Amenorrhoea & oligomenorrhoea — structured SAQ (15 marks)

(a) Definition and initial investigations (4 marks)

One mark for the definition; three marks for the investigations.

• Definition (FIGO): menstruation has not occurred by 14 years in the absence of secondary sexual characteristics, or by 16 years in their presence.^[1]
• Pregnancy test: in every patient with amenorrhoea who has secondary sexual characteristics.^[2]
• Bloods: thyroid function, prolactin, FSH, LH and oestradiol; add testosterone, 17-hydroxyprogesterone, androstenedione and DHEAS if there are signs of hyperandrogenism.^[2]
• Imaging: pelvic ultrasound to delineate urogenital anatomy, with MRI or CT when more detail is needed.^[2]
• Karyotype: in all individuals except cancer survivors.^[2]

(b) Diagnosis, contrast with MRKH, and the gonads (4 marks)

One mark each.

• Diagnosis: complete androgen insensitivity syndrome (CAIS): 46,XY, elevated testosterone, absent Müllerian structures; breasts develop through aromatisation of testosterone to oestrogen.^[2]
• Examination clue: pubic and axillary hair are sparse or absent, and a shortened blind-ending vagina is almost universal.^[3]
• Contrast with MRKH: MRKH is 46,XX with normal endocrine function and congenital absence of the uterus and upper two-thirds of the vagina.^[4]
• Gonads: the lower malignancy risk in CAIS allows the gonads to remain for spontaneous breast development; gonadectomy is then considered, with maintenance oestrogen afterwards.^[2]

(c) POI criteria and causal tests (5 marks)

Two marks for the criteria; three marks for the causal tests.

• ESHRE 2024: disordered cycles for at least 4 months and an FSH over 25 IU/l; repeat after 4 to 6 weeks only if there is diagnostic uncertainty.^[5]
• NICE NG23: elevated FSH on 2 blood samples taken 4 to 6 weeks apart; do not diagnose on a single blood test.^[6]
• Genetic: chromosomal analysis and FMR1 premutation testing for all women with non-iatrogenic POI.^[5]
• Autoimmune: 21-hydroxylase autoantibodies when the cause is unknown; no routine anti-ovarian or TPO antibody testing.^[5]
• Thyroid and bone: TSH at diagnosis, and DXA at diagnosis for all women with POI.^[5]

(d) Hormone therapy advice (2 marks)

One mark each.

• Duration: HT is recommended until the usual age of menopause, whether or not she has symptoms, with a progestogen if she has a uterus.^[5]
• Contraception: HRT is not a contraceptive, and ovarian activity may still occur, so she should use contraception if she wishes to avoid pregnancy.^[5]