Lecture 5 - Puberty And Disorders Of HPG

Question 1

What is puberty?

Answer 1

The stage of human development when sexual maturation and growth are completed and result in the ability to reproduce

Question 2

When are primary sexual characteristics established?

When does the repro system become activated?

Answer 2

Primary sexual characteristics = before birth

Repro system activation = puberty

Question 3

What is the normal age range for puberty in males/boys?

Answer 3

9-14 years

Question 4

What is the normal range for puberty in females/girls?

Answer 4

8-13 years

Question 5

What happens in the first stage of puberty for males?

Answer 5

Genital development/scrotum and testes enlarge

Question 6

What are the 4 stages of puberty in males?

Answer 6

Genital development (scrotum + testes enlarge)

Pubic hair growth

Spermatogenesis

Growth spurt

Question 7

What are male secondary sexual characteristics that occur during puberty?

Answer 7

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

Question 8

What is the first stage of puberty in girls?

Answer 8

Thelarche (Breast bud development)

Question 9

What is Thelarche?

Answer 9

The normal first stage of pubertal development in females where the breast bud develops

Question 10

What are the 4 normal stages of puberty in girls?

Answer 10

Thelarche (Breast bud development)

Adrenarche (Pubic hair growth)

Growth spurt

Menarche (menstrual cycle begins)

Question 11

What is Adrenarche?

Answer 11

When the adrenal glands become activated to produce androgens leading to the development of secondary sexual characteristics like pubic hair growth

Question 12

Does Adrenarche occur in men or women during puberty?

Answer 12

Both

Question 13

What are some female secondary sexual characteristics?

Answer 13

Pubic and axillary hair

Enlargement of labia minora and majora

Keratinisation of vaginal mucosa

Uterine enlargement

Increased fat in hips/thighs

Question 14

How does early and late pubic maturation socially affect boys and girls differently?

Answer 14

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

Question 15

What is the name of the condition referring to early puberty?

Answer 15

Precocious puberty

Question 16

What is precocious puberty?

(Refer to the ages)

Answer 16

Puberty that occurs at an age before the normal for the population

So younger than 8 in females
Younger than 9 in males

Question 17

What are the 2 types of precocious puberty?

Answer 17

Central/true precocious puberty

Peripheral/pseudo precocious puberty

Question 18

What is Central/true precocious puberty?

Answer 18

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)

Question 19

What is peripheral precocious puberty?

Answer 19

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

Question 20

What are some causes of precocious puberty?

Answer 20

Idiopathic or constitutional (most common)

CNS lesions (activate HPG axis early)
Pituitary gonadotropin releasing tumours
Systemic conditions:
-tuberous sclerosis
-neurofibromatosis

Obesity

Question 21

How can obesity lead to central precocious puberty?

Answer 21

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)

Question 22

What key hormone is elevated in central precocious puberty?

Answer 22

GnRH level

Question 23

What lab tests would be done to diagnose Central precocious puberty?

Answer 23

Increased LH and FSH levels

GnRH stimulation test done

Increased levels of testosterone or oestrogen

Question 24

Generally what causes peripheral precocious puberty?

Answer 24

Peripheral production of Androgens, oestrogen or Beta HCG without GnRH being elevated

Question 25

What can cause increased androgen production leading to peripheral precocious puberty?

Answer 25

Ovarian cyst (most common) Congenital Adrenal Hyperplasia (CAH)

Question 26

What is a cause of increased oestrogen production that can cause peripheral precocious puberty?

Answer 26

HCG-secreting germ cell tumours (granulosa cell tumour)

Question 27

What is a cause of increased B-HCG production that can cause peripheral precocious puberty?

Answer 27

Hepatoblastoma Primary hypothyroidism Obesity related

Question 28

What lab tests will show someone has peripheral precocious puberty?

Answer 28

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)

Question 29

What is the key difference between Central and Peripheral precocious puberty in terms of hormone levels?

Answer 29

Central = high GnRH levels and so high LH and FSH Peripheral = Low GnRH levels and so low LH and FSH

Question 30

Typically what is the first change that occurs in peripheral precocious puberty? Compare this to central

Answer 30

Peripheral = normally adrenarche (pubic/axillary hair) Central = breast development or testicular growth

Question 31

What is delayed puberty? (Refer to ages)

Answer 31

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)

Question 32

What can cause delayed puberty?

Answer 32

Constitutional delay (runs in family) Hypothalamic suppression Chromosomal abnormalities Hypogonadotrophic hypogonadism

Question 33

What can cause hypothalamic suppression leading to delayed puberty?

Answer 33

Systemic illness Weight loss

Question 34

At are 2 chromosomal abnormalities that can cause delayed puberty?

Answer 34

Turner’s syndrome Klinefelters syndrome

Question 35

What is Turner’s syndrome?

Answer 35

Affects only females Where theres is only 1 X chromosome So karyotype is 45,X

Question 36

What is Klinefelters syndrome?

Answer 36

Where boys are born with an extra X chromosome So karyotype 47,XXY

Question 37

What hormones are affected in Hypogonadotrophic hypogonadism?

Answer 37

Problem with pituitary gland or hypothalamus leading to little LH/FSH being made meaning the gonads aren’t stimulate to produce hormones

Question 38

How can you determine if a 16 year old girl that presents with amenorrhoea has delayed puberty or not?

Answer 38

Do they have other signs of puberty or not They could be delayed puberty or could be normal puberty with amenorrhoea

Question 39

How can lots of exercise cause delayed puberty?

Answer 39

Doing lots of exercise or being underweight means very low leptin levels preventing activation of the HPG axis

Question 40

What is hypergonadotropic hypogonadism? (primary hypogonadism)

Answer 40

Levels of FSH/LH are high so the gonads should be stimulated but there not due to some sort of problem with them