Precocious Puberty

1
Precocious Puberty

• Beth Ballard
• 1/10/08

2
Physiological puberty - girls

• In girls, breast enlargement is usually the first
  sign of puberty, followed by axillary hair and
  odor along with pubic hair.
• Menarche generally occurs 2-3 years after
  thelarche
• Pubertal growth spurt occurs early in girls
  puberty

3
Physiological puberty - boys

• Testicular enlargement is the first sign of
  puberty in boys
• Growth of the penis and pubic hair usually follow
  after about a year
• Growth spurt occurs later in male puberty

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Age of Puberty

• In the United States, precocious puberty is
  defined as
• the onset of breast and pubic hair growth before
  6yo in AA girls and 7yo in Caucasian girls
  (Hispanic girls seem to enter puberty at the same
  time as Caucasians)
• Onset of pubertal development in boys before 9yo,
  (ethnicity does not seem to effect age of onset
  in boys)

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Name that hormone

• GnRH is released from the pituitary and
  stimulates the release of LH and FSH
• LH and FSH stimulate release of estrogen and
  testosterone
• Estrogen and testosterone stimulate physical
  changes associated with puberty

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Isolated premature thelarche or pubarche

• These are isolated, benign findings, if not
  associated with other signs of puberty
• Premature thelarche is defined as breast
  development before age 3. Watch for normal
  linear growth and lack of other pubertal changes
• Premature pubarche is development of pubic hair
  before age 7 or 8 in girls or boys

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Central Precocious Puberty (CPP) vs.Precocious
Pseudopuberty

• CPP is gonadotropin dependent and results from
  early maturation of the HPG (hyopthalamic-pituitar
  y-gonadal) axis
• Precocious pseudopuberty is caused by an increase
  in production of sex steroids which is
  gonadotropin independent.

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Central Precocious Puberty

• CPP is by far the most common cause of precocious
  puberty and most cases are idiopathic
• Other causes or risks include
• Familial
• Tumors
• Hypothalmic hamartomas
• Aquired CNS injuries (surgery, trauma, radiation)
• Congenital anomalies (hydrocephalus, cysts)
• Incidence is 5 of girls in the US and lt 1 of
  boys
• Idiopathic CPP itself has no associated
  morbidity, but may result in short stature

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Precocious pseudopuberty

• CAH, simple virilizing, boys can be missed until
  4-7 yo when they have onset of early puberty
• HCG secreting tumors
• Tumors of the adrenals, ovary or testis
• McCune-Albright syndrome (congenital adrenal
  hyperplasia)
• Aromatase excess syndromes
• Exposure to exogenous sex steroid hormones

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Laboratory work up

• Testosterone (best to obtain in the AM, DHEA-S
  (the storage form), 17-OH serum progesterone, LH,
  FSH
• Estrogen is a less reliable test
• LH is the best single test for CPP lt 0.1 is
  prepubertal and gt 0.3 is pubertal
• Definitive test is LH/FSH 30 minutes after GnRH
  infusion. FSH rise gtgt LH is prepubertal, no
  increase suggests precocious pseudopuberty
• Thyroid only if other concerns for hypothyroidism

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Imaging Studies

• Bone age determination
• MRI of the brain after laboratory confirmation or
  suspicion of precocious puberty, need to ask for
  pituitary cuts.
• Girls less than 6 have much greater incidence of
  brain abnormalities associated with precocious
  puberty, may opt not to image girls over 6yo
• All boys should be imaged
• Pelvic ultrasound for girls with precocious
  pseudopuberty, looking for ovarian tumor or cyst

12
Treatment

• Gonadotropin-releasing hormone agonists (Lupron)
  suppress pituitary production of gonadotropins
• Given daily as an IM injection
• Annual cost is 10-15,000
• Nafarelin acetate (Synarel)
• Second line therapy
• Given intranasally

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Outcomes

• Without treatment, most girls with onset of
  precocious puberty after age 6 achieve a normal
  adult height and treatment generally provides a
  small height gain
• Treatment can be started anytime before bone
  maturation is too advanced and allows growth
  without rapid bone maturation, generally girls lt
  age 12 and boys lt age 13.