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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 www.heartandstroke.ca/profed Ischemic Stroke: Hyperdense MCA Sign Hyperdense MCA sign www.heartandstroke.ca/profed 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 www.heartandstroke.ca/profed 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 www.heartandstroke.ca/profed 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 123456789- 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 www.heartandstroke.ca/profed 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 www.heartandstroke.ca/profed 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 www.heartandstroke.ca/profed 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