Puberty Flashcards
What is puberty
Describes the physiological, morphological, and behavioural changes as the gonads switch from infantile to adult forms
What are the physical changes of puberty
-growth (have a growth spurt, rapid increase in heighr due to sex hormones)
Girls
* Breast development
– Controlled by ovarian oestrogens
* Pubic and axillary hair
– Controlled by ovarian and adrenal androgens
Boys:
* Development of penis, scrotum and pubic hair growth
* Enlargement of larynx and laryngeal muscles (voice deepening)
* increase of body muscle mass
– Controlled by testicular (and adrenal)
androgens
Growth: puberty changes increase in height velocity, peak and then decrease growth velocity (due to epiphyseal fusion)
-girls start puberty earlier and grow earlier, and peak height velocity for men is higher than women
What is the average height gain in puberty
boys 28cm
Girls 25 cm
What is the tanner stages for boys
tanner stages: to see how people develop
-look at pubic hair
-enlargement of penis
pubic hair
stage 1: no hair,
stage2: slighly curly hair on base of penis
stage 3: thicker curly hair on mons pubis
stage 4: adult type hair on medial surface of thighs
stage 5L spread of medial thigh
What are the tanners stages of girls
look at pubic hair and breast development
What is the first thing you see in boys and girls
boys: onset of pubic hair, then growth of testicles, height growth
girls: onset of pubic hair, then breast enlargment, height growth
How do we assess puberty start in boys
-use orchiodometer to see assess testciualr volume
-puberty starts at 4ml should increase to 15ml
How do we assess puberty start in girls
look at tanner stage 2
-outward dipping of areola, and it gets slightly darker
menarche is last stage of puberty: menarche use to 18 in 1830 -> 12
What do we need for humans
-sex chromsomes
-a hypothalamus
-a pituritary
-ovary/testes
-responsive tissues
How do male gonads develop
SRY gene
-enables gonads to differenate into testes
-sertoli cells: sperm production
-leydig cells: make testosterone, they also secrete AMH, to regress mullerin anatomical structures paramesonephric ducts (give rise to uterus and vagina)
-testosterone or DHT cause the devleopment he mesonephric ducts develop to form the primary male genital ducts (vas defferns, epididymis etc)
-DHT binding androgen receptor leads to penile enlargemnt
Do you know your HPA axis
YES OR NO
if not its very important cba to write down
inhibin produced by sertoli cell is an indicator of work
What is adrenarche
in childhood
you only have zona glomerulosa, and zona fasticulta
the zona reticualris randomally develops at a simialr time to puberty
What are clinical features of adrenarche
Clinical Features:
* Transient growth acceleration
* pubic / axillary hair
* oily skin, mild acne
* adult-type body odour
adrearche not puberty
Precocious puberty
onset of secondary sexual haracteristics before 8 yrs (girl), 9 yrs (boy)
Menarche before 9 yrs may lead to short stature
Delayed puberty
absence of secondary sexual characteristics by 13 yrs (girl), 14 yrs (boy)
Delayed puberty leads to reduced peak bone mass and osteoporosis
What is premature adrenarche
Increased adrenal androgen secretion (above age specfic age)
+have clinical eatures of androgen action (pubic/axillary hair, body dour, mild acne, oily hair and skin before 8 in girls and 9 in boys
How do we know if early puberty is central
GnRH dependant
-more common in girls than boys
-idiopathic
CNS tumors
CNS disorders
Secondary central precocious
puberty (i.e. CAH)
* Psychosocial
What is peripheral precocious puberty
GnRH independant
causes
-Increased androgen secretion
-Gonadotropin secreting tumours
McCune-Albright syndrome
* Ovarian cyst
* Oestrogen secreting neoplasm
* (Hypothyroidism)
* Iatrogenic or exogenous sex hormones
How do we know if its central or peripheral
Use GnRH test
-inject analgoue to GnRH
-measure LH, FSH at baseline and after GnRH if given
-if puberty is central, pituariatry cells respond, you see an increase of LH over FSH
if its peripheral
-you would not see LH, FSH levels increase
What are the consequences of early puberty
-growth -> short stature in growth
-increseing evidence children with PP develop metabolic conditions
-altered self image,
Treatment of central PP
Long acting GNRH analogues
-blocks release of LH, FSH stops puberty
-given as injection every 10 weeks
-usually discontinued when of pubertal age
What is meant by delayed puberty
Absence of secondary sexual
characteristics by
– 13 years in a girl
– 14 years in a boy
* First period after 15 years of age
What are the cause of delayed puberty
is it in brain or gonads
primary failure (hypergondatrophic hypogonadism) -> ovaries/testes does not respond to FSH, LH
secondary failure -> hypogondratrophic, hypogonadism (low FSH, LH), ovaries.testes don’t have hormones to respond to
How can you differnaite between intact or impaired HPG axis
intact
-can be due to chronic disease, poor nutrition, psychosocial deprivation,
steroid therapy, hypothyroidism
impaired GnRH
- Tumours adjacent to HP axis (cranio, optic glioma,
germinoma)
* Congenital anomalies (hypopituitarism, septo-optic
dysplasia)
* Irradiation & trauma
* GnRH/LH/FSH deficiency (including Kallmann, Prader-Willi,
Laurence-Moon-Bardet-Biedl syndrome).
What would be the peripheral causes of delayed puberty
Male
* Bilateral testicular damage (cryptorchidism, torsion,
haemochromatosis)
* Syndromes associated with cryptorchidism (Noonan,
Prader-Willi, Laurence-Moon-Bardet-Biedl syndrome)
Female
* Disorders of Sex Development (eg. Complete Androgen
insensitivity syndrome (CAIS)
* Toxic damage (thalassaemia, galactosaemia)
Both sexes
* Gonadal dysgenesis (female; Turner syndrome (45XO),
male; Klinefelter syndrome (47XXY))
* Irradiation/chemotherapy
Key investigations
LH, FSH,
Oestrodiol, teststorne
karoytpe
GnRh TEST
Treatment of delayed puberty
BOYS
* Testosterone: usually Sustanon® 50 (-250) mg intramusclary slowly up titrated
GIRLS
* Oestrogen: usually 17b-ethinyl-oestradiol transdermal patches (i.e. Evorel 25), slowly up titrated starting with ¼ patch 3 days on, 3 days off
