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Acute Stroke Management Resource: Types of Stroke & Anatomy and Physiology of Acute Stroke 2007.

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Presentation on theme: "Acute Stroke Management Resource: Types of Stroke & Anatomy and Physiology of Acute Stroke 2007."— Presentation transcript:

1 Acute Stroke Management Resource: Types of Stroke & Anatomy and Physiology of Acute Stroke 2007

2 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

3 Ischemic (80%)Hemorrhagic (20%)

4 Mechanism of Stroke FeatureHemorrhageInfarct Onset sedentaryWith activityNocturnal Hypertension presentUsually presentOften Clinical course staticRapidly progressiveStepwise or static Signs of  ICPPresentAbsent later CT scan changesPresence of bloodNormal or subtle changes

5 CT: Intracerebral Hemorrhage Intracerebral hemorrhage

6 Ischemic Stroke: Hyperdense MCA Sign Hyperdense MCA sign

7 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

8 Ischemic Stroke: Etiology  Large Vessel Disease  Cardioembolic  Atherosclerosis  Small Vessel Disease  Lacunar Infarction  Cryptogenic

9 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

10 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

11 Acute Stroke Management Resource Anatomy and Physiology Review

12 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

13 Cerebrum  Largest portion  Two hemispheres  Joined by the corpus callosum  Dominance Corpus Callosum

14 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

15 Cerebral Cortex  Divided into 4 lobes  Frontal  Parietal  Temporal  Occipital

16 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

17 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

18 Circle of Willis

19 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

20 Anterior Cerebral Artery

21 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

22 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

23 Middle Cerebral Artery

24 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

25 Posterior Cerebral Artery

26 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

27 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

28 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

29 Cerebellar Blood Supply

30 Brain Stem  Blood supply: PCA & Vertebrobasilar  Major divisions: midbrain, pons, medulla  Houses Cranial Nerves 3-12  Serves as a pathway  Reticular Activating System

31 Cranial Nerves

32 Reticular Activating System

33 Collateral Circulation  Not all vessels have capability – lenticulostriate  Common sites: o 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

34 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

35 Collateral Circulation

36 Stroke Syndromes and Patient Presentations Acute Stroke Management Resource

37 Ischemic Stroke: Carotid Syndromes  Sensory/motor deficit  Aphasia  Cortical sensory loss  Apraxia, neglect  Retinal ischemia  Visual field deficit

38 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

39 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)

40 Ischemic Stroke: Lacunar Syndromes

41 stroke/images/figure3.jpg

42 Ischemic Stroke: Lacunar Syndromes Type of SyndromePatient 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

43 Ischemic Stroke: Lacunar Syndromes Type of SyndromePatient 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

44 Case Examples  Add patient case examples of:  Anterior circulation strokes  Posterior circulation strokes  Lacunar Infarcts

45 Ischemic Stroke: Left (dominant) Hemisphere Stroke  Aphasia  Right field defect  Left gaze preference  Right upper motor neuron facial weakness  Right hemiparesis  Right hemisensory loss

46 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

47 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

48 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

49 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

50 Resources  American Association of Neuroscience Nurses  American Stroke Association  Brain Attack Coalition  Canadian Hypertension Education Program  Canadian Stroke Strategy  European Stroke Initiative

51 Resources  Heart and Stroke Foundation Prof Ed  Heart and Stroke Foundation of Canada  Internet Stroke Centre  National Institute of Neurological Disorders and Stroke  National Stroke Association  Scottish Intercollegiate Guidelines Network  StrokeEngine


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