Precocious puberty is defined as the onset of puberty before the age of 8 years in a girl or 9 years in a boy.
Types of precocious puberty
Precocious puberty is classified based on the causes into two:
- central (also called complete or true)
- peripheral (also called incomplete or pseudo)
Central causes of precocious puberty includes conditions that prematurely activate the hypothalamic GnRH pulsatile release, such as:
- Cerebral tumours (e.g. craniopharyngioma)
- Hypothalamic hamartoma
- Idiopathic (75% of cases).
Peripheral causes of precocious puberty are those conditions that increase sex hormone production independent of GnRH and the hypothalamo-pituitary-ovarian axis. They include:
- Granulosa cell tumour
- Functional ovarian cyst
- McCune Albright syndrome
- Adrenal tumours
- Autonomous oestrogen production from ovary due to genetic mutation
- Exogenous oestrogen
Investigations for precocious puberty
- Assay of serum LH, FSH, TSH and oestradiol
- Radiological: Pelvic ultrasound and CT scan, skull X-ray and MRI
TSH will be raised if hypothyroidism is the cause of the precocious puberty.
Raise FSH, LH and oestradiol indicates a central cause.
Raised oestradiol with normal or low FSH and LH indicates a peripheral cause.
Skull X-ray/MRI will show the presence of cerebral tumours, hypothalamic hamartoma or hydrocephalus as the cause.
Abdominopelvic USS and CT scan will detect the presence of ovarian cysts, granulosa cell tumours and adrenal tumors.
Treatment of precious puberty
- For central causes: long-acting GnRH analogues (e.g. Goserelin) till child is 11-12 years of age
- For tumours: surgery.