Cushing's Syndrome Flashcards
What is Cushing’s syndrome?
Adrenal gland is targeted by trophic hormones leading to excess glucocorticoids
What does Cushing’s syndrome result in?
Excess cortisol
What is the main ACTH dependent cause of Cushing’s syndrome?
Iatrogenic steroids
What type of cause are iatrogenic steroids?
An exogenous cause
What are the ACTH dependent causes of Cushing’s syndrome?
Cushing’s disease
Small cell lung cancer
What is Cushing’s disease?
Increased ACTH due to a pituitary adenoma
How does small cell lung cancer cause Cushing’s syndrome?
Releases ectopic ACTH
What are the main symptoms of Cushing’s syndrome?
Moon face Central obesity Abdominal striae Proximal limb wasting Buffalo hump Pigmentation Easy bruising Elevated blood pressure
Why is there pigmentation with Cushing’s syndrome?
Due to the increased ACTH
What is the best diagnosis of Cushing’s syndrome?
Overnight dexamethasone suppression test
What is low dose dexamethasone?
1mg
What is high dose dexamethasone?
8mg
What does low dose dexamethasone exclude if there is no response?
Cushing’s disease
What is an alternative investigation that can be done for Cushing’s syndrome?
24 hour urinary free cortisol
What can mimic cushing’s?
Psuedo-cushing’s
due to excess alcohol consumption or severe depression
What metabolic disturbance can occur in someone with cushing’s syndrome?
Hypokalaemic metabolic alkalosis
What is the management of cushing’s syndrome?
Removal of the tumour- main managment
What needs to be done before surgical management (removal of the tumour) in someone with Cushing’s syndrome?
Normalisation of hypercortisolaemia with medical therapy prior to operating
What medical management can be used in someone with Cushing’s syndrome?
Metyrapone
What is the function of metyrapone?
Blocks the steroid synthesis pathway
What is usually required in someone post operatively?
Successful treatment of Cushing’s disease leads to cortisol deficiency and subsequently steroid replacement post operatively is essential.
What would
Suppressed ACTH
Not suppressed cortisol
indicate?
Cushing’s syndrome due to other causes (e.g. adrenal adenomas)
What does suppressed ACTH and suppressed cortisol indicate?
Cushing’s disease (i.e. pituitary adenoma → ACTH secretion)
What would cortisol and ACTH not suppressed suggest?
Ectopic ACTH syndrome
