Adrenal Disease

Question 1

Diagnostic test for Addison’s?

Answer 1

synthACTHen test

(tried to stimulate production of endogenous cortisol)

note: can do 9am cortisol first (eg in GP), if <100 addisons likely, if 100-500 addisons possible so do ACTH test

Question 2

Electrolyte abnormalities in Addison’s disease

Answer 2

Na+ low, K+ high (as aldosterone usually tries to keep in salt and there is a lack of aldosterone)

can have hypoglycaemia (due to lack of cortisol, cortisol normally raises blood glucose)

Question 3

Addison’s is primary adrenal insufficiency.. list some causes of secondary adrenal insufficiency

Answer 3

exogenous steroid use is the most common cause
pituitary/hypothalamic disease
surgery/radiotherapy

note these will cause the same symptoms but no hyperpigmentation like in Addison’s disease

Question 4

List causes of Cushing’s syndrome (and name which one is Cushing’s DISEASE)

Answer 4

pituitary adenoma (DISEASE not syndrome)
adrenal adenoma
ectopic ATCH secretion

Question 5

Diagnostic test for Cushing’s syndrome

Answer 5

Low dose dexamethasone suppression test followed by high dose dexamethasone suppression test

Question 6

Which causes of Cushing’s cause high dose dexamethasone to be supressed

Answer 6

Only Cushing’s disease (pituitary adenoma) as the gland has negative feedback in response to high enough levels of ATCH

ectopic ATCH secretion and adrenal adenomas will not respond to low or high dose dexamethasone suppression tests

Question 7

Buzzword cancer which produces ectopic ATCH

Answer 7

small cell lung cancer

Question 8

what imaging may be used to look for Cushing’s culprit in the body

Answer 8

MRI pituitary (for Cushing’s disease)
CT thorax for SCLC (for Cushing’s syndrome)
CT abdo for adrenal adenoma (for Cushing’s syndrome)

Question 9

electrolyte abnormalities in Cushing’s

Answer 9

low K+ (cortisol has some mineralocorticoid effect like aldosterone)
hyperglycaemia