Ischaemic stroke Flashcards
Into what 2 groups can ischaemic strokes be further divided?
>24 hours = ischaemic stroke
<24 hours = transient ischaemic attacks
What is the definition of a transient ischaemic attack?
stroke in which the symptoms and signs last less than 24 hours
What proportion of all strokes are ischaemic strokes?
85%
What are 2 subtypes of ischaemic stroke based on the cause?
- Thrombotic: caused by thrombosis from large vessels e.g. carotid
- Embolic: usually blood clot but fat, air or clumps of bacteria may act as embolus
What is an important example of causes of embolic strokes?
AF is important cause of emboli forming in heart
What are 6 risk factors for cardiovascular disease?
- Age
- Hypertension
- Smoking
- Hyperlipidaemia
- Diabetes mellitus
- Atrial fibrillation
What are 5 general symptoms of stroke?
- Motor weakness
- Speech problems (dysphasia)
- Swallowing problems
- Visual field defects (homonymous hemianopia)
- Balance problems
What are 4 symptoms of cerebral hemisphere infarcts?
- Contralateral hemiplegia: initially flaccid then spastic
- Contralateral sensory loss
- Homonymous hemianopia
- Dysphasia
What is meant by lacunar infarcts?
small infarcts around the basal ganglia, internal capsule, thalamus and pons
What are 4 areas which may be the location of lacunar infarcts?
- Basal ganglia
- Internal capsule
- Thalamus
- Pons
What are 4 types of signs that lacunar infarcts may result in?
- Pure motor
- Pure sensory
- Mixed motor and sensory
- Ataxia
What is one of the formal types of classification system for strokes?
Oxford Stroke Classification (aka Bamford Classification) - classifies stroke based on initial symptoms
involves description of territory affected e.g. total anterior circulation infarcts (TACI)
What are 3 examples of types of stroke according to the Oxford Stroke Classification system, that considers initial symptoms?
- Unilateral hemiparesis and/or hemisensory loss of the face, arm and leg
- Homonymous hemianopia
- Higher cognitive dysfunction e.g. dysphasia
What are 4 types of stroke described by the territory affected?
- Total anterior circulation infarcts (TACI) - 15%
- Partial anterior circulation infarcts (PACI) - 25%
- Lacunar infarcts - 25%
- Posterior circulation infarcts (POCI) - 25%
Which 2 arteries are involved in total anterior circulation infarcts?
middle and anterior cerebral arteries
What are the criteria to diagnose a total anterior circulation infarct?
involve middle and anterior cerebral arteries
all 3 of the Oxford Stroke classification criteria are met:
- unilateral hemiparesis and/or hemisensory loss of the face, arm and leg AND
- homonymous hemianopia AND
- higher cognitive dysfunction e.g. dysphasia
What are the criteria to diagnose a partial anterior circulation infarct (PACI)?
involves smaller arteries of anterior circulation rather than middle/anterior cerebral, e.g. upper or lower division of middle cerebral artery. involves anterior OR middle cerebral artery
2 of Oxford Stroke criteria are present (hemiparesis/sensory loss, hemianopia, cognitive dysfunction) OR higher cerebral dysfunction alone
What are the criteria to diagnose a lacunar infarct (LACI)?
involves perforating arteries around the internal capsule, thalamus and basal ganglia
presents with 1 of the following:
- unilateral weakness (and/or sensory deficit) of face and arm, arm and leg or all three (pure motor stroke)
- pure sensory stroke
- sensorimotor stroke
- ataxic hemiparesis
What are 3 types of symptoms, 1 of which must be present to diagnose a lacunar infarct?
- Unilateral weakness (and/or sensory deficit) of face and arm, arm and leg or all three
- Pure sensory stroke
- Ataxic hemiparesis
What is the difference between hemiparesis and hemiplegia?
hemiparesis is weakness on half of body, hemiplegia is paralysis on half of body
What are the criteria to diagnose a posterior circulation infarct (POCI)? 6 aspects
involves vertebrobasilar arteries and presents with 1 of the following:
- cerebellar or brainstem syndromes
- conjugate eye movement disorder
- bilateral motor/sensory deficit
- ipsilateral cranial nerve palsy with contralateral motor/sensory deficit
- loss of consciousness
- cortical blindness/ isolated homonymous hemianopia
Which arteries are affected in a posterior circulation infarct (POCI)?
vertebrobasilar arteries
What are the 3 criteria, 1 of which the patient must present with, to diagnose posterior circulation infarct (POCI)?
- Cerebellar or brainstem syndromes
- Loss of consciousness
- Isolated homonymous hemianopia
What campaign exists to raise awareness of stroke symptoms?
FAST campaign:
- Face: has it fallen on one side, can they smile
- Arms: can they raise both arms and keep them there
- Speech: is speech slurred
- Time: time to call 999 if see any single one of these signs
What investigations are required in patients with suspected stroke?
emergency neuroimaging - to see if suitable for thrombolytic therapy to treat early ischaemic strokes
- non-contrast CT: must be done in first hour - checking for haemorrhagic stroke
- MRI
How long do transient ischaemic attacks typically last?
although by definition they are <24hr, vast majority <1 hour
What do NICE recommend for the immediate management of TIA?
give aspirin 300mg immediately, unless contraindicated e.g. bleeding disorder or taking anticoagulant (in which case, need immediate admission for imaging to exclude haemorrhage)
What are 2 situations that should make you discuss the need for admission or observation urgently with a stroke specialist for TIA?
- if patient has had >1 TIA (>1/week: crescendo TIA)
- patient has suspected cardioembolic source or severe carotid stenosis
What is the management if the patient has had a suspected TIA in the last 7 days?
arrange urgent assessment (witin 24 hours) by a specialist stroke physician
What is the management if a patient has had a suspected TIA which occurred more than a week previously?
refer for specialist assessment as soon as possible within 7 days
What are 4 vital signs to maintain within normal limits for ischaemic stroke management?
- blood glucose
- hydration
- oxygen saturation
- temperature
How should you approach the management of blood pressure when treating ischaemic stroke acutely?
should not be lowered in the acute phase unless there are complications e.g. hypertensive encephalopathy
What medication should be given immediately if ischaemic stroke is suspected AND haemorrhagic stroke has been excluded?
aspirin 300mg orally or rectally
(rectal if dysphagia)
What is the management of AF present alongside ischaemic stroke?
don’t start anticoagulants (DOAC/warfarin) until brain imaging has excluded haemorrhage, and usually not until 14 days have passed from the onset of an ischaemic stroke
What additional drug beyond antiplatelet therapy/thrombolysis should some patients who have had an ischaemic stroke be given?
statin
When are patients who have had ischaemic stroke offered a statin?
if cholesterol is >3.5 mmol/L
When is a statin often started following ischaemic stroke and why?
treatment often delayed until after at least 48 hours due to risk of haemorrhagic transformation
What are the 2 criteria which must be met for thrombolysis to be considered for acute ischaemic stroke?
- If it is administered within 4.5 hours of onset of stroke symptoms (unless part of clinical trial)
- Haemorrhage has been definitively excluded (i.e. imaging has been performed)
What are 11 absolute contraindications to thrombolysis following acute ischaemic stroke?
- Previous intracranial haemorrhage
- Seizure at onset of stroke
- Intracranial neoplasm
- Suspected subarachnoid haemorrhage
- Stroke or traumatic brain injury in preceding 3 months
- Lumbar puncture in preceding 7 days
- GI haemorrhage in preceding 3 weeks
- Active bleeding
- Pregnancy
- Oesophageal varices
- Uncontrolled hypertension >200/120 mmHg
What are 5 relative contraindications to thombolysis of acute ischaemic stroke?
- Concurrent anticoagulation (INR >1.7)
- Haemorrhagic diathesis
- Active diabetic haemorrhagic retinopathy
- Suspected intracardiac thrombus
- Major surgery / trauma in the preceding 2 weeks
Which drug is used for thrombolysis of acute ischaemic stroke?
IV alteplase (recombinant tissue plasminogen activator)
When is mechanical thrombectomy available to treat acute ischaemic stroke?
24 hours a day
What is required before decisions about thrombectomy are made?
they must take into account patient’s overall clinical status: pre-stroke functional status of less than 3 on the modified Rankin scale and more than 5 on the National Institutes of Health Stroke Scale (NIHSS)
After what time period following acute ischaemic stroke can thrombectomy be offered? What can it be given in combination with?
- as soon as possible and within 6 hours of symptom onset, together with IV thrombolysis (if within 4.5 hours)
- sometimes within 6-24 hours if meet certain criteria
What are 2 criteria for performing thrombectomy within 6 horus of ischaemic stroke symptom onset?
- Acute ischaemic stroke AND
- Confirmed occlusion of proximal anterior circulation demonstration by CT angiography (CTA) or magnetic resonance angiography (MRA)
What are 2 criteria that must be met for thrombectomy to be offered to those last known to be well between 6 and 24 hours prior to ischaemic stroke symptoms?
- Confirmed occlusion of proximal anterior circulation demonstrated by CTA or MRA AND
- if there is potential to salvage brain tissue, as shown by imaging such as CT perfusion or diffusion-weighted MRI sequences showing limited infarct core volume
What does the extension to within 6-24 hours of symptom onset for thrombectomy include?
wake-up strokes