endocrine infertility Flashcards
what is the normal reproductive physiology in males?
- GnRH stimulates LH and FSH release
- these act on Sertoli and Leydig cells in testis to produce testosterone and inhibin
what is the normal reproductive physiology in females?
- 28 day menstrual cycle
- follicular phase, ovulation and luteal phase
- high levels of oestradiol trigger switch to positive feedback on hypothalamus
- triggers large GnRH and LH release
what happens in luteal phase if implantation doesn’t occur?
endometrium is shed
define infertility
inability to conceive after 1 year of regular unprotected sex
what can infertility be due to?
- primary gonadal failure (high GnRH and LH/FSH but no inhibin/testosterone)
- hypo/pituitary disease (low FSH/LG and no inhibin/testosterone)
what are the clinical features of male hypogonadism?
- loss of libido
- impotence
- small testes
- dec. muscle bulk
- osteoporosis
what are the causes of male hypogonadism?
- hypothalamic-pituitary disease
- primary gonadal disease (Kleinfelter’s, testicualr torsion)
- hyperprolactinaemia
- androgen receptor def
what investigations would you carry our for male hypogonadism?
- LH, FSH, testosterone levels
- prolactin
- sperm count
- chromosomal analysis
what 2 things do you look for in a sperm count?
- azospermia: absence of sperm in ejaculate
- oligospermia: reduced sperm in ejaculate
what is the treatment of male hypogonadism?
- HRT - replace testosterone
- for fertlity - testosterone isn’t enough, give LH/FSH
- hyperprolactinaemia: dopamine agonist to inhibit prolactin
where are testosterone/androgens produced?
- leydig cells of testis
- adrenal cortex
- ovaries
- placenta
- tumours
what are the main actions of testosterone?
- development of male genital tract
- secondary sexual characteristics
- maintenance of adult fertility
- anabolic effects
how much testosterone is protein bound?
98%
what 2 enzymes can act on testosterone?
5 alpha reductase turns testosterone into DHT (acts on AR)
aromatase action turns testosterone into 17 beta oestradiol (acts on ER)
what are the clincial uses of testosterone?
in adulthood, testosterone will inc:
- lean body mass
- muscle size and strength
- bone formation and mass
- libido and potency
what is amenorrhoea? priamry/secondary?
- absence of periods
- primary: failure to begin spontaneous menstruation by 16
- secondary: absence of menstruation for 3 months in a woman that has previously had cycles
what is oligomenorrhoea?
irregular long cycles
what are the causes of amenorrhoea?
- pregnancy or lactation
- ovarian failure
- gonadotrophin failure
- hyperprolactinaemia
- androgen excess
what investigations should be done with someone with amenorrhoea?
- pregnancy test
- LH, FSH, oestradiol, androgen blood test
- day 21 progesterone (can tell if women ovulated in previous cycle)
- prolactin, thyroid function tests
- chromosomal analysis
- ultrasound scan
what is the treatment for amenorrhoea?
- treat the cause
- primary ovarian failure (infertile so HRT)
- Hypo/pit disease (HRT for oestrogen replacement and gonadotrophins for fertility treatment)
what is PCOS associated with?
- inc. CVS risk
- insulin resistance
what does the diagnosis of PCOS require?
2 of:
- polycystic ovaries on ultrasound
- irregular or no ovulation
- androgen excess
what are the clinical features of PCOS?
- hirsutism
- menstrual cycle disturbance
- inc. BMI
what is the treatment of PCOS?
- metformin
- clomiphene
- gonadotrophin therapy
what is clomiphene?
- oestrogen-antagonist
- binds to oestrogen receptors in hypothalamus
- blocks normal -ve feedback
- results in inc. GnRH and gonadotrophin secretion
what are the causes of hyperprolactinaemia?
- dopamine antagonist drugs (anti-emetics, anti-psychotics)
- prolactinoma
- stalk compression due to pituitary adenoma
- PCOS
- primary hypothyroidism
- oestrogens, pregnancy and lactation
what are the clinical features of hyperprolactinaemia?
- galactorrhoea
- hypogonadism
- prolactinoma (headache and visual field defects)
what is the treatment of hyperprolactinaemia?
- treat cause
- dopamine agonists (cabergoline, bromocriptine)
- prolactinoma (DA agonists, pituitary surgery)
