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
What signs and symptoms criteria must be met for TACS strokes? (3)
- patient has weakness and sensory deficit
- homonymous hemianopia (loss of vision)
- higher cerebral dysfunction (e.g. dysphasia ( loss of generation and comprehension of speech), dyspraxia (loss of coordination and movement), clumsiness)
Occlusion of which vessels leads to TACS strokes? (2)
- middle cerebral artery
- internal carotid artery
What percentage of strokes do PACS (partial anterior circulation strokes) make up?
35% of strokes
What signs and symptoms criteria must be met for PACS strokes? (1)
- 2/3 of TACS criteria or restricted motor/sensory deficit
e. g. one limb, face and hand or higher cerebral dysfunction alone ( might just have speech disturbance alone if occlusion is in Broca’s area)
Occlusion of which vessels leads to PACS? (2)
- more restricted cortical infarcts (brain cortex; grey matter)
- occlusion of branches of middle cerebral artery
What percentage of strokes do LACS (lacunar strokes) make up?
20% of strokes
What are 4 types of lacunar strokes?
- pure motor (commonest)
- pure sensory
- sensorimotor
- ataxis hemiparesis
What is pure motor lacunar stroke?
complete or incomplete weakness of 1 side, involving the whole of 2 of 3 body areas (face/arm/leg)
What is pure sensory lacunar stroke?
sensory symptoms and/or signs, same distribution
What is sensorimotor lacunar stroke?
combination of the above
What is ataxic hemiparesis lacunar stroke?
- hemiparesis and ipsilateral cerebellar ataxia
- small infarcts in basal ganglia or pons
- intrinsic disease of single basal perforating artery (end arteries)
What do lacunar strokes often present as?
often silent and therefore undiagnosed
Wha percentage of all strokes do POCS (posterior circulation strokes) make up?
25% of all strokes
What do POCS affect? (3)
- brainstem
- cerebellum
- occipital lobes
What is the presentation of POCS?
Variable and frequently complex presentation:
- bilateral motor/ sensory deficit
- isolated homonymous hemianopia (loss of vision)
- disordered conjugate eye movement
- ipsilateral cranial nerve palsy with contralateral motor/ sensory deficit
- coma
- disordered breathing
- tinnitus (hearing body sounds)
- vertigo (moving/spinning)
- Horner’s (when sympathetic trunk is damaged)
What is the mortality rate in 1st year for:
- TACs
- PACs
- LACs
- POCs
- TACs= 60%
- PACs= 16%
- LACs= 11%
- POCs= 19%
What is the recurrence rate in 1st year for:
- TACs
- PACs
- LACs
- POCs
- TACs= 6%
- PACs= 17% (high early)
- LACs= 9% (constant)
- POCs= 20%
Why do TACs have such a high mortality rate?
because white matter is affected (centre of brain)
In stroke, do symptoms appear rapidly?
Yes
What do stroke symptoms depend on?
depend on which part of the brain is affected
What are modifiable risk factors for stroke? (6)
- high BP
- atrial fibrillation (especially in elderly)
- cocaine use (+alcohol)
- diabetes control
- physical activity
- smoking
What are non-modifiable risk factors for stroke? (4)
- age
- race
- family history
- cardiac disease
Are ischaemic strokes more common in high income or low income countries?
Much more common in high income countries (possibly due to diet and environment)
Are haemorrhagic strokes more common in low income or high income countries?
More common in low income countries (could be linked to diabetes)
What investigations need to be done to confirm stroke? (6)
- full blood count (platelets, RBCs, lipids)
- ECG (24 hour ECG)
- CT scan (imaging)
- MRI scan (imaging)
- carotid doppler ultrasound (looking at vessels for atheroma dissection)
- echocardiogram ( to look for clots in heart)
What makes CT scan suitable to use in stroke diagnosis? (3)
- uses x rays
- shows up blood
- quick
What makes MRI scan suitable to use in stroke diagnosis? (3)
- uses magnet
- takes up to 30 minutes
- shows up ischaemic stroke better than CT does (but can be claustrophobic and noisy for patients)
In an untreated stroke, how many neurones are lost per minute?
1.9 million neurones
What treatment method is used in emergency for strokes to dissolve clots?
Thrombolysis
What is the main disadvantage to thrombolytic treatment?
benefit from thrombolysis declines with increasing delay from onset
What is the thrombolytic and fibrinolytic agent used in thrombolysis?
Alteplase (medicine)
When does thrombolytic therapy needs to be given following onset of stroke symptoms?
within 4.5 hours of stroke symptoms onset (if brain tissue is already dead then restoring blood supply isn’t going to help)
What is the main complication of thrombolysis therapy?
- Can cause unexpected bleeding in the brain if it has established damage
- Can cause bleeding elsewhere in the body (e.g. gut)
What 2 chemicals are thrombolytic?
- Alteplase
- recombinant tissue plasminogen activator (rt-PA)
According to SIGN guidelines, how much of rt-PA should be administered for acute stroke?
0.9mg/kg (up tot 90mg) IV rt-PA
What should never be used as treatment for acute phase of stroke?
streptokinase (this should be used in MI cases)
What are the FAST stroke signs? (neurological deficit)
F- facial weakness
A- arm weakness
S- speech problems (dysphasia or dysarthria)
T- time to call 999
H- hemianopia (blindness in half of vision)
What to do if patient has neurological deficit and a known time since onset is <4.5hours with no contraindications to thrombolysis?
- arrange urgent CT scan
2. contact stroke bleep via switchboard
What to do if patient has neurological deficit but known time since onset is >4.5 hours or unknown?
Contact stroke team to arrange admission
What to do if patient no longer has ongoing neurological deficit?
If resolved anterior circulation symptoms and/or atrial fibrillation, discuss with stroke bleep holder a re-urgent investigation
What are contraindications to thrombolysis?
- age
- possibly under 16s and over 80s should not have it
- licence limited only to <80 year olds
- recent MI (since recent bleeding, very high BP)
Why should patients over 80 not be put for thrombolytic treatment? (2)
- stroke outcomes worse for over 80s
- greater risk of bleeding the older the patient is
What are acute stroke treatments? (7)
- thrombolysis (0-4.5 hours)
- aspirin (0-48 hours)
- hemicraniectomy (0-48hours) ; surgery which relieves intracranial pressure in brain
- Warfarin (anticoagulant)
- Antiplatelets
(e. g. Clopodiogrel or Thienopyridine) - Control CV disease risk factors e.g. diet, smoking, alcohol, hyperlipidaemia,diabetes, high B)
- Carotid endarterectomy
Why are stroke units vital for effective stroke therapy and treatment? (5)
- evidence suggests patients do better 10 years after their admission
- patients mobilised ASAP (swallowing, positioning etc)
- early therapy avaialable
- concentrating of expertise
- swallow problems addressed immediately (present in 50% of stroke patients)
Are stroke patients at risk of another stroke?
Yes, very high at risk
What is the aetiology of a transient ischaemic attack? (TIA) (7)
the same as stroke:
- 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 can TIA be described as in simple terms?
- “warning stroke” or a “mini stroke:
- stroke-like symptoms present but persist for less than 24 hours that clears without residual disability
What is the risk for early recurrent stroke appearing again in TIA and stroke patients?
up to 14% within the first 2 weeks and sometimes up to 3 months
What is the link between TIA and stroke likeliness in the future?
about 1/3 of those who have a TIA will have an acute stroke in the future
Should TIAs or minor strokes be considered as emergencies? Why?
Yes: early initiation of preventive treatment for TIA or minor stroke can reduce the risk of early recurrent stroke by 80%
What are drugs used as secondary prevention for stroke? (4)
- Clopidogrel (75mg; antiplatelet); used to prevent MIs and stroeks
- Aspirin (75mg) + dipyridamole MR 200mg
- statin
- blood pressure drugs (even if BP is within normal range); antihypertensives
What are examples of antiplatelet drugs?
- aspirin (75mg after 2 weeks but initially 300mg)
- Clopidogrel (75mg)
- dipyridamole (200mg); increases cAMP and decreases thromboxane
When is carotid endarterectomy used?
At >50% stenosis in artery
From carotid endarterectomy, is the risk of stroke or death reduced more for 50-69% stenosis or >70% stenosis at 5 years after surgery?
Reduced more for >70% stenosis ( risk of stroke or death reduced by 14-19% compared to 7-9% for smaller stenosis)
When is surgery for carotid stenosis recommended?
- for anterior circulation
- when there is more than 70% occlusion/ stenosis
- if TIA/ stroke has a good predicted recovery (uncertainty if patient is asymptomatic)
What are side effects of antiplatelet drugs?
5 normal, 5 extreme
- bruising or bleeding under skin
- diarrhoea
- indigestion and abdominal pain
- nose bleeds
-increased bleeding from wounds
Extreme:
-blood in urine or stool - vomiting blood
-severe bleeding - weakness in limbs
-allergic reaction (anaphylaxis)
