Acute Stroke Flashcards
(149 cards)
What is stroke also known as?
Cerebrovascular event
What is a stroke?
A clinical syndrome caused by disruption to the blood supply of the brain
What is a stroke characterised by?
Rapidly developing signs of focal or global disturbance of cerebral functions, lasting for more than 24 hours or leading to death
What is a transient ischaemic attack?
A similar presentation that resolves within 24 hours
What are the 2 types of stroke?
- Ischaemic
- Haemorrhagic
Can ischaemic and haemorrhagic strokes be distinguished clinically?
Not reliably, but there are pointers
What clinical signs point towards a haemorrhagic stroke?
- Meningism
- Severe headache
- Coma within hours
What clinical signs point towards an ischaemic stroke?
- Carotid bruit
- Atrial fibrillation
- Past TIA
What happens in ischaemic stroke?
There is loss of blood supply to part of the brain
After how long does brain tissue cease to function when deprived of oxygen?
60-90 seconds
After how long does brain tissue suffer irreversible injury when deprived of oxygen?
After approx 3 hours
How might atherosclerosis be involved in stroke?
It can disrupt blood supply by narrowing the lumen of blood vessels, leading to a reduction in blood flow
By what methods can atherosclerosis cause the formation of blood clots?
- Due to the reduction in blood flow
- May release showers of small emboli through the disintegration of atherosclerotic plaques
What is an embolic infarction?
When the emboli formed elsewhere in the circulatory system
Where do the emboli typically form in embolic infarction?
- Heart
- Carotid arteries
What can cause embolic infarction originating from the heart?
AF
What happens in an embolic infarction?
The clots enter the cerebral circulation, then lodge in and block brain blood vessels
What are haemorrhagic stroke classified on the basis of?
Their underlying pathologies
Give 5 causes of haemorrhagic strokes
- Hypertensive haemorrhage
- Ruptured aneurysm
- Ruptured AV fistula
- Transformation of prior ischaemic infarction
- Drug-induced bleeding
How do haemorrhagic strokes result in tissue injury?
- Causing compression of tissue from an expanding haematoma(s)
- Blood released by brain haemorrhage appears to have direct toxic effects on brain tissue and vasculature
What might result from compression of brain tissue from a haematoma in haemorrhagic stroke?
It may lead to loss of blood supply to affected tissue, with resulting infarction
What are the causes of stroke in a younger patient?
- Vasculitis
- Thrombophilia
- Subarachnoid haemorrhage
- Venous sinus thrombosis
- Carotid artery dissection
What are the causes of stroke in older patients?
- Thrombosis in situ
- Atherothromboembolism
- Heart emboli
- CNS bleed
- Sudden BP drop
- Vasculitis
- Venous sinus thrombosis
What might cause heart emboli leading to stroke?
- Atrial fibrillation
- Infective endocarditis
- Myocardial infarction