I. What is precocious puberty? Before the age of 9 for boys and 8 for girls, the appearance of secondary sexual characteristics is precocious puberty. Second, the classification of precocious sexual maturity according to the nature of precocious sexual maturity into four types: 1, true precocious sexual maturity (central precocious sexual maturity) 2, pseudo-precocious sexual maturity (peripheral precocious sexual maturity) 3, pubertal developmental variation 4, heterosexual precocious sexual maturity 3, precocious sexual maturity physiological characteristics of the ovaries appear small consideration bubble – breast development – pubic hair external genitalia – menstrual flow armpit hair. -pubic hair external genitalia – menstrual flow axillary hair. (1) Idiopathic precocious puberty: no obvious organic lesions, some EEG abnormalities. (2) Familial precocious puberty: more common in boys. (3) Central nervous system lesions: congenital brain abnormalities: cerebral edema, cerebral cysts, malformation tumors. Inflammation: meningitis, encephalitis, brain abscess. Trauma: hypothalamus or pineal tumor, more than half of male true precocious puberty is caused by intracranial tumor. (4) Congenital hypothyroidism and increased secretion of TRH by the hypothalamus. (5) Multiple bone fiber development with precocious puberty syndrome: McCune-Albright syndrome, characterized by coffee milk spots on the skin, precocious puberty, multiple bone fiber dysplasia, and other endocrine problems, such as Cushing’s syndrome, hyperthyroidism, and vaginal bleeding in girls. (ii) Pseudoprecocious puberty The hypothalamic-pituitary-gonadal axis is not mature, but the exogenous or peripheral tissue production of sex hormones leads to symptoms of precocious puberty without ovarian ovulation or sperm production, and pubertal response to gonadotropin does not occur after testing with GnRH. Gonadal tumors: female granulosa cell tumor, follicular membrane cell tumor, male mesenchymal cell tumor, choriocarcinoma, etc. (C) Partial precocious puberty 1. Simple precocious breast development: girls with onset under 2 years old, breasts only gently develop, but often show cyclic changes, not accompanied by accelerated growth and early skeletal development, blood please estradiol and FSH basal values increase, FSH peak in LHRH stimulation test is significantly higher. 2. Simple precocious pubic hair development: V. Laboratory tests for precocious puberty 1. T3, T4, TSH measurement to exclude congenital hypothyroidism. 2.Testosterone and estradiol concentration measurement to exclude gonadal tumor. 3.Urine 17-ketosteroid to rule out congenital adrenal cortical hyperplasia. 4.LH, FSH, LHRH, to exclude idiopathic true precocious puberty. 5.Bone age determination: hand and wrist x-ray. 6.B ultrasound: ovaries, uterus, testes, adrenal glands. 7.CT, MRI to exclude brain tumor and adrenal cortical lesions. 8.LHRH, luteinizing hormone release stimulation test.