中国医大儿科学6.pdf

Congenital Hypothyroidism Congenital Hypothyroidism Department of pediatrics Xin Ying Definition and Summary Definition and Summary Hypothyroidism results from deficient production of thyroid hormone or defect in its receptor. The characteristics is retardation in growth and mental development. Category Sporadic Hypothyroidism results from hypoplasia or aplasia of the thyroid gland. Endemic Hypothyroidism (Cretinism) is due to iodine deficiency during mother pregnancy. Synthesis of Thyroid Hormone Synthesis of Thyroid Hormone Thyroid hormone triiodothyronine (T3) thyroxine (T4) Materials iodine, tyrosine Steps 1. Iodine trapping 2. Iodine oxidized 3. Tyrosine iodinate 4. Iodotyrosine condensation Regulation of Thyroid Function Regulation of Thyroid Function Hypothalamus TRH TRH thyrotropin-releasing hormone TSH thyroid-stimulating hormone Pituitary negative feedback TSH Thyroid T3, T4 Hypothalamus-Pituitary-Thyroid Axis 甲状腺素合成和释放的调节 TRH TSH T3,T4 Actions of Thyroid Hormone Actions of Thyroid Hormone Increase oxygen consumption and heat production Accelerate growth and development Promote central nervous system development Influence metabolism of lipids, carbohydrates, proteins, nucleic acids and vitamins Have important effects on other hormone actions Etiology Etiology Thyroid dysgenesis (aplasia, dysplasia, ectopic) 90%~95% Defective synthesis of thyroid ho