Cushing's Syndrome Flashcards
define
this is an excess of cortisol
when is cortisol normally raised?
during stress, illness and part of the diurnal rhythm
what is Cushing’s disease caused by?
a pituitary problem
what is Cushing’s syndrome caused by?
- adenoma of the adrenal (benign or malignant)
- ectopic ACTH production (thymus, lung and pancreas)
- pseudo (alcohol, depression or steroids- Cushingoid appearance)
what must always be included in a Cushing’s syndrome history?
drug history for exogenous steroids
excess cortisol causes protein breakdown which causes what presentations?
myopathy (wasting- proximal activities)
osteoporosis and fractures
thin skin, striae and bruising
what does excess cortisol cause?
- protein breakdown
- altered carbohydrate/lipid metabolism, DM and obesity
- hypertension
- altered psychological state= psychosis and depression
- excess mineralocorticoid
- excess androgens
what does excess mineralocorticoid cause?
hypertension
oedema due to fluid retention
what does excess of androgens cause?
virwlism
hirsutism
acne
oligo/amenorrhoea
what distinguishes Cushing’s from obesity?
thin skin striae testicular atrophy proximal myopathy frontal balding in women conjunctival oedema (chemosis) OP
diagnosis of Cushing’s
- dexamethasone suppression test
- measure ACTH to detect pituitary or ectopic
- image adrenal and other tumour sites
- CRH test
screening tests for Cushing’s
- 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
definitive test
2 day 2mg/day dexamethasone (low dose), if >130nmol its Cushing’s
can this have a cycle of dormancy?
yes
management of Cushing’s disease
hypophysectomy
external radiotherapy if recurs and bilateral adrenalectomy
management of adrenal Cushing’s
adrenalectomy
management of ectopic Cushing’s
remove source or bilateral adrenalectomy (last resort as ACTH will still be high with no production of cortisol)
pharmacological management of Cushing’s
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
