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).
