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Acute Stroke Management Resource:
Types of Stroke &
Anatomy and Physiology of Acute Stroke
2007
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
Ischemic (80%)
Hemorrhagic (20%)
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
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
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
Stroke Mimics

The following four conditions represent 62% of stroke
mimics
 Postictal deficit (unrecognized seizure)
 Systemic infection
 Tumour/abscess
 Toxic-metabolic disturbance

Other mimics
 Bell’s palsy
 Peripheral nerve palsies
 Old stroke
 Confusion
 Head trauma
Acute Stroke Management Resource
Anatomy and Physiology Review
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
Cerebrum
Corpus Callosum
Largest portion
 Two hemispheres
 Joined by the corpus
callosum
 Dominance

www.disenchanted.com/images/dictionary/corpus_callosum.gif
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 fieldhomonymous 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 fieldhomonymous hemianopsia
Cerebral Cortex

Divided into 4 lobes
 Frontal
 Parietal
 Temporal
 Occipital
www.tbirecoverycenter.org/treatment.htm
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
Circle of Willis
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
Anterior Cerebral Artery
www.cnsforum.com
Anterior 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
Middle Cerebral Artery
www.cnsforum.com
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
Middle Cerebral Artery
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
Posterior Cerebral Artery
www.strokecenter.org
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
Vertebrobasilar Circulation
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Posterior Cerebral
Superior Cerebellar
Pontine Branches of Basilar
Anterior Inferior Cerebellar
Internal Auditory
Vertebral
Posterior Inferior Cerebellar
Anterior Spinal
Basilar
www.ib.amwaw.edu.pl/anatomy/atlas/image_12e.htm
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,
www.daviddarling.info/images/cerebellum.jpg
equilibrium
Cerebellar Blood Supply
www.answers.com
Brain Stem
 Blood
supply: PCA & Vertebrobasilar
 Major divisions: midbrain, pons, medulla
 Houses Cranial Nerves 3-12
 Serves as a pathway
 Reticular Activating System
Cranial Nerves
http://images.encarta.msn.com/xrefmedia/aencmed/targets/illus/ilt/T012872A.gif
Reticular Activating System
www.colorado.edu/Kines/Class/IPHY3730/image/figure5-29.jpg
Collateral Circulation
 Not
all vessels have capability – lenticulostriate
 Common sites:
External and internal carotid via opthalamic artery
o Intracranial vessels of the Circle of Willis
o Small cortical branches of ACA, MCA,PCA and cerebellar
arteries
o
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
Collateral Circulation
www.clevelandclinic.org/heartcenter/images/guide/disease/cad/artery7.jpg
Acute Stroke Management Resource
Stroke Syndromes and Patient Presentations
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_functionalbrain.jpg
Ischemic Stroke: Vertebrobasilar Syndrome
Diplopia
 Vertigo
 Coma at onset
 Crossed sensory loss
 Bilateral motor signs
 Isolated field defect
 Pure motor and sensory
deficit
 Dysarthria
www.state.sc.us/ddsn/pubs/head/brain.gif
 Dysphagia

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)

Ischemic Stroke: Lacunar Syndromes
Ischemic Stroke: Lacunar Syndromes
www.clevelandclincimeded.com/diseasemanagement/neurology/
stroke/images/figure3.jpg
Ischemic Stroke: Lacunar Syndromes
Type of Syndrome
Patient Presentation
Pure motor hemiparesis
Results from an infarct in the
internal capsule or pons
Contralateral Hemiparesis of face,
arm and leg, dysarthria
Contralateral motor
hemiparesis with motor
aphasia
Results from an infarct of the left
frontal area with cortical
involvement
Hemiparesis of face, arm and leg
with inability to speak
Ischemic Stroke: Lacunar Syndromes
Type of Syndrome
Patient Presentation
Ataxic hemiparesis
Results 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
syndrome
Results 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 stroke
Results from an infarct in the
thalamus
Contralateral sensory loss to all
modalities that usually affect the
face, upper and lower extremities
May be painful
Case Examples
 Add
patient case examples of:
 Anterior circulation strokes
 Posterior circulation strokes
 Lacunar Infarcts
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

www.heartandstroke.ca/profed
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
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
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?pagename=HOME

Scottish Intercollegiate Guidelines Network
www.sign.ac.uk

StrokeEngine
www.medicine.mcgill.ca/strokengine