The normal developmental sequence in girls is thelarche (due to gonadarche) followed closely by pubarche (due to adrenarche) and finally menarche, 2 to 3 years later. In boys the first normal event is scrotal thinning followed by the enlargement of testes and by the appearance of pubic hair (long diameter of the testis greater than 2.5 cm, volume greater than 4 mL). Most of the enlargement of testes during puberty is the result of seminiferous tubule maturation.
Available @ StudentConsult.com
Puberty is delayed when there is no sign of pubertal development by age 13 years in girls and 14 years in boys living in the United States (Tables 174-1 and 174-2).
Patients with constitutional delay have delayed onset of pubertal development and significant bone age delay (2 standard deviations below the mean, which is equal to a 1.5to 2-year delay as a teenager). The height of the patient should remain close to the genetic potential, based on the parental heights, when reinterpreted for bone age (see Chapter 173). Usuallyheight gain is below, although fairly parallel to, the normal percentiles on the growth curve. The prepubertal nadir, or deceleration before their pubertal growth spurt, is prolonged or protracted. A family history of delayed puberty in a parent or sibling is reassuring. Spontaneous puberty usually begins in these patients by the time the bone age reaches 12 years in boys and 11 years in girls. Other causes of delayed puberty must be eliminated before a diagnosis of constitutional delay in puberty is made. Observation and reassurance are appropriate. Adult height normal for the genetic potential is generally attained. In some cases, boys may be treated with low-dose testosterone for a few months if the bone age is at least 11 to 12 years. Treatment is not required for longer than 4 to 8 months because endogenous hormone production usually ensues. Boys who do not initiate endogenous hormone production should be evaluated for other causes of hypogonadism. Estrogen treatment has been used in girls with constitutional delay, but there are no clear studies showing the added benefits. Young women with delayed puberty may need to be evaluated for primary amenorrhea.
As a cause of delayed or absent puberty, hypogonadotropic hypogonadism may be difficult to distinguish from constitutional delay (see Tables 174-1 and 174-2). Hypogonadotropic hypogonadism precludes spontaneous entry into gonadarche; adrenarche usually occurs to some degree. Throughout childhood and in early puberty, patients with hypogonadotropic hypogonadism have normal proportions and growth. When these patients reach adulthood, eunuchoid proportions mayensue because their long bones grow for longer than normal, producing an upper-to-lower ratio below the lower limit of normal of 0.9 and an arm span greater than their height. If a patient has concurrent growth hormone (GH) deficiency, however, stature is exceptionally short, and the condition may have been diagnosed in infancy with a microphallus.
Tumors (craniopharyngioma, germinoma, glioma, prolactinoma) Congenital malformations Radiation therapy Other causes