Puberty

Question 1

Define puberty

Answer 1

physiological, morphological and behavioural changes as the gonads switch from infantile to adult forms

Question 2

Describe the process of puberty

Answer 2

inhibition of puberty diminishes
increased FSH and LH secretion
initiation of sex steroid secretion
sexual maturation
adolescent growth spurt

Question 3

What factors influence timing of puberty?

Answer 3

genetic - strong correlation between parents and children/siblings

nutrition - obese children enter puberty earlier, 17% body fat needed for menses, 22% for ovulation

environment - earlier puberty in urban areas, closer to equator, lower altitudes

Question 4

Requirements for puberty

Answer 4

normal capacity for growth
adequate nutrients
normal body composition
emotional wellbeing
good physical health

Question 5

Secondary sexual characteristics in girls

Answer 5

ovarian oestrogens regulate the growth of breast and female genitalia

ovarian and adrenal androgens control pubic and axillary hair

Question 6

Secondary sexual characteristics in boys

Answer 6

testicular androgens:
- external genitalia and pubic hair growth
- enlargement of larynx and laryngeal muscles –> voice deepening

Question 7

What staging is used to classify puberty?

Answer 7

Tanner staging

Question 8

What stages of puberty are the tanner stages roughly relating to?

Answer 8

pre-puberty = Tanner stage 1
early puberty = Tanner stage 2-3
later puberty = Tanner stage 4-5

Question 9

What signifies the start of puberty in boys and girls?

Answer 9

boys = testicular volume 4mls
girls = breast stage 2

Question 10

Order of male puberty

Answer 10

testicular enlargement and pubic hair occur first
growth of penis and growth in height starts after about 12 months

Question 11

Order of female puberty

Answer 11

growth rate increases from onset of puberty
breast and pubic hair development is congruent
menarche occurs late and growth stops shortly thereafter

Question 12

What is done in an endocrine evaluation of puberty?

Answer 12

clinical evaluation
pubertal staging
FSH, LH, testosterone, oestradiol, prolactin, thyroid function, karyotype, androstenedione, DHEAS
GnRH test
bone age xray (dominant hand + wrist)
pelvic ultrasound (girls)

Question 13

What ages suggest precocious puberty?

Answer 13

girls <8y
boys <9y

Question 14

How is early puberty classified?

Answer 14

central or gonadotrophin-dependent:
- usually girls
- usually idiopathic
- CNS lesion may be present

gonadotrophin-independent:
- sex-steroid production independent of FSH/LH

Question 15

Name some puberty variants

Answer 15

premature thelarche
premature pubarche (adrenarche)
isolated premature menarche
adolescent gynaecomastia

Question 16

Describe premature thelarche

Answer 16

isolated breast development - typically very young girls (1-4y)
non-progressive with no growth spurt
remits spontaneously

Question 17

Describe premature pubarche

Answer 17

isolated pubic hair development
usually girls 5-7y

Question 18

Describe isolated premature menarche

Answer 18

early onset of periods
despite no or minimal pubertal development
exclude hypothyroidism

Question 19

Describe adolescent gynaecomastia

Answer 19

common in early to mid puberty in boys, particularly if obese

Question 20

When is central precocious puberty always pathological?

Answer 20

in boys
- suggests CNS lesion

Question 21

Causes of true (central) precocious puberty (GnRH dependent)

Answer 21

idiopathic precocious puberty

CNS tumours - optic glioma, hypothalamic astrocytoma

CNS disorders - developmental abnormalities, hypothalamic hamartoma, encephalitis, brain abscess, hydrocephalus, myelomeningocele, arachnoid cyst, vascular lesion, cranial irradiation

secondary central precocious puberty

psychosocial eg. adoption from abroad

Question 22

Causes of precocious pseudo-puberty (GnRH-independent)

Answer 22

increased androgen secretion - congenital adrenal hyperplasia, virilising neoplasm, leydig cell adenoma, familial male precocious puberty (testotoxicosis)

gonadotrophin secreting tumours

mccune-albright syndrome
ovarian cyst
oestrogen-secreting neoplasm
(hypothyroidism)

Question 23

Describe McCune-Albright syndrome

Answer 23

triad of:
- precocious puberty
- large irregular cafe au lait patches
- polyostotic fibrous dysplasia

mosaic expression of G-protein coupled receptor over-activity

spontaneous secretion of various hormones may occur

Question 24

Describe congenital adrenal hyperplasia

Answer 24

inborn error of cortisol and/or aldosterone synthesis

mostly 21 alpha hydroxylase deficiency
large amounts of adrenal androgens and testosterone secreted, producing virilisation but with small testes
may go unrecognised in boyd
treatment with hydrocortisone replacement

Question 25

Central precocious puberty treatment

Answer 25

GnRH analogues non-pulsatile stimulation of FSH and LH secretion results in down regulation of responsiveness to GnRH

Question 26

Gonadotrophin-independent precocious puberty

Answer 26

treatment of the underlying cause where possible anti-androgen/androgen receptor blockers/aromatase inhibitors

Question 27

What ages are classed as delayed puberty?

Answer 27

>13y girls >14y boys

Question 28

Causes of delayed puberty

Answer 28

constitutional delay in growth and adolescence illness/malnutrition failure of hypothalamus/pituitary (hypogonadotrophic hypogonadism) gonadal failure

Question 29

Describe constitutional delay

Answer 29

often familial more common in males associated short stature spontaneous puberty will occur relative disproportion reduced final height

Question 30

What illnesses can cause delayed puberty?

Answer 30

chronic disease: - cystic fibrosis - crohn's disease - juvenile arthritis - steroid therapy hypothalamic amenorrhoea: - anorexia nervosa - athletes/gymnasts - leptin deficiency

Question 31

What is Kallmann's syndrome?

Answer 31

hypothalamic GnRH deficiency with anosmia

Question 32

Name some causes of hypogonadotrophic hypogonadism

Answer 32

Kallmann's syndrome Prader-Willi syndrome Pituitary gonadotrophin deficiency

Question 33

Name some causes of gonadal failure

Answer 33

Klinefelter's syndrome Turner's syndrome

Question 34

Normal LH level pre-puberty

Answer 34

<0.3

Question 35

Klinefelter's syndrome karyotype

Answer 35

47XXY

Question 36

Klinefelter's syndrome features

Answer 36

mild developmental delay/autistic features small, hard testes gynaecomastia elevated FSH, LH, low testosterone

Question 37

Constitutional delay treatment

Answer 37

sex steroid replacement until puberty well-established