Cushing's

Question 1

Definition

Answer 1

Clinical state produced by chronic glucocorticoid excess

Question 2

Features - catabolic, glucocorticoid, mineralocorticoid

Answer 2

Catabolic:  
Proximal myopathy
  Striae
  Bruising
  Osteoporosis

GC:
DM
Obesity

MC:
HTN
Hypokalaemia

Question 3

Appearance

Answer 3

Moon face
  Acne and hirsutism
  Interscapular and supraclavicular fat pads
  Centripetal obesity
  Striae
  Thin limbs
  Bruising
  Thin skin

Question 4

ACTH independent Cushings

Answer 4

↓ACTH due to –ve FB

No suppression ̄c any dose of dex

Question 5

Cause of ACTH independent

Answer 5

Iatrogenic steroids: commonest cause
  Adrenal adenoma / Ca: carcinoma often → virilisation
  Adrenal nodular hyperplasia
  Carney complex: LAME Syndrome
  McCune-Albright

Question 6

ACTH dependent causes (2)

Answer 6

Cushing’s disease

Ectopic ACTH

Question 7

What is Cushing’s disease

Answer 7

Cushing’s disease:

Bilat adrenal hyperplasia from ACTH-secreting pituitary tumour (basophilic microadenoma)
Cortisol suppression ̄c high-dose dex

Question 8

What is ectopic ACTH

Answer 8

Small Cell Lung Ca
  Carcinoid tumour
  Skin pigmentation, metabolic alkalosis, wt. loss,
hyperglycaemia
  No suppression  ̄c any dose of dex

Question 9

Investigations

Answer 9

1st: 24h urinary free cortisol
  Late night serum or salivary cortisol
  Highest @ AM, lowest @ midnight
  Dexamethasone suppression tests
  ACTH (but ACTH degrades v. quick after venepuncture)
  Localisation: CT, MRI
  DEXA scan

Question 10

Treatment (3)

Answer 10

Cushing’s disease: trans-sphenoidal excision
Adrenal adenoma / Ca: adrenelectomy
Ectopic ACTH: tumour excision, metyrapone (inhibits
cortisol synthesis)

Question 11

What is Nelson’s syndrome

Answer 11

Rapid enlargement of a pituitary adenoma following bilateral adrenelectomy for Cushing’s syndrome
Not typically performed nowadays Presentation

Mass effects: bitemporal hemianopia and hyper pigmentation