Define puberty
Period during which adolescents reach sexual maturity + become capable of reproduction
What causes puberty to begin?
- all reproductive hormones exist at birth, go into hiding around 4-6 months then reappear 10-12 yrs later
- KISS gene produces molecule which stimulates gonadotrophins initiate puberty
- activation of HPG axis
Describe the HPG axis
FSH -> Testes -> Testosterone
LH -> Ovary -> Oestrogen + Progesterone
What is the timing of puberty in girls?
- 8-14 yrs
- breast budding then pubic hair
- growth spurt onset with breast budding
- menarche at end
What is the timing of puberty in boys?
- 9-15 yrs
- testicular + genital enlargement then pubic hair
- growth spurt mid-puberty
How is bone age assessed?
X ray of non-dominant hand + wrist
Normal children may have bone delay up to 2 yrs
Cannot be used to make diagnosis
What are the features of delayed puberty?
- small stature
- slow rate of growth in relation to age (low height velocity)
- delayed skeletal maturation (bone age)
- no evidence of sex-steroid production
What is Hypogonadotrophic hypogonadism?
- delayed puberty from defect/not switching on hypothalamic/pituitary axis
- constitutional delay in growth + puberty (CDGP)
- hypopituitarism
- hypothyroidism
- chronic
What is Hypergonadotrophic hypogonadism?
- delayed puberty with primary gonadal failure (from structural abnormalities in hypothalamic axis)
- gonadal dysgenesis =
- testicular + ovarian damage
What is the differential diagnosis of delayed puberty?
Normal or low serum gonadotrophins =
- constitutional delay of growth + puberty
- hypothyroidism
- hypopituitarism
High serum gonadotropins =
- gonadal dysgenesis
- bilateral primary gonadal failure
What is the treatment for delayed puberty?
- let nature take course or…
- give sex steroids (testosterone or oestrogen)
- used in patients with hypogonadotrophic and hypergonadotropic states
- treatment aimed at accelerating growth, inducing secondary sexual characteristics + boosting self-esteem
Define precocious puberty
- Physical + hormonal puberty signs at earlier than normal age
- Onset of secondary sexual characteristics before 8 in girls, before 9 in boys
- Menarche before 9
What are the features of precocious puberty?
- tall stature
- rapid growth rate
- advances skeletal maturation
- evidence of sex-steroid production: greasy skin + hair, acne, body odour, mood swings
What are the types pf precocious puberty?
- Independent
- sex steroids secreted WITHOUT activation of HPG axis
- sex steroids from adrenal or gonad
- isolated breast development
- virilisation = development of Mal characteristics in female or precociously in boys - excess androgen production - Dependent
- early activation of HPG axis
- majority idiopathic + girls
- CNS disruption - tumours of HP region
- post head injury/meningitis hydrocephalus
- post cranial surgery or radiotherapy
What is the UK protocol for investigation of precocious puberty?
- History
- Examination - pubertal staging
- Hormone measurements: testosterone/oestradiol, LH/FSH, adrenal androgens, TFT, GnRH test
- Radiology: bone age, pelvic US, MRI HP region
- DNA analysis for known genetic disorders
What is the treatment for dependent precocious puberty?
- Let nature take course or…
- Switch off pituitary hormones (gonadotropins) which trigger puberty -> will sloe down/stop physical changes but will not reverse
What is the outcome of GnRH therapy?
If treated before 8:
- 75% reach target height
- once treatment stopped, puberty continues
- long-term gonadal function unaffacted
