polycystic ovarian syndrome Flashcards
polycystic ovarian syndrome affects around
6% of females of reproductive age
aetiology is
unknown but there are strong familial and lifestyle implications
thought to be due to
a disturbance in the pulsatile secretion of GnRH which causes low FSH and high LH
in PCOS the LH: FSH ratio is
greater than 2
individuals with PCOS have
increased insulin resistance independent of there body mass causing impaired glucose tolerance
LH stimulates
the theca cells to produce andorstendione but because there is insufficient FSH there isn’t enough aromatase or 17-alpha-HSD to converted it to oestrogen, however oestrogen levels tend to be normal or even elevated because the androstenedione is converted in the peripheries
people with PCOS also have
lower levels of sex hormone binding globulin so although there levels of testosterone is actually normal they have more free testorerone as it is unbound so more is biologically active
presentation of PCOS
- an ovulation or hypo-ovulation due to the disturbed FSH and LH levels
- increased androgens causes hirsutism, acne, male patter baldness
- dyslipidaemia
- insulin resistacen
why does PCOS cause acne
increased androgens cause increased sebum production
why does PCOS cause male pattern baldness
certain hair follicles express 5-alpha reductase which converted testosterone to DHT
insulin resistance causes
acnthosis nigircans and type 2 diabetes mellitus
diagnosis
2 out of 3 of the ROTTERDAM CRITERIA
Rotterdam criteria
- oligo or an ovulation
- clinical or biochemical evidence of hyperandrogegism
- polycystic ovaries indentified sonographically
hirsutism
male pattern hair growth in females
causes of hirsutism in PCOS
androgen excess at the hair follicle due to an excess of circulating androgen or peripheral conversion at the hair follicle
