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
other causes of hirstutism
androgen secreting tumours of the ovaries or adrenals, exogenous androgens (doping in female athletes
in PCOS transvaginal ultrasound shows
string of pearl appearance
management of PCOS
- first line: lifestyle intervention
- for woman with oligo- or anovualtion: induce a withdrawal bleed and then start on the combined oral contraceptive pill
inducing a withdrawal bleed
MPA (medroxyprogesterone acetate) 10mg/day for 5 days then stop progesterone which should induce a withdrawal bleed as it causes the necrosis and subsequent shedding of the lining of the endometrium
combined oral contraceptive pill
ethyinylestradiol/ drospirenone
the peripheral conversion of
androstenedione to oestrogen (which is increased in obesity) causes endometrial hyperplasia which increases the risk of endometrial cancer, the progesterone in the combined oral contraceptive pill reduces this risk
for woman with PCOS who are trying to get pregnant
Clomiphene which is an anti-oestrogen which competes with oestrogen for oestrogen binding sites on the hypothalamus and pituitary causing increased gonadotrophin releasing hormone and FSH and LH secretion
what is used for insulins resistance in PCOS
metformin
hirsutism can be treated with
spironolactone (but NOT if someone trying to get pregnant) and topical eflornithine which is known as vaniqa
what is used for dyslipidaemia
STATINS
complications
- dyslipidaemai and cardiovascular disease
- endometrial neoplasia
- pbsturcitve sleep apnoea
- infertility/ sub fertility
- early miscarriage
- gestational diabetes and preterm birth
limitations of clomifene citrate
- only given on days 2-6 of the menstrual cycle to initiate follicular maturation
- its use is limited to 6 months and it increases the risk of multiple pregnancies by 11%
what else can metfomin be used for
as an alternative to clomifene or in addition to clomifene
2nd line therapy for infertility in PCOS
- ovarian diathermy or gonadotrophin induction
what is used last line for infertility
IVF
