Cushing's syndrome Flashcards

1
Q

summarise a typical presentation of a patient with cushing’s syndrome?

A
  • Increasing weight
  • fatigue
  • easy bruising
  • thin skin
  • poor wound healing
  • moon face
  • facial plethora
  • interscapular fat pads
  • proximal muscle weakness
  • central obesity and pink/purple striae
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

define cushing’s syndrome?

A

syndrome associated with innapropriate elevation of free circulating cortisol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are the risk factors for cushings?

A

exogenous corticosteroid use

pituitary adenoma

adrenal adenoma

adrenal carcinoma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

explain the aetiology/ risk factors for cushing’s syndrome?

A
  • It can be divided into ACTH Dependent (80%) and ACTH Independent (20%)
  • ACTH Dependent
  • Excess ACTH from a pituitary adenoma (Cushing’s disease)
  • Ectopic ACTH (e.g. lung cancer, pulmonary carcinoid tumours)

• ACTH Independent

  • Benign adrenal adenoma
  • Adrenal carcinoma

• TAKING STEROIDS - would cause bilateral adrenal atrophy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

summarise the epidemiology of cushing’s syndrome?

A

• Incidence: 2-4/1,000,000 per year

Peak incidence 20-40 yrs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what are the presenting symptoms of cushing’s

A
• Increasing weight 
• Fatigue 
• Muscle weakness 
• Myalgia 
• Thin skin 
• Easy bruising 
• Poor wound healing 
• Fractures 
• Hirsuitism 
• Acne 
• Frontal balding 
• Oligomenorrhoea/amenorrhoea 
Depression or psychosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what are the signs of of cushing’s on physical examination?

A
• Moon face 
• Facial plethora 
• 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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

outline the prognosis for cushing’s syndrome?

A

• Untreated - 5 yr survival = 50%

Depression persists for many years following treatment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what are the investigations for cushing’s syndrome?

A

urine pregnancy test
bloods
initial high sensitivity tests
tests to determine underlying cause ( measure plasma ACTH levels)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

describe bloods in cushing’s syndrome?

A

U&Es - hypokalaemia due to mineralocorticoid effect

BM - high glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

outline the initial high sensitvity tests for cushing’s syndrome?

A

24 hr Urinary free cortisol

9am cortisol

Late-night salivary cortisol

Overnight low-dose dexamethasone suppression test
▪ THIS IS USUALLY DONE
▪ 2mg dexamethanasone 11pm midnight
▪ Morning have blood test and failure to suppress cortisol

Low dose dexamethasone suppression test (LDDST)
▪ Give 0.5 mg dexamethasone orally ever 6 hrs for 48 hrs
In Cushing’s syndrome, serum cortisol measured 48 hrs after the first dose of dexamethasone fails to suppress below 50 nmol/L

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what are the tests to investigate the underlying cause of cushing’s syndrome?

A

○ ACTH-dependent (pituitary adenoma)
▪ High plasma ACTH
▪ Pituitary MRI
▪ High-dose dexamethasone suppression test - uses 2mg which is capable of producing partial/complete suppression of cortisol if the problem is a pituitary tumour (since the pituitary retains some feedback control)
▪ Inferior petrosal sinus sampling (SUPERIOR to high-dose dexamethasone suppression test)
• Central: peripheral ratio of venous ACTH > 2:1 (or > 3:1 after CRH administration) in Cushing’s disease

○ ACTH-dependent (ectopic)
▪ an ectopic source of ACTH would not be responsive to exogenous feedback and so it’s not suppressed by the High-dose Dexamethasone suppression test
▪ If lung cancer suspected: CXR, sputum cytology, bronchoscopy, CT san
▪ Radiolabelled octreotide scans can detect carcinoid tumours because they express somatostatin receptors

○ ACTH-independent (adrenal adenoma/carcinoma)
▪ Low plasma ACTH
CT or MRI of adrenals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

if the cause of cushion’s is iatrogenic- what should you do?

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what are the 2 drugs used in the medical treatment of cushion’s syndrome?

A

metyrapone or ketoconazole

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

outline the medical management of cushing’s syndrome?

A

Used pre-operatively or if unfit for surgery

Inhibit cortisol synthesis with metyrapone or ketoconazole

Treat osteoporosis

Physiotherapy for muscle weakness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

outline the surgical management of cushing’s syndrome

A

○ Pituitary Adenomas - trans-sphenoidal adenoma resection

○ Adrenal adenoma/carcinoma - surgical removal of tumour

○ Ectopic ACTH - treatment directed at the tumour

Bilateral adrenalectomy may be performed in refractory Cushing’s disease

17
Q

when is radiotherapy performed in cushion’s syndrome?

A

Performed in those who are not cured and have persistent high cortisol after trans-sphenoidal resection of the tumour

18
Q

what are the possible complications of cushing’s syndrome?

A
  • Diabetes
  • Osteoporosis
  • Hypertension
  • Pre-disposition to infections
• Complications of surgery: 
○ CSF leakage 
○ Meningitis 
○ Sphenoid sinusitis
○ Hypopituitarism 

• Complications of radiotherapy:
○ Hypopituitarism
○ Radionecrosis
○ Increased risk of second intracranial tumours and stroke

Bilateral adrenalectomy may be complicated by the development of Nelson’s syndrome (locally aggressive pituitary tumour causing skin pigmentation due to ACTH secretion)