Stroke

Question 1

Define stroke

Answer 1

Clinical term

Development of focal/global neurological deficit related to vascular event

Question 2

Can transient clinical events occur due to vascular events?

Answer 2

Yes

Question 3

Can vascular events go undetected clinically?

Answer 3

Yes

Question 4

What are the pathological processes involved in stroke?

Answer 4

Infarction
Haemorrhage
Subarachnoid haemorrhage

Question 5

What percentage of strokes are caused by infarction?

Answer 5

75%

Question 6

What is an infarction?

Answer 6

Death of tissue due to inadequate blood supply

Question 7

What percentage of strokes are caused by haemorrhage?

Answer 7

20%

Question 8

What is a haemorrhage?

Answer 8

Tissue injury due to escape of blood from vessels

Question 9

What percentage of strokes are caused by subarachnoid haemorrhage?

Answer 9

5%

Question 10

What is a subarachnoid haemorrhage?

Answer 10

Escape of blood primarily into subarachnoid space

Question 11

What is the third leading cause of death?

Answer 11

Stroke

Question 12

What are the risk factors for cerebral infarction?

Answer 12

Ageing
Hypertension
Cardiac disease; eg: atrial fibrillation
Hyperlipidaemia
Diabetes
Hypercoagulable states
Smoking
Obesity

Question 13

What happens in a cerebral infarct?

Answer 13

Necrosis of cerebral tissue in particular vascular distribution
Due to vessel occlusion/severe hypoperfusion

Question 14

What is cerebral infarction usually related to?

Answer 14

Arterial obstruction

Question 15

Where can the primary problem causing a cerebral infarct be?

Answer 15

Arterioles
Veins
Heart

Question 16

What are the possible mechanisms of infarction?

Answer 16

Inadequate supply of blood due to pump failure
Inadequate supply of blood due to narrowed vessel lumen
- Atherosclerosis
- Thrombosis
- Hypertensive vessel thickening
- Diabetes
- Amyloid angiopathy
Vessel occlusion by embolus

Question 17

Why is haemorrhage more likely than infarction if you have an amyloid angiopathy?

Answer 17

Wall thickens > weakens

Lumen narrowed

Question 18

What can cause a large artery occlusion?

Answer 18

Thrombosis

Embolus

Question 19

What can cause a small vessel occlusion?

Answer 19

Thrombosis

Embolus

Question 20

What can cause a venous occlusion?

Answer 20

Thrombosis

Question 21

How can infective endocarditis cause a cerebral infarction?

Answer 21

Mycotic embolus blocks vessel

Question 22

What percentage of people have a probe-patent interatrial septum?

Answer 22

30%

Question 23

What is a probe-patent interatrial septum?

Answer 23

Flap that can be open

Question 24

How can a probe-patent interatrial septum contribute to a cerebral infarct?

Answer 24

If right heart pressure increased > embolus crosses into left atrium from right > travels up into cerebral vessel > occlusion

Question 25

What are the common sites of atherosclerosis in the circle of Willis?

Answer 25

Anterior circulation at bifurcation Vertebral artery Basilar artery Internal carotid artery

Question 26

How do thrombi form in atherosclerotic vessels?

Answer 26

Narrowing of vessel lumen Irregularities in intima Lend themselves to thrombus formation

Question 27

Where is an embolus more common?

Answer 27

In aortic and internal carotid branches than vertebro-basilar system

Question 28

What does the brain look like within one hour of a cerebral infarct?

Answer 28

Relatively normal

Question 29

How does cerebral oedema form?

Answer 29

Cells swell because of cytotoxic oedema | Vasogenic oedema in vascularised edges

Question 30

What does cerebral oedema cause?

Answer 30

Raised intracranial pressure

Question 31

What happens to the gyri and sulci around the swelling tissue?

Answer 31

Gyri expand | Sulci are obliterated

Question 32

What does the brain look like macroscopically in the days/weeks after a cerebral infarct?

Answer 32

Clear interface between dead and normal tissue | Liquefactive necrosis

Question 33

What does liquefactive necrosis look like microscopically?

Answer 33

Massive influx of macrophages More and more cavitation Some surviving blood vessels with a little new growth Neurons don't regenerate

Question 34

What does the brain look like in the months/years after a cerebral infarct?

Answer 34

Infarcted area replaced by cavity

Question 35

What are most cerebral infarcts caused by: thrombus or embolus?

Answer 35

Embolus

Question 36

How does a haemorrhagic infarct happen?

Answer 36

Embolus lodges > tissue necrosis, damage to blood vessels > embolus removed, naturally/iatrogenically > reperfusion into necrotic area > weakened blood vessels rupture > haemorrhage over necrosis

Question 37

Why must blood be restored before complete necrosis?

Answer 37

Avoid haemorrhagic infarction

Question 38

What is hyaline arteriolosclerosis?

Answer 38

Small vessel disease associated with hypertension

Question 39

What causes lacunar infarcts?

Answer 39

Hyaline arteriolosclerosis

Question 40

In which areas do lacunar infarcts usually occur?

Answer 40

Basal ganglia | Internal capsule

Question 41

Why do people with cerebral infarction die?

Answer 41

``` Most people - Pneumonia - Cardiovascular disease - Pulmonary thromboembolism Involvement of vital centres Cerebral swelling ```

Question 42

What are the effects of raised intracranial pressure?

Answer 42

Transtentorial herniation | Brainstem haemorrhages

Question 43

What are the two most common causes of intracerebral haemorrhage?

Answer 43

Hypertensive small vessel disease | Congophilic/amyloid angiopathy

Question 44

Which demographic is amyloid angiopathy most common in?

Answer 44

Older people

Question 45

What are the causes of intracerebral haemorrhage?

Answer 45

``` Hypertensive small vessel disease Amyloid angiopathy Blood disorders Tumour Vasculitis Vascular malformation Drugs ```

Question 46

What is a hypertensive haemorrhage?

Answer 46

Presence of small vessel disease like hyaline arteriolosclerosis

Question 47

In which sites is hypertensive haemorrhage likely to occur?

Answer 47

``` Basal ganglia Thalamus Lobar white matter Cerebellum Pons ```

Question 48

What is amyloid angiopathy?

Answer 48

Deposition of beta amyloid in walls of superficial supratentorial blood vessels

Question 49

What type of haemorrhage is amyloid angiopathy associated with?

Answer 49

Superficial haemorrhages | Often multiple and of varying age

Question 50

Which neurodegenerative disease is amyloid angiopathy associated with?

Answer 50

Alzheimer's disease

Question 51

What are the non-traumatic causes of subarachnoid haemorrhage?

Answer 51

``` Rupture of saccular/berry aneurysm in circle of Willis and its branches Rupture of other aneurysms - Mycotic - Atherosclerotic Extension of intracerebral haemorrhage ```

Question 52

What does it mean by a congenital berry aneurysm?

Answer 52

Aneurysm develops at sites of congenital weakness | Aneurysm develops with ageing

Question 53

What are the risk factors for developing a saccular aneurysm?

Answer 53

``` Age Polycystic kidney disease Coarctation of aorta Type III collagen deficiency Hypertension Smoking/alcohol ```

Question 54

Where do 90% of aneurysms form?

Answer 54

In anterior circulation of circle of Willis

Question 55

Where are sites of congenital weakness in the circle of Willis?

Answer 55

Arterial bifucations

Question 56

What are the most common sites of berry aneurysm formation?

Answer 56

Bi/trifurcation of middle cerebral artery Junction of internal carotid artery and posterior communicating artery Anterior communicating artery

Question 57

What are the complications of an aneurysm rupture?

Answer 57

Subarachnoid haemorrhage Cerebral oedema and raised intracranial pressure Vasospasm and infarction Ventricular obstruction > hydrocephalus