HY lecture notes:
What’s LH do? –> stimulates theca interna cells (females) and Leydig cells (males) to make androgens
What’s FSH do? –> stimulates granulosa cells (females) and Sertoli cells (males) to make aromatase; also primes follicles
High BMI female + irregular menstrual cycles –> anovulation
Anovulation + hirsutism –> Dx = PCOS
PCOS is on the same spectrum as anovulation. We simply just call anovulation “PCOS” once it’s severe enough where there are 11+ anovulatory cysts visible bilaterally on pelvic USS (Amsterdam criteria) + the patient has hirsutism.
Anovulation means the girl will miss the period altogether –> period every 2-3 months or so.
By all means many young women have anovulation with some hirsutism, but it’s usually not full-blown PCOS. Anovulation is the most common cause of missed periods in young women (apart from pregnancy, which is technically most common; but pregnancy is physiologic, not pathologic).
Cause USMLE wants for anovulation / PCOS –> insulin resistance –> that’s why usually seen in high BMI.
Insulin resistance causes abnormal GnRH pulsation –> abnormal GnRH pulsation causes high LH/FSH ratio –> high LH means hirsutism; low FSH means follicles aren’t adequately primed by the time the LH spike occurs to signal ovulation –> anovulation
Why high LH/FSH ratio important in anovulation/PCOS –> once again, ovulation is stimulated when follicle not ready –> no ovulation (anovulation) –> follicle retained as cyst
Tx for PCOS –> if high BMI, weight loss first always on USMLE.
Tx for PCOS if they ask for meds and/or weight loss already tried –> OCPs (if not wanting pregnancy); clomiphene (if wanting pregnancy).
PCOS increases risk of what –> endometrial cancer (unopposed estrogen) + type II DM.
Ovulation means you get a corpus luteum –> corpus luteum secretes progesterone, so if you don’t have progesterone from the ovary –> unopposed estrogen –> endometrial hyperplasia.
Older woman with Hx of anovulation (will probably have high BMI too) + abnormal spotting –> endometrial biopsy
Cushing syndrome –> periods get longer and longer (i.e., 45-60 days)
Hirsutism + acanthosis nigricans can be seen in both Cushing and anovulation/PCOS.
Cortisol causes insulin resistance –> therefore anovulation –> therefore mechanisms/presentations can be fairly similar.
I explain to student toward the end that I’ve tried to hammer down concrete points for these presentations, but I’ve seen plenty of Qs with overlapping features –> meaning you need to actually understand these concepts for 2CK + obgyn –> but anovulation/PCOS and Cushing are HY, so that’s expected anyway.
Ruptured corpus luteum cyst vs adnexal torsion:
Ruptured corpus luteum cyst: sharp adnexal pain + no pelvic mass + 10-15 mL of serosanginous fluid in the cul de sac
Adnexal torsion: usually intermittent pelvic pain that becomes constant + large adnexal mass (i.e., 6-12 cm) + no fluid in cul de sac.
I’ve seen one Q for torsion where they didn’t mention intermittent pain goes to constant, but most of the time that’s how it presents.
Corpus luteum cysts are benign (often bilateral) cysts that tend to grow in early pregnancy because they are stimulated by beta-hCG –> greater risk in multiple gestation pregnancy, mole, and choriocarcinoma. No Tx necessary / just observe –> will spontaneously regress; if rupture occurs, treat symptomatically; surgery rare.
For torsion, laparoscopic detorsion is performed.
