Title text'

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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
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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

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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
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Ischemic Stroke Lacunar Syndromes
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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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