. Physiology of puberty. Flashcards
the mean age when puberty starts has lowered and menarche has stayed the same what does this mean ?
women stays more in their puberty
what are the features of puberty in females ?
estrogen dependant :
breast development - a palpable breast disc first sign between 8.5-12.5 years
pubic hair growth and rapid height growth immediately after breast development
enlargement of the ovaries , uterus , vagina , labia
fat redistribution in hips and breast and bone maturation
what are the pubic hair changes in males
sparse and pigmented , long and straight and mainly along the base of the penis
getting darker and coarser and curlier and spread in the medial thighs
what are the male genital changes in puberty ?
seminiferous tubules develop under FSH causing testicular enlargement over 4ml volume and measured using and orchidometer - which is the FIRST CLINICAL SIGN of puberty (earlier than pubic hair growth) = occurs between 10-14 years of age
long standing pulsation of LH causes the interstitial cells to differentiate into lydia cells - giving negative feedback fro lh secretion
there is the lengthening of the penis and it circumference
then there is development of gland penis , darkening of the scrotal skin
menarche occurs how many years after puberty ?
on average 2.5 years
menarche signals what ?
growth coming to an end an only 5 cm left to gain in height
when the testicular volume is around 12-15ml what occurs ?
rapid height growth with a delay of 18 months
what is the difference in growth spurts in puberty in males and females
the growth spurt in males occur later than to a women and of greater magnitude
MALE VOICE PITCH CHANGES
what are the there signs of puberty in both sexes ?
development of acne , axillary hair 13YEARS F AGE , body odour , mood changes
if puberty is early or late it can be further assessed by what ?
bone age measurement from a hand and wrist to determine skeletal maturation
pelvic ultrasound in females to asses the uterine size and endometrial thickness
what are the is the normal period cycle
cycle of 21-45 days is normal with a optimum of 28 days (+- 7 days)
and the menstruation length is on average 5 days (between 3-7 days)
what is the average blood loss per cycle ?
less than 80ml
what are the signs which imply heavy bleeding ?
passage of blood clots or are than 6 pads daily
amenorrhea is split into ?
primary and secondary
what is primary amenorrhea
patients who have no secondary sexual characteristics and no menarche by the age of 14 - delayed puberty
normal secondary sexual characteristics but no menarche by age of 16
what is secondary amenorrhea ?
absence of menstrual periods for more than 3 months who has previously been regular
what are the causes for primary amenorrhea ?
unbroken hymen vagina without cervix absence of vagina non perforated cervix asherman syndrome hypoplastic uterus
turner syndrome - ovarian dysgensisis , increased fsh and LH , congenital cardiac defects
androgen insensitivity- atresia o vagina , ovaries or fallopian tubes
clitorial hypertrophy
testicles inguinally
increased estrogen and LH bt normal FSH
Kallmann syndrome -olfactory genital dysplasia
anorexia nervosa
hyperprolactinemia - Ahumada-Del Castillo syndrome include the abnormal production of breast milk (galactorrhea) without childbirth and nursing
prolactinoma
hypopituitarism tumors , infection , radiation
hypothyrodism
low T4 –> inc TRH (hypothalamus)/ TSH (anterior pitutory)–> dec dopamine (inhibitor of prolactin) –> inc prolactin –> dec GnRH –> dec LH + FSH
addison disease
frolic syndrome -Adiposogenital Dystrophy
congenital adrenal hyperplasia
TRUNER SYNDROME -gonadal dysgenesis
increased fsh and LH , congenital cardiac defects
reason for secondary amenorrhea ?
anorexia nervosa
-Weight loss can cause elevations in the hormone ghrelin which inhibits the hypothalamic-pituitary-ovarial axis
hyperprolactinemia - chiari frommel syndrome - affects women who have recently given birth (postpartum) and is characterized by the over-production of breast milk/ excessive stress / pills
premature ovarian failure - genetic
Autoimmune diseases
smoking
pregnancy
sheehan’s syndrome - postpartum pituitary gland necrosis,
schemic necrosis due to blood loss and hypovolemic shock during and after childbirth
adrenal / ovarian tumors
PCOS
how to diagnose primary amenorrhea ?
US to visualise normal uterus and ovaries and vagina
check all the blood hormones
congenital adrenal hyperplasia - 17-hydroxyprogesterone checked
how do we diagnose secondary amenorrhea ?
pregnancy test
progesterone test performed - once you cease it bleeding occurs meaning normal endometrium
if bleeding does not occur oestrogen’s are applies followed by progesterone test - still no bleeding - asherman syndrome suspected
T3,T4,TSH measured
serum FSH- increased levels show ovarian insufficiency
if LH:FSH ratio over 3 = PCOS
prolactin tested
testosterone levels tested
increased testosterone but normal DHEAS = ovarian tumor
increase testosterone and DHEAS = PCOS , adrenal hyperplasia or neoplasia
abdominal US
CA125
what is precocious puberty?
Precocious puberty occurs when children younger than 8 in males and younger than 9 in males experience changes indicative of puberty, including development of breast buds (thelarche), pubic hair, menstruation,and a growth spurt.
cause of precocious puberty
central precocious puberty - gonadotropin dependant and premature activation of the hypothalamic-pituitary-ovarian axis eg - hypothalamic hamartomas brain tumours infections - most common tuberculous meningitis radiation hydrocephalus
Peripheral precocious puberty are GnRH independent
from gonads such as ovarian cyst , ovarian tumors (sex chord gonadal tumors that produce estrogen - granulose cell tumor /thecoma)
adrenals - tumors , congenital adrenal hyperplasia
germ cell tumor - producing ectopic hCG
exogenous sex hormone exposure
primary hypothyroidism
diagnosis of precocious puberty and treatment
media history - start of menstruaton usually before 10 years in girls
physical examination - hieght , weight
tanner staging - breast formation , pubic hair
blood tests - for LH and FSH , estradiol , testosterone , TSH and free t4
bone age and skeletal maturation
treatment continuous use of GnRH agonists decreases gonadotropins
what affects the time when puberty occurs ?
GENETICS ETHINICITY malnutrition chronic diseases socioeconomic condition environmental factors
1-3 years before the onset of puberty what are the clinical signs evident ?
nocturnal LH levels increase inpulsatile fashion showing the GnRH release - releasing gonadotropin
mid puberty the lh surge becomes evident
FSH stimulates the follicles
and LH stimulates the leading cell
lydig cells release testosterone
while the follicular cells generate estrogen
secretion of sex hormones
what begins to increase in 6-8 years of age ?
DHEA and sulphated DHEAS - adrenarche
precede menarche b 2 year’s
what ar the 3 critical changes in prepubertal period
adrenarche
increase gonadostat
gradual amplification of GNrh - gonadtropin interaction
is the mechanism initiating gonadarche the same as the mechanism initiating adrenarche ?
NO -
demonstrated by kallman syndrome -no gonadarche but adrenarche occurs
addison disease - gonadacrhe occurs even in the absence adrenarche
what causes the adrenals to mature and release sex hormones ?
pitutory adrenal androgen stimulating factor
local steroid inhibitors of key enzymes within the adrenals
which hormone is uncharge for the timing of the puberty ?
leptin - inhibits neuropeptide y gene expression
leptin levels increase in puberty - higher the leptin earlier the menarche and girls with precocious puberty has higher levels of leptin produced from the adipose tissue
also IGF-1
describe tanner staging
stage 1 - elevation of papilla only and no pubic hair
stage 2 - elevation for breast and papilla , areola diameter enlarged
age 9
sparse long , pigmented along labia major
age 10
stage 3 - further enlargement without separation of breast and areola
age -11
dark coarse and curly hair
age 11
stage 4 - secondary mounds of areola and papilla above the breast
age 12
adult type hair , abundant but limited to mons
age - 12
stage 5 - recession of areola to contour the breast
age : 14
adult type spread os pubic hair in quantity and distribution
median age 17
when does the average peak of growth occur ?
2 years before breast budding and one year prior to menarche
limited growth potential after menarche -
puberty is over when ?
sexual characteristics are fully developed
what is the median age for MENARCHE?
12-13 YEARS
RANGE OF 10-15 YEARS
WHEN DOES SPERMARCHE occur in men ?
14 years of age
