Cushings syndrome

Question 1

What is the difference between cushings syndrome and cushings disease?

Answer 1

Syndrome - excess glucocorticoids

Disease - excess glucocorticoids due to pituitary adenoma

Question 2

What happens in cushings disease

Answer 2

ACTH stimulation from the pituitary causes overstimulation of the adrenal glands
Increased production of
glucocorticoids
mineralocorticoids
Sex hormones

Question 3

Symptoms of cushings

Answer 3

Weight gain
Increased adiposity
Thin skin
bruising
Hyperglycaemia
Proximal myopathy
Striae
Hirsuitism
Increased risk of osteoporosis
Fatigue

SKIN hyperpigmentation in cushings disease due to excess ACTH
Hypertension
Visual disturbance if pituitary adenoma

Question 4

What are some complications of Cushings

Answer 4

Visual impairment due to VF defect secondary to adenoma
Diabetes
Hypertension
osteoporosis
Myopathy

Question 5

What are the causes of ACTH dependent cushings?

Answer 5

Cushings disease
ACTH producing tumour e.g. SCLC

Question 6

What are the causes of ACTH independent cushings?

Answer 6

Cushings syndrome - exogenous steroids
Adrenal adenoma

Question 7

How do we test for cushings?

Answer 7

Overnight low dose dexamethasone sup test (1mg)
- Give 1mg dex at midnight
- Measure cortisol at 9am
- If >500 likely cushing syndrome
- If <500 then unlikely

Can also measure urinary cortisol in a 24hr period

Question 8

How to determine the cause of cushings?

Answer 8

Measure ACTH
If ACTH raised - ACTH secreting tumour/ cushings disease

If ACTH low - adrenal adenoma (Pituitary is working ok and will be suppressed by the amount of steroid around)

Question 9

What is the point of doing a high dose dexamethasone test (2mg every 6hours for 2 days)

Answer 9

It helps tell if it is cushings disease - high dexamethasone doses will suppress pituitary adenomas and so CORTISOL WILL BE LOW

Question 10

What imaging can be done?

Answer 10

CT adrenals
MRI pituitary
Whole body CT - to locate ectopic ACTH producing tumour

Question 11

What is bilateral inferior petrosal sinus vein sampling?

Answer 11

Use this to confirm pituitary or ectopic production

Question 12

WHat is the medical management of cushings

Answer 12

Metyrapone

Question 13

What is nelsons syndrome

Answer 13

this is when there is adrenalectomies which then cause massive production of ACTH due to lack of feedback inhibition