2) Disorders of CNS, circulatory diseases

Question 1

What are the three types of strokes?

Answer 1

Ischaemic stroke
subarachnoid haemorrhage
intracerebral haemorrhage

Question 2

What is a stroke?

Answer 2

The sudden death of brain cells due to lack of oxygen, caused by blockage of an artery or the rupture of an artery

Question 3

Cerebral ischaemia (define, types, most common cause?)

Answer 3

• A term describing an acute episode of neurologic deficit
• Not enough blood flow to the brain to meet metabolic demand due to blockage of an artery (usually MCA). This causes death of brain tissue. Types:
• -> Thrombotic: Blood clot forms within the brain
• -> Embolic: Blood clot forms elsewhere in the body and travels to brain via bloodstream before becoming lodged in the brain
• -> lacunar: occlusion of small vessels
• can be acute (1 day to 1 week), subacute (1 week to 1 month), or chronic (> 1 month)
• Atherosclerotic disease is most common cause

Question 4

Subarachnoid haemorrhage (define, how is it different to intracerebral haemorrhage)

Answer 4

• When a vessel just outside the brain ruptures, rapidly filling subarachnoid space

Question 5

Intracerebral haemorrhage (define, how is it different to subarachnoid haemorrhage)

Answer 5

• Occurs when a diseased vessel within the brain bursts

Question 6

Atherosclerosis

Answer 6

A disease in which plaque builds up inside your arteries, causing them to narrow

Question 7

TIA

Answer 7

trans-ischemic attacks are focal neurologic deficits that resolve in less than 24hrs. Partial blockage of an artery, temporary decrease of blood supply

Question 8

Radiological features of cerebral ischaemia
CT (___, early___ signs, late signs)
MRI (better for___, early signs, ____)
Angio (Accurate___)

Answer 8

CT

• Dense artery sign (MCA) due to fresh thrombus occluding a vessel
• Early parenchymal signs: reduced grey matter density –> brain swelling
• Late signs: Atrophy with adjacent sulci & ventricle enlargement

MRI

• better for showing extent of ischaemic change and is more sensitive for early infarcts
• Early signs: reduced perfusion when the parenchyma still appears normal
• haemorrhagic transformation follows secondary bleeding into areas of reperfused tissue

Angiography
- accurate tandem lesion evaluation, where stenosis is close to 50% and not sure whether to treat medically or surgically

Question 9

Subarachnoid haemorrhage radiological features (CT, MRI)

Answer 9

CT: non-con shows high attenuation of blood in subarachnoid space

MRI: Best demonstrates chronic haemorrhages as hypointense areas on T2

Question 10

Intraparenchymal/intracerebral haemorrhage radiological features (CT)

Answer 10

CT: New haematoma appears homogenously dense, well defined, round or oval lesion, becoming isodense overtime. 6 month old lesion appears as well defined isodense lesion