Normal Puberty

Question 1

What is thelarche?

Answer 1

Onset of female breast development

Question 2

What is pubarche?

Answer 2

The appearance of pubic hair.

Question 3

What is adrenarche?

Answer 3

Onset of androgen-dependent body changes such as growth of axiliary and pubic hair, growth, acne, facial hair

Question 4

At what age do secondary sexual characteristics appear?

Answer 4

8-13 years (in 95% girls)

Question 5

What hormonal changes lead to the onset of puberty?

Answer 5

Hormonal changes can start severeal years before the physical signs of puberty begin.

Nocturnal pulsatile secretion of GnRH from the hypothalamus stimulates increased pulsatile secretion of LH from anterior pituitary

As the amplitude of gonadotrophin pulses increases and approaches adult levels, ovarian production of estradiol increases.

The development of secondary sexual characteristics is largely attributed to the increase in estradiol.

This describes the maturation of the HPO axis.

Question 6

What is the definition of puberty?

Answer 6

The transition from childhood to adulthood, characterised by a growth spurt and the development of secondary sexual characteristics.

Question 7

Thelarche precedes menarche by how long?

Answer 7

An average of 2-3 years

Question 8

Describe the main production pathway of androgens in women:

Answer 8

• All steroid hormones are derived from cholesterol.
• Androgen synthesis occurs mostly in zona reticularis of adrenal cortex, also in theca cells of ovary
• Cholesterol –> progesterone –> 17 OH-progesterone –> androstenedione –> testosterone
• Cholesterol –> pregnenolone –> DHEA –> androstenedione –> testosterone
• Primary adrenal androgen products are DHEA and androstenedione
• DHEA can be converted to androstenedione
• Androstenedione is then converted into testosterone, mostly >90% within the gonads (leydig cells of testes or theca cells of ovaries) and to a lesser extent within the zona reticularis of the adrenal cortex.

Question 9

What hormone (outside the HPO axis) plays a permissive role in the development of puberty?

Answer 9

Leptin.

Metabolic hormone produced by adipose tissue in response to fat deposition; the primary function is to stimulate satiety and reduce fat deposition when increased adiposity.

Also stimulate hypothalamus to secrete GnRH. Thus in fat and energy deplete states, women produce less leptin which can disrupt the normal HPO axis, causing Hypothalamic-hypogonadatropic ammennorrhea.

Question 10

Thelarche precedes menarche by…

Answer 10

2-3 years

Thelarche is often the first sign of puberty, and starts age 9-11 years.

Menarche is ususally the last stage of puberty, and the average age of onset is 13 years. It requires maturation of the HPO axis to start.

Question 11

What embryological tissue does the male and female genital systems arise from?

Answer 11

Female - Paramesonephric / Mullerian ducts

Male - Mesonephric / wolffian ducts

Both have elements from the urogenital sinus, part of the cloaca which has element of endoerm and ectoderm.

• lower 2/3 vagina and external genitalia

Question 12

At what gestation does sex differentiation occur?

Answer 12

Week 7
When the undifferentiated gonad becomes a testis or an ovary

Chromosomes determined at conception

Fetus is identifiable as male or female by 12/40

Question 13

What are the differences in the vulval anatomy pre-puberty?

Answer 13

Less prominent labia minora

Absence of labial fat pads

Abscence pubic hair

Thin, erythematous and sensitive vulvar skin

atrophic and alkaline vaginal mucosa (abscence of lactobacilli)

Question 14

What % adolescents will have a hymenal abnormality?

Answer 14

3%

Question 15

What are 5 types of hymenal abnormalities

Answer 15

Imperforate
Cribiform
Fimbriated
Hymenal bands
Microperforate

Question 16

What is the DDx for genital bleeding in childhood?

Answer 16

Vulvovaginitis
Foreign body
Genital trauma
Neonatal oestrogen withdrawal bleed (within 10 days of birth)
Premature menarche or precocious puberty
Urethral prolapse
UTI
Labial adhesions
Dermopathy
Pinworms with excoriation from scratching
Neoplasm

Question 17

What are streak gonads?

Answer 17

Reproductive tissue replaced with functionless, fibrous tissue
Atypical development of the gonads in an embryo

Question 18

What are the stages and timeframe of normal development during puberty?

Answer 18

Puberty can start from age 8

1) Thelarche (age 9-11)
2) Pubarche - 6 months later
3) Adrenarche (armpit hair, facial hair, acne, highest growth velocity) - usually around age 12
3) Menarche is a late development, and usually starts 2-3 years after thelarche; the average age is 13 years. Initial cycles will be anovulatory and often irregular.