cushings

Question 1

what will a bloods for someone with cushings show?

Answer 1

hypokalaemic metabolic acidosis, if its paraneolastic secondary to a small cell lung cancer then the hypokalaemia will be significant

Question 2

what is cushions disease?

Answer 2

Cushing’s disease: an ACTH-secreting pituitary adenoma

Question 3

what are the 4 causes of bushings syndrome?

Answer 3

Exogenous steroids (in patients on long term high dose steroid medications)

Cushing’s Disease (a pituitary adenoma releasing excessive ACTH)

Adrenal Adenoma (a hormone secreting adrenal tumour)

Paraneoplastic Cushing’s

Question 4

how does the dexamethasone suppression test work?

Answer 4

• low dose test is done first to see if person is suffering from any form of cushings syndrome. if the morning cortisol is suppressed it means they are normal. if they have cushings the small dose of dexamethasone won’t make a difference as the pituitary is already used to high levels of steroid
• a high dose dexamethasone suppression test is then done to indicate the location.
  pituitary: cortisol will be suppressed

adrenal adenoma: cortisol will not be suppressed

ectopic ACTH: cortisol will not be suppressed

in order to find out if it is an adrenal adenoma vs ectopic ACTH producer ACTH levels will be measured

adrenal adenoma: ACTH will be suppressed
ectopic ACTH: ACTH will not be surpressed as it is independent of the pituitary