Thyreopathy in children with Down syndrome

Thyropathy in children with Down syndrome. Clinical case

Diseases of the thyroid gland in patients with Down syndrome are quite common. The number of these ailments increases with age: from 4% to 54% of all children with this genetic feature. Read about the signs of thyroid diseases in people with Down syndrome and approaches to their treatment in the article by Viktoriya Sheveleva, a pediatrician and children's endocrinologist at Dobrobut MM.

Down syndrome is a genetic disease caused by the presence of an additional 21 chromosomes in human cells. The birth of a child with this syndrome does not depend on the state of health, nationality, wealth and religious beliefs of its parents. Today, the successes of prenatal diagnostics contribute to reducing the frequency of births of children with this pathology.

Symptoms of Down syndrome

Presumed diagnosis of the disease is usually established on the basis of external signs:

• "flat" face (90%);
• brachycephaly ("short head") (81%);
• skin fold on the neck (81%);
• anti-Mongoloid cut of the eyes (80%);
• epicant ("Mongolian fold" near the inner corner of the eye) (80%);
• hypermobility of joints (80%);
• muscular hypotonia (80%);
• short limbs (70%);
• arched palate (58%), etc.

Transverse palmar fold, which is considered a universal sign of Down syndrome, is observed in 45% of cases, and Brushfield spots (pigmented spots on the edge of the iris) in 19% of cases. Usually, a newborn with Down syndrome has some of the known signs. Sometimes similar manifestations are found in ordinary children. Therefore, the final diagnosis is made after receiving the results of the karyotype analysis.

Clinical symptoms of Down syndrome are characterized by delayed psychomotor and language development. They are often combined with birth defects, disorders of the immune and endocrine systems. Such children are called "sunny".

Endocrine pathologies in children with Down syndrome

Children with Down syndrome are usually seen by district pediatricians. In this case, the symptoms of the underlying disease may go unnoticed, although they occur quite often.

Hyperthyroidism (increased thyroid function) is a rare disease of the thyroid gland.

Clinical manifestations of hyperthyroidism: ophthalmopathy, enlargement of the thyroid gland, anxiety/hyperactivity, sensitivity to heat, weight loss, frequent pulse, increased sweating.

Treatment and management of patients with hyperthyroidism is non-specific. If medical therapy with thyrostatic drugs is ineffective, surgical treatment is used.

Among the diseases of the thyroid gland, hypothyroidism (congenital and subclinical) and autoimmune thyroiditis are most common.

Hypothyroidism

In the case of untimely detection, congenital hypothyroidism causes irreversible disorders of the child's physical and neuropsychological development. The frequency of its manifestations is 1 in 4000 newborns. One of the effective methods of early diagnosis of congenital hypothyroidism in newborns is neonatal screening, which consists in determining the level of thyroid-stimulating hormone (TSH). For children with Down syndrome, it is insufficient. Such patients require additional determination of the level of total thyroxine (total T4) and free (free T4), and in older children, the level of antibodies to thyroperoxidase (ATPO) and thyroglobulin (AT-TG).

Signs of hypothyroidism

Symptoms of acquired hypothyroidism in childhood may be missed due to the "scrubbiness" and delay of clinical manifestations, which include delayed growth and psychomotor development, body disproportion, dry skin, constipation, chronic fatigue, cold intolerance, excessive weight gain. Such symptoms are often overlooked by parents. In children with Down's syndrome, acquired hypothyroidism may be missed due to developmental features characteristic of this genetic pathology. In other words, short stature, lethargy, immobility, impaired psychomotor development are often attributed to signs of a genetic disease.

The danger of hypothyroidism in children, including those with Down syndrome, is that in the absence of treatment, the child's development is delayed. The level of intellectual and cognitive abilities depends to some extent on how timely the treatment is started.

Subclinical hypothyroidism is characterized by an increase in the level of TSH with a normal level of T3 and T4 in the blood. This condition is observed in 40% of children with Down syndrome under the age of 14.

Treatment of hypothyroidism

There is no unequivocal opinion about the need for replacement therapy of subclinical hypothyroidism in children with Down syndrome. Although a study conducted by Italian scientists showed that prescribing thyroxine in minimum doses of 8 μg/kg/day to children under the age of two allowed to significantly improve growth and psychomotor development.

Controversial remains the question of the influence of zinc on the function of the thyroid gland. It is known that a lack of zinc in the blood of children with Down syndrome causes disorders in the work of the immune system, a decrease in growth rates, and trophic skin changes. There is an opinion that the use of zinc phosphate improves the general condition, reduces morbidity and eliminates dry skin, brittle nails; laboratory indicators are normalized, in particular, a slightly increased level of TSH.

Autoimmune thyroiditis is characterized by the presence of antibodies to TPO and TG. Most often, this disease occurs in children older than eight years.

Case from practice

Below is a case from medical practice, which once again confirms the need for early diagnosis and timely initiation of treatment of autoimmune thyroiditis in a patient with Down syndrome.

Patient Ivan K., 8 years old, applied to the "Dobrobut" clinic.

From the anamnesis: a child from the first pregnancy, the first urgent delivery. On the basis of phenotypic signs, the presence of congenital malformations (duodenal atresia, heart defects), as well as karyotyping (47ХУ+21), the diagnosis: Down syndrome was established. By the age of one, the child practically did not lag behind in physical and psychomotor development. After a year, he began to noticeably lag behind in growth, psychomotor and speech development (parents and pediatricians associated these phenomena with the presence of genetic pathology). Over the past two years, the patient began to be bothered by constant constipation, significant dryness of the skin, hair loss (up to areas of baldness in the occipital region).

Family history burdened: presence of autoimmune thyroiditis in the mother.

During the examination, growth retardation, severe skin dryness, foci of hair loss, hypodynamia, delayed motor and psychospeech development, and bradycardia attracted special attention. On palpation, the thyroid gland is enlarged, 1-2 degrees, dense, heterogeneous, hilly. A rounded formation up to 0.8 cm in diameter is palpable in the right lobe.

Ultrasound of the thyroid gland: thyroid volume - 6.9 cm3 (increased to 1-2 degrees), the echo structure is significantly heterogeneous, with numerous small round hypoechoic foci, linear hyperechoic structures, as well as the presence a rounded heterogeneous formation of 0.8 cm in the right lobe.

Laboratory examination: TSH – 380,421 (normal up to 4), free T4 – less than 0.3 (normal 0.6-1.4), ATPO – more than 1000, ATTG – less than 20 (normal). Thyroglobulin – 269 (significantly elevated due to very high TSH level), calcitonin – less than 2 (normal).

Diagnosis: autoimmune thyroiditis. Nodular goiter of the I-II degree. Primary hypothyroidism, severe form, congenital, detected for the first time. Thyroid growth retardation. Delay in psychomotor development. Trisomy 21 syndrome.

Recommended: dispensary observation by an endocrinologist, permanent replacement therapy with levothyroxine, systematic control of the level of thyroid hormones with subsequent correction of its dose, dynamic ultrasound examination of the thyroid gland, scheduled consultation of a surgeon-endocrinologist regarding a neoplasm in the right thyroid lobe glands

Against the background of the ongoing treatment, positive dynamics were noted in the child's condition for eight weeks: dry skin and hair loss decreased, psychomotor development and memory improved, as well as the nature of bowel movements. Laboratory indicators of TSH are kept at the level of 2.2.

Thus, in the case of thyroid diseases in children with Down syndrome, the following is relevant for them:

• constant observation of an endocrinologist;
• control of the level of thyroid hormones in the first year of life, then annually;
• Drug correction of subclinical hypothyroidism in early childhood.

The thyroid gland is the most important regulator of all human organs and systems. Its condition significantly affects the activity of the body as a whole. Therefore, in addition to observation by a pediatrician, children with Down syndrome are recommended to undergo an examination by a pediatric endocrinologist.

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