Stroke Flashcards
Cerebellar stroke - pathophysiology
Circulation to the cerebellum is impaired due to a lesion of:
- the superior cerebellar artery,
- anterior inferior cerebellar artery or
- the posterior inferior cerebellar artery (also known as lateral medullary syndrome)
Features of cerebellar stroke?
It may present similarly to vestibular neuritis
- vertical nystagmus
- patients can’t stand without support - even with eyes open
What is vertical nystagmus suggestive of?
A CENTRAL cause of vertigo
Criteria of Total anterior circulation infarct
- unilateral hemiparesis and/or hemisensory loss of the face, arm & leg
- homonymous hemianopia
- higher cognitive dysfunction e.g. dysphasia
involves middle and anterior cerebral arteries
all 3 of the above criteria are present
Criteria of Partial anterior circulation infarcts
involves smaller arteries of anterior circulation e.g. upper or lower division of middle cerebral artery
2 of the criteria are present
- unilateral hemiparesis and/or hemisensory loss of the face, arm & leg
- homonymous hemianopia
- higher cognitive dysfunction e.g. dysphasia
Criteria of lacunar infarcts
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 sensory stroke.
- ataxic hemiparesis
Most commonly presents as a pure MOTOR HEMIPARESIS, pure SENSORY stroke
SENSOTIMOTOR stroke
ATAXIC hemiparesis or dysarthria/clumsy hand syndrome
Criteria of posterior circulation infarcts
involves vertebrobasilar arteries presents with 1 of the following: 1. cerebellar or brainstem syndromes 2. loss of consciousness 3. isolated homonymous hemianopia
Lateral medullary syndrome?
(posterior inferior cerebellar artery)
aka Wallenberg’s syndrome
ipsilateral: ataxia, nystagmus, dysphagia, facial numbness, cranial nerve palsy e.g. Horner’s
contralateral: limb sensory loss
Weber’s syndrome
type of stroke midbrain stroke syndrome ipsilateral III palsy - diplopia; ptosis; afferent pupillary defect contralateral weakness (contralateral hemiplegia)
Indications a stroke is ischaemic rather than haemorrhagic?
Carotid bruit
previous TIA
atrial fibrillation
ischaemic heart disease
What is the ROSIER score
A variant of the FAST screening tool which is useful for medical professionals
What is incorporated in the ROSIER score
Loss of consciousness or syncope = - 1 point
Seizure activity = - 1 point
New, acute onset of: • asymmetric facial weakness = + 1 point • asymmetric arm weakness= + 1 point • asymmetric leg weakness = + 1 point • speech disturbance = + 1 point • visual field defect = + 1 point A stroke is likely if >0.
What is the first investigation fro a suspected stroke ?
A NON contrast CT head scan
DVLA - stroke or TIA
1 month off driving, may not need to inform DVLA if no residual neurological deficit
DVLA - multiple TIAs
3 months off driving and inform DVLA
Management of a TIA
Immediate antithrombotic therapy:
give ASPIRIN 300 mg immediately, unless:
1. the patient has a bleeding disorder or is taking an anticoagulant (needs immediate admission for imaging to exclude a haemorrhage)
2. the patient is already taking low-dose aspirin regularly: continue the current dose of aspirin until reviewed by a specialist
3. Aspirin is contraindicated: discuss management urgently with the specialist team
If patient has had more than 1 TIA, or a cardioembolic source or severe carotid stenosis…
(Crescendo TIA)
Discuss the need for admission or observation urgently with a stroke specialist
If the patient has had a suspected TIA in the last 7 days…
Arrange urgent assessment (within 24 hours) by a specialist stroke physician
Advise the person not to drive until they have been seen by a specialist.
If the patient has had a suspected TIA which occurred more than a week previously…
Refer for specialist assessment as soon as possible within 7 days
Advise the person not to drive until they have been seen by a specialist.
Further management for a stroke…
After initial management
Antithrombotic therapy:
- clopidogrel is recommended first-line (as for patients who’ve had a stroke)
- aspirin + dipyridamole should be given to patients who cannot tolerate clopidogrel
Definition of TIA
The definition of a TIA is now TISSUE-based, not time-based: a transient episode of neurologic dysfunction caused by focal brain, spinal cord, or retinal ischaemia, WITHOUT acute infarction
It is no longer a focal ischaemic event with symptoms lasting <24 hours.
(Even if symptoms have resolved, evidence of infarct on imaging leads to a diagnosis of stroke rather than a TIA.)
Management of acute ischaemic stroke
Aspirin 300mg immediately
Continued for 2 weeks after which time long - term antithrombotic treatment should be initiated.
- Clopidogrel
- Aspirin + dipyridamole if clopidogrel
Lacunar stroke pathophysiology
Occlusion of one of the penetrating arteries that provides blood to the brain’s deep structures.
Thrombectomy in acute ischaemic stroke
An extended target time of 6-24 hours may be considered 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
NICE recommends to offer thrombectomy and thrombolysis to people who have had an ischaemic stroke with CT evidence within 6 hours of symptom onset
Mechanical thrombectomy
NICE recommend that all decisions about thrombectomy take into account a patient’s overall clinical status:
- NICE recommend 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)
Offer thrombectomy 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)
Offer 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
Consider thrombectomy together with intravenous thrombolysis (if within 4.5 hours) as soon as possible for people last known to be well up to 24 hours previously (including wake-up strokes):
who have acute ischaemic stroke and confirmed occlusion of the proximal posterior circulation (that is, basilar or posterior cerebral artery) 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
Stroke by anatomy - Anterior cerebral artery
Contralateral hemiparesis and sensory loss, lower extremity > upper
Stroke by anatomy - Middle cerebral artery
Contralateral hemiparesis and sensory loss, upper extremity > lower
Contralateral homonymous hemianopia
Aphasia
Stroke by anatomy - Posterior cerebral artery
Contralateral homonymous hemianopia with macular sparing
Visual agnosia
Stroke by anatomy - Weber’s syndrome (branches of the posterior cerebral artery that supply the midbrain)
Ipsilateral CN III palsy
Contralateral weakness of upper and lower extremity
Stroke by anatomy - Posterior inferior cerebellar artery (lateral medullary syndrome, Wallenberg syndrome)
Ipsilateral: facial pain and temperature loss
Contralateral: limb/torso pain and temperature loss
Ataxia, nystagmus
Stroke by anatomy - Anterior inferior cerebellar artery (lateral pontine syndrome)
Symptoms are similar to Wallenberg’s (Ipsilateral: facial pain and temperature loss
Contralateral: limb/torso pain and temperature loss
Ataxia, nystagmus),
but:
Ipsilateral: facial paralysis and deafness
Stroke by anatomy - Retinal/ophthalmic artery
Amaurosis fugax
Stroke by anatomy - Basilar artery
‘Locked-in’ syndrome
What can mimic a TIA?
hypoglycaemia - can lead to focal neurological symptoms
TIA - first line for further management?
clopidogrel
If a patient is on warfarin/a DOAC/ or has a bleeding disorder and they are suspected of having a TIA, what should occur?
They should be admitted immediately for imaging to exclude a haemorrhage
Other patients should be given 300mg of aspirin immediately then assessed by a specialist within 24 hours. First-line secondary prevention is clopidogrel 75mg once daily.
thrombectomy in acute ischaemic stroke
Thrombectomy should 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)
therefore thrombolysis and thrombectomy if less than 4.5hrs
Lower extremities affected more than upper - what type of stroke
Anterior cerebral artery
Who is eligible for a carotid artery endarterectomy?
- 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%
Contraindications to thrombolysis
- 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
- Gastrointestinal haemorrhage in preceding 3 weeks
- Active bleeding
- Pregnancy
- Oesophageal varices
- Uncontrolled hypertension >200/120mmHg
Relative:
- Concurrent anticoagulation (INR >1.7)
- Haemorrhagic diathesis
- Active diabetic haemorrhagic retinopathy
- Suspected intracardiac thrombus
- Major surgery / trauma in the preceding 2 weeks
If the patient has had a suspected TIA in the last 7 days, what is the Mx?
should have 300mg aspirin immediately
arrange urgent assessment (within 24 hours) by a specialist stroke physician
Secondary prevention for ischameic stroke
- Clopidogrel
- If not tolerated - aspirin + dipyridamole
- MR dipyridamole alone is recommended after an ischaemic stroke only if aspirin or clopidogrel are contraindicated or not tolerated, again with no limit on duration of treatment
Up to what time can thrombectomy be offered?
For acute ischaemic stroke
Standard target time for thrombectomy is within 6 hours.
However:
Offer 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)
-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
What is thrombolysis and what is the latest time it can be administered?
Alteplase
Within 4.5 hours of onset of stroke symptoms
After 14 days, what medication should be given for ischaemic stroke?
- Clopidogrel
- if the cholesterol is > 3.5 mmol/l patients should be commenced on a statin. Many physicians will delay treatment until after at least 48 hours due to the risk of haemorrhagic transformation
