Precocious Puberty
Definition
True precocious puberty is the result of premature initiation of the function of the hypothalamic-pituitary axis. Premature release of the luteinizing hormone releasing hormone (LHRH) by the hypothalamus triggers secretion of the pituitary gonadotropin hormones. As a consequence, the gonads function at an inappropriately early age. Precocious puberty per se has many subdivisions: isosexual, heterosexual, gonadotropin-dependent (true precocious puberty), gonadotropin-independent, male-limited (familial testotoxicosis), cerebral, central, and idiopathic (unknown) precocious puberty. Precocious puberty is also known as familial testotoxicosis, gonadotropin-independent familial sexual precocity, and pubertas praecox.
Description
This is the appearance of sexual characteristics at a very early age, usually defined as before 10 years in males and 8.5 years in females. It has been reported as early as age three. Approximately one in every 10,000 children starts puberty prematurely. Boys grow facial, pubic and underarm hair, are prone to develop acne, and the penis and testicles enlarge. Viable sperm may be produced. Girls may develop breasts, grow pubic and underarm hair, menstruate and may ovulate. Adult height in both males and females is usually reduced. Though it is of unknown origin, familial cases of precocious puberty have been observed. While in general precocious puberty is much more common in females than males, hereditary forms are more common in males. Perhaps 5 percent to 10 percent of these males brought to medical attention have inherited precocious puberty. Two autosomal dominant forms have been identified. Less than 1 percent of affected females inherit the condition, and the mode of inheritance for the female form is unknown.
Causes
Usually precocious puberty is idiopathic (unknown cause). In some instances, it is due to an endocrine disorder. Cerebral precocious puberty is associated with a brain abnormality. Precocious puberty may also be a feature of McCune-Albright syndrome, neurofibromatosis, Russell-Silver syndrome and disorders of the adrenal glands. Affected individuals may encounter psychological problems due to their accelerated growth and may feel alienated from their peers. They may exhibit increased aggressiveness and hyperactivity. Male-limited precocious puberty (familial testotoxicosis) is considered hereditary.
Symptoms
In females, the breasts start to develop before age 8, or menstruation occurs before age 10, and growth is rapid. In males, onset is before age 10; boys grow facial, underarm, and pubic hair; growth, including that of the penis, accelerates; the voice deepens; and behavior becomes more aggressive. Puberty may take place before age 3 in some children. Children with precocious puberty are taller than their peers. Since bone maturity is usually hastened in precocious puberty, closure of growth occurs prematurely, and patients are short in stature in adulthood. In isosexual precocious puberty, feminizing signs appear in girls, masculinization in boys. Heterosexual precocious puberty causes signs of masculine characteristics in girls and feminization in boys. Cerebral precocious puberty differs in cause but mimics true precocious puberty. Central precocious puberty is attended by changes that concern the central nervous system. Gonadotropin-dependent precocious puberty is marked by high gonadotropin levels in girls. Gonadotropin-independent precocious puberty usually affects boys, who have low levels of gonadotropin. Idiopathic precocious puberty is associated with EEG (Electroencephalogram) irregularities in girls. The cause of the unusual brain waves is unclear.
Diagnosis
Diagnosis is made through a combination of clinical exam, blood tests for levels of hormones described above, and bone x-rays (if necessary) to determine bone age.
Treatment
Therapy depends on the cause of precocious puberty. Glucocorticoid suppression of ACTH (adrenocorticotropic hormone) is indicated for girls with heterosexual precocious puberty due to congenital adrenal hyperplasia. Girls with precocious puberty and McCune-Albright syndrome respond to the aromatase-inhibitor testolactone, a blocker of estrogen synthesis. Some hypothalamic lesions and ovarian tumors or cysts can be excised. Once identified, exogenous hormones can be eliminated. Replacement therapy with levothyroxine is indicated for girls with precocious puberty caused by primary hypothyroidism, in whom closure of growth is late. Genetic counseling is recommended for families of patients with male-limited precocious puberty and other hereditary types of this disorder.
Questions
What tests need to be done to diagnose the condition? What is the cause? What subdivision does this fall under? What treatment do you recommend? Will you be prescribing any medication? What are the side effects? How will this affect his/her growth stature in adulthood? Do you recommend a psychological workup and therapy?
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