Cushing's Syndrome

Question 1

define

Answer 1

this is an excess of cortisol

Question 2

when is cortisol normally raised?

Answer 2

during stress, illness and part of the diurnal rhythm

Question 3

what is Cushing’s disease caused by?

Answer 3

a pituitary problem

Question 4

what is Cushing’s syndrome caused by?

Answer 4

• adenoma of the adrenal (benign or malignant)
• ectopic ACTH production (thymus, lung and pancreas)
• pseudo (alcohol, depression or steroids- Cushingoid appearance)

Question 5

what must always be included in a Cushing’s syndrome history?

Answer 5

drug history for exogenous steroids

Question 6

excess cortisol causes protein breakdown which causes what presentations?

Answer 6

myopathy (wasting- proximal activities)
osteoporosis and fractures
thin skin, striae and bruising

Question 7

what does excess cortisol cause?

Answer 7

• protein breakdown
• altered carbohydrate/lipid metabolism, DM and obesity
• hypertension
• altered psychological state= psychosis and depression
• excess mineralocorticoid
• excess androgens

Question 8

what does excess mineralocorticoid cause?

Answer 8

hypertension

oedema due to fluid retention

Question 9

what does excess of androgens cause?

Answer 9

virwlism
hirsutism
acne
oligo/amenorrhoea

Question 10

what distinguishes Cushing’s from obesity?

Answer 10

thin skin
striae
testicular atrophy 
proximal myopathy
frontal balding in women
conjunctival oedema (chemosis)
OP

Question 11

diagnosis of Cushing’s

Answer 11

• dexamethasone suppression test
• measure ACTH to detect pituitary or ectopic
• image adrenal and other tumour sites
• CRH test

Question 12

screening tests for Cushing’s

Answer 12

• overnight 1mg dexamethasone orally. cortisol <50nmol/l is normal, >130 is Cushing’s
• urine free cortisol (24hr) total <250 normal and cortisol/creatinine ratio <25 is normal
• diurnal cortisol variation (midnight/8am) lost in Cushing’s

Question 13

definitive test

Answer 13

2 day 2mg/day dexamethasone (low dose), if >130nmol its Cushing’s

Question 14

can this have a cycle of dormancy?

Answer 14

yes

Question 15

management of Cushing’s disease

Answer 15

hypophysectomy

external radiotherapy if recurs and bilateral adrenalectomy

Question 16

management of adrenal Cushing’s

Answer 16

adrenalectomy

Question 17

management of ectopic Cushing’s

Answer 17

remove source or bilateral adrenalectomy (last resort as ACTH will still be high with no production of cortisol)

Question 18

pharmacological management of Cushing’s

Answer 18

metyrapone (waiting for radiotherapy to work or unfit for surgery, blocks synthesis of cortisol). Alternatives include ketoconazole or pasireotide

surgery is done when cortisol has reached its correct level via pharmacological therapy