Disorders of Ovulation Flashcards
What is premature ovarian failure also known as?
Primary ovarian insufficiency
What is premature ovarian failure?
The loss of normal ovarian function before the age of 40, leading to amenorrhoea (primary/secondary)
What can cause premature ovarian failure?
- Autoimmunity
- X chromosome abnormality (e.g. Turner Syndrome)
- Genetic predisposition
- Latrogenic (due to surgery, radiotherapy or chemotherapy)
What causes Turner syndrome?
Partial or complete X monosomy (in females)
What proportion of people have Turner syndrome?
Approximately 1 in 2500 live births of females
What are some associated problems with Turner syndrome?
- Short stature
- Aortic dissection
- Hypertension
- Congenital renal abnormalities
- Osteoporosis
- Hypothyroidism
Why can Growth Hormone treatment be considered for people with Turner syndrome?
Because of their short stature
What are all adrenal steroids synthesis from?
Cholesterol
How is progesterone synthesised from cholesterol?
Cholesterol ——–> Pregnenolone
Pregnenolone ——–> Progesterone OR 17-hydroxypregnenolone
What is Congenital Adrenal Hyperplasia (CAH)?
A disorder of cortisol biosynthesis and 95% of cases are due to a deficiency of 21-hydroxylase (the enzyme that converts 17a-hydroxyprogesterone to 11-deoxycortisol)
Why is it possible to have an aldosterone deficiency with CAH?
Because 21-hydroxylase is involved in the synthesis of aldosterone, so a deficiency would lead to less aldosterone being synthesised.
Why do the levels of CRH and ACTH rise in CAH?
The lack of cortisol means that there is no negative feedback on CRH and ACTH, so their levels rise.
What proportion of people are carriers of CAH?
1 in 60
How is CAH diagnosed?
Synacthen test which detects high levels of 17-hydroxyprogesterone
Why does hyperplasia occur in CAH?
The insufficient production of cortisol leads to a response to grow so that more can be produced (although the lack of 21-hydroxylase means more won’t be produced).
Why are more sex hormones produced in CAH?
Because hyperplasia occurs and the adrenal glands are able to synthesise more since they are unaffected in CAH.
What can the high levels of sex hormones in CAH lead to?
- Early puberty
- Irregular periods
- Hirsutism
- Acne
- Hypovolaemia (due to salt wasting)
- Ambiguous genitalia (females)
- Virilisation (development of male features like body hair in boys at a very early age)
What is CAH treated with?
- Glucocorticoids (e.g. hydrocortisone)
- Mineralocorticoids (e.g. fludrocortisone)
What do glucocorticoids do when they are used to treat CAH?
Suppress CRH and ACTH
How can ambitious genitalia be treated?
Surgical management
What neurones are potent stimulators of GnRH and what stimulates them?
Kisspeptin and KNDy
They are stimulated by high oestrogen
Where are the neurons that produce GnRH located?
Pre-optic area (POA) of the hypothalamus
In what fashion is GnRH released into the portal system?
Pulsatile (every 60-90)
Where in the ovaries does FSH act on?
Primary follicle granulosa cells
How many days of bleeding is there at the start of a menstrual cycle?
5 days
Why is there mid-cycle pain during ovulation?
Leakage of follicle fluid during ovulation - which irritates the peritoneum
How can ovulation be diagnosed biochemically?
- Day 21 progesterone blood test
- LH detection kits
How do LH detection kits work?
Urinary test done daily from day 10 and once LH surge is detected, ovulation will occur 24-36 hours later
Hypothalamic causes of ovulation problems (lack of GnRH)
- Kiss1 gene deficiency
- GnRH gene deficiency
- Weight loss / excessive exercise
- Anorexia
Pituitary causes of ovulation problems (lack of FSH and LH)
- Pituitary adenoma (e.g. prolactinoma)
- Pituitary surgery / radiotherapy
What is amenorrhoea?
Lack of period for > 6 months
What are the two types of amenorrhoea?
- Primary: Never had a period
- Secondary: Has menstruated before
What is oligomenorrhoea?
Irregular periods that usually occur more than 6 weeks apart
What is polymenorrhoea?
Periods occurring less than 3 weeks apart
What is hirsutism?
Androgen-dependednt excess body hair in a male distribution (hypertrichosis is when it isn’t androgen-dependent)
What is an anovulation?
When the ovaries don’t release an egg during menstruation
