Congenital hypothyroidism is caused by congenital defects in the thyroid gland of the child or by iodine deficiency in the mother’s diet during pregnancy, the former being called sporadic hypothyroidism and the latter endemic hypothyroidism. Its main clinical manifestations are physical and intellectual developmental disorders. It is a common endocrine disorder in pediatric patients. The main function of the thyroid gland is to synthesize thyroxine (T4) and triiodothyronine (T3). The main raw materials of thyroid hormones are iodine and tyrosine. After iodine ions are taken into the thyroid epithelial cells, they are combined with tyrosine by a series of enzymes. The synthesis and release of thyroxine are controlled by thyrotropin-releasing hormone (TRH) secreted by the hypothalamus and thyrotropic hormone (TSH) secreted by the pituitary gland, while serum T4 reduces the responsiveness of the pituitary gland to TRH and decreases TSH secretion through a negative feedback effect. Thyroxine accelerates intracellular oxidative processes; promotes metabolism; promotes protein synthesis and increases enzyme activity; enhances sugar absorption and utilization; accelerates lipolysis and oxidation; promotes the anabolism of calcium and phosphorus in bone; and promotes the growth and development of the central nervous system. When the thyroid gland function is insufficient, it can cause metabolic disorders, low physiological function, growth retardation, and intellectual impairment. The main cause of congenital hypothyroidism is an underdeveloped or underdeveloped thyroid gland, which may be related to the presence of immunoglobulins in the body that inhibit the growth of thyroid cells; followed by an enzyme defect in the thyroxine synthesis pathway (an autosomal recessive disorder); thyrotropin deficiency is rarely associated with a low response of the thyroid gland or target organs. Currently there is an increase in secondary infections causing hypothyroidism. Clinical manifestations II. Clinical manifestations 1. Symptoms in the neonatal period Most children with congenital hypothyroidism are asymptomatic at birth because maternal thyroxine (T4) can pass through the placenta and maintain 25% to 75% of the normal T4 concentration in the fetus at birth. The early appearance and severity of the symptoms of the disease in the neonatal period are related to the intensity and duration of hypothyroidism. About 1/3 of children born with great and gestational age, large head circumference, significantly widened fontanelle and cranial suture, may have temporary hypothermia, low heart rate very little crying, little movement, feeding difficulties, easy vomiting and choking cough, much sleep, apathy, hoarse crying, delayed dispatch of fetal stool, persistent constipation, prolonged period of physiological jaundice, no weight gain or There is no or slow weight gain, large abdomen, often with umbilical hernia, and hypotonia. Due to poor perfusion of peripheral tissues, the extremities are cold, pale, and often patterned. The forehead is wrinkled and looks like an old man, the face is bloated, the nose is flat, the distance between the eyes is wide, the eyelids are thickened, the lid fissure is small, the hair is dry, the hairline is low, the lips are thick, the tongue is large and often sticks out of the mouth, and in severe cases, breathing difficulties can result. 2, the typical performance of children (1) special facial manifestations are collapsed nose, wide eye spacing, thick tongue often sticking out of the mouth, sluggish expression, puffy face, rough, dry skin, anemic appearance. Pale yellow face, thickened nose and lips, thinning hair, dry and brittle, eyebrow loss. (2) Mental retardation, sluggish neural reflexes, slow speech, slurred pronunciation, low voice, excessive sleepiness and hyperactivity. Dull expression, dull vision, hearing, smell and taste. There are hallucinations, delusions, depression, xylophobia, lethargy, and in severe cases, psychosis. (3) Growth and development are backward, bone age is backward, short stature, short limbs, upper body volume is larger than the lower volume, slow movement, walking posture like duck gait. Inadequate dental development. Delayed sexual development and puberty. (4) There may be constipation, generalized mucinous edema-like, heart may be enlarged, and there may be pericardial effusion. (5) There may be bone pain and muscle aches, and muscle tone in endemic hypothyroidism The inability to synthesize adequate amounts of thyroid hormone due to fetal iodine deficiency severely affects the development of the central nervous system. There are two types of clinical manifestations. One is dominated by neurological symptoms, with ataxia, spastic paralysis, deafness and mental retardation, while other manifestations of hypothyroidism are not evident. The other type is predominantly mucinous edema, with a specific facial and physical appearance and delayed intellectual development while the neurological examination is normal. Because of the high incidence of congenital hypothyroidism, the damage to neurological function in the early stages of life and the ease and efficacy of treatment, early diagnosis and early treatment are of utmost importance. 1, newborn screening China’s “Maternal and Child Health Law” promulgated in June 1995 has included this disease as one of the screening diseases. At present, most of the newborn dried blood drops 2-3 days after birth to test the concentration of TSH as the initial screening, the results are greater than 20mU / L, and then test serum T4, TSH to confirm the diagnosis. This method is easy to collect specimens and has a low rate of false positives and false negatives, so it is an excellent prevention and treatment measure for early diagnosis of children, avoiding serious defects in neuropsychiatric development and reducing the burden on families and the country. 2.Serum T4, T3, TSH measurement Any child with suspicious newborn screening results or clinical suspicion should be tested for serum T4 and TSH concentrations, and the diagnosis can be confirmed if T4 is reduced and TSH is significantly increased. Serum T3 concentration may be reduced or normal. 3, TRH stimulation test If serum T4 and TSH are low, then TRH and TSH secretion is suspected to be insufficient, further TRH stimulation test should be done: 7ug/kg of TRH should be injected, and the peak TSH should appear within 20-30 minutes of injection in normal patients, and return to the base value after 90 minutes. If the peak does not appear, pituitary lesions should be considered; if the peak of TSH appears for a longer time, it suggests hypothalamic lesions. 4.X-ray examination X-ray of the left hand and wrist is done to assess the bone age of the child. The bone age of the child is often significantly behind the actual age. 5.Nucleotide examination is performed by intravenous injection of 99m_Tc followed by single photon emission computed tomography (SPECT) to detect the development of the thyroid gland and the size, shape and location of the thyroid gland. Diagnosis and differential diagnosis of congenital hypothyroidism is not difficult based on typical clinical symptoms and thyroid function measurements. However, the diagnosis is not easily confirmed in the neonatal period and group screening should be performed in newborns. In older children, the following diseases should be differentiated: Congenital 1. Congenital megacolon Children with constipation and abdominal distension starting after birth, and often with umbilical hernia, but their faces, mental reactions and cries are normal, and barium enema shows spastic and dilated segments of the colon. 2.21-Trisomy syndrome The child has backward development of intelligence and movement, but has special facial features: wide eye spacing, upward sloping external eye angle, low nasal bridge, tongue sticking out of the mouth, normal skin and hair, no mucinous edema, often accompanied by other congenital malformations. Chromosomal karyotype analysis can identify the difference. 3, rickets The child has delayed motor development, growth lag and other manifestations. However, normal intelligence, normal skin, signs of rickets, blood biochemistry and X-ray can be distinguished. 4, skeletal development disorders such as osteochondrodysplasia, mucopolysaccharidosis, etc. have growth retardation symptoms, skeletal X-ray and urine metabolite examination can be distinguished. Treatment of congenital hypothyroidism 1, treatment of fetal hypothyroidism due to rapid turnover of amniotic fluid, and T3, T4 is easily absorbed by the fetus, so the prenatal examination of suspected congenital hypothyroidism fetus can be treated by intra-amniotic injection of T4 or T3, or direct injection of thyroid hormone to the fetus and intra-amniotic injection of hypothyroidism. After 32 weeks, Na-L-T 4500μg will be injected once every 2 weeks or 120μg once a week. 2, thyroxine replacement therapy plus or minus once diagnosed, should immediately start the combination of Chinese and Western treatment, the earlier the treatment is more beneficial to brain development, and must be full amount and full course of treatment, even if pregnant is no exception. After the start of treatment, thyroid hormone and TSH should be checked regularly, once a week at the beginning, and then once every 3 months after the hormone concentration reaches the normal range, and once every 6 months to once a year after the condition has stabilized. It is important to check 10,000 femoral x-rays annually to observe the development of bone age. During the treatment process, it is important to observe the child’s mental condition. Generally, after 2 to 3 weeks of herbal treatment, there is an increase in appetite, increased speech and activity, improved constipation and increased urine output. After a period of treatment, some children must exclude the possibility of temporary hypothyroidism. Generally, after 1 month to several months of continuous medication, the medication should be temporarily stopped to observe the changes of T3, T4 and TSH. In cases of thyroid dysplasia, the treatment time is longer. Due to the rapid growth and development of the child during the treatment process, the child should also be supplemented with nutrients and multivitamins, such as calcium tablets, iron, vitamins B, C, A, D, etc., especially B vitamins. Hypothyroidism caused by familial enzyme defects should also be supplemented with iodine. The prognosis of congenital hypothyroidism is closely related to the age of starting treatment. The earlier the diagnosis and the earlier the treatment, the better the prognosis. If treated in the first 3 months of life, 74% of cases have an IQ score of 90 or higher. However, about 15% of patients may have irreversible sequelae of brain damage, which may be related to factors such as the type of hypo, the time of onset and duration, especially in children with intrauterine hypothyroidism whose T4 concentration and bone age are low at the time of diagnosis. The most crucial thing is that whenever hypothyroidism is detected it should be treated with timely herbal medicine. The disease should be diagnosed early and treated as soon as possible to minimize the damage to brain development. Once the diagnosis is established, thyroid preparations should be taken for life without interruption, otherwise the previous work will be lost. The diet should be rich in protein, vitamins and minerals. There are two types of thyroid preparations: ① Sodium L-thyroxine: 100ug or 50ug/tablet, containing T4, with a half-life of one week, with only small daily changes in T4 concentration and stable serum concentration. The dosage is 8-14ug/kg/day for infants and 4ug/kg/day for children. ② Dry thyroid tablets: 40mg/tablet, extracted from animals, contains T3 and T4, if taken for a long time, it can increase T3, so care should be taken when using it. Dry thyroid tablets 60mg is equivalent to 100ug of sodium L-thyroxine, the initial amount should be increased from small to large at intervals of 1 to 2 weeks until clinical symptoms improve and serum T4 and TSH are normal, that is, as a maintenance amount. If the dosage is too small, it may affect the mental and physical development. The dosage can be adjusted according to the thyroid function and clinical performance, which should make ① normal TSH concentration, normal or high blood T4 value, in order to prepare for partial conversion of T4 to T3; ② clinical performance: normal stool once a day, improvement of appetite, disappearance of abdominal distension, heart rate maintained at 110 beats in children and 140 beats in infants, and progress of intelligence. Drug overdose may cause irritability, excessive sweating, wasting, abdominal pain, diarrhea, fever, etc. Therefore, attention should be paid to the follow-up during the treatment. At the beginning of the treatment, the follow-up should be once every 2 weeks; after the serum TSH and T4 are normal, once every 3 months; after taking the drug for 1 to 2 lunches, once every 6 months. During the follow-up, attention should be paid to the observation of growth and development and serum T4 and TSH concentration, and the dose should be adjusted at any time. If treatment for congenital hypothyroidism is started within 3 months after birth, the prognosis is better and the majority of intelligence can reach normal; if treatment is not diagnosed early and started only after 6 months, although thyroxine can improve growth, intelligence will still be seriously impaired.