Stroke Flashcards
what is a stroke?
rapidly developing clinical symptoms and/or signs of focal and at times global loss of brain function with symptoms lasting more than 24 hours or leading to death with no apparent cause other than that of vascular origin
key features?
rapid (few mins-hours)
focal (can identify lesion in part of brain causing symptoms)
loss of brain function (visual, speech, movement issues, not pain)
vascular
how common are stroke mimics?
1/3 of all stroke presentations
what can mimic stroke?
seizures sepsis toxic/metabolic (glucose etc) SOL (space occupying lesions) syncope/pre-syncope acute confusion/delirium vestibular dysfunction functional (neurological with no real pathological cause) dementia
what is the rosier score?
recognition of stroke in the emergency room -1 point each for - loss of consciousness or syncope - seizure activity \+1 point each for - asymmetrical facial weakness - asymmetrical arm weakness - asymmetrical leg weakness - speech disturbance - visual field defect score >0 = likely stroke
what is the FAST score?
aimed at public Face Arms Speech Time
Is stroke a diagnosis?
no
experience of persisting neurological complications of cardio disease
what are the 3 types of stroke?
haemorrhagic
subarachnoid haemorrhage
infarct
types of haemorrhagic stroke?
structural abnormality (poor quality vessels)
hypertensive
amyloid angiopathy
types of infarct stroke?
artheroembolic (same process as MI - plaque disease)
small vessels (damage to small vessels over time - hypertension, diabetes etc - cause clots to form and small vessels occlude easily)
cardioembolic (AF causing clots)
how can you tell between infarct and haemorrhage stroke clinically?
no real way until imaging
stroke imaging?
CT (quicker and sensitive to picking up blood)
how does haemorrhage appear in the brain on imaging?
white areas of blood
iron in blood absorbs X rays
how does an infarct stroke show on CT?
mushy, blurry, darker shadowy area of the brain
(increase in oedema and fluid caused by the inflammatory response to the necrosis of tissue after infarct appears darker)
infarct stroke may be missed initially on CT, why is this?
takes time for oedema etc to develop so CT can be clear if done very quickly
what is used if CT is clear but infarct stroke still suspected?
MRI
shows diffusion weighted abnormality (abnormalities of fluid and ion flow)
infarct shows as a white area or black area depending on type of MRI
how may a haemorrhagic stroke appear on CT after 2-3 weeks?
darker, almost like an infarct as blood has disappeared but damage is seen
what is done if imaging is performed weeks after symptoms?
MRI instead of CT
acute management of stroke?
thrombolysis/thrombectomy imaging swallow assessment (risk of aspiration pneumonia after stroke) nutrition and hydration antiplatelets stroke unit care DVT prevention
how quickly is brain damaged in stroke?
230 million synapses lost per second
14 billion per min
how can stroke damage differ in people?
some people have more of a collateral blood supply to the brain so can cope better and for longer with an occlusion
what is used in thrombolysis?
inject artificial TPA which breaks down clots
what is taken into account when deciding whether to thrombolyse?
age
time since onset (quicker = better benefit)
previous intracerebral haemorrhage or infarct (more risk of bleed)
atrophic changes (bleeding risk)
BP (bleeding risk, >185 = contraindication)
diabetes
potential benefit (possible QoL after)
at what time after symptoms onset does thrombolysis stop being beneficial?
around 5 hours
don’t really thrombolyse after 4.5 hours
why is imaging always performed before thrombolysis?
incase its haemorrhagic
establishes diagnosis
what else might indicate infarct on CT?
hyperdense middle cerebral artery sign
single, asymmetrical which spot/blood vessels showing the clot
what types of clots are less likely to benefit from iv tPA? what is done in this case?
large and proximal clots
endovascular therapy, interventional radiology
- put wire in through the vessel and through to other side of clot, open stent and then pull the clot out
which is more successful, thrombolysis or endovascular therapy?
endovascular therapy (thrombectomy) not currently available in Scotland yet
how effective is the stroke unit care?
1 extra survivor for every 33 people in the unit
1 person sent home for every 20
important immediate therapy for infarct?
300mg aspirin ASAP to reduce risk of further infarct (don’t give for 24 hours after thrombolysis)
CT first to exclude bleed
300mg aspirin for 2 weeks after
how is DVT prophylaxis delivered after stroke?
heparin (including LMWH) causes a bleeding risk
TED stockings don’t make a difference
best = intermittent pneumatic compression (stockings with pumps)
how is dysphagia managed?
initial swallow screen
assess by speech and language therapist if abnormal
may need NG tube or textured diet and thickened fluids depending on swallow
what is a TIA?
transient ischaemia attack
same process as stroke but shorter symptoms
technically should be under 24 hours
is TIA safe?
no
still causes brain damage and risk of further stroke (almost the same risk as a minor stroke)
what is involved in the rapid access neurovascular TIA clinic?
rapid assessment - history - carotid imaging - ECG - blood tests diagnosis - immediate therapy - medication, carotid endarterectomy hugely decreases risk of further stroke after TIA
how can further stroke be prevented after TIA?
rapid access clinic
any statin
any antiplatelet (or dual antiplatelet - aspirin + clopidogrel)
ABCD2?
risk assessment for recurrent TIA
how is haemorrhagic stroke managed?
aggressive BP control (IV treatment if seen <6 hours)
stop any anticoagulant or reverse anticoagulation
- can give vit K if on warfarin
