Hyperadrenal disorders Flashcards
What is the main problem in Cushing’s
Too much cortisol
What can too much cortisol caused by?
Tumour in pituitary that’s making ACTH which makes adrenal grow
Rarely, benign tumour of the adrenal gland
What does cortisol do?
Switches protein synthesis off and fat synthesis on
What is Cushings DISEASE caused by?
Tumour of the pituitary
What are the clinical features of Cushings?
Too much cortisol Centripetal obesity Buffalo hump and moon face Proximal myopathy Hypertension and hypokalaemia Red striae, thin skin and easy bruising Osteoporosis
What are the causes of Cushing’s syndrome?
Taking too many oral steroids (cortisol like steroids- glucocorticoids)
Ectopic ACTH from lung cancer
Adrenal adenoma
What is the first thing you do if you see a patient presenting with all the symptoms of cushings?
Measure their cortisol
What is the problem with measuring cortisol?
It varies throughout the day- it is high in the morning and low in the evening (midnight it is very low)
Also pain and stress of blood test will increase cortisol
What would you see if someone has Cushing’s and you measure their cortisol at midnight?
It wouldn’t be low
What is another test to see if someone has Cushing’s?
Use the negative feedback system- if you gave a normal person dexamethasone your pituitary will detect extra steroid and it will turn off the ACTH and within hours you will have zero cortisol
What are the three tests you can do to identify the cause of Cushings?
24 hour urine collection for urinary free cortisol
Blood diurnal cortisol levels
Low dose dexamethasone suppression test (Gold standard)
What is the treatment of Cushing’s syndrome?
Depends on cause
Pituitary surgery (transphenoidal hypophysectomy)
Bilateral adrenalectomy- can’t make anymore cortisol
Unilateral adrenalectomy for adrenal mass
What is the main problem in Conn’s?
Too much aldosterone
Where are catecholamines produced?
Adrenal medulla
What is a tumour of the adrenal medulla that leads to lots of catecholamines called?
Phaeochromocytoma
What is the first step to block the effects of the excess catecholamines?
Give an alpha blocker
Why do you give an alpha blocker first when treating phaeochromocytoma?
The urgent issue is really high blood pressure caused by catecholamines binding to alpha receptors in vasculature leading to vasoconstriction
What do you give once the blood pressure has decreased when treating phaeochromocytoma?
Beta blocker
What does metyrapone inhibit?
11beta-hydroxylase
What does inhibiting 11beta-hydroxylase do?
Slows down the cortisol synthesis pathway by inhibiting the conversion of 11-deoxycorticosterone to corticosterone and conversion of 11-deoxycortisol to cortisol so it decreases levels of corticosterone and cortisol
What happens due to the decrease in cortisol when using metyrapone?
The levels of ACTH rise
When is metyrapone used for Cushing’s patients? (2)
Prior to surgery- Cushings patients are not good surgical candidates as predisposed to infection and do not heal easily (thin skin)
After radiotherapy- effects of radiotherapy are slow to be seen so metyrapone is used till then
What are the two negative things about metyrapone?
Leads to accumulation of 11-deoxycorticosterone and 11-deoxycortisol- 11-deoxycorticosterone has mineralocorticoid properties, it leads to retention of sodium and excretion of potassium in the kidneys so you get salt retention and hypertension
Second problem- Because two limbs of pathway are blocked, all the precursors are funnelled towards sex steroid synthesis so there is an increase in adrenal androgens which can cause hirsuitism and is particularly unpleasant in women
What is hirsuitisim ?
Excess body hair
