30. Stroke: Presentation and Investigation Flashcards
How old are most stroke patients?
60+
What is stroke?
- sudden onset of loss of neurological function and deficit
- lasts more than 24 hours
- of vascular origin
- result from ischaemic infarction or bleeding into part of the brain with rapid onset of CNS signs and symptoms
How to differentiate between stroke and transient ischaemic attack?
- stroke lasts for more than 24 hours
- transient ischaemic attack lasts less than 24 hours and its effects are only temporary
What are symptoms of stroke? (5)
- loss of power and movement
- loss of sensation (part of body feels cold/ dead)
- loss of speech and comprehension
- loss of vision
- loss of coordination
What history aspects need to be considered? (6)
- time of onset
- witnesses +observations
- headache/ vomiting/neck stiffness/ photophobia (suggests haemorrhage)
- loss of consciousness
- fit
- inconsistence
What neurological related loss of function signs are seen on taking history and examination in stroke patients? (7)
- motor (clumsy or weak limb)
- sensory (loss of feeling)
- speech (dysarhria (slurring of speech or not articulating)/ dysphasia (not comprehending))
- neglect ( visuospatial problems)
- vision ( loss in one eye, or hemianopia)
- gaze palsy
- ataxia/vertigo/incoordination/ nystagmus (loss of control of body movements)
What causes a stroke? (7)
- small vessel occlusion/ cerebral angiopathy/ thrombosis in situ (damage to brain due to blockage of blood due to thrombus or embolus)
- cardiac emboli
- atherothromboembolism
- CNS bleeds (trauma, aneurysm rupture, anticoagulation, thrombolysis) due to rupture of blood vessels
- disease of vessel wall
- rupture of vessel wall (haemorrhage)
- disturbance of normal properties of blood
What makes blood vessels more fragile and more susceptible to stroke?
hypertension (makes vessels weaker)
What is meant by penumbra?
area in the brain not getting enough oxygen, is asleep/dead and needs blood flow restored to it otherwise tissue will die
In which arteries of the brain are clots most likely to appear in?
Most likely to appear in middle cerebral arteries
What do external carotid arteries supply?
the face
What do internal carotid arteries supply?
anterior portion of the brain
How should a link between vessel obstruction and stroke be made?
signs and symptoms of the patient should make sense; fit with an artery territory and an area of the brain (e.g. if numb left leg then numb left arm), if if doesn’t fit together then problem most likely is function rather than caused by stroke
What do the carotid systems mainly supply? (2)
- most of the hemispheres
- cortical deep white matter
What does the vertebro-basilar system supply?
-brain stem
- cerebellum
- occipital lobes
(posterior aspects of the brain)
What are 2 main vascular supplies in the brain?
- carotid system
2. vertebro-basilar system
Where does Broca’s area sit and what does it do?
- sits at the frontal and parietal lobes joining
- area of speech formation
What part of the brain is most likely affected if person doesn’t understand speech AND cannot form speech?
most likely a bigger portion of the brain; e.g. cerebrum or both frontal and parietal lobes affected
What is the most likely location of problem if patient cannot move or feel anything and has weakness everywhere?
most likely problem is closer to mid-brain as it affects brain fibres extending to many brain locations (small stroke in midbrain can result in major deficit as fibres packed close together in mid-brain)
What percentage of strokes are as a result of:
- infarction
- haemorrhage
- 85% infarction (ischaemic)
- 15% haemorrhage (haemorrhagic)
What are the main causes of ischaemic (infarction) stroke; 85%? (5)
- large artery atherosclerosis (e.g. carotid)
- cardioembolic (AF)
- small artery occlusion
- undetermined/ cryptogenic
- rare causes: arterial dissection or venous sinus thrombosis
What are the main causes of haemorrhagic stroke; 15%? (2)
- primary intracerebral haemorrhage
2. secondary haemorrhage e.g. subarachnoid haemorrhage or arteriovenous malformation
What is meant by haemorrhagic stroke?
haemorrhage/ blood leaks into brain tissue and puts pressure on surrounding vessels
What is meant by ischaemic stroke?
clot stops blood supply to an areas of the brain (obstruction/infarction)
In which region is carotid vessels are clots and plaques more likely to occur?
at bifurcation of carotids ( due to carotid stenosis increased risk)
What is the commonest cause of a cardioembolic stroke?
atrial fibrillation; atria wobble and and overstimulated which makes clots likely to occur (blood not properly pushed out)
What is a small vessel lacunar stroke?
Stroke that occurs when one of the small arterial vessels deep within the brain become blocked (more likely to occur in elderly since vessel lumen gets thicker and smaller)
What can cause a carotid dissection which is a rarer cause of a stroke?
- idiopathic (related to an illness or underlying condition e.g. excessive exercise)
- trauma
What occurs in a carotid dissection?
wall of carotid artery tears and clot forms at the area of damaged vessels
Which parts of the brain can be affected? What questions should be asked when working out a stroke? (4)
- left or right?
- carotid territory or vertebrobasilar territory?
- cerebral hemispheres or brainstem?
- cortex (grey matter) or deep white matter?
How can links be made between affected brain area and body function?
For example; if right side of brain effected then numbness in left side of the body
What can be worked out from patient’s signs and symptoms relating to stroke? (5)
- what side of the brain is affected? (right or left)
- whether lesion is in the brainstem (cerebral or brainstem stroke?)
- whether the cortex is involved (cortical stroke?
- is the lesion deep within white matter? (lacunar stroke)
- what blood vessels are involved?
Why is stroke localisation so important? (4)
- confirms diagnosis of stroke 2. allows better selection of imaging
- gives indication of cause
- gives indication of prognosis (outcome)
What are 4 stroke subtypes?
- TACS; total anterior circulation stroke
- PACS; partial anterior circulation stroke
- LACS: lacunar stroke
- POCS: posterior circulation stroke
When is complete vision lost in relation to clot location?
usually when clot is nearer the front of the brain (nearer the eye)
When is partial/ half vision lost in relation to clot location?
usually when clot is further away from the eye and cerebrum
What percentage of strokes do TACS (total anterior circulation strokes) make up?
20% of strokes