Lecture 5 - Puberty And Disorders Of HPG Flashcards
What is puberty?
The stage of human development when sexual maturation and growth are completed and result in the ability to reproduce
When are primary sexual characteristics established?
When does the repro system become activated?
Primary sexual characteristics = before birth
Repro system activation = puberty
What is the normal age range for puberty in males/boys?
9-14 years
What is the normal range for puberty in females/girls?
8-13 years
What happens in the first stage of puberty for males?
Genital development/scrotum and testes enlarge
What are the 4 stages of puberty in males?
Genital development (scrotum + testes enlarge)
Pubic hair growth
Spermatogenesis
Growth spurt
What are male secondary sexual characteristics that occur during puberty?
Increased and thicker hair on trunk, pubis, ,Axillae and face
Larger laryngeal size (Adams apple)
Dee ping of voice
Inc bone mass, muscle mass and strength
What is the first stage of puberty in girls?
Thelarche (Breast bud development)
What is Thelarche?
The normal first stage of pubertal development in females where the breast bud develops
What are the 4 normal stages of puberty in girls?
Thelarche (Breast bud development)
Adrenarche (Pubic hair growth)
Growth spurt
Menarche (menstrual cycle begins)
What is Adrenarche?
When the adrenal glands become activated to produce androgens leading to the development of secondary sexual characteristics like pubic hair growth
Does Adrenarche occur in men or women during puberty?
Both
What are some female secondary sexual characteristics?
Pubic and axillary hair
Enlargement of labia minora and majora
Keratinisation of vaginal mucosa
Uterine enlargement
Increased fat in hips/thighs
How does early and late pubic maturation socially affect boys and girls differently?
Early maturation for boys = +
Ealry maturation for girls = - (periods early)
Late maturation for boys = - (boys compare to peers)
Late maturation for girls = not really negative
What is the name of the condition referring to early puberty?
Precocious puberty
What is precocious puberty?
(Refer to the ages)
Puberty that occurs at an age before the normal for the population
So younger than 8 in females
Younger than 9 in males
What are the 2 types of precocious puberty?
Central/true precocious puberty
Peripheral/pseudo precocious puberty
What is Central/true precocious puberty?
Early puberty that follows the normal pattern of development due to the Hypothalamic pituitary axis being prematurely activated
So this type of Puberty is GnRH dependent (Gonadotropin releasing hormone)
What is peripheral precocious puberty?
Early pubertal development that doesn’t follow the normal pattern of puberty (first stage not breast bud development or increased testicular size)
Is GnRH independant since peripheral hormones being released which leads to development of secondary sexual characteristics
What are some causes of precocious puberty?
Idiopathic or constitutional (most common)
CNS lesions (activate HPG axis early)
Pituitary gonadotropin releasing tumours
Systemic conditions:
-tuberous sclerosis
-neurofibromatosis
Obesity
How can obesity lead to central precocious puberty?
Obesity leads to increased levels of leptin
Leptin activates the HPG axis triggering puberty (why puberty seems to be happening earlier in an increasingly obese population)
What key hormone is elevated in central precocious puberty?
GnRH level
What lab tests would be done to diagnose Central precocious puberty?
Increased LH and FSH levels
GnRH stimulation test done
Increased levels of testosterone or oestrogen
Generally what causes peripheral precocious puberty?
Peripheral production of Androgens, oestrogen or Beta HCG without GnRH being elevated
What can cause increased androgen production leading to peripheral precocious puberty?
Ovarian cyst (most common)
Congenital Adrenal Hyperplasia (CAH)
What is a cause of increased oestrogen production that can cause peripheral precocious puberty?
HCG-secreting germ cell tumours (granulosa cell tumour)
What is a cause of increased B-HCG production that can cause peripheral precocious puberty?
Hepatoblastoma
Primary hypothyroidism
Obesity related
What lab tests will show someone has peripheral precocious puberty?
Increased oestrogen or testosterone
Low levels of LH and FSH since GnRH levels are being suppressed by the elevated levels of gonadal hormones (oestrogen and androgens)
What is the key difference between Central and Peripheral precocious puberty in terms of hormone levels?
Central = high GnRH levels and so high LH and FSH
Peripheral = Low GnRH levels and so low LH and FSH
Typically what is the first change that occurs in peripheral precocious puberty?
Compare this to central
Peripheral = normally adrenarche (pubic/axillary hair)
Central = breast development or testicular growth
What is delayed puberty?
(Refer to ages)
When no pubertal changes have occured in a girl 13yrs or older or a boy aged 14yrs or older
Or the failure of developmental progression over a 2 year period (so first stage might happen but then no further development for the next 2 years)
What can cause delayed puberty?
Constitutional delay (runs in family)
Hypothalamic suppression
Chromosomal abnormalities
Hypogonadotrophic hypogonadism
What can cause hypothalamic suppression leading to delayed puberty?
Systemic illness
Weight loss
At are 2 chromosomal abnormalities that can cause delayed puberty?
Turner’s syndrome
Klinefelters syndrome
What is Turner’s syndrome?
Affects only females
Where theres is only 1 X chromosome
So karyotype is 45,X
What is Klinefelters syndrome?
Where boys are born with an extra X chromosome
So karyotype 47,XXY
What hormones are affected in Hypogonadotrophic hypogonadism?
Problem with pituitary gland or hypothalamus leading to little LH/FSH being made meaning the gonads aren’t stimulate to produce hormones
How can you determine if a 16 year old girl that presents with amenorrhoea has delayed puberty or not?
Do they have other signs of puberty or not
They could be delayed puberty or could be normal puberty with amenorrhoea
How can lots of exercise cause delayed puberty?
Doing lots of exercise or being underweight means very low leptin levels preventing activation of the HPG axis
What is hypergonadotropic hypogonadism? (primary hypogonadism)
Levels of FSH/LH are high so the gonads should be stimulated but there not due to some sort of problem with them
