Biological Aspects of Puberty

Question 1

Types of feedback in the H-P-Gonadal axis

Answer 1

Only long!

Estradiol, progesterone and testosterone feedback to AP and hypothalamus

Question 2

Onset of puberty

Answer 2

Reactivation of the HPGA axis
Leads to increased nocturnal pulsatile secretion of LH and early morning secretion of gonadal steroid hormones
Appearance of an LH-predominant response during GnRH stimulation testing

Question 3

Adrenarche

Answer 3

2-3 years before pubertal onset
Rise in adrenal androgen levels
Occurs independently of GnRH

Question 4

Thelarche

Answer 4

Breast development

In 85% of girls it is the first outward sign of puberty

Question 5

First sign of puberty in

1. Girls
2. Boys

Answer 5

1. 85%: breast development, the rest its pubic hair

2. Testicular enlargement

Question 6

Average age of menarche

Answer 6

12-13

Question 7

Peak growth velocity at what stage for

1. Girls
2. Boys

Answer 7

1. 3

2. 4

Question 8

Pubertal progression in boys

Answer 8

Onset between age 9-14
Voice breaks around 13
Axillary, facial hair around age 14
Gynecomastia frequent at stage 4
Continued virilization into late teens

Question 9

Ages of precocious puberty for

1. Girls
2. Boys

Answer 9

1. Breast budding or pubic hair before age 8 or menarche before age 10
2. Testicular enlargement or pubic hair before 9

Question 10

Isosexual vs contrasexual pubertal development

Answer 10

Iso: seeing a lot of the correct hormone (ex: girls seeing estrogen)
Contra: seeing a lot of the opposite sex hormone (ex: girls seeing testosterone)

Question 11

Is GnRH dependent/independent going to be iso or contrasexual?

Answer 11

Dependent: always isosexual
Independent: can be either

Question 12

GnRH dependent precocious puberty

Answer 12

Brain has woken up early and started into puberty
Can be idiopathic in girls (rarely in boys)
CNS lesions
Prolonged exposure to sex hormones (tumors, CAH)

Question 13

GnRH independent precocious puberty

Answer 13

From the periphery

Many causes, depends on your gender

Question 14

McCune-Albright syndrome

Answer 14

G protein activating mutation
Precocious puberty, menarche
Bony lesions
Irregular cafe-au-lait spots
May have other autonomous endocrine tumors
May have non-endocrine involvement

Question 15

Premature thelarche

Answer 15

May appear at any age, usually < 5
Often asymmetrical, may regress
May be first sign of true precocious puberty
May be associated with ‘smouldering early puberty’
Generally benign if bone age not advancing

Question 16

Premature adrenarche

Answer 16

Usually warrants some investigation
May also have body odor, axillary hair, acne, hirsutism, acanthosis nigricans
Benign if bone age not advancing
Associated with later development of PCOS

Question 17

2 signs of Klinefelters

Answer 17

Gynecomastia

Small testicles

Question 18

Treatment of central precocious puberty

Answer 18

Medroxyprogesterone acetate (DepoProvera) injections
Can control menstrual periods and some sexual behaviours, without affecting adult height

Question 19

GnRH agonists

Answer 19

GnRH inhibits gonadotropin secretion if it’s given continuously
Halts pubertal development and menses
May cause some regression of secondary sex characteristics
Increases final height most in those who start puberty earliest and those with the most advanced bone age

Question 20

Leuprolie acetate (Lupron Depot)

Answer 20

Only GnRH agonist licensed for treatment of central PP in Canada
Only available to ped endos
IM every 3-4 weeks
Requires frequent monitoring

Question 21

Signs of delayed puberty in

1. Girls
2. Boys

Answer 21

1. No breast development by 13 or menarche by 16. Or absence of menarche within 5 years of pubertal onset
2. No increase in testicular size by age 14

Question 22

Treatment of CDGA for

1. Girls
2. Boys

Answer 22

1. Ethinyl estradiol (low dose). Not before 13 yo

2. Watch and wait. Then low dose depot testosterone. Not before 13 yo