Cushing’s Syndrome

Question 1

Definition of Cushing’s syndrome

Answer 1

Syndrome that results in chronic inappropriate elevation of glucocorticoid (Cortisol)

Question 2

Aetiology of Cushing’s syndrome

Answer 2

• Causes are split into:
‣ ACTH dependent:
◦ Cushing’s disease: Due to corticotrophic adenoma (pituitary tumour) that would over-secrete ACTH
◦ Ectopic ACTH: produced from a lung cancer (usually small cell)

				‣ ACTH independent:
						◦ Exogenous corticosteroid exposure: Taking excess steroid by mouth (most COMMON cause of Cushing’s syndrome). Can be seen in those with asthma or rheumatoid arthritis
						◦ Adrenal adenoma/carcinoma

Question 3

History and examination of Cushing’s syndrome

Answer 3

• Increasing weight
• Moon face
• Purple striae
• Fat pads (supraclavicular fullness)
• Central obesity: commonly around abdomen
• Acne
• Proximal myopathy: muscle weakness, difficulty getting out of chair
• Glucose intolerance/Diabetes: most patients would develop this
• Hypertension
• Easy bruising
• Poor wound healing
• Osteoporosis: usually premature (in the young)
• Depression
• Decreased libido
• Facial rounding
• Irregular menses
• Female sex: more common in females

Question 4

Investigations for Cushing’s syndrome

Answer 4

• Overnight dexamethasone suppression test: First line test. Would give 1mg of dexamethasone in the middle of the night, and the plasma cortisol levels would be checked at 8am in the morning. A high morning cortisol would indicate a positive test
• Can confirm results with 24hour urine free cortisol test or late night salivary cortisol test

• Serum glucose: likely to have diabetes

Question 5

Treatment for Cushing’s syndrome

Answer 5

Depends on the underlying cause:
Iatrogenic (steroid related):
1) Stop steroids if possible or sue lower dose/steroid sparing agent

Cushing’s disease:
1) Transsphenoidal pituitary adenomectomy: Resect the pituitary tumour

Ectopic ACTH:
1) Surgical resection of the tumour

Adrenal adenoma:
1) Unilateral or bilateral adrenalectomy
Radiotherapy for adrenal carcinoma

Question 6

Prevention and prognosis of Cushing’s syndrome

Answer 6

Reduce corticosteroid use to an absolute minimum
Standard CVD screening for Cushing’s patients

Untreated Cushing’s syndrome has a high risk of mortality due to CVD
When treated, the prognosis is good
Complications need to be managed

Question 7

Complications of Cushing’s syndrome

Answer 7

• Adrenal insufficiency secondary to adrenalectomy
• Cardiovascular disease: major cause of mortality in Cushing’s syndrome
• Hypertension
• Diabetes
• Osteoporosis