The simple idea (no memorising)
Don't memorise thirty syndromes. Ask, in order:
- Are breasts present? → tells you if estrogen has been working.
- Is the uterus present? → tells you if the Müllerian ducts developed.
- Then add FSH to locate the level of any failure.
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The signature diagnoses
- Imperforate hymen — everything works, but the exit is sealed. Periods happen but can't escape, causing monthly pain and a bulging bluish membrane. (The blood pools in the vagina — haematocolpos.) A small surgical opening cures it.
- MRKH — 46,XX, working ovaries (so normal breasts), but no womb (Müllerian failure). Normal pubic hair.
- Androgen insensitivity (CAIS) — 46,XY, testes present (so no womb, because AMH removed it), a female appearance and breasts, but sparse pubic hair (the body can't "hear" androgens).
- Turner syndrome — 45,X, streak ovaries → high FSH, short stature, poor breast development.
- Kallmann — the brain never sends GnRH → low FSH + a lost sense of smell.
The two neat contrasts
- MRKH vs CAIS: both have breasts and no uterus. The tell: MRKH = normal pubic hair (46,XX); CAIS = sparse pubic hair (46,XY).
- Turner vs Kallmann: both have low estrogen. The tell: Turner = FSH high (ovary failed); Kallmann = FSH low (brain silent) + anosmia.
Why it matters
This two‑question map (breasts? uterus?) turns a frightening list into a calm, logical flowchart — and it's exactly how a good clinician thinks at the bedside.
Quick check ✅
- Breasts present, no uterus, normal pubic hair — which diagnosis?
- What does a high FSH tell you about the level of the problem?
Remember this 🌟
Where we're going next → And if the periods started, then stopped? A different first step entirely. Concept 36.