Puberty

Puberty

Dr Haider Al Shamma’a

Objectives

Know the definition of puberty The student should be able to understand and describe the physiology of the pre-puberty and puberty The student able to detect the normal sequence of puberty The student should be able to detect the somatic changes associated with puberty The student can diagnose abnormal puberty ( history , examination )

Objectives continue…. Able to request the suitable investigations to diagnose the cause and type of abnormal puberty Can describe the outline of treatment for precocious puberty


Puberty :- is the sequence of events in the transformation of a child into young adult with the development of secondary sexual characteristics and reproductive capability


During this process there are Physical Endocrine Psychological changes a Increased sex steroid hormone

Age of onset 10 – 16 yearsOnset depend on:-Genetic factorsGeographic locationNutritional statusPsychological factors

Endocrinological changes of puberty

The physiology of pre-pubertal period Fetal period Neonatal period Childhood period Late pre-pubertal period Pubertal onset


Fetal period
By 20 wks. FSH & LH start to increaseSome ovarian follicular developmentsE2 → -ve feedback →↓FSH & ↓LHMost estrogens from placental origin

New born period

↓↓ estrogen and progesterone (from placental origin) → FSH ↑ & LH ↑At 3 months FSH & LH near adult level but estrogen remain lowFSH & LH gradually reduced reaching lowest level at 4 years of age

Childhood period (4-10 years)

Low estrogenLow FSH & LHSuppression of FSH & LH due to 2 mechanismsIntrinsic central inhibition of hypothalamic GnRH release ( main mechanism)Very sensitive –ve feedback inhibition

Late prepubertal period ( 6-9 years)

Gradual ↑ androgen from zona reticularis of the adrenals ( ↑ DHEA , ↑DHEAS & androstendione ) → pubic and axillary hair growth ( pubarche & adrenarche )

Pubertal onset (11 years)

↓sensitivity of the –ve feedback ( ie higher estrogen needed to suppress the pituitary secretion of FSH & LH )Loss of the intrinsic CNS inhibition of GnRH from the hypothalamusAt first nocturnal GnRH secretion then Adult type pulsetile pattern ( every 90-120 min )

Pubertal onset (11 years)

↑ovarian follicular developments↑ steroid production ( E2)Development of secondary sexual characteristics By mid – late puberty maturation of the +ve feedback mechanism of E2 on LH release and ovulatory cycle established at 14 -16 years

Somatic changes

Breast buding ( thelarche) Axillary & pubic hair ( adrenarche ,pubarche) Accelerated linear growth (growth spurt) First menstrual cycle (menarche) Adult shape breast and pubic hairs * Somatic changes takes about 4.5 years average , ( range 1.5 - 6 years )

Precocious puberty

Precocious puberty :- the development of any sign of secondary sexual maturation at an age earlier than 2.5 standard deviations below the expected age of puberty 8 years Incidence 1/ 10000 Male / female ratio 1/5 75% of all cases are constitutional idiopathic Typically taller than their peers as children but short as adult due to premature closure of epiphyses

Classification of female precocious puberty

Heterosexual precocious puberty (male type puberty) a. virilizing neoplasm (tumors secreting androgens ) ovarian adrenal b. congenital adrenal hyperplasia c. exogenous androgen exposure


2. Isosexual precocious puberty:- (female type maturity) A. complete I . true precocious puberty i) idiopathic (constitutional) 90% ii) brain disease 10% II. Pseudo precocious puberty i) ovarian tumor secret estrogen ii) adrenal tumor iii) hypothyroidism in girls* (delayed bone age) iv) exogenous v) McCune –Albright syndrome vi) Peutz-Jegher syndrome (associated with ov.tumor) B. incomplete I . Premature thelarche (breast bud only) II. Premature pubarche ( pubic hair only ) 50% CNS disease III . Premature adrenarche ( axillary hair only )

True precocious puberty

McCune-Albright syndrome

Polyostotic fibrous dysplasiaMcCune-Albright syndrome

True precocious puberty
There is activation of the hypothalamus pituitary ovarian axis (like normal adults) Normal sequence of events ( 1st breast bud ,2nd axillary & pubic hair, 3rd accelerated growth, menarche )

Diagnosis of precocious puberty

History:-Similar family historySequence of sexual maturationSpeed of sexual maturationExposure to drug or hormonesCNS (meningitis, encephalitis, abscess, TB, tumor, neurofibromatosis trauma, seizures, headache, blurring of vision, numbness, muscle weakness,… etc.)

Physical examination

Investigations
Skull X ray Serial bone age estimations X ray hands&elbow CT, MRI head sella turcica & hypothalamous U/S , MRI abdomen & pelvis FSH, LH, hCG DEHAS, androsteindione, testosterone, E2, P4 Prolactin Thyroid functon tests GnRH stimulation test EEG Visual field

Treatment of precocious puberty

75% constitutional true precocious puberty The most important problem of untreated girls is short stature (< 150 cm )* due to early closure of epiphysis of long bones

Treatment

GnRH analogues (triptorrilin , decapeptyl )It is similar to GnRH but it is of long action attach to pituitary GnRH receptors permanently and cause stimulation of FSH & LH at first week and then cause down regulation of pituitary receptors ie. Decrease the number of functioning receptors → suppression of the pituitary gland → suppression of ovarian activities.

Triptorrilin injection every 28 daysTill reach the determined height by 13-14 years then stop GnRH analogues and the hypothalamo - piuitary – ovarian axis resume normal activities

Treatment of other types of precocious puberty

GnRH analogues are ineffective in cases of pseudo-precocious puberty CNS diseases have unfavorable outcomes


Treatment of other types of precocious puberty
Ovarian, adrenal, brain tumors treated surgically Exogenous hormones by remove source McCune-Albright syndrome by antiestrogen (aromatase inhibitor Lotrizole + orthopedic care Hypothyroidism by thyroxine

Precocious thelarche no treatment usually transientPremature pubarche more common in boys 50% CNS disease ………exclude CNS disease …..no treatment Premature adrenarche……exclude adrenal disease …………..no treatment

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