Precocious puberty, also called pubertas praecox, refers to the unusually early onset of puberty or the appearance of physical and hormonal signs of pubertal development at an earlier age than is considered normal. Precocious puberty may be a deviation from normal development, or may be caused by a disease or abnormal hormone exposure.
There are two types of precocious puberty; the first is called idiopathic central precocious puberty which is natural in every aspect exceptfor age. Central precocious puberty can develop if there is abnormality or damage in the inhibitory system of the brain, or a hypothalamic hamartoma produces pulsatile gonadotropin-releasing hormone (GnRH). The other type is termed peripheral precocious puberty orprecocious pseudopuberty which is characterized by secondary development triggered by sex steroids from other aberrant sources such as congenital adrenal hyperplasia, gonadal tumors, etc.
The possible causes of precocious puberty in some children can be better understood by, knowing what exactly causes puberty to start. It involves a complex process referred to as the hypothalamic-pituitary-gonadal axis (HPG axis) which takes over once puberty occurs. Theprocess involves a series of steps: the brain’s hypothalamus produces gonadotropin-releasing hormone (Gn-RH) which triggers thepituitary gland to release luteinizing harmone (LH) and follicle-stimulating harmone (FSH). LH and FSH in turn stimulatethe ovaries to produce estrogen which is responsible for the growth and development of female sexual characteristics and the testes to produce testosterone which is responsible for the growth and development of male sexual characteristics. The production of estrogen and testosterone causes the physical changes of puberty.
What causes the process to commence early in some children depends on the type of precocious puberty they have. In central precocious puberty, the HPG axis starts prematurely. Even though the process begins earlier than it should, the sequence and timing of the steps are otherwise normal. In most children with this condition, there is no underlying medical condition and no specific reason for the HPG axis totake its course. On the other hand, peripheral precocious puberty occurs independent of the Gn-RH. The cause is the release of estrogen or testosterone into the body due to problems or abnormalities with the ovaries, testes, adrenal glands or the pituitary gland.
The symptoms of precocious puberty vary; in females menstruation may appear before age 10 and the breasts may begin to develop before age eight. In males, the typical age of onset is before age 10; they may start to develop facial, underarm, and pubic hair; the voice deepens;growth accelerates; and behavior tends to be more aggressive. Those with precocious puberty may grow quickly at first and be taller thantheir peers. However, because their bones mature faster than normal, they usually stop growing earlier than usual. As a result, the affected individual is short in stature by the time he/she reaches adulthood.
It is important to note that there is no reliable age limit which delineates normal from abnormal developments in children nowadays;however, there are certain age thresholds that can be used for evaluation to detect a potential medical problem. The following are tell tale signs: breast development in girls before age seven or the appearance of pubic hair before age eight; start of menstruation before age 10;growth of pubic hair or genital enlargement in boys before age nine; breast development in boys prior to the appearance of pubic hair andtesticular enlargement. For definitive diagnosis, a combination of clinical exam, blood tests for levels of hormones, CT scan or MRI of the brain, and bone X-rays can be done.
The treatment for precocious puberty depends on the cause. Most patients with central precocious puberty with no underlying medical condition can be effectively treated with medication. The treatment is called Gn-RH analogue therapy, which normally incorporates a monthly injection of a medication which blocks the hypothalamic-pituitary-gonadal (HPG) axis thereby delaying further development. The patient continues to receive the medication until he or she reaches the normal age of puberty. Another viable treatment is with the drug anastrozole. A GnRH-specific drug Histrelin acetate, may also be used. In case another medical condition is causing the child’s precocious puberty, treating the other condition is imperative in order to stop the progress of puberty.