3.1 lecture: endocrinology: pubertal disorders

Question 1

what are the types of pubertal disorders?

Answer 1

precoccious puberty

delayed puberty

Question 2

what is precocious puberty?

Answer 2

onset of puberty is defined as occurring younger than 2 standard deviations before the average age

Question 3

what is the prevalence of precocious pubery?

Answer 3

1/5000 - 1/10,000

5-10x > in girls

Question 4

what age is defined as precocious puberty in boys and girls?

Answer 4

girls < 8 years old

boys < 9 years old

Question 5

what are the causes of precocious puberty?

Answer 5

majority: unknown cause
gonadotrophin dependent (central)
gonadotrophin independent (neurological): early stimulation of central maturation

Question 6

what are examples of gonadotrophin-dependent precocious puberty?

Answer 6

1. hormone secreting tumours:
   gliomas, astrocytomas, hamartomas, pineal tumours
2. CNS trauma / injury (infection, radiation, surgery)
3. hamartomas of the hypothalamus
4. congenital disorders e.g. hydrocephalus, arachnoid cysts
   (gonadotrophin secretion tumours v rare)

Question 7

what is gonadotrophin-independent precocious puberty?

Answer 7

precocious pseudopuberty
appearance of secondary sexual characteristics (generating sex steroid hormones artificially without the regulation of the cascade of FSH/LH)

Question 8

why does gonadotrophin-independent precocious puberty cause appearance of secondary sexual characteristics?

Answer 8

increased production of female / male hormones (oestrogen / testosterone independent of HPG axis)
gonads mature without GnRH stimulation - levels of testosterone + oestrogen are elevated, LH + FSH are suppressed (negative feedback)
(no GnRH, high oestrogen, low LH/FSH)

Question 9

what are the causes of gonadotropin independent pernicious puberty?

Answer 9

1. congenital adrenal hyperplasia
2. tumours
3. testotoxicosis (autosomal dominant)
4. exogenous oestrogen / androgen exposure (therapeutic / accidental)

Question 10

what are examples of tumours which causes gonadotropin independent pernicious puberty?

Answer 10

1. HCG-secreting tumours in the liver (not uncommon)
2. choriocarcinomas of gonads, pineal gland, mediastinum:
   - ovarian tumours can cause masculinisation / feminisation
   - testicular Leydig-cells (LH, secrete testosterone) tumours may cause early virilisation in males

Question 11

describe testotoxicosis (familial male precocious puberty)

Answer 11

autosomal dominant

rapid physical growth, skeletal maturation, sexually aggressive behaviour in first 2-3 years of life

Question 12

what is the definition of delayed puberty in girls?

Answer 12

initial physical changes of puberty are not present by age 13 years

Question 13

what is the definition of delayed puberty in boys?

Answer 13

initial physical changes of puberty are not present by age 14 years

Question 14

how do you define pubertal development as inappropriate?

Answer 14

the interval between first signs of puberty and menarche in girls / completion genital growth in boys is > 5 years

Question 15

what are causes of delayed puberty?

Answer 15

1. gonadal failure

2. gonadal deficiency

Question 16

what are examples of gonadal failure causing delayed puberty?

Answer 16

hyPERgonadotrophic hypogonadism: (hypo secretion)
e.g. Turner’s syndrome
post malignancy chemo / radiotherapy / surgery (gonads damaged)
polyglandular AUTOIMMUNE syndromes

Question 17

what are examples of gonadal deficiency?

Answer 17

congenital hyPOgonadotrophic hypogonadism (+anosmia)
hypothalamic/pituitary lesions (tumours, post-radiotherapy)
rare gene mutations INactivating FSH/LH or their receptors (gonads not stimulated)

Question 18

what is Turner’s syndrome?

Answer 18

karyotype 45,X (only 1 X - can’t affect males)

structural abnormalities of X chromosome

Question 19

how do patients with Turner’s syndrome appear?

Answer 19

short stature (final height 144-146cm)
gonadal dysgenesis (loss of germ cells on gonads)
skeletal abnormalities
cardiac + kidney malformation
dysmorfic face
no mental defect
no impairment of cognitive function

Question 20

what are the therapies for Turner’s syndrome?

Answer 20

growth hormone

sex hormone substitution