Cushings

Question 1

What is Cushing’s syndrome

Answer 1

• Clinical features due to
  
  • chronic excess glucocorticoid production
  • loss of normal feedback mechanism of HPA axis
  • loss of circardian rythm of cortisol secretion

Question 2

What is Cushing’s disease?

Answer 2

• Pituitary adenoma secretes ACTH

Question 4

What are the causes of Cushing’s syndorme?

*categorise to ACTH dependent & ACTH independent

Answer 4

• ACTH dependent
  
  • Cushing’s disease (common)
  • Ectopic ACTH production
    
    • Small cell lung cancer
• ACTH independent
  
  • Steroids (most common)
  • Adrenal adenoma/carcinoma
  • Adrenal hyperplasia
  • Carney complex
  • Mc-Cune Albright Syndrome

Question 5

What are the diagnostic features of Cushing’s disease?

Answer 5

• 30-50 yo
• Dexamethasone test
  
  • low dose: no change in cortisol
• MRI
  
  • Bilateral adrenal hyperplasia

Question 6

What are the diagnostic features of Paraneoplastic Cushings (ectopic ACTH production)?

Answer 6

• Sx
  
  • Hyperpigmentation
  • Absent classical cushings features
  • hypokalaemic metabolic alkalosis
• Dexamethasone test
  
  • High dose: fail to suppress cortisol
• CXR
  
  • hilar/perihilar masses

Question 7

What are the obervable signs of Cushing’s syndrome?

Answer 7

• Plethoric moon face
• Buffalo hump
• supraclavicular fat distribution
• purple abdominal striae
• Central obesity
• Proximal limb muscle wasting

Question 8

What are the clinical features of cushing’s?

*dont include observable signs

Answer 8

• HTN
• Hyperglycaemia
• Depression, lethargy, irritability, psychosis
• irregular menses, erectile dysfunction
• Osteoporosis
• Easy bruising of skin

Question 10

How does the dexamethasone suppression test work?

*recall diagram inserted

Answer 10

Question 11

What conditions can give false positives in low dose dexamethasone suppresion test?

Answer 11

• depression
• obesity
• alcohol excess
• Medications
  
  • phenytoin
  • phenobarbital
  • rifampicin

Question 12

Apart from the dexamethasone suppresion test, what other Ix would you order for Cushings?

Answer 12

• Bedside
  
  • 24hr urinary free cortisol
  • FBC, U&E- low K
• Imaging
  
  • MRI - pituitary adenoma
  • Chest CT - SSC
  • Abdo CT - adrenal tumours

Question 13

What is the sensitivity of MRI to detect pituitary adenomas?

Answer 13

• 70%
• pituitary tumours are too small

Question 14

How would you Mx Cushings?

Answer 14

• Steroids
  
  • Stop medications
• Cushing’s disease
  
  • Trans-sphenoidal removal of pituitary tumour
• Adrenal adenoma/carcinoma
  
  • Adrenelectomy
• Paraneoplastic Cushings
  
  • surgery- if not spread elsewhere

Question 15

What are the complications of cushings?

Answer 15

• Vascular mortality (if untreated)
• Obesity
• DM
• Osteoporosis
• Menstrual irregularity
• Myopathy
• HTN