GYNAE Flashcards
MENSTRUAL CYCLE
When is the last menstrual period?
What are the stages of the menstrual cycle?
- 1st day of last period (cycle runs from 1st day of last to 1st day of next
- Menstruation (D1-5) > proliferation (D6-14) > ovulation (D14) > secretion (D16-28)
MENSTRUAL CYCLE
What 2 cycles exist within the menstrual cycle?
- Ovarian cycle (development of follicle + ovulation)
- Uterine cycle (functional endometrium thickens + shreds)
MENSTRUAL CYCLE
What happens in the menstrual and proliferative phases?
- Old endometrial lining from previous cycle shed marking day 1 (lasts 5d)
- High oestrogen > thickening of endometrium, growth of endometrial glands + emergence of spiral arteries from stratum basalis to feed the functional endometrium
- Consistency of cervical mucus changes to make more hospitable for sperm
MENSTRUAL CYCLE
What happens in the follicular phase?
- Independently primordial follicles mature into primary + secondary follicles with FSH receptors
- Low oestrogen + progesterone = pulses of GnRH > LH + FSH release
- FSH leads to follicular development + recruitment
MENSTRUAL CYCLE
What happens as secondary follicles grow during follicular phase?
- Theca cells develop LH receptors + secrete androgens
- Granulosa cells develop FSH receptors + secrete aromatase
- Leads to increased oestrogen > -ve feedback on pituitary to reduce LH + FSH leading to some follicles to regress
MENSTRUAL CYCLE
What occurs during ovulation?
- Follicle (dominant) with most FSH receptors continues developing
- Secretes further oestrogen which at a threshold causes spike in LH (+ slight rise in FSH) causing release of ovum on day 14
MENSTRUAL CYCLE
What occurs during the luteal phase?
- Dominant follicle > corpus luteum + luteinised granulosa cells converts cholesterol into progesterone for 10d to facilitate implantation + reduce FSH/LH + oestrogen
- Also secretes inhibin to reduce FSH
MENSTRUAL CYCLE
What happens if the egg is fertilised?
- Syncytiotrophoblast of embryo secretes human chorionic gonadotropin (hCG) which maintains corpus luteum
MENSTRUAL CYCLE
What happens if the egg is not fertilised?
- hCG absence > corpus luteum degenerates into corpus albicans
- Fall in progesterone + oestrogen causes endometrium to breakdown + menstruation occurs
- FSH + LH levels rise
- Stromal cells of endometrium release prostaglandins to encourage endometrium breakdown + uterine contraction
MENSTRUAL CYCLE
What happens in the early secretory phase of the menstrual cycle?
- Progesterone mediated + signals ovulation occurred to make endometrium receptive, cause spiral arteries to grow longer + uterine glands to secrete more mucus
MENSTRUAL CYCLE
What happens in the late secretory phase of the menstrual cycle?
- Cervical mucus thickens + less hospitable for sperm
- Decrease in oestrogen + progesterone > spiral arteries collapse + constrict + functional layer prepares to shred
1* AMENORRHOEA
What is primary amenorrhoea?
Absence of menstruation by –
- 14y if no secondary sexual characteristics (more indicative of a chromosomal abnormality)
- 16y with secondary sexual characteristics (breast buds)
1* AMENORRHOEA
What is the difference between hypogonadotrophic hypogonadism and hypergonadotrophic hypogonadism?
- Deficiency in gonadotrophins (LH + FSH) stimulating ovaries due to abnormal hypothalamus or pituitary means they do not respond by producing sex hormones (oestrogen)
- Gonads fails to respond to stimulation of gonadotrophins meaning no negative feedback + increasing amounts of FSH/LH
1* AMENORRHOEA
What are some causes of hypogonadotrophic hypogonadism?
- Constitutional delay (temporary delay, no pathology, ?FHx)
- Hypopituitarism
- Kallmann’s (failure to start puberty + anosmia)
- Excessive exercise, dieting or stress causes hypothalamic failure
- Endo = Cushing’s, prolactinoma, thyroid
- Damage (cancer, surgery)
1* AMENORRHOEA
What are some causes of hypergonadotrophic hypogonadism?
- Turner’s syndrome XO
- Congenital absence of ovaries
- Previous damage to gonads (torsion, cancer, infections like mumps)
1* AMENORRHOEA
What are some other causes of primary amenorrhoea and how may they present?
- Congenital adrenal hyperplasia (tall, deep voice, facial hair)
- Androgen insensitivity syndrome (46XY but female phenotype)
- Congenital malformations of genital tract (if ovaries unaffected = secondary sexual characteristics but no menses)
- Gonadal dysgenesis (no ovaries or uterus form)
1* AMENORRHOEA
What are some first line investigations for primary amenorrhoea?
- Examination = signs of puberty, PV exam, BMI, visual fields
- FBC + ferritin (anaemia), U+E for CKD, anti-TTG for coeliac, urinary beta-hCG crucial
1* AMENORRHOEA
What hormonal blood tests would you do for primary amenorrhoea?
- FSH + LH (low or high)
- TFTs, prolactin (if indicated)
- Free androgens raised in PCOS, AIS + CAH
- Insulin-like growth factor I used for screening for GH deficiency
1* AMENORRHOEA
What other investigations may be useful for primary amenorrhoea?
- XR of wrist to assess bone age + Dx constitutional delay
- Pelvic USS for structural causes
- ?MRI head if pituitary
- Karyotyping for Turner’s syndrome, AIS
1* AMENORRHOEA
What is the management of…
i) constitutional delay?
ii) ovarian causes (PCOS, damage/absence of ovaries)
iii) genital tract abnormalities?
iv) pituitary tumour?
v) stress?
i) May only require reassurance + observation
ii) COCP can induce regular menstruation + prevent Sx of oestrogen deficiency
iii) Surgery
iv) Surgery, chemo, radio or bromocriptine if prolactinoma
v) CBT, healthy weight gain, stress reduction
1* AMENORRHOEA
What is the management of hypogonadotrophic hypogonadism?
- Pulsatile GnRH can induce ovulation, menstruation + potentially fertility
- COCP if pregnancy not wanted to replace sex hormones, induce regular menstruation + prevent Sx of oestrogen deficiency
2* AMENORRHOEA
What is secondary amenorrhoea?
What is oligomenorrhoea?
- Previously normal menstruation ceases for >3m in a non-pregnancy woman
- Where menses are >35d apart (up to 6m), can be ovarian normality but exclude PCOS
2* AMENORRHOEA
What are the causes of secondary amenorrhoea?
- Pregnancy (most common), breastfeeding, menopause (physiological)
- Iatrogenic (contraception)
- Hypothalamic/pituitary
- Ovarian causes (PCOS, POI)
- Thyroid, uterine pathology (Asherman’s)
- Excessive exercise, stress or eating disorders
2* AMENORRHOEA
What are the hypothalamic or pituitary causes of secondary amenorrhoea?
- Sheehan’s syndrome = pituitary necrosis following PPH
- Pituitary tumour like prolactinoma leading to hyperprolactinaemia which prevents GnRH
- Trauma, radiotherapy or surgery