Pubertal Disorders Flashcards
What is precocious puberty?
Onset of puberty occuring younger than 2SD below the average age
What is the prevalence of precocious puberty?
1 in 5,000 to 1 in 10,000, fairly common
How does the prevalence of precocious puberty differ in males and females?
5-10 times more common in girls than boys
What age is considered to be precocious puberty in boys?
<9 years old
What age is considered to be precocious puberty in females?
<8 years
What is true of the majority of cases of precocious puberty?
It is of unknown cause
What are the categories of causes of precocious puberty?
- Gonadotrophin dependant (central)
- Gondotrophin independant (neurological)
How do gonadotrophin dependant mechanisms of precocious puberty work?
Through the pituitary axis
What are the gonadotrophin dependant causes of precocious puberty?
- Tumours
- CNS trauma or injury
- Hamartomas of hypothalamus
- Gonadotrophin secreting tumours
What tumours can can precocious puberty?
- Gliomas
- Astrocytomas
- Hamartomas
- Pineal tumours
What are the causes of CNS trauma or injury leading to precocious puberty?
- Infection
- Radiation
- Surgery
What congenital disorders can cause gonadotrophin dependant precocious puberty?
- Hydrocephalus
- Arachnoid cysts
How common are gonadotrophin secreting tumours?
Very rare
What is a more common mechanism for tumours causing precocious puberty than gonadotrophin secreting tumours?
Normally, have a tumour that causes hypothalamic machinery to secrete, rather than doing it itself
What is gonadotrophin independant precocious puberty also known as?
Precocious pseudopuberty
What happens in precocious psuedopuberty?
There is early stimulation of central maturation, and so you get the apperance of secondary secxual characteristics due to increased production of female or male hormones
Does precocious pseudopuberty involve the HPG axis?
No, it occurs independantly of the HPG axis
What happens to LH and FSH levels in precocious pseudopuberty?
They are suppressed
What are the causes of precocious pseudopuberty?
- Congenital adrenal hyperplasia
- Tumours
- Testotoxicosis
- Exogeneous oestrogen or androgen exposure
What tumours can cause precocious pseudopuberty?
- HCG-secreting tumorus in the liver
- Choricocarcinomas of the gonads, pineal gland, or mediastinum
What can ovarian tumours cause?
Either masculisation or feminisation
What may testicular Leydig-cell tumours cause?
Early virilisation in males
What is testitoxicosis also known as?
Familial male precocious puberty
What is the inheritance pattern of familial male precocious puberty?
Autosomal dominant
How does familial male precocious puberty present?
- Rapid physical growth
- Sexual maturation
- Sexually aggressive behaviour in the first 2-3 years of life
How can exogenous oestrogen or androgen exposure occur?
- Therapeutic
- Accidental
What is delayed puberty?
When initial changes of puberty are not present
What is considered to be delayed puberty in females?
- No initial physical changes of puberty by age 13
- Primary amenorrhea at 15.5-16 years
- When the interval between first signs of puberty and menarche is greater than 5 years
What is considered to be delayed puberty in males?
- No signs on the Tanner scale by age 14
- When the interval between first signs of puberty and completion of genital growth is greater than 5 years
What are the causes of delayed puberty?
- Gonadal failure (hypergonadotrophic hypogonadism)
- Gonadal deficiency
What are the causes of gonadal failure?
- Turners syndrome
- Post-malignancy chemo/radiotherapy/surgery
- Polyglandular autoimmune syndromes
What is Turners syndrome?
A genetic condition that causes primary gonadal failure in development
What is the karyotype for Turners syndrome?
(45, X) or (46,XX) with structural abnormalities of X chromosome
What are the symptoms of Turners syndrome?
- Short stature
- Gonadal dysgenesis
- Skeletal abnormalities
- Cardiac and kidney malformation
- Dysmorfic face
- No mental defect
- No impairment of cognitive function
What is the final height of someone with Turners syndrome?
144-146cm
What therapy is used for Turners syndrome?
- Growth hormone
- Sex hormone substitution
What is the purpose of therapy in Turners syndrome?
Can’t correct gonadal dysgenesis, but can correct physical characteristics
What can cause a gonadal deficiency?
- Congenital hypogonadotrophic hypogonadism
- Hypothalamic/pituitary lesions
- Rare gene mutations inactivating FSH/LH or their receptors
What can cause hypothalamic/pituitary lesions?
- Tumours
- Post-radiotherapy
