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Types of Stroke

• Objectives
• To review the two common types of stroke
• To review the stroke mechanism for the two common
  types of stroke
• To review the etiology of the two types of stroke
• To describe common patient presentations of
  stroke mimics

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Ischemic (80)
Hemorrhagic (20)
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Mechanism of Stroke
Feature Hemorrhage Infarct
Onset sedentary With activity Nocturnal
Hypertension present Usually present Often
Clinical course static Rapidly progressive Stepwise or static
Signs of ? ICP Present Absent later
CT scan changes Presence of blood Normal or subtle changes
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CT Intracerebral Hemorrhage
Intracerebral hemorrhage
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Ischemic Stroke Hyperdense MCA Sign
Hyperdense MCA sign
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Ischemic Stroke Early CT Signs

• Hyperdense middle cerebral artery sign
• Subtle decreased attenuation of grey matter
• Loss of grey-white differentiation
• Loss of cortical ribbon
• Disappearing basal ganglia
• Early mass effect
• Sulcal effacement
• Shift

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Ischemic Stroke Etiology

• Large Vessel Disease
• Cardioembolic
• Atherosclerosis
• Small Vessel Disease
• Lacunar Infarction
• Cryptogenic

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Intracerebral Hemorrhage Etiology

• Secondary
• Vascular Malformations
• Aneurysms
• Tumors
• Hemorrhagic transformation of cerebral infarction
• Venous infarction with hemorrhage secondary to
  cerebral venous thrombosis
• Moya Moya disease

• Primary
• Chronic hypertension
• Cerebral amyloid angiopathy
• Anticoagulant/fibrinolytic use
• Antiplatelet use
• Drug use
• Other bleeding diathesis

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Stroke Mimics

• The following four conditions represent 62 of
  stroke mimics
• Postictal deficit (unrecognized seizure)
• Systemic infection
• Tumour/abscess
• Toxic-metabolic disturbance
• Other mimics
• Bells palsy
• Peripheral nerve palsies
• Old stroke
• Confusion
• Head trauma

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Acute Stroke Management Resource

• Anatomy and Physiology Review

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Objectives

• Review the major blood vessels of the cerebral
  circulation
• Anterior Cerebral Artery
• Middle Cerebral Artery
• Posterior Cerebral Artery
• Review the key functional areas of the brain
• List the common patient presentations related to
  carotid, vertebrobasilar and lacunar syndromes

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Cerebrum
Corpus Callosum

• Largest portion
• Two hemispheres
• Joined by the corpus callosum
• Dominance

www.disenchanted.com/images/dictionary/corpus_call
osum.gif
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Left and Right Hemisphere

• Right Hemisphere
• Spatial-perceptual deficits
• Left sided weakness/sensory loss
• Neglect of the affected side
• Distractible
• Impulsive behavior
• Poor judgment
• Loss of flow of speech
• Defects in left visual field-homonymous
  hemianopsia

• Left Hemisphere
• Expressive aphasia
• Receptive aphasia
• Global aphasia
• Right sided weakness/sensory loss
• Intellectual impairment- alexia, agraphia,
  acalulia
• Slow and cautious behavior
• Defects in right visual field-homonymous
  hemianopsia

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Cerebral Cortex

• Divided into 4 lobes
• Frontal
• Parietal
• Temporal
• Occipital

www.tbirecoverycenter.org/treatment.htm
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Blood Supply to the Brain

• Arterial supply from carotid and vertebral
  arteries which begin extracranially
• Internal carotid arteries supply anterior 2/3 of
  hemispheres
• Vertebral and basilar arteries supply posterior
  and medial regions of hemispheres, brainstem,
  diencephalon, cerebellum and cervical spinal cord

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Circulation Review

• Circle of Willis
• Anterior Cerebral Artery (ACA)
• Anterior Communicating Artery
• Middle Cerebral Artery (MCA)
• Posterior Communicating Artery
• Posterior Cerebral Artery (PCA)

Anterior Circulation
Posterior Circulation
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Circle of Willis
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Anterior Cerebral Artery
Anterior Cerebral Artery

• Arises from internal carotid
• Supplies anterior portion of basal ganglia,
  corpus callosum, medial and superior portions of
  frontal lobe and anterior parietal lobe
• Key Functional Areas
• Primary motor cortex for leg and foot areas,
  urinary bladder
• Motor planning in medial frontal lobe
• Middle and anterior corpus callosum-
  communication between hemispheres

www.cnsforum.com
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Anterior Cerebral Artery
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Middle Cerebral Artery
Middle Cerebral Artery

• Arises from the internal carotid
• Passes laterally under frontal lobe and between
  the temporal and frontal lobes
• M1 segment- lentriculostriate arteries supply
  basal ganglia and most of internal capsule
• Superior MCA branch- supplies lateral and
  inferior frontal lobe and anterior parts of
  parietal lobe
• Inferior MCA branch-supplies lateral temporal
  lobe, posterior parietal and lateral occipital
  lobe

www.cnsforum.com
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Middle Cerebral Artery

• Key Functional Areas
• Primary motor cortex for face, arm and leg
• Brocas language area (Superior MCA)
• Wernickes language area (Inferior MCA)
• Primary somatosensory cortex for face, arm, leg
• Parts of lateral frontal and parietal lobes used
  in 3D visual-spatial perceptions of own body,
  outside world and ability to interpret and/or
  express emotions

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Middle Cerebral Artery
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Posterior Cerebral Artery
Posterior Cerebral Artery

• Blood supply for midbrain, hypothalamus and
  thalamus, posterior medial parietal lobe, corpus
  callosum, inferior and medial temporal lobe and
  inferior occipital lobe
• Key Functional Areas
• Primary visual cortex
• 3rd nerve in midbrain
• Sensory control-temperature, pain, sleep, ADH
• Communication between hemispheres

www.cnsforum.com
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Posterior Cerebral Artery

• www.strokecenter.org

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Vertebrobasilar Circulation

• Arise from the subclavian arteries
• Run alongside the medulla
• Blood supply for brainstem and cerebellum
• Key Functional Areas
• Spinal cord tracts-pyramidal and spinothalamic
• Cranial nerves 3-12

www.ib.amwaw.edu.pl/anatomy/atlas/image_12e.htm
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Vertebrobasilar Circulation

• 1- Posterior Cerebral
• 2- Superior Cerebellar
• 3- Pontine Branches of Basilar
• 4- Anterior Inferior Cerebellar
• 5- Internal Auditory
• 6- Vertebral
• 7- Posterior Inferior Cerebellar
• 8- Anterior Spinal
• 9- Basilar

www.ib.amwaw.edu.pl/anatomy/atlas/image_12e.htm
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Cerebellum

• Blood supply-own arteries from vertebrobasilar
• Superior cerebellar
• Anterior Inferior
• Posterior Inferior
• Major Functions
• Control of fine motor movement
• Coordinates muscle groups
• Maintains balance, equilibrium

www.daviddarling.info/images/cerebellum.jpg
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Cerebellar Blood Supply

• www.answers.com

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Brain Stem

• Blood supply PCA Vertebrobasilar
• Major divisions midbrain, pons, medulla
• Houses Cranial Nerves 3-12
• Serves as a pathway
• Reticular Activating System

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Cranial Nerves

• http//images.encarta.msn.com/xrefmedia/aencmed/ta
  rgets/illus/ilt/T012872A.gif

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Reticular Activating System

• www.colorado.edu/Kines/Class/IPHY3730/image/figure
  5-29.jpg

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Collateral Circulation

• Not all vessels have capability
  lenticulostriate
• Common sites
• External and internal carotid via opthalamic
  artery
• Intracranial vessels of the Circle of Willis
• Small cortical branches of ACA, MCA,PCA and
  cerebellar arteries

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Collateral Circulation

• Effectiveness depends on vessel size
• Effectiveness depends upon speed of occlusion
• Atherosclerosis
• Circle of Willis vessels are often narrow and
  cannot adapt for sudden onset of blockage

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Collateral Circulation
www.clevelandclinic.org/heartcenter/images/guide/d
isease/cad/artery7.jpg
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Acute Stroke Management Resource

• Stroke Syndromes and Patient Presentations

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Ischemic Stroke Carotid Syndromes

• Sensory/motor deficit
• Aphasia
• Cortical sensory loss
• Apraxia, neglect
• Retinal ischemia
• Visual field deficit

• www.valleyhealth.com/images/image_popup/bn7_functi
  onalbrain.jpg

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Ischemic Stroke Vertebrobasilar Syndrome

• Diplopia
• Vertigo
• Coma at onset
• Crossed sensory loss
• Bilateral motor signs
• Isolated field defect
• Pure motor and sensory deficit
• Dysarthria
• Dysphagia

www.state.sc.us/ddsn/pubs/head/brain.gif
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Ischemic Stroke Lacunar Syndromes

• Makes up 25 of all ischemic strokes
• Presumed to be occlusion of single small
  perforating artery
• Predominantly in the deep white matter, basal
  ganglia, pons
• Blood vessel lenticulostriate branches of the
  Anterior Cerebral and Middle Cerebral Arteries
• 30 of patients are left dependant and some long
  term data suggests up to 25 have a second stroke
  within 5 years (Wardlaw, 2007)

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Ischemic Stroke Lacunar Syndromes
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Ischemic Stroke Lacunar Syndromes

• www.clevelandclincimeded.com/diseasemanagement/neu
  rology/stroke/images/figure3.jpg

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Ischemic Stroke Lacunar Syndromes
Type of Syndrome Patient Presentation
Pure motor hemiparesisResults from an infarct in the internal capsule or pons Contralateral Hemiparesis of face, arm and leg, dysarthria
Contralateral motor hemiparesis with motor aphasiaResults from an infarct of the left frontal area with cortical involvement Hemiparesis of face, arm and leg with inability to speak
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Ischemic Stroke Lacunar Syndromes
Type of Syndrome Patient Presentation
Ataxic hemiparesisResults from an infarct in the pons Paresis of the contralateral leg and side of the face, ataxia of the contralateral leg and arm
Dysarthria and clumsy hand syndromeResults from an infarct in the pons or internal capsule Dysarthria, dysphagia, contralateral facial and tongue weakness, paresis and clumsiness of the contralateral arm and hand
Pure sensory strokeResults from an infarct in the thalamus Contralateral sensory loss to all modalities that usually affect the face, upper and lower extremities May be painful
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Case Examples

• Add patient case examples of
• Anterior circulation strokes
• Posterior circulation strokes
• Lacunar Infarcts

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Ischemic Stroke Left (dominant) Hemisphere Stroke

• Aphasia
• Right field defect
• Left gaze preference
• Right upper motor neuron facial weakness
• Right hemiparesis
• Right hemisensory loss

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Ischemic Stroke Right (non-dominant) Hemisphere
Stroke

• Left neglect, inattention
• Left field defect
• Right gaze preference
• Left upper motor neuron facial weakness
• Left hemiparesis
• Left hemisensory loss, sensory extinction

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Ischemic Stroke Cerebellar Infarct

• Headache, nausea/vomiting
• Vertigo, imbalance
• Normal tone, power, reflexes
• Inability to sit or stand
• Ataxia
• Late signs
• Decreasing level of consciousness
• Diplopia, gaze palsy
• Ipsilateral V,Vll impairment

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Ischemic Stroke Brainstem Stroke

• Decreased LOC
• Crossed findings
• Ipsilateral lower motor neuron facial weakness or
  sensory loss
• Contralateral hemiparesis
• Pupillary changes
• Hiccoughs, vertigo
• Bilateral motor findings
• Diplopia, gaze palsies, intranuclear
  opthalmoplegia
• Dysphagia
• Dysarthria
• Ataxia

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Conclusions

• Rapid assessment and triage key to optimal
  treatment
• CT scan required to exclude hemorrhage
• Knowledge of typical stroke symptoms key
• Anatomical and etiological diagnosis necessary
• Exclusion of stroke mimics vital

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Resources

• American Association of Neuroscience Nurses
• www.aann.org
• American Stroke Association
• www.strokeassociation.org
• Brain Attack Coalition
• www.stroke-site.org
• Canadian Hypertension Education Program
• www.hypertension.ca/chep/en/default.asp
• Canadian Stroke Strategy
• www.canadianstrokestrategy.ca
• European Stroke Initiative
• www.eusi-stroke.com

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Resources

• Heart and Stroke Foundation Prof Ed
• www.heartandstroke.ca/profed
• Heart and Stroke Foundation of Canada
• www.heartandstroke.ca
• Internet Stroke Centre
• www.strokecenter.org
• National Institute of Neurological Disorders and
  Stroke
• www.ninds.nih.gov
• National Stroke Association
• www.stroke.org/site/PageServer?pagenameHOME
• Scottish Intercollegiate Guidelines Network
• www.sign.ac.uk
• StrokeEngine
• www.medicine.mcgill.ca/strokengine

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