Stroke Flashcards
what is the window for reversal in thrombolysis and thrombectomy
thrombolysis 4.5hrs
thrombectomy 6 hrs
how is a scan diagnosed
acute onset
focal neuropathy
imaging to rule out other presentations
what is an intracranial bleed
NOT A STROKE
extradural/subdural/subarachnoid
causes neurosigns due to compreesion
what is an intracerebral bleed
haemorrhagic stroke
when is neurosurgery used in haemorrhagic strokes
to relieve compression- will not relieve disability
will only do when risk to life (coning, obstructive hydrocephalus)
causes of haemorrhagic stroke
blood- anticoagulants/platelets, excessive bleeding
vessel- HTPN, atherosclerosis, vasculitis, aneurysms, AVM, amyloid angiopathies
extravascular- bleeding into a tumour
what type of stroke does atherosclerosis cause
ischaemic (high cholesterol/diabetes causes formation of atheromas)
what type of stroke does arteriosclerosis cause
haemorrhagic stroke
thickening of lumen (middle layer) due to HPTN (calcification)
name stroke mimics
migraine, post seizure focal deficits, hypoglycaemia, acute presentation of SOL, bells palsy
which carotid supplies anterior circulation
internal
which artery supplies posterior circulation
vertebral
what does the circle of willis provide
collateral blood supply when blockage occurs - if acute blockage occurs before circle of willis will not be able to compensate
what is the cortex if the brain
outermost part
grey matter
has communicating vessels
what is the cerebral medulla
the inner part of brain
white matter (axons)
has non communicating vessels (if occluded no collateral)- perforating arteries (are end arteries)
what is causes when a cerebral artery is blocked
large artery occlusion- grey and white natter will die
what happens when a perforating artery is blocked
deep infarct, small artery occlusion
what does the internal carotid divide into
anterior and middle cerebral
what is the basilar artery
formed from vertebral arteries
what does the basilar artery divide into
posterior cerebral
what is a embolus
a thrombus that occludes an artery distal to where it was formed
what is a thrombus
blocks artery where it was formed
is an embolus or thrombus more likely to cause a stroke
embolus
thrombus forms slowly, large vessels have collaterals
are large vessel infarcts usually embolic or thromobic
embolic (needs acute occlusion due to collateral vessels)
do embolic strokes usually affect cortex or medulla
cortex
what should you think when there is multiple infarcts in multiple locations
source- e.g. heart
what are the cortical signs of a stroke
dominant hemisphere: (usually left, controls communication)
- dysphagia (expressive understand cant express, receptive fluent but cant understand- usually mixed)
-agnosia (cant recognise objects)
right hemisphere
-hemispatial neglect
-personality changes
-sensory inattention
what can cause a pure motor stroke
large vessels embolic cortical OR small vessel thrombotic deep infarct
what causes a wedge shaped infarct
embolic large vessel occlusion
what causes just a hand/leg motor stroke
thrombotic small vessels deep infarct in internal capsule
what is a TACS
total anterior circulation stroke
what are the features of a TACS
hemiparesis
hemisensory loss
hemianopia
higher cerebral dysfunction (cortical signs)
what causes a TACS
embolus (large vessel)
could also be a large lobar bleed
what is a PACS
partial anterior circulation stroke
what are the features of a PACS
can be isolated in cortex (Cortical signs)
or can have any 2 features of TACS (usually cortical + hemi symp)
need to have cortical as this shows is an embolic large vessel block
what causes a PACS
large vessel embolus
what is a POCS
posterior circulation stroke
what are the features of a POCS
brain stem- syncope occipital lobe- visual disturbance, hemianopia (isolated) pariatal lobe- sensory cerebellum- ataxia, diplopia low MN facial weakness
what causes a POCS
embolic/thrombotic in vertebral basilar artery
if isolated hemianopia then embolic
what is a LACS
lacunar stroke
what are the features of a LACS
pure physical (ataxic hemiparesis if occurs in internal capsule, if anywhere else may go unnoticed) pure sensory
what causes a LACS
small deep vessels thrombosis
do you get cortical signs in a LACS
no
what usually causes large vessel stokes
atheroembolic
what can cause a stroke in infants
dissection (only painful stroke)
hypoperfusion - causes watershed infarcts between two artery territories)
what is a venous infarct
blockage in IJV causes brain swelling and haemorrhage due to back pressure (Tx anticoagulation)
what is a paradoxical embolism
when hole in heart means DVT goes to brain (Tx thrombolysis, anticoagulation and 2ndary prevention)
what is a TIA
true TIAs only last few minutes
if hours then stroke with neuroplasticity
need urgent Ix and Tx as most recovery to gain and high risk of recurrence
what are the IX for stroke
blood- general, lipids, glucose ECG- AF carotid doppler -ambulatory monitoring -PAF ECHO- AF, mitral/aortic valve disease CT best for acute haemorrhage (all Pts get CT), doesnt always show infarct but diagnosis is clinical anyway - use CT to find contraindication to thrombolysis if cant tell after 1-2 weeks if ischaemic/haemorrhagic do MRI if TIAS do MRI if possible
what are the indications for a carotid endartectomy
stenosis >70% in stroke causes artery/ >50% in young males NOT DONE IN ASYMPTOMATIC ARTERY EVEN IN >80% AS RISK OF STROKE
needs to be within 14 days of TIA/stroke
what is the treatment for venous clots
anticoagulation
what is the treatment for arterial clots
antiplatelets
what strokes can hyperacute treatments be used for
ischaemic
what are the hyperacute treatments and when can they be used
thrombolysis- within 4.5 hrs (risk of haemorrhagic transformation after), aim to reduce disability (cant reverse stroke)
thrombectomy- 6 hrs, only for large vessel proximal occlusions (ICA), need CT angiogram
what is the secondary prevention following strokes
antiplatelet-75 mg clopidogrel (aspirin if CI, dual if high risk)
anticoagulants- TIAs start day 1, large infarcts 1-14 days later to prevent haemorrhage, use aspirin 300mg in interim
statins (only for atherosclosis: 20-80mg
antiHPTNsives (HPTN biggest RF for stroke, very important to control in acute setting for haemorrhagic strokes)
diabetic/ lifestyle management
MDT rehab
Tx pathway for stroke and TIA
300mg aspirin when suspected, continue for 2 weeks (offer PPI
CT for stroke
for TIA only CT if considering other diagnosis, consider MRI. Do carotid doppler for TIA. Carotid endarectomy for TIA and non disabling stroke with stenosis >50/70%
ischaemic stroke:
thrombolysis with alteplase within 4.5 hours
thombectomy with thrombolysis, if within time frame, within 6 hours
venous sinus thrombosis:
anticoag: heparin and then warfarin
haemorrhagic stroke:
Bp control if hypertensive
