Cushings syndrome

Question 1

define cushings syndrome?

Answer 1

syndrome associated with chronic inappropriate elevation of free circulating cortisol

Question 2

how can we categories the causes of cushings syndrome?

Answer 2

• ACTH Dependent

* ACTH Independent

Question 3

what are ACTH dependent causes of cushings syndrome?

Answer 3

o Cushing’s disease: Excess ACTH from a pituitary adenoma

o Lung cancer, Ectopic ACTH

Question 4

what are ACTH independent causes of cushings syndrome?

Answer 4

o Iatrogenic: steroids – MOST COMMON CAUSE

Question 5

what is the epidemiology of cushings syndrome?

Answer 5

• Peak incidence 20-40 yrs

Question 6

presenting symptoms of cushings?

Answer 6

• Increasing weight
• Fatigue
• Muscle weakness
• Myalgia (pain in muscles)
• Thin skin
• Easy bruising
• Poor wound healing
• Fractures
• Hirsuitism
• Acne
• Frontal balding
• Oligomenorrhoea/amenorrhoea
• Depression or psychosis

Question 7

signs of cushings?

Answer 7

• Moon face
• Flushed face
• Interscapular fat pad
• Proximal muscle weakness
• Thin skin
• Bruises
• Central obesity
• Pink/purple striae on abdomen/breast/thighs
• Kyphosis (due to vertebral fracture)
• Poorly healing wounds
• Hirsuitism, acne, frontal balding
• Hypertension
• Ankle oedema (due to salt and water retention from the mineralocorticoid effect of excess cortisol)
• Pigmentation in ACTH dependent cases

Question 8

what is the first line investigation for cushings syndrome?

Answer 8

o 24 hour urinary free cortisol

o Overnight dexamethasone suppression test

Question 9

what might the blood show for cushings syndrome?

Answer 9

o U&Es - hypokalaemia due to mineralocorticoid effect
o BM - high glucose
o ABG – hypokalaemia metabolic alkalosis

Question 10

how to localise the cause of the high cortisol?

Answer 10

we can use both a low does dex and a high dose dex test

Question 11

what will a normal person show with
low dose dex
high dose dex
ACTH

Answer 11

↓
↓
↓

Question 12

what will a adrenal adenoma person show with
low dose dex
high dose dex
ACTH

Answer 12

↔
↔
↓

Question 13

what will a cushings disease person show with
low dose dex
high dose dex
ACTH

Answer 13

↔
↓
↑

Question 14

what will a ectopic ACTH disease person show with
low dose dex
high dose dex
ACTH

Answer 14

↔
↔
↑

Question 15

what extra tests might be used for adrenal adenomas?

Answer 15

• CT or MRI of adrenals

Question 16

what extra tests might be used for pituitary adenomas?

Answer 16

• Pituitary MRI

* Inferior petrosal sinus sampling

Question 17

what extra tests might be used for ectopic ACTH?

Answer 17

• If lung cancer suspected: CXR, sputum cytology, bronchoscopy, CT scan

Question 18

management plan for iatrogenic cushings?

Answer 18

discontinue steroids, use lower dose or use a steroid-sparing agent

Question 19

how to medically treat cushings?

Answer 19

o Inhibit cortisol synthesis with metyrapone or ketoconazole
o Treat osteoporosis
o Physiotherapy for muscle weakness

Question 20

how to surgically treat cushings?

Answer 20

o Pituitary Adenomas - trans-sphenoidal adenoma resection
o Adrenal adenoma/carcinoma - surgical removal of tumour
o Ectopic ACTH - treatment directed at the tumour

Question 21

complications of cushings syndrome?

Answer 21

• Diabetes
• Osteoporosis
• Hypertension
• Pre-disposition to infections

Question 22

prognosis for cushings syndrome?

Answer 22

• Untreated - 5 yr survival = 50%

* Depression persists for many years following treatment