Stroke Flashcards
What is a stroke
A stroke (also known as cerebrovascular accident, CVA) represents a sudden interruption in the vascular supply of the brain
Two main types of strokes
Ischaemic
Haemorrhagic
Subtypes of ischaemic stroke
Thrombotic
Embolic
What is an important risk factor for embolic stroke
AF
General risk factors for ischaemic stroke
age hypertension smoking hyperlipidaemia diabetes mellitus
General risk factors for haemorrhagic stroke
age hypertension arteriovenous malformation anticoagulation therapy Alcohol
Features of cerebral hemisphere infarcts
contralateral hemiplegia: initially flaccid then spastic
contralateral sensory loss
homonymous hemianopia
dysphasia
Features of brainstem infarction
may result in more severe symptoms including quadriplegia and lock-in-syndrome
Features of lacunar infarcts
small infarcts around the basal ganglia, internal capsule, thalamus and pons
this may result in pure motor, pure sensory, mixed motor and sensory signs or ataxia
Which criteria are assessed in the Oxford stroke classification
- unilateral hemiparesis and/or hemisensory loss of the face, arm & leg
- homonymous hemianopia
- higher cognitive dysfunction e.g. dysphasia
Arteries affected by total anterior circulation infarcts(TACI)
Middle and anterior cerebral arteries
Criteria for TACI
- unilateral hemiparesis and/or hemisensory loss of the face, arm & leg
- homonymous hemianopia
- higher cognitive dysfunction e.g. dysphasia
Arteries affected in partial anterior circulation infarcts(PACI)
involves smaller arteries of anterior circulation e.g. upper or lower division of middle cerebral artery
Criteria for PACI
2 of the Oxford criteria are present
Arteries affected by lacunar infarcts
involves perforating arteries around the internal capsule, thalamus and basal ganglia
How do lacunar infarcts present
presents with 1 of the following:
- unilateral weakness (and/or sensory deficit) of face and arm, arm and leg or all three.
- pure sensory stroke.
- ataxic hemiparesis
Arteries affected by posterior circulation infarcts(POCI)
involves vertebrobasilar arteries
Presentation of POCI
presents with 1 of the following:
- cerebellar or brainstem syndromes
- loss of consciousness
- isolated homonymous hemianopia
What features are patients with haemorrhagic strokes more likely to have
decrease in the level of consciousness
Headache
Nausea and vomiting
Seizures
Blood pressure management in strokes
Blood pressure should not be lowered in the acute phase unless there are complications e.g. Hypertensive encephalopathy
Criteria for thrombolysis in acute ischaemic stroke
it is administered within 4.5 hours of onset of stroke symptoms
haemorrhage has been definitively excluded
Absolute contraindications to thrombolysis
Previous intracranial haemorrhage
Seizure at onset of stroke
LP in preceding 7 days
GI haemorrhage preceding 3 weeks
Active bleeding
Uncontrolled HTN
when should thrombectomy and IV thrombolysis be offered
As soon as possible and within 6 hours of symptom onset, together with intravenous thrombolysis (if within 4.5 hours), to people who have:
acute ischaemic stroke and
confirmed occlusion of the proximal anterior circulation demonstrated by computed tomographic angiography (CTA) or magnetic resonance angiography (MRA)
Criteria for just offering thrombectomy
as soon as possible to people who were last known to be well between 6 hours and 24 hours previously (including wake-up strokes):
confirmed occlusion of the proximal anterior circulation demonstrated by CTA or MRA and
if there is the potential to salvage brain tissue, as shown by imaging such as CT perfusion or diffusion-weighted MRI sequences showing limited infarct core volume
Recommended patient clinical status for thrombectomy
A pre-stroke functional status of less than 3 on the modified Rankin scale and a score of more than 5 on the National Institutes of Health Stroke Scale (NIHSS)
Anticoagulation in secondary prevention of stroke
Clopidogrel
Alternatives for anticoagulation in secondary prevention of stroke
Aspirin plus MR dipyridamole is now recommended after an ischaemic stroke only if clopidogrel is contraindicated or not tolerated
When should carotid artery endarterectomy be considered for stroke management
recommend if patient has suffered stroke or TIA in the carotid territory and are not severely disabled
should only be considered if carotid stenosis > 70% according ECST** criteria or > 50% according to NASCET*** criteria
Why is mortality raised in patients with poor glycemic control post-stroke
This is likely due to increased tissue acidosis from anaerobic metabolism, free radical generation, and increased blood brain barrier permeability post injury
What can mimic stroke-related neurological deficits
Hypoglycaemia
Why should anti-hypertensive therapy only be initiated in certain co-morbidities in stroke management
This is because lowering blood pressure too much can potentially compromise collateral blood flow to the affected region, and possibly hasten the time to complete and irreversible tissue infarction
Recommended anti-hypertensive therapy in stroke management if appropriate
intravenous labetalol, nicardipine and clevidipine as first-line agents, due to the possibility for rapid and safe titration to control blood pressure
Why should BP be reduced in thrombolytic therapy candidates
Elevated BP can affect thrombolytic eligibility and delay treatment
Recommended 185/110mmHg
NICE advice regarding SALT assessment following stroke
This should preferably within 24 hours of admission and not greater than 72 hours after
Prior to assessment is undertaken, a patient should remain nil by mouth to prevent complications
Management of feeding post stroke in patients deemed unsafe for oral intake
NG within 24 hrs unless thrombolytic therapy
Nasal bridle tube/gastrostomy if NG not tolerated
Index used to measure disability
Barthel index
This index should be used to assess the functional status of a patient post stroke, and to monitor their improvement with ongoing rehabilitation to regain independence after the event
Recommended tool for assessment of stroke
ROSIER score
1st line ix for suspected stroke
Non-contrast CT head
Recommended anticoagulation for AF following a stroke
Warfarin or direct thrombin or factor Xa inhibitor
In the absence of haemorrhage, anticoagulation therapy should be commenced after 2 weeks
Anterior cerebral artery lesion effects
Contralateral hemiparesis and sensory loss, lower extremity > upper
Middle cerebral artery lesion effects
Contralateral hemiparesis and sensory loss, upper extremity > lower
Contralateral homonymous hemianopia
Aphasia
Posterior cerebral artery lesion effects
Contralateral homonymous hemianopia with macular sparing
Visual agnosia
What is weber’s syndrome(branches of the posterior cerebral artery that supply the midbrain)
Ipsilateral CN III palsy
Contralateral weakness of upper and lower extremity
Posterior inferior cerebellar artery lesion effects
aka lateral medullary syndrome, Wallenberg syndrome
Ipsilateral: facial pain and temperature loss
Contralateral: limb/torso pain and temperature loss
Ataxia, nystagmus
Anterior inferior cerebellar artery(lateral pontine syndrome) lesion effects
Symptoms are similar to Wallenberg’s ,but:
Ipsilateral: facial paralysis and deafness
Retinal artery/ophthalmic artery lesion effects
Amaurosis fugax
Basilar artery lesion effects
‘Locked-in’ syndrome
What are lacunar strokes associated with
HTN
When should oxygen be given in acute stroke
If less than 95%
General advice for secondary prevention of stroke
Physical activity Smoking cessation Balanced diet Alcohol intake limited to 14 units/week Advise against routine dietary supplementation
Medications used in secondary prevention of stroke
Clopidogrel
Statins - Aim to reduce non-HDL cholesterol by >40%
Anti-hypertensives
How long is anticoagulation deferred for in patients with a stroke
Treatment is deferred until at least 14 days from onset in people with disabling ischaemic stroke. In the interim aspirin 300 mg daily will be used
