stroke Flashcards
how is stroke defined
rapid onset cerebral deficit lasting >24h or leading to death with no other cause apparent other than a vascular one
what is the definition of TIA
brief episode of neurological deficit temporary focal cerebral or retinal ischaemia without infarction. seconds to minutes with complete recovery
what are the types of stroke
ischaemic, haemorrhagic, other (dissection, venous, vasculitis)
what leads to ischaemic stroke
thrombotic, large artery stenosis, small vessel disease, cardioembolic, hypoperfusion
what causes haemorrhagic stroke
intracranial haemorrhage and subarach haem
what is the most modifiable risk factor for stroke
hypertension
features of TIA (anterior system)
amaurosis fugax, hemiparesis, aphasia, hemisensory loss, hemianopic visual loss
features of TIA (posterior system)
diplopia, vertigo, vomiting; ataxia, choking and dysarthria, hemisensory loss, visual loss, tetraparesis, LOC
what is amaurosis fugax
suddent transient visual loss in one eye- emboli in retinal artery. shows internal carotid stenosis
differential diagnosis TIA
hypoglycaemia, migraine with aura, focal epilepsy, hyperventilation, retinal bleeds
tests in TIA
FBC, ESR, U&Es, glucose, lipids, CXR, ECG, carotid doppler and angio, CT or MRI
which circulation carries a higher risk for stroke and MI
anterior circulation
what is the ABCD2 score used for
stratify risk of stroke in the first 2 days after TIA
what is the ABCD2
Age >60; BP >140 systolic and or >90 diastolic; Clinical features- unilateral weakness (2), isolated speech disturbance (1), other (0); duration of symptoms in mins >60 (2), 10-59 (1),
what is high risk on the ABCD2 score
6 high risk
treatment of TIA
control cardio risk factors; antiplatelets- clopidogrel, aspirin, dipyridamole; warfarin in cardiac emboli; carotid endarterectomy if >70% stenosis do surgery within 2 weeks. endovascular carotid stenting is an alternative
what is the ischaemic penumbra
swollen area around the infarcted region which doesnt function but is structurally intact and can regain function
what features are seen in stroke
contralateral hemiplegia or hemiparesis with facial weakness, weak limbs at first flaccid and areflexic, conciousness usually preserved
causes of stroke
small vessel occlusion, atherothromboembolism, CNS bleeds
other causes of stroke to consider especially in younger patients
sudden drop in bp >40mmHg boundary zone/watershed stroke eg in sepsis; dissection; vasculitis; SAH
features of cerebral infarction
contralat sensory loss or hemiplegia, dysphasia, homonymous hemianopia
features of brainstem infarction
quadriplegia, disturbances gaze and vision, locked in syndrome, coma, psuedobulbar palsy, lateral medullary syndrome
what is lateral medullary syndrome
posterior inferior cerebellar artery (PICA) or one vertebral artery. Wallenberg syndrome. acute vertigo with cerebellar signs
features of lacunar infarct
small infarcts seen on MRI often asymptomatic. minor strokes- ataxic hemiparesis, pure motor, pure sensory, sensorimotor, dysarthria/clumsy hand
what is Webers syndrome
ipsilateral 3rd nerve palsy with contralat hemiparesis, unilateral infarct in the midbrain
hemi/tetraparesis
corticospinal tracts
sensory loss
medial lemniscus/spinothalamic tracts
diplopia
oculomotor
facial numbness
5th nerve
facial weakness
7th nerve
nystagmus/vertigo
vestibular connections
coma/altered conciousness
reticular formation
left MCA
right weakness, involve face arm > leg with dysphagia
right MCA
left weakness face and arm > leg with visual and or sensory neglect
lateral medulla- posterior inferior cerebral artery
ipsilateral horners syndrome, Xth palsy, facial sensory loss, limb ataxi
posterior cerebral arery
homonymous hemianopia
internal capsule
motor, sensory, sensorimotor loss. face=arm=leg. dysarthria
carotid artery dissection
ipsilateral horners syndrome- compression of sympathetic plexus around the carotid artery
stroke general management at first
airways, O2, monitor BP, look for source of emboli
brain imaging in stroke
non contrast CT shows haemorrhage immediately so can be used to rule out; diffusion weighted MRI shows infarction straight away
signs that it is likely to be a haemorrhagic stroke
decr GCS, signs incr ICP, severe headache, meningism, progressive symptoms
if CT excludes haemorrhage
thrombolytic therapy immediately, if contraindicated then aspirin 300mg/day
if CT shows haemorrhage
give no drugs that can interfere with clotting, neurosurgery
when can thrombolysis be used
what is the thrombolysis agent and dose
recombinant tissue plasminogen activator (tPA)- alteplase. 0.9mg/kg. 10% total dose in first minute bolus then remainder over 60 mins
CI to thrombolysis
have to be >18. major infarct/haem; mild/non disabling deficit; recent birth, trauma, surgery, artery/venous puncture at uncompressible site; past CNS bleed; AVM/aneurysm; severe liver disease; anticoags or INR
medication after stroke
clopidogrel monotherapy, aspirin or dipyridamole used if clopidogrel CI. warfarin 2 weeks after stroke if due to AF (antiplatelets until then)
complications after stroke
aspiration pneumonia, pressure sores, contractures, constipation, depression
signs lateral medullary syndrome
vertigo, vomiting, dysphagia, nystagmus, ipsilat ataxia, soft palate paralysis, ipsilat horners, crossed pattern sensory loss- analgesia to pin prick on ipsilateral face and contralateral trunk
