xs steroids 
exogenous - steroids
endogenous - 80% Pituitary adenoma (ACTH) 20% ectopic ACTH (small cell lung ca) or hypersecreting adrenal tumour

hypoK and HT (like Conn's)

diagnose with 24hr urine cortisol or overnight dexamethasone suppression test (1mg)
Remember CXR looking for ectopic ACTH

inc mortality due to CVS / HT / VTE
ACTH dependant - 80-85% is mostly caused by pituitary adenoma (cushings disease) and rarely by ectopic ACTH,
ACTH independant - Cushings syndrome is adrenal adenoma or bilateral hyperplasia

most signs disappear with treatment but some (HT, osteoporosis, gonadal and diabetes) may persist and quality of life may stay impaired