Precocious puberty--perspectives on diagnosis and management.

The term 'precocious puberty' signifies the onset of secondary sexual characters before the age of 9 y in boys and 8 y in girls. Menarche before 9.5 y is also considered precocious. These definitions are constantly evolving due to the secular trends observed all over the world. It is crucial to decide whether the child has central (gonadotropin-dependent, GDPP) or peripheral (gonadotropin-independent, GIPP) form of precocious puberty. Some benign conditions such as premature thelarche and premature pubarche may mimic precocious puberty. A systematic approach with detailed history and clinical examination helps to arrive at a diagnosis in most cases. An underlying neurologic disorder is more likely in a very young boy. Basal LH level is the best screening test to diagnose GDPP. LH level less than 0.1 IU/L by a very sensitive assay indicates prepubertal stage. Stimulation tests using gonadotropin releasing hormone (GnRH) or its analog (GnRHa), leuprolide help to confirm the diagnosis of GDPP. High resolution MRI of brain helps to detect abnormalities in hypothalamus and pituitary region. GnRH analogs (GnRHa) are the only effective treatment for GDPP at present. In girls, breast size may regress; menses ceases and vaginal mucosa becomes non-estrogenized. In boys testicular volumes remain static or decrease and genital growth regresses. The effects of GnRH analogs are reversible on discontinuation of therapy, with restoration of normal function within 3 mo after stopping treatment. Treatment of GIPP however is far from satisfactory.