Cushing's Syndrome

Question 1

What is cushing’s syndrome?

Answer 1

• Too much cortisol

- Cushing’s syndrome can be caused by Cushing’s disease, the syndrome is more a collection of symptoms

Question 2

What gender and age range is Cushing’s syndrome most common in?

Answer 2

Women 20-40

Question 3

What is the most common cause of cortisol XS?

Answer 3

Iatrogenic cushing’s syndrome

• Due to prolonged high dose steroid therapy for eg asthma, RA, IBD, transplants
• Chronic suppression of pituitary ACTH production and adrenal atrophy

Question 4

What does long term steroid treatment do?

Answer 4

Suppresses ACTH production (-ve feedback to anterior pituitary)

Question 5

Types of Cushing’s?

Answer 5

• Cushing’s disease (pituitary cushing’s)
• ACTH-independent Cushing’s
• Ectopic ACTH

Question 6

What accounts for 70% of Cushing’s syndrome?

Answer 6

Cushing’s disease

Question 7

What causes ACTH independent Cushing’s?

Answer 7

• Adrenal adenoma/carcinoma

- Bilateral macronodular adrenal hyperplasia

Question 8

What is a cause of ectopic ACTH?

Answer 8

Malignancy

Question 9

Presentation of Cushing’s syndrome?

Answer 9

• Thin skin: easy bruising
• Facial plethora
• Striae
• Proximal myopathy
• Frontal balding in women
• Conjunctival oedema (chemosis)
• Osteoporosis
• XS cortisol symptoms
• XS mineralocorticoids
• XS androgen

Question 10

What are the signs of XS cortisol?

Answer 10

• Protein loss
• Myopathy; wasting
• Osteoporosis; fractures
• Thin skin; striae, bruising
• Altered carb/lipid metabolism, DM, Obesity
• Altered psyche; psychosis, depression

Question 11

Signs of XS mineralocorticoids?

Answer 11

• HT

- Oedema

Question 12

Signs of XS androgen?

Answer 12

• Virilism
• Hirsutism
• Acne
• Oligo/amenorrhoea

Question 13

Bulletpoint steps of diagnosing Cushing’s syndrome?

Answer 13

• Establish XS cortisol
• Formal diagnostic test: Low dose dexamethasone suppression test
• Imaging tests also a possibility

Question 14

How to establish a cortisol XS?

Answer 14

• 1mg dexamethasone overnight suppression test
• 24h urinary free cortisol
• Midnight cortisol
• Late night salivary cortisol

Question 15

Interpretation of a formal diagnostic test for Cushing’s disease?

Answer 15

Low dose dexamethasone suppression test
- Failure to suppress the cortisol = Cushing’s syndrome
-Measure ACTH to determine further investigation
If low: adrenal origin is likely
If raised: distinguish between Cushing’s disease and ectopic ACTH

Question 16

What does a rise in ACTH and cortisol on a CRH test indicate?

Answer 16

Pituitary source rather than ectopic

Question 17

How is pituitary caused Cushing’s syndrome managed?

Answer 17

• Hypophysectomy (Transsphenoidal route) and external radiotherapy
• Bilateral adrenalectomy if it recurs

Question 18

Management of adrenal caused Cushing’s syndrome?

Answer 18

Adrenalectomy

Question 19

Management of ectopic cause Cushing’s syndrome?

Answer 19

Remove source
OR
Bilateral adrenalectomy

Question 20

Drug treatment of Cushing’s syndrome?

Answer 20

• Metyrapone: if other treatments fail
• Ketoconazole
• Pasireotide LAR (10-20mg monthly)