Hormonal Abnormalities Flashcards
How does the contraceptive pill work?
The pill causes high oestrogen levels, oestrogen gives negative feedback, halting the menstrual cycle.
What hormone causes thickening of the endometrium?
Oestrogen
What hormone maintains the thickened endometrium?
Progesterone
What are the clinical features of polycystic ovarian syndrome?
Hirsuitism Acne Oligomenorrhoea / Amenorrhoea Multiple cysts in the ovary Infertility
Hirsuitism
Excessive hair growth
Oligomenorrhoea
Irregular periods
What causes the clinical presentation of hirsuitism and acne?
Hyperandrogenism (excess testosterone)
What hormone produced by the anterior pituitary is seen raised in women with PCOS?
LH
What is the effect of raised LH in women with PCOS?
When LH increases relative to FSH it causes the ovaries to synthesise androgens instead of oestrogen.
What is the effect of excess androgens on the menstrual cycle?
The excess androgen stops follicular development and causes anovulation.
What is thought to be the main cause of PCOS?
Insulin insensitivity
How does insulin insensitivity cause PCOS?
The insulin insensitivity results in hyperinsulinaemia.
Insulin acts synergistically with LH causing increased androgen production from the theca cells and the adrenal gland.
What is the role of theca cells in PCOS?
The theca cells are responsible for converting androgen precursors into testosterone.
How does insulin indirectly increase testosterone levels in the blood?
Insulin inhibits production of SHBG (sex hormone binding globulin).
Therefore there is more testosterone available in the blood as SHBG cannot bind to testosterone.
How are oestrogen levels affected in PCOS?
Oestrogen levels are sometimes increased as production normally continues and additionally some testosterone is converted into oestrogen in peripheral fat (aromatisation).
What is the Rotterdam criteria for diagnosing PCOS?
2/3 of the following:
Oligo / anovulation
Hyperandrogenism - elevated testosterone
Polycystic ovaries seen on ultrasound
Why are prolactin levels also tested in PCOS?
Prolactinaemia causes oligo/anovulation therefore a pituitary tumour must be ruled out.
Why are TSH levels also tested in PCOS?
Hypothyroidism can cause PCOS like symptoms.
What lifestyle change is PCOS commonly associated with?
Weight gain
How is PCOS managed?
Conservative management e.g healthier lifestyle
Glucose and cardiovascular disease screening (due to risk of developing type 1 diabetes).
Weight loss
Endometrial protection through induction of periods.
Insulin sensitising drugs