Vascular stroke Flashcards
What is the definition of a stroke?
Damage to the brain or spinal cord caused by an abnormality in the blood supply.
What are the 2 things that strokes are recognised by?
- Sudden onset of focal neurological symptoms over a few seconds or minutes that PERSIST for more than 24 hours.
- Symptoms and signs of a focal brain lesion (except subarachnoid haemorrhage)
How many people per year in NZ have a stroke?
8000
Does the incidence in stroke increase with age?
Yes.
What is the mean age of having your first stroke?
75
What % of strokes occur under the age of 65?
25%
Is stroke the third most common cause of death?
Yes. Also the most common cause of prolonged adult disability.
Are strokes contralateral?
No, they are unilateral (affect one side)
How many types of stroke are there? What are they?
3
- Ischaemic stroke (infarction)
- Intracerebral Haemorrhage (ICH) - artery rupture
- Subarachnoid Haemorrhage (SAH) - by aneurysm
What type of stroke is the most common?
Ischaemic stroke (80-85% of all strokes)
What happens during an ischaemic stroke?
Loss of blood flow to part of the brain or spinal cord, depriving the tissue of oxygen and glucose –> NECROSIS –> INFARCTION
How common is ICH?
Causes about 15% of all strokes.
What is ICH?
Bleeding into the brain itself, usually from small artery supplying the deep white matter and basal ganglia. Haematoma causess symptoms due to cutting off pathways and exerting pressure on surrounding tissue.
How common is SAH?
Least common. About less than 5% of all strokes. Usually younger patients with other types of stroke.
What happens in SAH?
Bleeding into the subarachnoid space around the brain and the spinal cord. Most people, usually caused by blood leakage -> aneurysm.
What are symptoms of SAH that make it different to other stroke types?
Extremely severe headache (usually at back of head) and sometimes abrupt loss of consciousness, neck stiffness due to irritation of the meninges.
What are the 3 main symptoms of ischaemic stroke?
Anterior circulation
Posterior circulation
Lacunar infarcts
Does Calcium moving into the cell compromise mitochondrial function?
Yes
Eventually, ischaemia leads to…..
irreversible cell damage.
Where is ischaemia most severe?
The core of the infarct.
What is the ischaemic penumbra?
The outer edges of infarct with reduced perfusion and electrical failure and dysfunction. It may be salvageable if early reperfusion.
What are the four types of ischaemic stroke?
Total anterior circulation infarct (TACI)
Posterior anterior circulation infarct (PACI)
Posterior circulation infarct (POCI)
Lacunar infarct (LACI)
Isolated homonymous hemianopia is usually caused by what?
Occlusion of a posterior cerebral artery (POCI)
How to treat an ischaemic stroke.
Prevention of clots: Anti-platelet drugs (aspirin)
Removing the thrombus: Thrombolytic agents. Can cause bleeding in the brain.
Increase collateral circulation and perfusion of the ischaemic punumbra: Not a lot helps this/useful.
Increasing resistance of brain to ischaemia: neuroprotection. Hypothermia, free radical scavengers, calcium channel blocking agents. NOT BENEFICIAL TO HUMANS.
What is a transient ischaemic attack? (TIA)
Sudden focal neurological symptoms over a few seconds/mins that persist for less than 24 hours.
What causes a TIA?
Focal interruption of blood supply to part of brain. Causes functional impairment. Blood restored spontaneously before permanent damage.
“Step before a stroke”
When is the risk of ischaemic stroke greatest after TIA?
First weeks and months following TIA.
How do you prevent ischaemic stroke?
Modify risk factors
- lower BP, don’t smoke, exercise…
Treat with anticoagulants
Carotid endarterectomy
Anti-platelet meds
- aspirin
ICH is more common in who?
Blacks, chinese and japanese.
Symptoms of ICH?
More severe headaches than ischaemic stroke, and loss of consciousness.
How do you distinguish between ICH and ischaemic stroke?
MRI and CT scan
What causes ICH?
Hypertension
Cerebral amyloid angiopathy (affects cerebral BV’s)
- Beta-amyloid deposited
malformations of blood vessels, brain tumors, etc.
haemorrhages due to cerebral amyloid angipathies tend to recur?
yes.
How often do hypertensive assoc. ICHs recur?
Rarely.
Cerebral amyloid angiopathy often associated with what disease?
Alzheimer’s.
The incidence of SAH is higher in who?
women.
What is a berry aneurysm?
Ruptured aneurysm.
In how many patients can the source of SAH not be found
About 15%
What is the only environmental factor that has been consistently identified as a risk factor for aneurysmal SAH?
Smoking
How do we diagnose SAH?
Using a CT scan.
Treatment of SAH?
Clipping the neck of the aneurysm or occluding it via a catheter.
Stroke is a focal neurological deficit?
Yes
How many NZrs will have stroke?
1/8
How many infarcts are due to embolism?
20%
Where do embolisms form?
heart
What is Stroke topography?
The symptoms and signs that you see with a stroke are determined by which part of the brain has been effected.
What symptoms are there in Left MCA territory stroke?
Right sided weakness
Right sided sensory loss
Dysphasia
Right MCA territory stroke symptoms?
L weakness
L sensory loss
L neglect
Anosagnosia
Right PCA territory stroke symptoms?
L homonymous hemianopia
Right ACA territory stroke?
L leg weakness
Right cerebellar stroke symptom?
R limb incoordination
2 types of vascular formations.
Arteriovenous malformation
- 1/3 patients with ICH < 45 yrs
Saccular aneurysms
- 1/13 patients with ICH
