Cerebral Infarction Flashcards
How does stroke risk change with age?
Increases with age?
What is an example of public awareness being used to help treat stroke?
- Remember FAST
- Facial weakness
- Arm weakness
- Speech problems
- Time to call 999
What is a stroke?
Sudden onset of focal or global neurological symptoms caused by ischaemia or haemorrhage and lasting more than 24 hours
What are the 2 different broad categories of strokes?
Ischaemic stroke (85%)
Haemorrhagic stroke (15%)
Are most strokes ischaemic strokes or haemorrhagic strokes?
Ischaemic (85%)
What does TIA stand for?
Transient ischaemic attack
What is a transient ischaemic attack (TIA)?
Term used if symptoms resolve within 24 hours
How long do most TIAs take to resolve?
Most TIAs resolve within 1 to 60 minutes
What are the different causes of haemorrhagic stroke?
1) Primary intracerebral haemorrage
2) Secondary haemorrhage (subarachnoid haemorrhage or arteriovenous malformation)
What are the different causes of ischaemic stroke?
1) Large artery atherosclerosis (such as carotid)
2) Cardioembolic (such as atrial fibrillation)
3) Small artery occlusion
4) Undetermined/cryptogenic
5) Rare causes (arterial dissection, venous sinus thrombosis)
What are some modifiable risk factors for stroke?
- Smoking
- 2x increases risk of cerebral infarction
- 3x increased risk of subarachnoid haemorrhage
- Some of the increased risk relates to cardiac problems
- Obesity
- Independent risk factor for vascular disease including stroke
- AF
- 5x increased risk of embolic stroke
- Antiplatelets (such as aspirin) have no benefit in reducing ischaemic stroke
- Anticoagulants (warfarin and COACs) reduce risk by 2/3rds
- DOACs have less risk of causing bleeding than warfarin
- Cocaine
- Diabetes
- Diabetes increases incidence 3x
- Hyperlipidaemia
- Hypertension, smoke and diabetes contribute to LDL-C deposition in arterial walls
- Risk related to development of atheroma in blood vessel walls
- Hypertension
- Most important modifiable risk factor
- Chronic hypertension exacerbates atheroma and increases involvement of smaller distal arteries
- No exercise
- Diet
- Alcohol
- Small amounts may decrease stroke risk, heavy drinking increases risk 2.5x
- Oral contraceptives
What are some non-modifiable risk factors for stroke?
- Previous stroke
- Age
- Male
- Family history
What can reduce the risk of AF leading to a stroke?
- Anticoagulants (warfarin and DOACs) reduce risk by 2/3rds
- DOACs have less risk of causing bleeding than warfarin
How do small end arteries coming directly off large arteries have a higher risk of causing stroke?
Small end arteries coming directly off large arteries experience higher pressure and are at risk of lipohyalinosis (small vessel wall thickening, decreasing luminar diameter) causing:
- Lacunar ischaemic stroke
- Small vessel haemorrhages
What parts of the brain are at particular risk of lipohyalinosis?
- Brainstem
- Basal ganglia
- Subcortical areas
What is lipohyalinosis?
Small vessel wall thickening, decreasing luminar diameter
What can the circulation of the brain be seperated into?
Anterior circulation
Posterior circulation
What is the anterior circulation of the brain composed of?
What is the posterior circulation of the brain composed of?
What does the carotid system supply?
Most of the hesmispheres of the brain and cortical deep white matter
What does the vertebro-basilar system supply?
The brainstem, cerebellum and occipital lobes
Signs and symptoms of stroke should correlate to what?
Fit in with an artery territory and an area of the brain
Diagnosis of a stroke should give an answer to what questions?
- What is the neurological deficit
- Where is the lesion
- What is the lesion
- Why has the lesion occurred
- What are the potential complications and prognosis
What are some frontal lobe functions?
- High level cognitive functions
- Such as abstraction, concentration, reasoning
- Memory
- Control of voluntary eye movements
- Motor control of speech (dominant hemisphere)
- Motor cortex
- Urinary continence
- Emotion and personality
What are examples of high level cognitive functions?
- Such as abstraction, concentration, reasoning
What are some parietal lobe functions?
- Sensory cortex
- Sensation (identify modalities of touch, pressure, position)
- Awareness of parts of the body
- Spatial orientation and visuospatial information (non dominant hemisphere)
- Ability to perform learning motor tasks (dominant)
What cortex is found in the parietal lobe?
Sensory cortex
What are some temporal lobe functions?
- Primary auditory receptive area
- Comprehension of speech (dominant)
- Visual, auditory and olfactory perception
- Important role in learning, memory and emotional affect
What lobe is the primary auditory receptive area found?
Temporal lobe
In what lobe is the visual cortex found?
Occipital lobe
What are some occipital lobe functions?
- Primary visual cortex
- Visual perception
- Involuntary smooth eye movement
Does does ACA stroke stand for?
Anterior cerebral artery stroke
What does MCA stroke stand for?
Middle cerebral artery stroke
Where does most weakness occur in a stroke due to the anterior cerebral artery?
Leg more than arm weakness
Where does most weakness occur in a stroke due to middle cerebral artery?
Face and arm more than leg weakness
Why does a small stroke of deep white matter cause major defects?
Affects major tracts where fibres are pact closely together, such as spinothalamic tract
What is the function of the cerebellum?
Balance and coordination
What is the brainstem composed of?
Composed of midbrain, pons and medulla
How many of the cranial nerves arise from the brainstem?
10 of the 12
Why doo strokes lead to contralateral hemiparesis?
Due to crossing of cortical tracts in lower medulla
What is hemiparesis?
Weakness of one entire side of the body
What are some major functions of the brainstem?
- Eye movements
- Breathing
- Swallowing
- Heart beat
- Consciousness
What is the clinical presentation of stroke?
- Motor (clumsy or weak limb)
- Sensory (loss of feeling)
- Speech (dysarthria/dysphasia)
- Neglect/visuospatial problems
- Vision, loss in one eye (amaurosis fugax) or hemianopia
- Gazy palsy (inability to move both eyes in a single direction)
- Ataxia, vertigo, incoordination, nystagmus
What is gaze palsy?
Inability to move both eyes in a single direction
What are strokes classified by?
Oxford community stroke project classification (OSCP)
What are the different classes of stroke?
- Total anterior circulation stroke (TACS)
- Partial anterior circulation stroke (PACS)
- Lacunar stroke (LACS)
- Posterior circulation stroke (POCS)
What does TACS stand for?
Total anterior circulation stroke
What does PACS stand for?
Partial anterior circulation stroke
What does LACS stand for?
Lacunar stroke
What does POCS stand for?
Posterior circulation stroke
What are the requirements for a stroke to be considered LACS?
What are the requirments for a stroke to be considered PACS?
What are the requirements for a stroke to be considered TACS?
Known as full house as effects 3 of 3:
- Complete hemiparesis/numbness
- Loss of vision on one side (hemianopia)
- Loss of awareness on one side (inattention) non-dominant or dysphasia dominant
What are the requirments for a stroke to be considered POCS?
What does a stroke in the right hemisphere cause?
- Left hemiplegia, homonymous hemianopia, neglect syndromes (agnosias)
- Visual agnosia
- Sensory agnosia
- Anosagnosia (denial of hemiplegia)
- Prospagnosia (failure to recognise faces)
In general, blockage of a what causes TACS?
Main artery to one hemisphere
What is TACS often due to?
In general, blockage of a what causes PACS?
Branch of main artery
In general, blockage of a what causes LACS?
Small perforating artery
What is the clinical presentation of LACS?
Weakness/numbness of:
- Face and arm and leg
- Or face and arm
- Or arm and leg
May have dysarthria
Ataxic hemiparesis
No affect on higher function, will not have dysphasia, inattention or hemianopia
What is nonoparesis?
Weakness to one limb
Blockage to what causes POCS?
Any posterior artery
What is the clinical presentation of POCS?
- Loss of balance/coordination
- Vertigo
- Double vision
- Dysarthria
- Visual loss (hemianopia)
What is the medical term for vision loss?
Hemianopia
Where does basilar artery occlusion cause ischaemia?
Ischaemia in pons
Describe the clinical presentation of basilar artery occlusion?
Predominantly motor/oculomotor signs/symptoms
Bilateral but asymmetrical
Alteration in level of consciousness common:
- May progress over 12 to 24 months
May present as reduced responsiveness
What kind of stroke has the worst mortality?
1) TACS
2) POCS
3) PACS
4) LACS
What are some conditions that stroke mimics?
What are the symptoms of stroke?
What is migraine with aura?
Recurring headache that strikes after or at the same time as sensory disturbances called aura
Why does migraine aura occur with stroke?
- Due to cortical spreading depression
What occurs in migraine aura?
- Visual disturbances
- Scintillating scotomata
- Geometric patterns
- Positive symptoms
- Can include sensory, motor or speech disturbance
- Headache onset can be >1 hour after the end of the aura or no headache
What is functional anxiety disorder?
Are able to accomplish tasks and appear to function well in social situations but internally they are feeling the same symptoms as anxiety disorder
What anxiety disorder do some people get after stroke?
Functional anxiety disorder
What is Hoover’s sign?
- When pressure is felt in the paretic leg when the non-paretic leg is raised and no pressure is felt in the non-paretic leg when the paretic leg is being raised
What is the clinical presentation of acute vestibular syndrome?
- Can be very disabling
- Vertigo
- Nystagmus
- Unidirectional, increase in intensity when patient looks in direction of fast phase
- Vomiting
- MRI can be helpful
What are the aims of therpies for stroke?
- Restored blood supply
- Prevent extension of ischaemic damage
- Protect vulnerable brain tissue
What are some potential therapies for stroke?
- Aspirin
- Heparin
- Neuroprotectant
- Tissue plasminogen activator (TPA)
Intra-arterial therapy/thrombectomy
What does TPA stand for?
Tissue plasminogen activator
What does NNT mean?
Number needed to treat to prevent 1 death or dependent
What is the best treatment for stroke?
Thrombectomy
What professionals are found in stroke clinics?
- Clinical staff
- Stroke nurses
- Physiotherapists
- Speech and language therapists
- Occupational therapists
- Dietician
- Psychologist
- Orthoptist
What is the criteria for TPA use?
- <4.5 hours from symptom onset
- Disabling neurological deficit
- Symptoms present more than 60 minutes
- Consent obtained
What is the exclusion criteria for IV TPA?
- Anything that increases probability of haemorrhage
- Blood on CT scan
- Recent surgery
- Recent episodes of bleeding
- Coagulation problems
- BP > 185 systolic or >110 diastolic
- Glucose <2.8 or >22mmol/L
How do the benefits of TPA change with time?
Decreases with time, whilst harm increases
What should be used with medical treatment for strokes?
Endovascular treatment
What can the risk of stroke recurrence be reduced by?
- Antiplatelet
- Antihypertensive
- Statins and endarterectomy
What is an example of a endarterectomy?
Example of endarterectomy is carotid endarterectomy (used for internal carotid artery stenosis)
What investigations are done for stroke?
- All/most patients:
- Routine blood tests
- FBC, glucose, lipids, ESR…
- CT or MRI head scan
- Infarct vs haemorrhage
- ECG and holter
- Look for AF, LVH
- Carotid Doppler ultrasound
- Look for stenosis
- Some patients:
- Echocardiogram
- Valves, ASD, VSD, PFO
- Cerebral angiogram/venogram
- Vasculitis
- Hyper-coagulable blood screen
