🩺 Polycystic Ovary Syndrome (PCOS)

Definition	A common endocrine disorder in reproductive-age females characterized by hyperandrogenism, chronic anovulation, and polycystic ovaries. A major cause of reduced fertility.
Pathophysiology	Insulin Resistance: Hyperinsulinemia → altered hypothalamic feedback. Hormonal Shift: ↑ LH:FSH ratio (relative). Androgen Excess: ↑ Androgen production (testosterone) by theca interna cells. Anovulation: ↓ Follicular maturation → unruptured follicles (cysts).
Clinical Features	Signs/Symptoms: Hirsutism, acne, male-pattern baldness Amenorrhea or Oligomenorrhea Obesity & Acanthosis nigricans Morphology: Enlarged, bilateral cystic ovaries ("string of pearls" on US).
Long-term Risks	USMLE Key Point: Increased risk of Endometrial Cancer due to unopposed estrogen from chronic anovulation. Also ↑ risk for Type 2 DM and Metabolic Syndrome.
Management	1st Line: Weight reduction (improves insulin sensitivity). Cycle Control: OCPs (prevent endometrial hyperplasia). Fertility: Clomiphene or Letrozole (induces ovulation). Hirsutism: Spironolactone (anti-androgen).

✨ High-Yield Pearls

• 💎 Theca vs Granulosa: LH stimulates Theca cells (Androgens); FSH stimulates Granulosa cells (Estrogen). In PCOS, the balance shifts to Theca cells.
• 💎 Metformin: Useful for metabolic control and can restore ovulation in some cases.
• 💎 Diagnosis: Rotterdam criteria (2 out of 3: Anovulation, Hyperandrogenism, Polycystic ovaries on US).