Cushing's Syndrome (0) Flashcards
What does Cushing’s syndrome refer to?
Signs and symptoms that develop after prolonged abnormal elevation of cortisol
What does Cushing’s disease refer to?
Specific condition where pituitary adenoma secretes Excessive ACTH. CAUSES Cushing’s
Cushing’s syndrome is always caused by Cushing’s disease. True or False?
FALSE
Way to remember presentation of Cushing’s syndrome?
Picture patient with very round middle and thin, weak limbs who is havin effects of XS stress hormone
Presentation of Cushing’s syndrome?
- Moon face
- Central obesity
- Abdominal striae
- Buffalo hump
- Proximal limb muscle wasting
- Hypertension
- Cardiac hypertrophy
- Hyperglycaemia
- Insomnia
- Depression
- Osteoporosis
- Easy bruising and poor healing of skin
Causes of Cushing’s syndrome?
Exogenous roids
Cushing’s disease (pituitary adenoma releasing XSive ACTH)
Adrenal adenoma
Paraneoplastic Cushing’s
What is paraneoplastic Cushing’s?
When XS ACTH is released from cancer (non-pituitary adenoma) & stimulating XSive cortisol release-> ectopic ACTH (SCLC)
Common cause of paraneoplastic Cushing’s?
SCLC
Best investigation for Cushing’s?
Dexamethasone suppression tests
What occurs in a dexamethasone suppression test?
Initially giving patient “low dose test”. If normal, exclude Cushing’s
If abnormal then high dose test performed to differentiate underlying cause
Low dose dexamethasone test normal result?
For dexamethasone to suppress release of cortisol by effecting negative feedback on hypothalamus & pituitary
- Hypothalamus responds by reducing CRH output
- Pituitary responds by reducing ACTH output
- Lower CRH and ACTH levels result in low cortisol level
Abnormal result in low dose dexamethasone test?
If cortisol isnt suppressed (Seen in Cushing’s syndrome)
High dose dexamethasone test dose?
8mg
Low dose dexamethasone test dose?
1mg
Response to high dose dexamethasone test for Cushing’s disease?
Pituitary still shows some response to negative feedback & 8mg of dexamethasone is enough to suppress cortisol
