Cushing’s syndrome

Question 1

What is Cushing’s syndrome?

Answer 1

This is when free circulating glucocorticoid (cortisol) is increased.

Question 2

What are the causes of Cushing’s syndrome?

Answer 2

ACTH-dependent disease
Non-ACTH-dependent disease

Question 3

What are the signs and clinical features of Cushing’s syndrome?

Answer 3

• Pigmentation (only with ACTH-dependent causes)
• Cushingoid appearance
• Impaired glucose tolerance
• Hypokalaemia
• Hypertension

Signs include:
- moon face
- purple or red striae
- acne
- thin skin
- bruising

Question 4

How is Cushing’s syndrome diagnosed?

Answer 4

By doing these test:
- Low dose dexamethasone suppression test
- 24-hour urinary free cortisol measurements
- Circadian rhythm – midnight plasma or late night salivary cortisol

Question 5

What is used to treat Cushing’s syndrome?

Answer 5

If caused by long term use of corticosteroids, the dose should be gradually reduced to the lowest
dose that controls the condition being treated.

If caused by a tumour, cortisol-inhibiting medications, radiotherapy or surgery are potential options. Cortisol-inhibiting medications include metyrapone.

These drugs are usually used shot term prior to surgery, or following surgery or radiotherapy to increase the effectiveness of these treatments.