Stroke Flashcards
On average how many strokes occur in one year in the UK?
120,000-150,000
Define a stroke
Sudden onset of focal or global neurological symptoms caused by ischaemia or haemmorhage lasting more than 24 hours
How is a Transient Ischaemic Attack different to stroke?
Symptoms resolve within 24 hours
2 Main causes of stroke
Ischaemic
Haemorrhagic
Causes of ischaemic stroke?
Large artery atherosclerosis Cardioembolic (infective endocarditis) Small artery occlusion (Lacunar) Undetermined Rare causes - arterial dissection, venous sinus thrombosis
Causes of haemorrhagic stroke
Intracerebral haemorrhage
Secondary haemorrhage- SAH, Arteriovenous malformation
Define ischaemia
failure of cerebral blood flow; interrruption in blood supply
Ischaemia leads to…
Hypoxia
Prolonged –> anoxia –> infarction –> necrosis: STROKE
Further damage following prolonged hypoxia
Oedema
Secondary haemorrhage into stroke
Pathogenesis of ischaemic stroke (4)
Disruption or injury to plaque surface
Platelet ahdesion/aggregation and fibrin formation
Thrombus formation
Total arterial occlusion
Non-modifiable risk factors of stroke
Previous stroke
Family history
Age
Male
Modifiable risk factors
Hypertension Diabetes Smoking Lipids Alcohol Obesity (abdominal)
Other risk factors
Hypercoagulable states (pregnancy, cancer, sickle cell disease) Impaired cardiac function (Atrial fibrillation) OC & HRT - high estrogen content
Arterial supply to anterior brain
Internal carotid artery
Divides into Anterior Cerebral artery and Middle Cerebral Artery
Arterial supply to posterior brain
Vertebral to Basilar
3 pairs of cerebellar arteries - Superior, Anterior inferior, Posterior inferior
2 Posterior cerebral arteries PCA
Name the anastomoses of the arterial blood supply to the brain
CIRCLE OF WILLIS
Anterior and posterior communicating arteries
Branches of the ACA
Medial orbitofrontal Frontopolar Callosomarginal Pericallosal Paracenral Precuneal artery
ACA occlusion symptoms
Contralateral paralysis of foot and leg, sensory loss over foot and leg, impaired gait and stance
Branches of the MCA
Anterior/Middle/Posterior Temporal Lateral orbitofrontal Ascending frontal Precentral Central Anterior/Posterior Parietal Angular artery
Symptoms of MCA occlusion
Contralateral paralysis of face/arm/leg, sensory loss,
Homonymous hemianopia
Gaze paralysis to opposite side
Aphasia if stroke on dominant side
Unilateral neglect and agnosia for 1/2 external space if non-dominant (usually RHS)
Left hemisphere MCA territory contains which functional areas
Broca’s
Wernicke’s
Auditory complex
Symptoms if left hemisphere affected
Hemiplegia, homonymous hemianopia, dysphasia
Right hemisphere symptoms
Left hemiplegia, homonymous hemianopia, neglect syndromes (Agnosias)
4 Types of Agnosia
Visual agnosia
Sensory agnosia
Anosagnosia (denial of hemiplegia)
Prosopagnosia (failure to recognise faces)
Which arteries are occluded when stroke occurs in area of basal ganglia and name the type of stroke
MCA –> Medial and Lateral Lenticulostriate arteries
Lacunar stroke
Name the 4 Lacunar Stroke Syndromes
Pure motor stroke
Pure sensory stroke
Dysarthria (clumsy hand syndrome)
Ataxic hemiparesis
What signs are devoid in Lacunar stroke?
Cortical
No dysphasia, neglect or hemianopia experienced
Name the arteries within the posterior circulation to the brain
Basilar artery Superior cerebellar Anterior inferior cerebellar Posterior temporal Calcarine artery Parietooccipital Posterior pericallosal artery
Think of the anatomy involved in a stroke within the posterior circulation
Brainstem, thalamus, Cerebellum, Occipital and medial temporal
Symptoms of posterior stroke
Brainstem dysfunction Coma, vertigo, nausea, vomiting, cranial nerve palsie, ataxia Hemiparesis, hemisensory loss Cossed sensori-motor deficit Visual field deficits
3 Goals of Acute Ischaemic Stroke treatment
Restore blood supply
Limit ischaemic damage
Protect vulnerable brain tissue
Treatments for acute ischaemic stroke
Thrombolysis - alteplase
Aspirin 300mg
Thrombectomy
Stroke Unit
Classification system for stroke
Bamford/ Oxfordshire Community Stroke Project (OCSP) classification
Lacunar Stroke (LACS)
Partial Anterior Circulation Stroke (PACS)
Total Anterior Circulation Stroke (TACS)
Posterior Circulation Stroke (POCS)
What system is used to differentiate from stroke mimics?
ROSIER
Recognition of Stroke in the Emergency Room
-Seizures, loss of consciousness - not typically stroke
Assymetric facial, leg and arm weakness
Speech disturbance
Visual defect
All score 1 point
Bamford classification of Lacunar Stroke (LACS)
Motor +/- sensory loss
Bamford classification of Partial Anterior Circulation Stroke
Motor +/- sensory loss 1 from Hemianopia Dysphasia Neglect
Bamford classficiation of Total Anterior Circulation Stroke
Motor +/- sensory loss
2 from
Hemianopia +
Neglect or Dysphasia
Bamford classficiation of Posterior Circulation Stroke (POCS)
Motor +/- sensory loss
Hemianopia/dysphasia/neglect
Brainstem and or cerebellar signs
Highest death rates in which type of stroke from Bamford Classification
Total Anterior Circulation Stroke (TACS) - 96%- includes dependence in 6 months
What is thrombolysis?
Tissue Plasminogen Activator (TPA)- Alteplase
Breaks down the clot
Criteria for TPA
Less than 4.5 hours since symptom onset
Disabling neurological deficit
Symptoms present > 60 minutes
Consent
Exclusion criteria for TPA
Evidence of haemorrhage - blood on CT - Surgery - Bleeding - Coagulation problems BP > 185 systolic or 110 diastolic Glucose less than 2.8 or > 28mmol/L
What is supplied by the carotid system?
Anterior cerebral and middle cerebral hemispheres and cortical deep white matter
What is supplied by the vertebro-basilar system?
Brainstem, cerebellum and occipital lobe
What function is determined by the motor cortex?
Movement
What is determined by the sensory cortex?
Pain, heat and other sensations
What function is determined by the parietal lobe?
Comprehension of language
What functions are determined by the temporal lobe?
Hearing
Intellect
Emotion
What area does the occipital lobe belong to?
Primary visual area
What function is determined by Wernicke’s area?
Speech comprehension
What function is determined by the cerebellum?
Coordination
What functions are determined by the brainstem?
Swallowing, breathing, heartbeat, wakefulness center and involuntary functions
What functions are related to the frontal lobe?
Smell
Judgement
Foresight
Voluntary movement
What area is related to speech?
Broca’s
Wernicke’s for comprehension
What key areas need to be explored in the nuerological history and examination for stroke?
Motor Sensory - loss of feeling Speech - dysarthria, dysphasia (weakened muscles of face and mouth) Neglect/visuospatial problems Vision Gaze palsy Ataxia/vertigo.incoordination, nystagmus
Which areas are most commonly unaffected or recover well in smaller strokes?
Frontal and speech cortex
Damage to which area due to stroke results in locked in syndrome/locked-in like states?
Pons
Why would damage to the pons cause a locked in syndrome?
Catches all of the motor and sensory fibres in cortex
Why are cancer patients more vulnerable to stroke?
Prothrombotic state
Causes of stroke
Blockage of vessel with thombus/embolus
Disease of vessel wall
Disturbance of normal properties of blood
Rupture of vessel wall (haemorrhage)
Symptoms of carotid stenosis
Sudden severe headache Dizziness Loss of balance Unable to move limbs Sight Weakness, numbness on one side
Most common cause of cardioembolic stroke?
Atrial fibrillation
What arteries are branches of the middle cerebral artery?
Medial and lateral lenticulostriate arteries
Which stroke occurs after HT and hypertrophy of the lenticulostriate arteries?
Small lacunar stroke
Motor +/- sensory
What rare cause of stroke is the commonest cause of painful Horner’s syndrome?
Carotid dissection
Drooping eye, can’t perspire
What vessels are usually occluded in a Total anterior circulation stroke?
Proximal middle cerebral artery or internal carotid
Which vessels are more commonly occluded in a partial anterior circulation stroke?
Branches of MCA
Which type of stroke is often silent or misdiagnosed?
Lacunar Stroke
What type of presentation of lacunar stroke is most common?
Pure motor symptoms - complete/incomplete weakness of 1 side, 2 or 3 areas
Which investigations should be carried out when someone presents with stroke like symptoms?
Bloods ECG CT MRI Carotid doppler - examine vessels Echocardiogram - clots in heart
What is a priority to optimise recovery and discharge after a stroke?
Get the patient mobilising
What treatment alongside intravenous thrombolysis improves outcomes?
Clot retrieval/thrombectomy
When is hemicraniectomy indicated?
Acute MCA territory ischaemic stroke complicated by massive cerebral oedema
Individuals up to 60 years of age
In what time frame should thrombolysis be considered for acute stroke treatment?
Within 4.5 hours onset of symptoms
Is CT offered for a suspected TIA?
No, unless suspicion of other condition that could be picked up by CT
Treatment for stroke prevention in TIA or otherwise
Clopidogrel 75mg or Aspirin
Dipyridamole MR 200mg bd
Statin
BP drugs - even if BP normal
What are patients at risk of if swallow affected after stroke?
Aspiration pneumonia
Mechanism of aspirin
Inhibits thromboxane production
Prevents platelet aggregation and vasoconstriction
ANTIPLATELET
Mechanism of clopidogrel
Inhibits ADP receptor activated platelet aggregation
Newer agents to clopidogrel
Ticagrelor and prosugrel
Mechanism of statins (simvastatin,pravastatin, atorvastatin)
HMG CoA Reductase inhibitors
Stabilise atheromatous plaques and reduce inflammatory properties
Risk associated with aspirin and clopidogrel (antiplatelets)
GI bleeding
Treatment for carotid stenosis
Best Medical therapy - smoking cessation, BP control, antiplatelet, statin, diabetic control
Confirmed TIA - carotid doppler
Carotid endarterectomy
Complications of carotid endarterectomy
Wound infection Bleeding Scar Anaesthetic risk Nerve damage Perioperative stroke
Which nerves are at risk of damage during a carotid endarterectomy?
Glossopharyngeal
Hypoglossal
Vagus
Symptoms of nerve damage from carotid endarterectomy
Numbness along jaw
Issues swallowing and with speech
When is stenting considered in a carotid endarterectomy?
Inaccessible disease
Scarring
Previous surgery
Area too high up for open surgery
Categories of ischaemic stroke
Thrombotic
Embolic
Hypoperfusion
Lacunar
Causes of thrombotic stroke
Atherosclerosis
Prothrombotic state
Which group of patients are in a prothrombotic state?
Pregnant
Cancer patients
Antiphospholipid syndrome
Sickle cell anaemia
3 examples of embolic stroke causes
Atrial fibrillation
Paradoxical embolus
Infective endocarditis
What is meant by a paradoxical embolus?
Clot occurs within venous system, embolises through right side of heart to the left via default in ventricular septum
Travels to brain
What is the pathophysiology of lacunar strokes?
Hypertension
Occurs in basal ganglia
Categories of haemorrhagic stroke
Intracerebral haemorrhage
Subarachnoid haemorrage
Causes of intracerebral haemorrhage
Trauma
Hypertension
Cerebral amyloid
Causes of Subarachnoid haemorrhage
Trauma
Berry aneurysm
Arteriovenous malformation
What is Todd’s paresis and what does this condition score on the ROSIER scale?
Hemiplegia following tonic clonic seizure
-1 - seizure; unlikely to be a stroke
