Cushing's Syndrome Flashcards
Definition
Any excess of cortisol
Subtypes
Pituitary driven ACTH dependent (cushing’s disease)
ACTH independent
Ectopic ACTH
Iatrogenic
Who gets it?
Young women (20-40)
Cause
Pituitary tumour
Adrenal tumour
Ectopic ACTH
Exogenous steroid use
Clinical features
Thin skin Easy bruising Stretch marks Striae Proximal myopathy Frontal balding Central obesity with skinny legs - lemon on matchsticks Moon face Facial plethora Weakness Acne Hirsutism Amenorrhoea Oedema Thirst Polyuria
Examination findings
Hypertension
Investigations
Need a suppression test (as too much hormone is being produced)
- overnight low dose dexomethasone test
Measure ACTH
MRI
1mg low dose overnight dexamethasone test
Give the patient 1mg dexamethasone at bed time
The following morning, the cortisol level should have lowered to less than 50nmol/L in normal patients
Failure to suppress cortisol levels (remain above 100nmol/L) means it is likely the patient has cushing’s.
Need further testing
2mg high dose dexamethasone test
For patients who failed the low dose dexamethasone test
If pt has cushings, there will be no suppression of cortisol levels
Low ACTH levels
Adrenal origin
High ACTH levels
Pituitary origin
Ectopic origin
Management
Metyraprone (decreases cortisol levels)
Ketoconazole (decreases cortisol levels)
Pasireotide
Consider surgery when cortisol levels are under control
Cushing’s disease - definition
Pituitary driven cushing’s syndrome
Pituitary adenoma arises from corticoph cells of the anterior pituitary gland
ACTH dependent
Cushing’s disease - investigations
Low dose (1mg) dexamethasone suppression test
High dose (2mg) dexamethasone suppression test
Increased cortisol levels
Increased ACTH levels
Increased sex hormone levels
Cushing’s disease - management
Pituitary surgery (transphenoidal approach)
