Lecture 5 - Puberty And Disorders Of HPG Flashcards

1
Q

What is puberty?

A

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

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2
Q

When are primary sexual characteristics established?

When does the repro system become activated?

A

Primary sexual characteristics = before birth

Repro system activation = puberty

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3
Q

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

A

9-14 years

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4
Q

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

A

8-13 years

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5
Q

What happens in the first stage of puberty for males?

A

Genital development/scrotum and testes enlarge

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6
Q

What are the 4 stages of puberty in males?

A

Genital development (scrotum + testes enlarge)

Pubic hair growth

Spermatogenesis

Growth spurt

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7
Q

What are male secondary sexual characteristics that occur during puberty?

A

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

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8
Q

What is the first stage of puberty in girls?

A

Thelarche (Breast bud development)

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9
Q

What is Thelarche?

A

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

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10
Q

What are the 4 normal stages of puberty in girls?

A

Thelarche (Breast bud development)

Adrenarche (Pubic hair growth)

Growth spurt

Menarche (menstrual cycle begins)

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11
Q

What is Adrenarche?

A

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

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12
Q

Does Adrenarche occur in men or women during puberty?

A

Both

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13
Q

What are some female secondary sexual characteristics?

A

Pubic and axillary hair

Enlargement of labia minora and majora

Keratinisation of vaginal mucosa

Uterine enlargement

Increased fat in hips/thighs

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14
Q

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

A

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

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15
Q

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

A

Precocious puberty

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16
Q

What is precocious puberty?

(Refer to the ages)

A

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

So younger than 8 in females
Younger than 9 in males

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17
Q

What are the 2 types of precocious puberty?

A

Central/true precocious puberty

Peripheral/pseudo precocious puberty

18
Q

What is Central/true precocious puberty?

A

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)

19
Q

What is peripheral precocious puberty?

A

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

20
Q

What are some causes of precocious puberty?

A

Idiopathic or constitutional (most common)

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

Obesity

21
Q

How can obesity lead to central precocious puberty?

A

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)

22
Q

What key hormone is elevated in central precocious puberty?

A

GnRH level

23
Q

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

A

Increased LH and FSH levels

GnRH stimulation test done

Increased levels of testosterone or oestrogen

24
Q

Generally what causes peripheral precocious puberty?

A

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

25
Q

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

A

Ovarian cyst (most common)

Congenital Adrenal Hyperplasia (CAH)

26
Q

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

A

HCG-secreting germ cell tumours (granulosa cell tumour)

27
Q

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

A

Hepatoblastoma
Primary hypothyroidism
Obesity related

28
Q

What lab tests will show someone has peripheral precocious puberty?

A

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)

29
Q

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

A

Central = high GnRH levels and so high LH and FSH

Peripheral = Low GnRH levels and so low LH and FSH

30
Q

Typically what is the first change that occurs in peripheral precocious puberty?

Compare this to central

A

Peripheral = normally adrenarche (pubic/axillary hair)

Central = breast development or testicular growth

31
Q

What is delayed puberty?

(Refer to ages)

A

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)

32
Q

What can cause delayed puberty?

A

Constitutional delay (runs in family)

Hypothalamic suppression

Chromosomal abnormalities

Hypogonadotrophic hypogonadism

33
Q

What can cause hypothalamic suppression leading to delayed puberty?

A

Systemic illness

Weight loss

34
Q

At are 2 chromosomal abnormalities that can cause delayed puberty?

A

Turner’s syndrome

Klinefelters syndrome

35
Q

What is Turner’s syndrome?

A

Affects only females

Where theres is only 1 X chromosome

So karyotype is 45,X

36
Q

What is Klinefelters syndrome?

A

Where boys are born with an extra X chromosome

So karyotype 47,XXY

37
Q

What hormones are affected in Hypogonadotrophic hypogonadism?

A

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

38
Q

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

A

Do they have other signs of puberty or not

They could be delayed puberty or could be normal puberty with amenorrhoea

39
Q

How can lots of exercise cause delayed puberty?

A

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

40
Q

What is hypergonadotropic hypogonadism? (primary hypogonadism)

A

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