Types of Stroke

Acute Stroke Management Resource:Types of Stroke &Anatomy and Physiology of Acute Stroke

2007

Types of Stroke

ObjectivesTo 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 StrokeFeature 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

www.heartandstroke.ca/profed

Intracerebral hemorrhage

Ischemic Stroke: Hyperdense MCA Sign

Hyperdense MCA sign


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


Ischemic Stroke: Etiology

Large Vessel DiseaseCardioembolicAtherosclerosis

Small Vessel DiseaseLacunar 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 circulationAnterior Cerebral ArteryMiddle Cerebral ArteryPosterior Cerebral Artery

Review the key functional areas of the brain List the common patient presentations

related to carotid, vertebrobasilar and lacunar syndromes

Cerebrum Largest portion Two hemispheres Joined by the corpus

callosum Dominance

Corpus Callosum

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 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

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 www.heartandstroke.ca/

profed

Circulation Review

Circle of WillisAnterior Cerebral Artery (ACA)Anterior Communicating ArteryMiddle Cerebral Artery (MCA)Posterior Communicating ArteryPosterior 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


Key Functional AreasPrimary motor cortex for face, arm and legBrocas language area (Superior MCA)Wernickes language area (Inferior MCA)Primary somatosensory cortex for face, arm, legParts 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

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

Posterior Cerebral Artery

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

1- Posterior Cerebral2- Superior Cerebellar 3- Pontine Branches of Basilar4- Anterior Inferior Cerebellar5- Internal Auditory6- Vertebral7- Posterior Inferior

Cerebellar8- Anterior Spinal9- 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,

equilibrium www.daviddarling.info/images/cerebellum.jpg

Cerebellar Blood Supply

www.answers.com

Brain Stem

Blood supply: PCA & VertebrobasilarMajor divisions: midbrain, pons, medullaHouses Cranial Nerves 3-12Serves as a pathwayReticular 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 – lenticulostriateCommon sites:

o External and internal carotid via opthalamic arteryo Intracranial vessels of the Circle of Williso Small cortical branches of ACA, MCA,PCA and

cerebellar arteries


Effectiveness depends on vessel sizeEffectiveness depends upon speed of

occlusionAtherosclerosis

Circle of Willis: vessels are often narrow and cannot adapt for sudden onset of blockage


www.clevelandclinic.org/heartcenter/images/guide/disease/cad/artery7.jpg

Stroke Syndromes and Patient Presentations

Acute Stroke Management Resource

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 Dysphagia www.state.sc.us/ddsn/pubs/head/

brain.gif

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


www.clevelandclincimeded.com/diseasemanagement/neurology/stroke/images/figure3.jpg


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

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

Case Examples

Add patient case examples of:Anterior circulation strokesPosterior circulation strokesLacunar 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


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 extinctionwww.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


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


Conclusions

Rapid assessment and triage key to optimal treatment

CT scan required to exclude hemorrhageKnowledge of typical stroke symptoms keyAnatomical and etiological diagnosis

necessaryExclusion 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

Types of Stroke

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