Endocrine infertility Flashcards
What are the clinical features of male hypogonadism?
- Loss of libido
- Impotence
- Small testes
- Decreased muscle bulk
- Osteoporosis (testosterone has anabolic action in bone
What are the causes of male hypogonadism?
- Hypothalamic-pituitary disease
- Hypopituitarism
- Kallmann syndrome
- Illness/underweight - leptin - Primary gonadal disease
- Congenital: Klinefelter’s syndrome (XYY)
- Acquired: testicular torsion, chemotherapy - Hyperprolactinaemia - can inhibit gonadal function
- Androgen receptor deficiency - v rare
How is male hypogonadism investigated?
- Check LH, FSH, testosterone
- If all low –> MRI pituitary - Prolactin –> check if hyperprolactinaemia
- Sperm count - check no. + motility
- Azoospermia = no sperm in ejaculate
- Oligospermia = reduced - Chromosomal analysis
- Klinefelter’s XYY
How is male hypogonadism treated?
- Testosterone replacement
- Increases muscle bulk + protects against osteoporosis - S.c. gonadotrophin injections (LH/FSH) for fertility if hypothalamic/pituitary disease
- Induce spermatogenesis - Dopamine agonist if hyperprolactinaemia
What are the effects of testosterone replacement?
Increases:
- Lean body mass
- Muscle size + strength
- Bone formation + bone mass (in young men)
- Libido and potency
- Does NOT restore fertility
What are the adverse effects of testosterone replacement?
- Increased risk of CV and metabolic disease in men with multiple cardiovascular comorbidities
- Uncommon: sleep apnoea, acne, breast englargement
What is amenorrhoea?
Absence of periods
Primary = failure to begin spontaneous menstruation by 16y
Secondary = absence of menstruation for 3 months in a woman who has previously had cycles
What are the causes of amenorrhoea?
- Pregnancy/lactation
- Ovarian failure:
- Premature ovarian insufficiency (early menopause)
- Oophorectomy
- Chemotherapy
- Ovarian dysgenesis (Turner’s 45XO) - Gonadotrophin failure:
- Hypothalamic/pituitary disease
- Kallmann’s syndrome
- Low BMI
- Post-pill amenorrhoea (downregulates hypothalamus + pituitary)
- Hyperprolactinaemia
- Androgen excess: gonadal tumour
How is amenorrhoea investigated?
- Pregnancy test
- LH, FSH, oestradiol
- Day 21 progesterone (should rise at ovulation)
- Prolactin
- TFT
- Androgens
- Chromosomal analysis
- Ultrasound scan of ovaries/uterus
How is amenorrhoea managed?
- Treat cause, e.g. low weight
- Primary ovarian failure - HRT, infertile
- Hypothalamic/pituitary disease - HRT for oestrogen replacement; fertility: gonadotrophins as part of IVF
What are the diagnostic criteria for PCOS?
2 of the following:
- Polycystic ovaries on ultrasound scan
- Oligoovulation/anovulation
- Clinical/biochemical androgen excess, e.g. increased growth of hair in a male pattern
What are the clinical features of PCOS?
- Hirsuitism
- Menstrual cycle disturbance
- Increased BMI
How is PCOS investigated?
- Ultrasound of ovaries (look for cysts)
- Measure androgen levels (excess)
- Examination: increased growth of hair in male pattern
- History - oligoovulation/anovulation
How is PCOS treated?
- Metformin
- Insulin sensitiser - Clomiphene
- Anti-oestrogenic effect on HPA
- Binds to oestrogen receptors in hypothalamus + blocks -ve fb
- Increase in GnRH + gonadotrophin secretion
- Used in short periods to kickstart HPG axis - Gonadotrophins as part of IVF treatment
How is prolactin secretion regulated?
- Dopamine (-ve effect) = main hypothalamic hormone controlling prolactin release
- TRH = mild stimulatory effect
What are the causes of hyperprolactinaemia?
- Dopamine antagonists (anti-emetics, anti-psychotics)
- Prolactinoma - pituitary tumour
- Stalk compression due to pituitary adenoma
- PCOS
- Hypothyroidism - high TRH, stimulates prolactin
- Oestrogens - pill, pregnancy, lactation
- Idiopathic
What are the clinical features of hyperprolactinaemia?
- Galactorrhoea
- Hypogonadism - reduced GnRH secretion/LH action
- Prolactinoma: headache, visual field defect
How is hyperprolactinaemia treated?
Treat cause, e.g. stop drugs
- Dopamine agonist: bromocriptine, cabergoline
- Prolactinoma: dopamine agonist, pituitary surgery rarely needed bc drugs usually work
What is infertility?
Inability to conceive after 1 year of regular unprotected sex
What is primary gonadal failure?
- Defect of gonads
- Testes/ovaries not producing testosterone/oestrogen –> no -ve fb on HPG axis –> high GnRH, LH, FSH
