I. Hypothyroidism in newborns and children When mothers take antithyroid drugs (tabazol or propylthioxypyrimethamine) in excessive doses during pregnancy, or when pregnant women inadvertently take radioisotope iodine during pregnancy, or when they take iodine-containing drugs for asthma or acetaminophen for heart rhythm disorders in excessive doses during pregnancy, or when there is endemic iodine deficiency or congenital thyroid dysplasia can lead to goiter in newborns, and in severe cases Cretinism occurs, manifesting severe mental retardation, deafness and impaired growth. If treatment of congenital hypothyroidism can be started within one month after birth, the damage to the nervous system can be reduced; if treated within 3 months, the IQ of the child can reach 90; if treated at 6 months, the IQ can be reduced to 75, so early diagnosis and early treatment of neonatal hypothyroidism is particularly important. Neonatal hypothyroidism: 1, neurological developmental disorders, drowsiness, poor response, dull, can not recognize people, reduced pain perception, less crying and more sleep, etc., severe cases can also be accompanied by deafness and constipation. 2. Slow growth, stagnation of height after 1 to 2 years of age, and significant lag in bone age. 3, special face, large head, short neck, pale, swollen, wide eye spacing, short nasal bridge, thick lips and large tongue, thin, yellow and dry hair, hoarse and low cry, indifferent and dull expression, large abdomen with umbilical hernia, unstable gait. 4, low metabolism, poor milk intake or refusal, abdominal distension, low body temperature, slow heart rate. Serum TSH rises rapidly in normal newborns 30 minutes after birth and drops to normal after three days, so screening for hypothyroidism in newborns should be measured in the heel blood 72 hours after birth, and if TSH is elevated, T4 should be measured to help diagnose. In young children, hypothyroidism is characterized by growth retardation, mental retardation, less activity, later teething, toddling and speaking than children of the same age, and yellowing of the skin, palms and soles of the feet, but not the sclera. Adolescents with hypothyroidism often have delayed sexual development, and a few show true precocious puberty. The onset of hypothyroidism in the elderly is often insidious and the symptoms are often atypical. Mucinous edema and constipation are often the complaints of hypothyroid patients, causing weight gain, swelling of the limbs, vocal cord edema causing hoarseness and low voice, anorexia and constipation are very common in hypothyroidism in the elderly. Patients with normal serum thyroid hormones (T4, T3, FT4, FT3) and elevated thyroid stimulating hormone (TSH) are called subclinical hypothyroidism. Since thyroid hormones are at normal levels, there are no clinical symptoms and signs of hypothyroidism other than goiter and TSH elevation. Subclinical hypothyroidism generally does not require treatment. Replacement therapy with thyroid hormone preparations is effective in the treatment of goiter, but the goiter will recur after stopping the medication. Clinical hypothyroidism occurs in 5% of subclinical hypothyroid patients each year.