Cushings Syndrome (and Disease)

Question 1

If somebody had high levels of cortisol due to an adrenal tumour, what would their ACTH levels be like?

Answer 1

Low

Due to negative feedback

Question 2

If you suspected cushings, when would you take a blood sample for cortisol?

Answer 2

Midnight

When cortisol is naturally at its lowest

Question 3

How may you diagnose Cushing disease?

Answer 3

Dexamethasone supression test

Question 4

How would serum potassium levels appear in mineralocorticoid excess? Why?

Answer 4

Low cause mineralocorticoid triggers the excretion of K+ and reabsorption of Na+

Question 5

Why may someone with cushings have hypertension?

Answer 5

High levels of cortisol have some mineralocorticoid effect therefore increasing reabsorption of Na+ in kidneys

Question 6

Symptoms/signs of cushings

Answer 6

Purple striae, thin arms & legs (proteolysis), easy bruising (weakened/thin skin), hypertension (mineralocorticoid effect), reditrubution of fat (LIPOLYSIS), hyperglycaemia (gluconeogenesis, glycogenolysis etc)

Question 7

What is dexamethasone supression test?

Answer 7

Taken orally, potent steroid suppresses ACTH & cortisol release. If cortisol decrease isn’t more than 50%–> Cushings disease

Question 8

What is another way of diagnosing cushings?

Answer 8

Make them hypoglycaemic, if their ACTH levels don’t rise–> pituitary ACTH deficiency

Question 9

What is the most common cause of cushings (would be disease)?

Answer 9

Pituitary adenoma

Others- hyper activity of adrenal gland and ectopic ACTH release- not disease

Question 10

What is congenital adrenal hyperplasia?

Answer 10

Autosomal recessive, rare, deficiency of enzyme needed in cortisol synthesis pathway TF cholesterol instead converted to androgens. No - feedback TF high ACTH- causes adrenal hyperplasia (growth)

Question 11

If left untreated, how may the blood results for Na, K and sugar present?

Answer 11

Hypernatraemia, Hypokalaemia, hyperglycaemia