Flashcards in Stroke Deck (57):
Development of focal/global neurological deficit related to vascular event
Can transient clinical events occur due to vascular events?
Can vascular events go undetected clinically?
What are the pathological processes involved in stroke?
What percentage of strokes are caused by infarction?
What is an infarction?
Death of tissue due to inadequate blood supply
What percentage of strokes are caused by haemorrhage?
What is a haemorrhage?
Tissue injury due to escape of blood from vessels
What percentage of strokes are caused by subarachnoid haemorrhage?
What is a subarachnoid haemorrhage?
Escape of blood primarily into subarachnoid space
What is the third leading cause of death?
What are the risk factors for cerebral infarction?
Cardiac disease; eg: atrial fibrillation
What happens in a cerebral infarct?
Necrosis of cerebral tissue in particular vascular distribution
Due to vessel occlusion/severe hypoperfusion
What is cerebral infarction usually related to?
Where can the primary problem causing a cerebral infarct be?
What are the possible mechanisms of infarction?
Inadequate supply of blood due to pump failure
Inadequate supply of blood due to narrowed vessel lumen
- Hypertensive vessel thickening
- Amyloid angiopathy
Vessel occlusion by embolus
Why is haemorrhage more likely than infarction if you have an amyloid angiopathy?
Wall thickens > weakens
What can cause a large artery occlusion?
What can cause a small vessel occlusion?
What can cause a venous occlusion?
How can infective endocarditis cause a cerebral infarction?
Mycotic embolus blocks vessel
What percentage of people have a probe-patent interatrial septum?
What is a probe-patent interatrial septum?
Flap that can be open
How can a probe-patent interatrial septum contribute to a cerebral infarct?
If right heart pressure increased > embolus crosses into left atrium from right > travels up into cerebral vessel > occlusion
What are the common sites of atherosclerosis in the circle of Willis?
Anterior circulation at bifurcation
Internal carotid artery
How do thrombi form in atherosclerotic vessels?
Narrowing of vessel lumen
Irregularities in intima
Lend themselves to thrombus formation
Where is an embolus more common?
In aortic and internal carotid branches than vertebro-basilar system
What does the brain look like within one hour of a cerebral infarct?
How does cerebral oedema form?
Cells swell because of cytotoxic oedema
Vasogenic oedema in vascularised edges
What does cerebral oedema cause?
Raised intracranial pressure
What happens to the gyri and sulci around the swelling tissue?
Sulci are obliterated
What does the brain look like macroscopically in the days/weeks after a cerebral infarct?
Clear interface between dead and normal tissue
What does liquefactive necrosis look like microscopically?
Massive influx of macrophages
More and more cavitation
Some surviving blood vessels with a little new growth
Neurons don't regenerate
What does the brain look like in the months/years after a cerebral infarct?
Infarcted area replaced by cavity
What are most cerebral infarcts caused by: thrombus or embolus?
How does a haemorrhagic infarct happen?
Embolus lodges > tissue necrosis, damage to blood vessels > embolus removed, naturally/iatrogenically > reperfusion into necrotic area > weakened blood vessels rupture > haemorrhage over necrosis
Why must blood be restored before complete necrosis?
Avoid haemorrhagic infarction
What is hyaline arteriolosclerosis?
Small vessel disease associated with hypertension
What causes lacunar infarcts?
In which areas do lacunar infarcts usually occur?
Why do people with cerebral infarction die?
- Cardiovascular disease
- Pulmonary thromboembolism
Involvement of vital centres
What are the effects of raised intracranial pressure?
What are the two most common causes of intracerebral haemorrhage?
Hypertensive small vessel disease
Which demographic is amyloid angiopathy most common in?
What are the causes of intracerebral haemorrhage?
Hypertensive small vessel disease
What is a hypertensive haemorrhage?
Presence of small vessel disease like hyaline arteriolosclerosis
In which sites is hypertensive haemorrhage likely to occur?
Lobar white matter
What is amyloid angiopathy?
Deposition of beta amyloid in walls of superficial supratentorial blood vessels
What type of haemorrhage is amyloid angiopathy associated with?
Often multiple and of varying age
Which neurodegenerative disease is amyloid angiopathy associated with?
What are the non-traumatic causes of subarachnoid haemorrhage?
Rupture of saccular/berry aneurysm in circle of Willis and its branches
Rupture of other aneurysms
Extension of intracerebral haemorrhage
What does it mean by a congenital berry aneurysm?
Aneurysm develops at sites of congenital weakness
Aneurysm develops with ageing
What are the risk factors for developing a saccular aneurysm?
Polycystic kidney disease
Coarctation of aorta
Type III collagen deficiency
Where do 90% of aneurysms form?
In anterior circulation of circle of Willis
Where are sites of congenital weakness in the circle of Willis?
What are the most common sites of berry aneurysm formation?
Bi/trifurcation of middle cerebral artery
Junction of internal carotid artery and posterior communicating artery
Anterior communicating artery