PCOS

Question 1

pathophysiology of PCOS

Answer 1

loss of cyclic hormonal pattern:
↑ LH (disordered release of GnRH results in more LH secretion vs FSH)
↑ LH:FSH ratio (>2:1)
↑ androgens (↑LH stimulation of theca cells, relatively less FSH stimulation - less estradiol produced)
↑ insulin (due to insulin resistance, insulin also stimulates theca cells to produce androgens)
↑ estrone (androgen converted in adipose tissue via aromatsae) → chronic estrogen prevents ovulatory cycles, stimulates proliferation of endometrium
↓SHBG (synthesis in liver is suppressed by androgens/insulin) → less available to bind to circulating estrogen/androgen → ↑ free hormone circulating to cause effects

Question 2

diagnosis of PCOS

Answer 2

clinical: need at least 2/3
1) oligo-ovulation or anovulation (no LH surge→ menstrual irregularities (amenorrhea, oligomenorrhea, menometrorrhagia, infertility)
2) hyperandrogenism: masculinzation = acne, hirsutism (coarse terminal hairs in lips, sideburns, chin, lower abdomen)
3) polycystic ovaries on US (follicles around the periphery)
other signs of PCOS:
obesity
insulin resistance (impaired glucose tolerance)
infertility

Question 3

“string of pearls” sign

Answer 3

PCOS

Question 4

complication of PCOS

Answer 4

endometrial hyperplasia/carcinoma
no progesterone (2nd half of menstrual cycle)

Question 5

treatment of PCOS

Answer 5

diet + exercise for weight loss →↑ ovulation cycles
OCP: inhibit release of LH →↓ androgen → ↓ hirsutism, estrogen ↑ SHBG levels → less circulating free hormone, progesterone ↓ risk of endometrial hyperplasia
cyclic progestin: protect against endometrial hyperplasia
spironolactone (aldosterone receptor antagonist + antiandrogen properties): treat hirsutism
metformin: ↓ insulin →↑ ovulation cycles
clomiphene: ovulation induction if infertile