such violations occur in cases of combined pathologies of many hormones secreted by the anterior pituitary gland (STH, ACTH, FSH and others) and are more often observed in organic brain damage. For example, with anomalies in the development of the central nervous system, severe birth trauma or asphyxia, tumor formation.
Tertiary hypothyroidism (hypothalamic)
The cause of the pathology in this case also lies in the functioning of the brain, but unlike secondary forms, it is located in the hypothalamus. These structures normally regulate the work of the pituitary gland and together with it form the hypothalamic-pituitary system.
Therefore, specialists refer to Tuesday and tertiary forms of the disease as central hypothyroidism (associated with abnormal functioning of the central nervous system).
Peripheral form (transport, tissue)
The disease can develop not only because of the pathology associated with the release of necessary hormones. It happens that initially a sufficient amount of biologically active substances is formed in the body, the susceptibility of tissues to them is impaired (usually this is due to the pathology of certain receptors).
Sometimes a child has a pathology of formation or metabolism of thyroid hormones. Such situations in most cases are hereditary.
How does the disease manifest itself?
The manifestations of the disease largely depend on the form and severity of the disease. With a pronounced lack of hormones, the disease can be suspected immediately after the baby is born. But such situations occur infrequently, about 5% of cases, mostly children with a congenital ailment do not differ significantly from other babies.
The symptoms of the disease usually develop gradually, starting from the 7th day of the baby's life. But this gap can increase if the baby receives a small amount of the hormones he needs in breast milk. Some manifestations of the disease, although they are not specific, but their combination may indicate already in the first weeks of the baby's life on congenital hypothyroidism.
Symptoms in newborns, due to which the disease can be suspected:
- post-term pregnancy;
- baby's body weight at birth is about 4 kg;
- swelling of the child's face;
- open small fontanelle;
- signs of decreased tone;
- enlarged tongue;
- the presence of an umbilical hernia;
- pallor, dry skin, or development of neonatal jaundice that lasts more than 3 weeks.
The characteristic manifestations of the disease develop gradually, and the symptoms of hypothyroidism without adequate treatment become more and more pronounced. Already by 3 - 6 months, the crumbs have typical signs of the disease.
The baby looks edematous, because due to the lack of hormones, the liquid is easily retained in the tissues. The child's face seems to be rough, the eye slits are narrow, and is carried wide, there is a delay in the development of the facial skeleton. Attention is drawn to the enlarged tongue, which becomes clearly visible due to the constantly parted mouth.
In the case of the development of the disease, the skin color also changes, an icteric or grayish tint appears. The hair of the crumbs becomes brittle and dry, and the nail plates atrophy. The child's voice acquires a low timbre, seems hoarse and rough. Often there is cyanosis around the lips of the baby, the rhythm of breathing is disturbed.
A developmental delay becomes noticeable, the baby does not master the skills necessary for a given age, apathy appears, the baby does not show interest in the world around him. The older the child becomes, the more pronounced are the signs of a lag in intellectual and mental development.
Mental retardation in children with congenital hypothyroidism is irreversible. Therefore, hormonal therapy started on time is very important in the prevention of complications.
These children are prone to a decrease in body temperature, chilliness, their limbs are often cold. The children later erupt their teeth and the fontanelles do not close for a long time. Babies with hypothyroidism may have a slow pulse and low blood pressure, an enlarged heart.
As the child grows up, these symptoms progress, and a gross delay in intelligence and mental development is formed. The rate of ossification of the skeleton, the formation of secondary sexual characteristics are slowed down, due to the presence of significant endocrine problems.
Diagnosis of the disease
Neonatal screening
Important! There may be no clear signs of the disease in a baby after birth, and the clinical picture develops gradually, irreversibly disrupting the development of the child. Therefore, the time of diagnosis is of great importance in the effectiveness of treatment and prognosis of the disease.
In order to timely recognize a dangerous ailment even in the maternity hospital, all newborns undergo a special examination - screening for hereditary diseases. This is an absolutely free procedure, which involves taking 5 drops of blood from the baby's heel onto filter paper to diagnose hereditary diseases, including congenital hypothyroidism.
During neonatal screening in Russia, 5 genetic ailments are determined - phenylketonuria, congenital hypothyroidism, adrenogenital syndrome, cystic fibrosis and galactosemia. These diseases may not have any manifestations in a newborn, but without proper treatment, they can lead to an irreversible delay in mental and physical development.
During the study of a dry drop of blood for hypothyroidism, the level of thyroid-stimulating hormone of the pituitary gland (TSH) is determined, which increases compensatory with a decrease in thyroid hormones of the thyroid gland. A positive screening result for this disease may warrant the appointment of hormone replacement therapy.
Sometimes an increase in TSH can indicate transient hypothyroidism in newborns - a condition that can be caused by iodine deficiency, prematurity, diseases of the newborn (intrauterine infections, sepsis, malnutrition), thyroid diseases in a woman during pregnancy. This form of the disease responds well to treatment and is temporary.
Physical examination
In cases where the signs of the disease were not recognized in the neonatal period, the baby develops typical manifestations of the disease. The appearance of the crumbs changes, attention is drawn to apathy, developmental delay, hypotension, lowered body temperature in a child.
Laboratory research
To clarify the form of the disease and determine the necessary therapy, it is recommended to study the level of hormones in the child. The most informative is the repeated change in TSH and T4 (thyroxine) in blood plasma.
Indirectly, congenital hypothyroidism may be indicated by normochromic anemia in a clinical blood test, an increase in the amount of lipoproteins and cholesterol during a biochemical study.
Instrumental methods
These methods become informative when the baby develops a vivid clinical picture of the disease. With the help of radiography, it is possible to detect a delay in ossification, epiphyseal dysgenesis. The ECG shows signs of a slowing heart rate, a decrease in voltage.
Blood pressure in such babies is usually below normal, and ultrasound of the thyroid gland often detects signs of a violation of the structure of the organ. Changes found during computed and magnetic resonance imaging may indicate damage to the brain, hypothalamic-pituitary system.
Treatment of the disease
The appointment of substitution therapy is carried out immediately after the diagnosis. Treatment can be started already on the 8th - 9th day of the baby's life, when its effectiveness is maximum. This disease is an absolute indication for the use of hormonal therapy with levothyroxine.
A delay in the start of treatment for more than 1 month may lead to disruptions in the mental and physical development of the baby.
Therapy of the disease is carried out under the control of the level of hormones in the blood (TSH, T4), regular laboratory examination of the baby. Perhaps the appointment of symptomatic therapy, vitamin and mineral preparations in the complex treatment of hypothyroidism.
Forecast and prevention
The course of the disease largely depends on the timeliness and quality of the treatment. If substitution therapy is prescribed on time, the child develops according to age norms. Usually, babies have to take hormones for life.
In cases where there was a delay in the appointment of treatment (especially if the interval was 3 - 6 months), the child develops irreversible intellectual dysfunctions, up to oligophrenia, damage to the skeletal system and a slowdown in metabolism.
Prevention of the disease consists in the timely treatment of thyroid diseases in a pregnant woman, sufficient intake of iodine with food during gestation, and neonatal screening.
Conclusions
Congenital hypothyroidism is one of the most common endocrine diseases in childhood. This ailment can bring serious health problems to the crumbs, lead to irreversible consequences. At the same time, timely detection and treatment of the disease ensures the normal development of the child and the minimum number of manifestations of the disease.
It is important for parents to understand the importance of early diagnosis and adequate treatment of the disease and not to abandon neonatal screening, because the health of the baby in the future depends on it.
