Stroke Flashcards
Define stroke
Stroke is defined as an acute neurological deficit lasting more than 24 hours with infarction
ISCHAEMIC vs HAEMORRHAGIC STROKE %
ischaemic - 80
haemorrhagic 20
What is ischaemic stroke caused by
- Reduction in cerebral blood flow due to arterial occlusion/ blockage or stenosis. Typically divided into lacunar , thrombotic and embolic
- Sites such as carotid, verebral and basilar arteries - mostly carotid
- Infarcted area dies causing permanent deficit
Aetiology of ischaemic stroke
- Atherothromboembolism
- Cardioembolism - AF, post MI, IE
- Vasculitis
- Fat emboli
- Hyperviscosity syndrome - blood becomes too thick
What is an embolic stroke usually caused by
- usually a blood clot but fat ,air or clumps of bacteria
- atrial fibrilation
What are thrombotic strokes usually caused by
- thrombosis from large vessels
Primary investigations for stroke
- 1st line- non contrast CT head - to allow exclusion of haemorrhage
- Diffusion weighted MRI- gs to confirm after CT
- ECG- asses for AF or MI
- Bloods; hba1c, lipids, clotting screen, FBC (RBC), ESR (vasculitis), cholesterol
- CTA
What are haemorrhagic strokes caused by
- ruptured bv
- berry aneurysm rupture
What can haemorrhgaic strokes further be divided into
- intracerebral - bleeding within brain parenchyma
- subarachnoid- bleeding between pia mater and arachnoid mater
Stroke in ACA
ACA- weakness of feet and legs with maybe sensory loss, incontinence, drowsiness, Truncal ataxia
Stroke in MCA
MCA (contralateral) - speech comprehension and understanding, hands and arms weakness, dysphasia, aphasia, Homonymous hemianopia,
Stroke in PCA
- PCA - visual problems,
- Propagnosia - inability to recognise faces,
- Visual agnosia - cannot interpret visual ino
What happens if vertebrobasilar artery is infarcted
- Quadriplegia - symptom of paralysis that affects all a person’s limbs and body from the neck down
- Dysarthria
- Vertigo
- N/V
- Drowsiness
Stroke in either hemisphere would exhibit ?
Hemiparesis
Hemisensory loss
Visual field defect
CONTRALATERAL
Lacunar infarct
Deep branches of MCA that feed the basal ganglia , damaged vessels form cysts due to hyaline arteriosclerosis
FEAUTURES of stroke in dominant hemisphere
- usually left
- Language dysfunction
- Expressive dysphasia
- Receptive dysphasia
- Dyslexia
- Dysgraphia
non dominant hemisphere stroke features
- Anosognosia
- Neglect of paralysed limb
- Denial of weakness
- Visuospatial dysfunction
- Geographical agnosia
- Dressing apraxia
- Constructional apraxia
Key diagnostic factors for stroke ?
- unilateral weakness or paralysis in the face, arm or leg
- dysphasia
- ataxia
- visual disturbance
posterior circulation symptoms
- Unsteadiness
- Visual disturbance
- Slurred speech
- Headache
- Vomiting
- Others e.g. memory loss, confusion
Risk factors
- older age
- family history of stroke
- history of ischaemic stroke or TIA
- hypertension
- Smoking
- Male
- diabetes
- Vasculitis
- Hyperlipidaemia
What do haemorrhagic strokes tend to show ..
increased intracranial pressure
What is ROSIER
Recognition of Stroke in the Emergency Room
DD for stroke
- Hypoglycaemia
- Hyponatraemia
- Hypercalcaemia
- Uraemia
- Hepatic encephalopathy
increase in intracranial pressure is likely to cause ..?
midline shift
Management of ischaemic stroke
- immediate aspirin 300mg until 2 weeks after symptoms
- thrombolysis with IV alteplase ( tissue plasminogen ) to restablish blood flow - 4.5 hours within symptom onset
- contraindcations of Thrombolysis
prevention of ischaemic stroke
- clopidogrel daily life long
- aspirin 75mg daily
- manage RF
What would you need before doing a thrombectomy
Confirmation of stroke requires CTA or MR angiogram prior to thrombectomy
thrombectomy for Proximal anterior circulation stroke?
offer thrombectomy within 6 hours with IV thrombolysis (if within 4.5 hours), or within 6 to 24 hours without IV thrombolysis if there is potential to salvage brain tissue
Haemorrhagic stroke management ?
- neurosurgery referral
- intense monitoring of ICP
Epidemiology of stroke
- third leading cause of mortality in the US
- stroke rates higher in asian and black
Cause of a TIA
- thrombosis
- emboli- eg from AF
- small vessel occlusion
What is a transient ischemic attack
- sudden onset focal neurological deficit that is temporary , lasts less than 24hrs WITHOUT INFARCTION
- Acute loss of cerebral ocular function with sudden symptoms lasting less than 24 hours
How long does a TIA typically last
5-15 mins
What is the pathophysiology of a TIA
- type of cerebral ischaemia
- lack of oxygen and nutrients to the brain resulting in cerebral dysfunction
RF for TIA
Same as IHD
- smoking
- dm
- obesity
- HTN
- AF
TIA symptoms in carotid territory symptoms - more common here
- Amaurosis fugax
- Aphasia
- Hemiparesis
- Hemisensory loss
- Hemainopic visual loss
Symptoms of a TIA if in ACA
Weak numb contraletral leg
Symptoms of a TIA if in MCA
- Weak numb contralateral side of body
- face drooping with forehead spared
- dysphasia
General clinic presentation of a TIA
- sudden loss of function lasting for minutes
- complete recovery
- focal neurological deficit
- no sign of infarction
What percentage of TIA affect the anterior or posterior circulation
anterior -90%
posterior - 10%
What is amaurosis fugax and how can it be caused
Otherwise known as transient visual disturbance
- sudden transient loss of vision in one eye
- occlusion/ reduced blood flow to retina through opthalmic, retinal ciliary artery
- signals that a stroke is impending
What is todds paralysis
transient weakness of arm, hand , leg after a seizure
Investigations for TIA
- 1st line - Diffusion weighted CT/MRI
- Carotid imaging with doppler sound then MR/CT angiogrpahy if stenosis found
- Bloods - Glucose, ESR, INR, U&E
- ECG- AF
- Echo
How to diagnose TIA
- based mostly on description
- FAST - FACE ARM SPEECH TIME
When are patients at a high risk of an early stroke
- AF
- more than one TIA in a week
- TIA whilst on anticoagulant
What visual problems may occur in a TIA
- sudden transient loss of vision in one eye (amaurosis fugax)
- diplopia
- homonymous hemianopia
Immediate management of TIA
aspirin 300mg
for what reasons would you not give aspirin right away after a TIA
- the patient has a bleeding disorder or is taking an anticoagulant (needs immediate admission for imaging to exclude a haemorrhage)
- the patient is already taking low-dose aspirin regularly: continue the current dose of aspirin until reviewed by a specialist
- Aspirin is contraindicated: discuss management urgently with the specialist team
What imaging is used in TIA and why
NAME?
What would a carotid bruit indicate
Carotid artery stenosis
Secondary prevention of stroke ?
- Clopidogrel 75mg once daily
- Atorvastatin 80mg should be started but not immediately
- Carotid endarterectomy or stenting in patients with carotid artery disease
- Treat modifiable risk factors such as hypertension and diabetes
if clopidogrel is contraindicated in TIA what would you offer instead
- MRI to determine the area of ischaemia , or to detect haemorrhage
what stroke has the poorest prognosis
anterior circulation stroke
what are the car or motorcycle rules for those who have had a stroke
- Patients must not drive for 1 month after a TIA or stroke
- Driving may resume after 1 month if there has been satisfactory clinical recovery
- Patients may not need to inform the DVLA if there is no residual neurological deficit beyond 1 month
- Multiple TIAs over a short period requires no driving for 3 months and the DVLA must be notified
Heavy goods vehicle license rules?
- Patients must not drive for 1 year after a TIA or stroke and the DVLA must be notified
- Relicensing may be considered after 1 year if there is no significant residual neurological impairment and no other significant risk factors
rules of thumb for stroke criteria
- ABRUpt DEFICIT
- NEGATIVE quality
- the maximal deficit at the start
rules of thumb for non stroke
- gradual onset
- predominantly non-focal
- positive
- increases w time
dd for stroke
- epileptic seizure - positive history
- space occupying lesion- gradual, headache, confusion
- infection- gradual, fever
less common dd for stroke
- metabolic (hyponatraemia, hypoglycaemia)
- multiple sclerosis- young sub acute progression
- functional neurological disorder
- migraine- history of previous attacks
common sites of atheroma
- LARGE AND MEDIUM VESSELS
- carotid artery
- confluence of arteries
small vessel ischaemic stroke involves ?
- Small deep perforator arteries blocked
- Caused by high blood pressure, diabetes, smoking, age
- In situ microatheroma or lipohyalinosis
- At postmortem small holes + “cobweb” mesh
- Hence term “lacunes”
Dissection stroke of carotid or vertebral artery
Causes 25% ischaemic strokes in <45 yo
Risk factors
- trauma or cervical manipulation
- vigorous physical activity (eg weightlifting)
- vasculopathy (fibromuscular dysplasia, Marfan’s)
- sympathomimetic drug abuse
- Often painful
rare causes of stroke
vasculitis
venous thrombosis
Other Investigations over first few days after a stroke
- Blood tests can include vasculitis screen
- ECG +- 72 hour tape
- CT head
- MRI brain with diffusion weighted imaging
- Carotid Doppler
- ECHO
- CT or MR angiogram
