Puberty is one of the last developmental milestone in the transition from childhood to adult. Any variation, early or late may cause significant psychological concern for parents and may indicate an underlying problem in the Hypothalamo-Pituitary Gonadal axis (HPG axis). Puberty leads to sexual maturation and reproductive capability when to HPG axis is intact.
Gonadotrophin Releasing Hormone (GnRH) produced by the Hypothalamus acts on the pituitary to produce both LH and FSH which act the gonads in both sexes to cause gametogenesis and sex steroid synthesis. While both LH and FSH are required for gametogenesis in both sexes, only LH is required for androgen synthesis in male. Both LH and FSH are required for estrogen synthesis in female.
HPG axis is active during the fetal, neonatal and infantile period and last up to 6 months in boys and 2 years in girls after which there is a period of quiescence till reactivation at puberty. What triggers puberty still remains unknown.
Puberty normally starts between the age group of 9years and 14 years in boys and 8 years and 13 years in girls. Puberty is assessed clinically by Tanners staging. In girls, onset of puberty is indicated by Tanner Staging 2, ie palpable glandular breast tissue. In boys, onset of puberty is indicated by Tanner Staging 2, ie, testicular volume more than or equal to 4cc. Tanner Staging also takes into consideration the changes in genital and pubic hair development. Development of pubic hair is usually not considered in the definition as pubarche may result from maturation of the adrenal glands (adrenarche). Onset of pubic hair can be independent of HPG-axis activation.
Appearance of any sign of secondary sexual maturation before
The prevalence of early puberty is 10 times as high in girls as in boys.
This is often idiopathic and present less than 2 years of age. PT is usually non-progressive and can undego spontaneous remission or rarely in 10 – 20% of cases progress in to CPP. PT is characterized by Isolated breast development unilateral/bilateral, typically not beyond Tanner stage 3. Other secondary sexual characters are absent. Height velocity and bone age are normal. Serum luteinizing hormone (LH) and estradiol concentrations are typically in the prepubertal range.
CPP is also called as True precocious puberty or gonadotropin-dependent precocious puberty as it is due to early maturation of the hypothalamic-pituitary-gonadal axis. There is a sequential maturation of breasts and pubic hair in girls, and of testicular and penile enlargement and pubic hair in boys and is isosexual. CPP is pathologic in 40 to 75 % boys and 10 to 20 % girls.
PPP is also called as gonadotropin-independent precocious puberty and is caused by sex steroid production from gonads or adrenal glands, exogenous sources of sex steroids, or ectopic production of gonadotropin from a germ cell tumor. PPP can be Isosexual or contrasexual.
McCune Albright Syndrome, Primary Hypothyroidism and Familial Male Limited Testotoxicosis are unique forms of gonadotrophin independent precocious puberty. Some cases of PPP like congenital adrenal hyperplasia evolve into CPP later.
Delayed Puberty is defined as absence of physical changes of puberty by age
CDGP is the most common cause of delayed puberty in both boys and girls. Although the exact cause is unknown, it has a strong genetic basis with AD pattern of inheritance. 75 % have similar history in siblings or parents. CDGP is often a diagnosis of exclusion. Often it becomes very difficult to distinguish from CHH. In patients with delayed puberty, a presumptive diagnosis of CHH can be made when there is
Sex steroids (Estradiol/Total Testosterone), LH and FSH both basal and stimulated form the most important biochemical investigations. In Sexual Precocity, Free T4, TSH and HCG may be required based on clinical presentation. In Delayed puberty, IGF-1, GH stimulation testing, Inhibin B may be required based on clinical presentation. Assessment of Growth and bone age also give important clues to the underlying etiology. Biochemical investigations will identify the type of pubertal sexual disorders. USG abdomen/pelvis and MRI pituitary will help to identify the cause of pubertal sexual disorders.
Treatment depends on the underlying etiology. Children with PT needs close follow up for assessment of growth velocity and pubertal progression. CPP is often treated by GnRH agonist to suppress the sex steroids. PPP is treated with inhibitors of ovarian or testicular steroidogenesis or anti-androgen or aromatase inhibitors. CDGP usually dose not require any treatment. If there is significant psychosocial concern, short term treatment with testosterone or estrogen for 3 – 6months is usually sufficient to induce spontaneous puberty. For Permanent hypogonadism, treatment is with sex steroids starting at low dose and gradually increasing to full adult dose.