Session 10 - Lecture 1 - Stroke Flashcards
1 - Title
Stroke
“Stroke with a focus on neuroanatomy”
2 - Learning Objectives
Learning Objectives
• Describe the blood supply of the brain and the mechanisms and consequences of its failure
• Apply knowledge of cerebral vasculature to interpret different presentations of stroke
3 - What is a stroke?
What is a stroke?
• Cerebrovascular accident (CVA)
• ‘A serious life-threatening medical condition that occurs when the blood supply to part of the brain is cut off.’
- Transient Ischaemic Attack (TIA)
- ‘mini stroke’
- Similar symptoms to a stroke but complete resolution within 24 hours.
“Stroke = cerebrovascular accident
TIAs – colloquially called mini stroke – essentially symptoms of a stroke but resolves completely in 24 hrs.”
4 - Types of stroke
Types of stroke
• Ischaemic – 85%
• Haemorrhagic – 10%
• Other – 5%
“So within strokes we’ve got diff types – we’ve got Ischaemic, haemorrhagic and other”
5 - Types of stroke and causes
Types of stroke
Ischaemic – 85%
• Thromboembolic
Haemorrhagic – 10%
• Intracerebral
• Subarachnoid
Other – 5%
• Dissection
• Venous Sinus Thrombosis
• Hypoxic brain injury (e.g. post cardiac arrest)
“1. by far the most common
1a. more than often thromboembolic – so the same mechanisms we have for heart attacks, narrowing of blood vessels, full of emboli which then block off arteries.
2. different areas that bleed can come from in the brain. 3a. Carotid artery dissection into cerebral vasculature.
3b. problem with blood clotting in venous sinuses of the brain
3c. after a cardiac arrest.”
6 - What do we need to do when we suspect an acute stroke?
What do we need to do when we suspect an acute stroke?
• Are they within the thrombolysis window?
• Is it a bleed?
URGENT CT HEAD
“Two key clinical questions when suspecting stroke –
2. 10% of all strokes is a bleed.
When someone comes in with an acute stroke what we need is an urgent CT head.”
7 - What do we hope to see in a CT head?
What do we hope to see?
- In acute ischaemic stroke no findings on CT
- Purpose of CT is to exclude haemorrhagic cause
- If clear in acute setting (<4 hours) can proceed with thrombolyisis
Case courtesy of Dr Derek Smith, Radiopaedia.org, rID: 46232
https://radiopaedia.org/cases/normal-ct-head-1?lang=us
“And What would we hope to see on urgent CT head?
- Essentially is NO FINDINGS. In an acute stroke – we won’t see any finding on a CT head so will look like a normal CT
- reason for doing this is to exclude 10% haemorrhagic
- if judged clear by seniors, then if we’re within thrombolysis window (<4 hrs) then we’ll do thrombolysis to preserve that brain and get rid of thromboembolism.”
8 - How can we visualise ischaemia in an acute stroke?
MRI shows the ischaemia
“If we were to do an MRI in an acute stroke we would see the change. Here’s the CT scan which looks nomal – in MRI see changes in ischaemic region – don’t normally do MRIs if we’re expecting a stroke though.”
9 - Why do we do CT scans in an acute stroke?
Haemorrhage shows on CT
Case courtesy of Hugo Neves (RT), Radiopaedia.org, rID: 17507
https://radiopaedia.org/cases/acute-haemorrhagic-stroke?lang=us
“And As I said, the reason to do the scan is to check for the bleed, so the reason to do the CT scan is to exclude the haemorrhage – can see haemorrhags are all v clear on CT scans.”
10 - Relate timing to CT scan presentation
[See IMG]
More established infarcts show on CT
Case courtesy of A.Prof Frank Gaillard, Radiopaedia.org, rID: 21459
“If we were to leave a stroke, or a stroke presents late (established stroke) we do get changes on CT scans – late stroke, can see hypodense region there where brain has died.”
11 - The blood supply to the brain…
The blood supply to the brain…
• From the ICA (anterior cerebral circulation)
• From the vertebral arteries (posterior cerebral circulation)
• Forming the circle of Willis
• Terminal branches create 3 main arterial territories that lead to specific pathologies
“Blood supply of brain comes from ICA and vertebral arteries which forms circle of WIllis. “
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