21. Menopause: the endocrinology of ovarian failure

First principle: follicular depletion → the axis "shouts"

Signature: low estradiol + high FSH/LH — the same feedback logic as Concept 5, at the end of reproductive life.

Consequences by organ system

Diagnosis — reasoning, not reflex testing

Red flags 🚩

• Postmenopausal bleeding is never "just menopause" → investigate for endometrial carcinoma (Concept 37).
• Menopause before 40 = primary ovarian insufficiency → needs estrogen replacement to at least the natural age of menopause (bone/cardiovascular protection).

Pitfalls

• Ordering FSH to "confirm" typical menopause; over‑investigating a clinical diagnosis while under‑investigating postmenopausal bleeding.

Pearls

• 🎯 Low estradiol + high FSH = menopause. Hot flush is the signature symptom; GSM and bone loss are the long game.
• 🩺 Reframe "vaginal atrophy" as GSM — it captures the urinary component and guides local estrogen therapy.

Next → How do we replace hormones safely — and the one rule that prevents harm (Concept 22).