Precocious, Delayed puberty, CAH Flashcards
What is precocious puberty?
- Development of secondary sexual characteristics BEFORE: 8yrs in females and 9yrs in males.
- More common in females
Aetiology of precocious puberty?
1) Gonadotropin-dependant/central/true precocious puberty:
- activation of the hypothalamic-pituitary-gonadal axis
- most cases are idiopathic, could be neoplasms e.g. hypothalamic tumour, hypothyroidism.
- FSH and LH raised
2) Gonadotropin-independant/pseudo/false precocious puberty:
- Excess steroids
- Ovarian causes - follicular cysts of the ovary, ganulosa cell tumours
- Testicular causes - Leydig cell tumours
- Adrenal tumours/congenital adrenal hyperplasia
- FSH and LH low
Precocious puberty differences in men and women?
- Usually idiopathic/familial in females - organic causes are rare.
- Uncommon in males but usually has an organic cause - examine testes and bilateral enlargement suggestive of gonadotropin-dependant, and unilateral - gonadal tumour. Small testes - adrenal cause (tumour or hyperplasia).
Presentation of precocious puberty?
- Normal puberty (TANNER STAGES) occur earlier:
- Females before 8 years:
1) Breast buds, 2) Pubic hair/growth spurt 3) Menarche - Males before 9 years:
1) Testicular enlargement, 2) Pubic hair 3) Growth spurt
Ddx of precocious puberty?
1) Premature thelarche - breast enlargement that may be asymmetrical and rarely progresses beyond Tanner Stage 3. Ddx from precocious puberty as absence of axilla + pubic hair, and growth spurt.
2) Premature adrenarche - common in africans and asians - early pubic hair development (<8yrs in females or 9yrs in boys) - NO OTHER SIGNS of sexual development. USS of ovaries and uterus and a bone age - to exclude central precocious puberty, urinary steroid profile helps ddx premature adrenarche from CAH.
Diagnosis of precocious puberty?
1) Growth charts
2) Tanner charts
3) Bone assessment - left wrist XR to estimate skeletal age
4) CT/MRI to exclude neoplasia
5) Serum FSH/LH - raised in central
6) Serum testosterone and oestrogen
Treatment of precocious puberty?
- Detect and treat underlying pathology
- Reducing rate of skeletal maturation (early spurt may result in early cessation of growth)
1) Gonadotropin-dependant - GOSERELIN - GnRH analogue, increased GnRH release overstimulates pituitary and reducing sensitivity - reduces LH and FSH - continue until normal age for puberty
2) Gonadotropin-independant - Source of excess steroids need to be identified. KETOCONAZOLE - inhibits androgen/oestrogen production.
What is delayed puberty? Ex and Ax?
- Lack of pubertal sings in >13yrs girls and >14yrs in boys.
- More common in boys
1) Constitutional delay in growth and puberty (CDGP) - MOST COMMON: familial, excess dieting/physical training (temporary), delayed skeletal maturity on bone age.
2) Low gonadotropin secretion (Hypogonadotrophic hypogonadism): - CF, Crohn’s, anorexia nervosa (systemic)
- Hypothalamo-pituitary disorders: Kallmann’s (lack of GNRH-secreting neurones in hypothalamus), Growth Hormone deficiency, acquire hypothyroidism.
3) High gonadotropin secretion (hypergonadotrophic hypogonadism) - chromosomal abnormalities (Kleinfelter, Turner), acquired gonadal damage (chemo/radio, surgery, torsion)
Presentation of delayed puberty?
- Delayed puberty after 13yrs in girls and 14 yrs in boys.
Diagnosis of delayed puberty?
- Boys: Puberty staging, especially testicular volume, identify chronic disorders
- Girls: Karyotype testing for Turner’s syndrome, thyroid and sex steroid hormones should be measured.
Treatment of delayed puberty?
Treat cause.
For CDGP:
- Boys: Not usually required as puberty eventually will occur. OXANDROLONE (catch up growth only, no sex Cx) and IM TESTOSTERONE (accelerate growth and secondary sexual characteristics)
- Girls: Oestrogen - e.g. oestradiol
What is Congenital Adrenal Hyperplasia (CAH)?
- Family of autosomal recessive disorders that result in enzyme deficiencies that impair normal corticosteroid biosynthesis by the adrenal cortex.
- More common in offspring of consanguineous (INCEST) marriages.
- Deficiency in 21-HYDROXYLASE needed for corticosteroid biosynthesis.
Pathophys of CAH?
- Adrenal cortex has 3 zones: glomerulosa (mineralocorticoids - aldosterone), fasciculata (glucocorticoids - cortisol), reticularis (Androgens converted to testosterone).
- 21-hydroxylase deficiency leads to cortisol deficiency - pituitary production of ACTH results in overproduction of testosterone (androgens get converted to testosterone peripherally).
- Also commonly unable to produce aldosterone resulting in salt loss - HYPONATRAEMIA, HYPERKALAEMIA.
Presentation of CAH?
G: Virilisation (masculinisation) of external female genitalia: Cllitoral hypertrophy and fusion of labia, girls may be masculinised.
B: Penis may be enlarged and scrotum pigmented in infant male, boy may be normal at birth but have precocious puberty, OR ambiguous genitalia.
SALT-LOSING ADRENAL CRISIS - 1-3wks of age - vomiting, W/L, floppiness, and circulatory collapse.
- NON-SALT LOSERS - develop muscular build adult body odour, pubic hair, acne from excess androgen production.
- FHx of neonatal death due to salt-losing crisis?
Diagnosis of CAH?
- Raised levels of the 21-hydroxylase pre-cursor: 17 a-hydroxyprogesterone in the blood.
- In salt-losers: Low Na+, high K+, metabolic acidosis from low aldosterone, hypoglycaemia (low cortisol).
