pediatrics
Precocious Puberty
Diagnosis of Precocious Puberty
Bone age x-rays Serum hormone measurement Possibly pelvic ultrasonography and brain MRI Diagnosis of precocious puberty is clinical. X-rays of the left hand and wrist are done to check for accelerated skeletal maturation as a result of sex hormone effect. Unless history and examination suggest an abnormality, no further evaluation is required for children with pubertal milestones that are within 1 year of population standards. Girls and boys with isolated premature adrenarche and girls with premature thelarche also do not require further evaluation as long as x-rays confirm that skeletal maturation is not accelerated. When further evaluation is necessary, blood tests should be chosen according to the features present. For patients who have mainly androgen effects, the most useful initial tests include measurements of totaltestosterone, dehydroepiandrosterone sulfate, 17-hydroxyprogesterone, and luteinizing hormone (LH); all should be measured using high-sensitivity assays designed for pediatric patients and preferably in the morning. Measurement of morning LH levels is the best initial biochemical test for the diagnosis of central precocious puberty, with values > 0.20 mIU/L (> 0.2 units/L) considered pubertal. For patients who have onlyestrogeneffects, the most useful screens for girls include ultrasensitive LH andestradiol, and, for boys, LH, beta-human chorionic gonadotropin, andestradiol. Follicle-stimulating hormone (FSH) levels have more limited usefulness in differentiating children with GnRH-dependent precocious puberty from nonprogressive variants. Pelvic and adrenal ultrasonography may be useful if any of the steroid levels are elevated, and MRI of the brain may be done to rule out intracranial anomalies in younger patients or in males with central precocious puberty. A GnRH stimulation test may be considered to confirm GnRH-dependent precocious puberty when initial tests are inconclusive in the setting of clinically progressive puberty. Previously, a 1-hour stimulation test with the GnRH agonist gonadorelin was used, but becausegonadorelinis no longer available, other GnRH agonists such asleuprolideare used.Leuprolideacetate 10 to 20 mcg/kg subcutaneously is given and LH, FSH,testosterone(only in boys), andestradiol(only in girls) are measured at 0, 1, and 2 hours. At 24 hours post-leuprolide,estradiolortestosteronemay be measured to improve sensitivity of the test. In GnRH-dependent precocious puberty, gonadotropin responses are pubertal, with stimulated LH levels > 5.00 mIU/L (> 5 units/L) in response toleuprolide. In GnRH-independent precocious puberty, gonadotropin responses toleuprolideare prepubertal. Genetic testing may be considered in familial cases of GnRH-dependent precocious puberty, but this remains controversial. 