Cerebrovascular Disease Flashcards
What is a stroke?
An acute, focal, neurological deficit of cerebrovascular origin that persists >24hrs or leads to death
What is a transient ischaemic attack (TIA)?
An acute, focal, neurological deficit of cerebrovascular origin that persists <1hr, w/o signs of cerebral infarction on MRI scanning
What is the main complication of a TIA?
High risk of stroke w/i 4wks
What is amaurosis fugax?
Sudden, transient loss of vision in one eye
Often occurring w/ TIAs/ICA stenosis
Also found in ocular disease/migraine
What are the irreversible risk factors contributing to ischaemic stroke?
Age
Personal/family hx
Hyper-coagulable states
AF
What are the reversible risk factors contributing to ischaemic stroke?
HTN Hypercholesterolemia DM Smoking/alcohol Poor diet/low exercise/obesity Oestrogen containing contraceptives
What are some of the less common risk factors contributing to ischaemic stroke?
Endocarditis Migraine Polycythaemia APL syndomre Vasculitis Amyloidosis
What are the risk factors for haemorrhagic stroke?
Family hx Uncontrolled HTN Vascular abnormalities Coagulopathies/anticoag therapy Heavy, recent alcohol intake
What are the two main types of stroke?
Infarction (85%) - thrombosis or embolus
Haemorrhagic (15%)
What are the common sites of arterial thrombosis in infarction strokes?
Carotid
Vertebral
Basilar
What are the two common types of haemorrhagic stroke?
Sub-arachnoid haemorrhage (10%)
Intra-cerebral haemorrhage (15%)
What are the different types of cerebral ischaemia?
Regional infarction
Lacunar infarction
Global ischaemia
Describe regional infarction
Thrombosis/embolus in large vessels
Affects cortical areas
Describe lacunar infarctions
Microinfarcts caused by small vessel disease
Affects subcortical areas
Can be asymptomatic
What are the potential long term complications of a lacunar infarct?
Vascular pseudo-Parkinsonism
Vascular dementia
Describe global ischaemia?
Infarcts at arterial boundary zone due to global reduction in blood flow due to severe hypotension
What is the main acute complication of global ischaemia?
Cortical laminar necrosis
- death of majority of neurons 24hrs after insult
- pt remains in vegetative state
What are the three zones of areas of cerebral ischaemic damage?
Infarct core (tissue certain to die) Oligaemic periphery (tissue that will survive) Ischaemic penumbra (tissue in b/w, either outcome possible)
What infarct changes can be seen >24hrs?
Focal swelling
Loss of normal grey-white differentiation
In what way may large cerebral infarcts cause death?
Associated tissue oedema –> herniation –> brainstem compression
Infarcts in critical sites incompatible w/ life
What is the most common cause of 2o death in stroke patients?
Pneumonia, 2o to aspiration/immobility
What are the clinical features of ischaemic stroke?
Contralateral limb weakness/hemiplegia
-at first flaccid, reflexes then return and become brisk w/ extensor plantar
-weakness maximal at first, returns over wks/mo
Facial weakness
Higher dysfunction
Visual disturbances
Epileptic fit
What are the common sx of higher dysfunction present in ischaemic stroke?
Expressive aphasia Receptive aphasia Apraxia Asterognosis Agnosia Inattention (neglect)
What is expressive aphasia?
Inability to express language despite intact comprehension
What is receptive aphasia?
Inability to understand commands/world
Fluent but meaningless speech
What is apraxia?
Difficulty performing tasks despite intact motor function
What is asterognosis?
Inability to identify objects in both hands by touch alone despite intact sensation
What is agnosia?
Inability to recognise objects, persons, sounds, shapes or smells despite the specific sense being intact and no memory loss
What is inattention (neglect)?
Inability to attend to stimuli despite intact senses
What is the Oxford (Bamford) classification of Stroke?
Simple bedside method of classifying acute strokes using pts sx to identify the region affected
Allows prognostic prediction
What are the four types of Bamford stroke?
TACS
PACS
LACS
POCS
What is a TACS, and which vessel is affected?
Total Anterior Circulation Syndrome
-proximal MCA occlusion
What is a PACS and which vessel is affected?
Partial Anterior Circulation Syndrome
-distal MCA OR ACA occlusion
What is a LACS and which vessel is affected?
Lacunar Anterior Circulation Syndrome
-occlusion of lacunar branch of MCA
What is a POCS and which vessel is affected?
Posterior Circulation Syndrome
-occlusion of PCA
What are the diagnostic criteria for a TACS?
ALL OF
- higher dysfunction
- homonymous hemianopia
- contralateral hemiplegia/sensory loss
- > 2 of face/arm/leg involvement
What are the diagnostic criteria for a PACS?
2/3 OF TACS CRITERIA -higher dysfunction -homonymous hemianopia -hemiplegia/sensory loss OR Higher dysfunction alone w/ spared vision
What are the diagnostic criteria for a LACS?
Pure motor sx (>2/3 face/arm/leg) OR
Pure sensory sx (>2/3 face/arm/leg) OR
Pure sensorimotor sx (>2/3 face/arm/leg) OR
Ataxic hemiparesis
What are the diagnostic criteria for a POCS?
Cranial nerve palsy AND contralateral motor/sensory deficit Bilateral motor/sensory deficit Conjugate eye movement problems Cerebellar dysfunction Isolated homonymous hemianopia
What is the 1yr prognosis for a TACS?
Dead - 60%
Dependent - 25%
Independent - 5%
Recurrence 1 yr - 5%
What is the 1yr prognosis for a TACS?
Dead - 15%
Dependent - 30%
Independent - 55%
Recurrence 1 yr - 20%
What is the 1yr prognosis for a LACS?
Dead - 10%
Dependent - 30%
Independent - 60%
Recurrence 1 yr - 10%
What is the 1yr prognosis for a POCS?
Dead - 20%
Dependent - 30%
Independent - 50%
Recurrence 1 yr - 20%
What is the NHISS?
National institute of health stroke scale
- 15 item neurological exam
- gives insight into location of stroke/severity
What investigations are appropriate in a suspected stroke?
Bloods --> FBCs, U&Es, G6, HbA1c, lipids, coag, ESR Brain imaging w/i 1hr -if considering thrombolysis -if bleeding risk/headache at onset -if decreased consciousness -if neck stiffness ECG
What is the aim of brain imaging in a suspected stroke?
Define arterial territory
Exclude stroke mimics
Determine haemorrhagic/thrombo-embolic pathology
What imaging modalities are used in suspected stroke?
MRI - gold standard, high resolution, less available
CT - rapid, used to exclude haemorrhage
What are the signs of an infarct on CT?
Early signs -loss of grey-white differentiation -sulcal effacement -loss of insular ribbon Lesions visible by day 7 (50%)
What is the emergency management of acute stroke?
ABCDE (exclude hypoglycaemia)
Withhold antiplatelet therapy until haemorrhage excluded
-if excluded give aspirin 300mg
Thrombolysis
What is the time limit for thromboylsis?
<4.5hrs
What medication is used for thrombolysis?
Alteplase 0.9mg/kg
10% bolus over 1min, remainder over 60mins
What is the ward management of an acute stroke?
SALT assessment w/i 2hrs
Physiotherapy –> To relieve spasticity/contractures (baclofen)
Occupational therapy –> Limb splinting, ward groups
Nutrition
LMWH anticoagulation (3/7 post ischaemic stroke)
What are the absolute contraindications to ischaemic stroke?
Intracranial haemorrhage on CT SAH Neurosurgery/head trauma/stroke in past 3mo Uncontrolled HTN Active internal bleeding Known AV malformation Suspected/confirmed endocarditis
What steps should be taken post-thrombolysis?
Pt closely monitored over 24hrs
Avoid catheterisation during infusion
Avoid aspirin/heparin for 24hrs
Avoid NG tube insertion for 24hrs
What sx indicate the need for an emergency CT post-thrombolysis?
Severe headache
Acute HTN
N/V
What treatment should be given if thrombolysis is contraindicated?
Manage supportively on ward
Continue 300mg aspirin OD
2o prevention measures
What 2o prevention measures should be taken post stroke?
Identify/tackle lifestyle risk factors (smoking/alcohol/exercise)
Antihypertensive therapy –> Start w/i 2wks, lower slowly
Antiplatelet therapy –> Aspirin 300mg OD, clopidogrel 75mg
Statin –> 48hrs post-stroke
Manage co-morbidities (AF, carotid USS)
What legislation surrounds driving and strokes?
Pts w/ normal license must not drive for 4wks
If clinical improvement then may return to driving
What are the potential post-stroke complications?
Malignant MCA syndrome DVT/PE Aspiration/hydrostatic pneumonia Pressure sores Depression Seizures Incontinence Post-stroke pain
What is malignant MCA syndrome?
Rapid neurological deterioration due to effects of cerebral oedema following MCA stroke
High morbidity/mortality
What is the presentation of malignant MCA syndrome?
Increased agitation/restlessness
Reducing GCS
Haemodynamic/thermal instability
Signs of raised ICP
What is the management of malignant MCA syndrome?
Decompressive hemicraniectomy
What is the indication for decompressive hemicraniectomy in malignant MCA syndrome?
CT/MRI showing infarct >50% of MCA territory in a pt <60yrs w/ any decrease in consciousness
What are the high-risk features of TIAs?
Recurrent TIAs w/i short period of time AF/TIA whilst anticoagulated ABCD2 score >4 -Age (>60, 1 point) -BP (>140/90, 1 point) -Clinical features (Unilateral weakness, 2 points. Speech disturbance w/o weakness, 1 point) -Duration of sx (>60mins, 2 points. 10-59 mins, 1 point) -Diabetes (Pre-existing DM, 1 point)
What is the management of TIA if high-risk features are present?
Statin (40mg)
300mg Aspirin
Referral to specialist clinic w/i 24hrs
Advise pt not to drive until seen by specialist
What is the management of low-risk TIA?
Same as high risk but referral w/i 1wk instead of 24hrs
How is carotid artery stenosis assessed?
Carotid artery doppler
When should carotid endarterectomy be offered?
Stenosis >50%
What are the benefits of carotid endarterectomy?
Reduces risk of further stroke/TIA by 75%
Reduces mortality
What is available as an alternative to carotid endarterectomy?
Percutaneous luminal angioplasty +/- stenting
