T2 L6: Disorders of ovulation Flashcards
What is the role of kisspeptin in ovulation?
It stimulates the secretion of GnRH. It’s found at the apex of the reproductive axis in the hypothalamus
Kisspeptin neurones are very responsive to oestrogen
What is Amenorrhoea?
Lack of period for more than 6 months
Primary amenorrhoea- has never had a period (never went through menarche)
Secondary amenorrhoea- has menstruated before
What is Oligomenorrhoea?
Irregular periods
Usually occurring 6 weeks apart
What is Polymenorrhoea?
Period occurring less than 3 weeks apart
What causes ovulation problems?
Hypothalamus (lack of GnRH)
Pituitary (lack of FSH and LH)
Ovary
Hyperandrogenism
What is anosmia?
Inability to smell
What are some Hypothalamic ovulation problems?
Hypothalamus (lack of GnRH)
- Kallmann’s syndrome (GnRH deficiency)
- Functional hypothalamic amenorrhoea caused by weight loss, stress, excessive exercise, anorexia
What are some Pituitary ovulation problems?
Pituitary (lack of FSH and LH)
- pituitary tumours Eg. Prolactinoma
- Post pituitary surgery/radiotherapy
What are some ovary associated ovulation problems?
Ovary
-Premature ovarian insufficiency caused by chromosomal abnormalities like Turner syndrome, autoimmune, or iatrogenic
What are some hyperandrogenism ovulation problems?
Hyperandrogenism
- Polycystic ovarian syndrome (commonest cause)
- Congenital adrenal hyperplasia
What is Hirsutism?
Excessive hair in a male distribution
Not androgen-independent hair growth (Hypertrichosis) or familial/racial hair growth
What is Hypertrichosis?
Excessive hair growth over and above the normal for the age, sex and race of an individual
What can cause Hirsutism?
PCOS (95%)
Non-classical congenital adrenal hyperplasia (CAH)
Cushing’s syndrome
Adrenal/ovarian tumour
How prevalent is PCOS?
5-10% of women
What are some clinical features of PCOS?
- Hyperandrogenism (Hirsutism and acne)
- Chronic oligomenorrhoea/ amenorrhoea
- Obesity
What is a USS appearance of polycystic ovaries?
> 10 subcapsular follicles 2-8mm in diameter arranged around a thickened ovarian stroma
What are some hormonal abnormalities in PCOS?
- Raised baseline LH levels and normal FSH
- Raised androgens and free testosterone
- Reduced sex hormone binding globin (SHBG)
- Oestrogen is usually normal
What is sex hormone binding globin (SHBG)?
It binds to testosterone and oestradiol
It’s produced by the liver
If testosterone is found, it’s inactive. Levels of SHBG are increased by oestrogens and decreased by testosterone
How does PCOS affect metabolic syndrome?
- Insulin resistance
- Impaired glucose tolerance
- Dyslipidaemia
- Vascular dysfunction
What are the reproductive effects of PCOS?
- 80% lack ovulation
- Increased risk of miscarriage
- Increased risk of gestational diabetes
How does PCOS increase the risk of endometrial cancer?
Because the patients are not ovulating but the levels of oestrogen are high causing endometrial hyperplasia and cancer
Endometrial cancer is also associated with T2 diabetes and obesity
What are the effects of lifestyle changes like diet, exercise and stopping smoking in PCOS?
- Decreased insulin resistance
- Increased SHBG
- Decreased free testosterone
- Improved fertility
- Improved metabolic syndrome risk factors
What effect does a combined oral contraceptive have on PCOS?
- Increases SHBG and thus decreases free testosterone
- Decreases LH and FSH which decreases ovarian stimulation
- Regulates cycle and decreases endometrial hyperplasia
May cause weight gain, venous thrombosis, adverse effects on metabolic risk factors
Why is Cyproterone Acetate used to treat PCOS symptoms?
It’s an oral pill that inhibits binding of testosterone and 5 alpha dihydrotestosterone to androgen receptors
It acts on the androgen imbalance
