2. Precocious Puberty
• Definition :-
Precocious puberty is generally defined as the onset of secondary
sexual characteristics before 8 years of age in girls and 9yrs in boys.
Menarche before the age of 10 yrs in girls is also considered as
precocious.
• Precocious puberty is divided into 3 groups –
1 Gonadotropin dependent ,or Central, or True.
2 Gonadotropin independent, or peripheral, or pseudo.
3 Mixed.
• True precocious puberty is due to activation of hypothalmic-pituitary-
gonadal axis and isosexual.
• Pseudoprecocious puberty is HPG axis independent and isosexual or
heterosexual.
5. Physiology of puberty
• Prepubertal stage :-
- Early childhood to 8-9 yrs.
- Hypothalamus-pituitary-gonadal axis dormant.
- LH, Estrogen and testosterone are undetectable.
• Peripuberty :-
- 1-3 yrs before puberty.
- Low LH during sleep and pulsatile.
• Early Puberty :-
- Sustaind effect
• Mid Puberty :-
- LH pulse present in day and night.
- Occur at interval of 90-120 minutes
6. Physiology of puberty
• Age of onset of puberty :-
Girls –
Breast bud – 10-11 yrs.
Pubic hair – 6-12 months
Peak height velocity – 11-12 yrs.
Menarche – 2 - 2.5 yrs. ( 12.75 yrs )
Boys –
Testes growth – 9.5- 13.5 yrs. ( > 3ml or 2.5 cm.)
Thinning of scrotum –
Penile growth – 10.5 – 12.5 yrs.
Pigmentation of scrotum –
Pubic hair – 12 yrs.
Peak height velocity – 13 -14 yrs.
8. Gonadotropin dependent Precocious puberty
• M : F 1:10
• Idiopathic – 90 %.
• Structural CNS abnormality may be present in 25-75 % of boys and
in some girls.
• Secondary sexual characteristics develop in boys and girls before
puberty.
• Height, weight and osseus maturation are advanced.
• Mental development is compatible with chronological age.
• Emotional behavior and mood swing are common.
9. Diagnosis
• Blood –
FSH, LH, Testosterone, Estradiol,
GnRH stimulation test.
DHEA, DHEAS, hCG.
T3, T4, TSH.
• X – ray –
Xray wrist & hand
USG abdomen
CT scan head
MRI brain
10. Treatment
• GnRH agonist-
• Leuprolide acetate 0.25 – 0.3 mg/kg, IM, once every 4 wks.
• Sterile fluid collection at local site, < 5% cases.
• IF side effects, Treatment is changed to SC injection of aqueous
Leuprolide, given once or twice daily ( total dose 60 µg/kg/d ).
• Treatment results in decrease in growth rate and osseous
maturation rate in both sexes.
• In girls, breast development may regress. Menses, if present,
cease. Ovarian and uterine size may decrease. Pubic hair remains
stable.
• IN boys, decrease in testicular size, regression in pubic hair,
decrease in frequency of erections.
11. Precocious puberty resulting from organic brain lesions
• Hypothalamic hamartoma are most common ( 70 %) oganic brain
lesions.
• Hypothalamus may be affeced by scarring, invasion or pressure and
interrupting pubertal restraint pathway.
• Neoplasms –
Astrocytoma, ependymoma, optic glioma, germinomas hCG
secreting (only boys).
• S / S –
DI, adipsia, hyperthermia, gelastic seizures, obesity,
cachexia and precocious puberty
• Treatment –
- GnRH analogs.
- Neurosurgical intervention only in intractable seizures.
- GH therapy, if associated GH deficiency
12. Precocious puberty & Hypothyroidism
• Precocious puberty in untreatedHypothyroidism is unphysiological
association. ( 50 %).
• In girls, breast enlargement, menstrual bleeding, large multicystic ovaries.
Only ovarian estrogen and no androgens.
• In boys, testicular enlargement, no testosterone secretion, no penile
enlargement, no pubic hair development.
• Enlargement of sella by MRI, increased TSH, low FSH, undectable LH.
• TSH intreract with FSH receptor ( specificity spillover ), thus inducing FSH
like effects in the absence of LH effects on gonads.
• Treated by thyroid hormone.
13. Gonadotropin secreting tumors
• Hepatoblastoma may be associated with isosexual precocious
puberty.
• All males, age b/w 4m - 8 yrs.
• Tumor cells secret hCG, which stimulates LH receptor in leydig cells
of testes and causing inerstitial cell hyperplasia without
spermatogenesis.
• High hCG, α FP & testosterone;
• Low FSH and LH.
• Mediastinal tumors, but not gonadal tumors, cause precocious
puberty in boys with Klinefelter syndrome.
14. McCune-Albright syndrome
Precocious puberty with polyostotic fibrous dysplasia and abnormal pigmentation
• Missense mutation in the gene encoding the α subunit of of Gs, the
G protein that stimulates the cAMP formation, resulting in the
formation of putative gsp oncoprotein.
• Activation of receptors, ACTH, TSH, FSH and LH occur.
• In girls, precocious puberty, suppressed LH and FSH, no GnRH
stimulation, estradiol N - high
• In boys, symmetrical testicular enlargement, phallus and pubic hair
enlargement, large seminiferous tubules and no leydig cell
hyperplasia.
• When bone age reaches pubertal age, true precocious puberty
overides the antecedent pseudoprecocious puberty.
• Extraglandular manifestion – Hyperthyroidism, Cushing
syndrome,gigantism or acromegaly, phosphaturia and rickets.
15. Familial male gonadotropin independent precocious puberty
• Autosomal dominant
• Testes only slightly enlarged, maturation of leydig cell and
seminiferous tubules are present.
• Low LH, not pulsatile, no response to GnRH stimulation.
• Missense mutation of the LH receptor leading to activation of cAMP
production.
• When osseous maturation reaches at puberty, pubertal
development is shifted to gonadotropin dependent one.
• Treatment –
Ketoconazole 600 mg/d tds
Spironolactone & aromatase inhibitors ( testolactone, letrozole,
anastrozole )
16. Incomplete ( Partial ) Precocious puberty
Premature Thelarche –
• Present at 2 yrs of age.
• Breast development is unilateral , asymmetrical and often fluctuates.
• Growth and osseous maturation are normal.
• Genitals show no estrogen stimulation.
• Basal FSH increased, FSH response to GnRH stimulation high.
• LH and estradiol less than normal.
Premature Pubarche ( Adrenarche ) –
• Appearance of sexual hair before puberty without any evidence of maturation
• 3β HSD decreased, C-17,20 lyase increased
• Premature Pubarche is a benign condition that requires no therapy.
Premature Menarche –
• Isolated vaginal bleeding without any sexual maturation.
• Gonadotropin normal, estradiol increased.
• Diagnosis of exclusion.
17. Medicational precocity
• Estrogens, anabolic steroids, testosterone gel.
• Exogenous estrogen may produce an intense, dark brown color in
the areola of the breasts that is not usually seen in endogenous type
of precocity
