Cushing Disease + Syndrome

Question 1

What is cushings?
Definition

Answer 1

Hypercortisolemia
High levels of cortisol

Question 2

What causes Cushing disease?

Answer 2

Pituitary adenoma secreting excess ACTH

Question 3

What is Cushing syndrome?

Answer 3

Hypercortisol of any cause

Question 4

What are the causes of hypercortisolemia?

Answer 4

ACTH Dependent=
Cushing disease - ACTH secreting from pituitary adenoma

Ectopic ACTH production (from small cell lung cancer)

ACTH independent=
Iatrogenesis (steroid use - main cause)

Adrenal adenoma (produces high cortisol)

Question 5

What is the pathology of hypercortisol?

Answer 5

CRH (hypothalamus) —> ACTH (pituitary)—> cortisol (Zona fasiculata)

Negative feedback from cortisol on CRH and ACTH

CRH typically released with circadian rhythm (high in morning, low at night)

Here, rhythm is lost, excessive unregulated CRH, ACTH and cortisol

Question 6

What is the symptoms of cushings?

Answer 6

Moon face, central obesity, purple abdominal striae, buffalo hump, thin easy bruising skin, acne, hypertension, plethoric complexion, easy infections , muscle atrophy

Question 7

How to diagnose cushings? What tests would you do?

Answer 7

Rule out oral steroids, if on steroids, stop

Random serum/plasma cortisol, if increased then 1st line test is to measure cortisol at 12am (cortisol at lowest)

Dexamethasone suppression test (overnight)- healthy patient should show neg feedback HPA axis and decreased cortisol

Question 8

What happens in the dexamethasone suppression test?
What results are shown?

Answer 8

Give dexamethasone and measure cortisol (before giving dex)

Measure cortisol 8 hours later

Non cushings = suppression >50mmol/L
Cushings = little/no suppression

Question 9

If first line tests are positive, what do we then measure?

Answer 9

Plasma ACTH
Increased = ACTH dependent cause - look for cushings on pituitary MRI

Decreased = ACTH independent cause - consider adrenal adenoma

Question 10

What is the treatment for Cushing disease?

Answer 10

Transsphenoidal surgery/resection
Or bilateral adrenalectomy

Question 11

What is a complication for the treatment for cushings disease?

Answer 11

Nelson syndrome
Pituitary tumour will continue to enlarge with no negative feedback from adrenals, high ACTH + skin pigmentation

Question 12

Treatment for adrenal adenoma and ectopic ACTH

Answer 12

Adrenalectomy
Surgical removal (eg, SCLC)

Question 13

What is a complication of cushings?

Answer 13

Osteoporosis and T2DM

Question 14

What can alcohol do relating to cushings?

Answer 14

Alcohol makes pseudo-cushings
Resolves in 1-3 weeks