Stroke

1. Stroke Core Rounds Mark Y. Wahba Preceptor: Dr. Ian Rigby Oct. 16th, 2003

2. WHO definition: Stroke • “a neurological deficit of sudden onset accompanied by focal dysfunction and symptoms lasting more than 24 hours that are presumed to be of a non-traumatic vascular origin”

3. WHO definition: Transient Ischemic Attack • “neurological events that have a duration shorter than 24 hours, followed by complete return to baseline”

4. Outline • Introduction • clinical features, pathophysiology, types of stroke, differential diagnosis • Vascular Anatomy • Stroke Patterns • TIA • Management in the ED • Thrombolysis: good or bad?

5. Facts • Leading cause of adult disability • 3rd leading cause of death in US • 75% of all strokes occur in pts >65yrs of age • In the US annual medical costs of stroke care is $30 billion • 20% of expenditures occur in the first 90 days after an event • The National Stroke Association.  The brain at risk – Understanding and preventing stroke.  1998

6. Emergency Care Facts • 2% of all 911 calls • 4% of all hospital admissions from the ED involve patients with potential strokes

7. Prognosis • Many pts present to ED with a ‘devastating neurological picture’ • Substantial improvement may occur over time, even in the absence of specific therapy • 20% of patients who survive the initial event eventually have full or partial resolution of hemiparesis

8. Risk of repeated stroke is highest within the first 30 days • 25-40% of patients will have a repeat stroke within 5 yrs • EMR Sept 29,1997. Stroke: Comprehensive Guidelines for Clinical Assessment and Emergency Management (Part 1)

9. Risk Factors • Hypertension-primary risk factor • Atrial fibrillation • Increasing age (particularly > 65) • Cigarette smoking • Diabetes • Black population • Hx of TIA • Male : Female 3:2

10. Stroke in the young Pt • 3-4% of strokes occur in people aged 15-45 • Sickle Cell anemia • Hypercoaguable states • Pregnancy, OCP use, antiphospholipid antibodies, protein C and S deficiencies • Drugs • Cocaine, phenylpropanolamine, amphetamines

11. Pathophysiology • Cerebral blood flow provides brain with oxygen and glucose for energy at rate of 40-60ml/100g of brain/min • When rate is <10ml/100g of brain/min cell membrane failure occurs: •  extracellular K,  intracellular Ca •  ATP, profound cellular acidosis • Cell death • Electrical ‘silence’

12. Pathophysiology:Ischemic penumbra • the area surrounding the primary injury • CBF is 10-18ml/100g of brain/min • Electrical silence but irreversible damage has not yet occurred • Animal studies: • reversible neurologic deficit if cerebral vessel occlusion lasts less than 2h • after 6h of occlusion: irreversible neurologic deficit • Thus the 2-6 hour therapeutic window for thrombolysis

13. Ischemic Hemorrhagic What are the types of stroke?

14. Ischemic Stroke • 85% of strokes • Thrombotic or Embolic • One month mortality: 15%

15. Ischemic: Thromboticlocal origin of clot • Usually develops at night during sleep • Symptoms perceived in morning • Suspect in hx of atherosclerosis, hypercoaguable states, and collagen vascular disorders

16. Ischemic: Embolicproximal origin of clot • Occurs at any time • Frequently during periods of vigorous activity • Hx of Atrial fibrillation, valvular vegetations, thromboembolism from MI, ulcerated plaques in carotid system • Seizures in 20% of cases

17. Hemorrhagic Stroke

18. Hemorrhagic Stroke • 15% of strokes • intracerebral hemorrhage > subarachnoid hemorrhage • Occur during stress or exertion • Focal deficits rapidly evolve • Confusion, coma or immediate death

19. Hemorrhagic • One month mortality: • 50% for SAH • 80% for intracerebral hemorrhage

20. Vascular Anatomy

21. Anterior Circulation From carotid system Supplies 80% of brain Posterior Circulation From vertebral system Supplies 20% of brain Cerebral Blood Supply

22. Internal carotid territory

23. Internal Carotid Artery • Anterior portion of the brain involving the frontal, temporal, and parietal lobes, is supplied by the carotid arteries (CA) • CA arises from the innominate artery on the right and aortic arch on the left. At level of upper neck CA branches into internal and external • the internal carotid artery terminates into the middle (MCA) and anterior (ACA) cerebral arteries • MCA perfuses the cortex, parietal lobe, temporal lobe, internal capsule, and portions of the basal ganglia • ACA forms the anterior portion of the circle of Willis and supplies portions of the frontal lobe

24. Carotid Artery • Approximately half of patients with moderate stenosis (greater than 50% occlusion) will have a carotid bruit • about 90% of patients with a carotid bruit have at least moderate stenosis • Wiebers D, Whisnant J, Sanok B, et al. Prospective comparison of a cohort with asymptomatic carotid bruit and a population-based cohort without carotid bruit. Stroke 1990;21:984-988. • Ingall T, Homer D, Whisnant J, et al. Predictive value of carotid bruit for carotid atherosclerosis. Arch Neurol. 1989;46:418-422

25. Vertebrobasilar System • Perfuses the posterior part of the brain including the occipital lobe, cerebellum, and brainstem • vertebral arteries arise from the subclavian arteries • give off branches supplying the medulla and portions of the cerebellum • basilar artery is formed by the junction of the two vertebral arteries and gives off a variety of penetrating arteries supplying the brainstem and portions of the basal ganglia before dividing into the posterior cerebral arteries

26. Vertebrobasilar System Posterior cerebral arteries Basilar artery Vertebral arteries

27. Stroke Patterns

28. Dominant Hemisphere • Majority of right handed and most left handed patients have dominance for speech and language located in the left hemisphere • Left hemisphere infarction is characterized by aphasia (both motor [Broca’s] and sensory [Wernicke’s]) and apraxia

29. Nondominant Hemisphere • Less predictable syndromes • Attention defects: extinction and neglect • Behavioral changes: acute confusion and delirium

30. Aphasia: Important? • Yes: usually localizes a lesion to the dominant cerebral cortex in the middle cerebral artery distribution • Rosen’s Emergency Medicine 5th edition • Aphasia and dysphasia are used interchangeably • Don’t confuse with Dysphagia

31. Case • 80 yr old male • Sudden onset right side hemiplegia, hemianesthesia • eyes deviated to left • “babbling”

32. MCA territory(image is of vascular territory, not specifically of previous case)

33. Middle Cerebral Artery

34. Middle Cerebral Artery • Embolism from ICA or heart to MCA is most common cause of cerebral infarction • Supplies most of the convex surface of brain • Deep tissue: basal ganglia, putamen, and parts of globus pallidus, caudate nucleus, and internal capsule

35. MCA stroke • Contralateral hemiplegia and hemianesthesia: arm and face > leg • Deviation of the head and eyes toward side of infarct “Gaze preference” • Global aphasia (in dominant hemisphere) • Hemianopia, Hemineglect

36. Case • 80 yr old female • Awoke with weakness in right leg • Slight right side weakness leg>arm • Family states she has “impaired judgment and insight” • “seems like a baby: sucking and grasping”

37. Anterior Cerebral Artery

38. Anterior Cerebral Artery • Supplies basal and medial aspects of the cerebral hemispheres • Extends to anterior two thirds of parietal lobe • Perforating branches supply anterior caudate nucleus, parts of internal capsule, putamen and anterior hypothalamus

39. Anterior Cerebral Artery Infarction • weakness of the leg • +/- proximal muscle weakness in the upper extremities • Affect frontal lobe: impaired judgment and insight, change in affect • Presence of primitive grasp and suck reflexes • Language impairment (common finding)

40. Case • 77 yr old male • Sudden onset of dizziness, double vision • On exam has pain and temp deficit on half of face and on opposite side of body

41. Posterior Circulation

42. Posterior Circulation/ Vertebrobasilar System • 2 Vertebral arteries  basilar artery posterior cerebral arteries • Supplies brainstem, cerebellum, thalamus, auditory and vestibular centers of the ear, visual occipital cortex

43. Vertebrobasilar System • Heterogeneous syndromes and presentations • Cranial nerve deficits and involvement of cerebellum and neurosensory tracts • diplopia, dysphagia, dysarthria, dizziness, vertigo, ataxia • pain and temp deficits in face occur on opposite side of body

44. Vertebrobasilar System • Thalamic lesions: sensory symptoms involving loss of tactile, temp, and pain sensation, ‘numbness’ on side of body opposite face • Occipital lesions: homonymous visual field defect (hemianopia or quadrantanopia)

45. Case • 85 yr old black male • Diabetic, hypertension • Sudden onset of being unable to move left side of body • Able to talk • Sensation intact

46. Lacunar Infarction • Lesion of small penetrating branch arteries into BG, thalamus, pons, internal capsule • “Pure” strokes • Motor, sensory, ataxic hemiparesis • Usually result in hemiparesis of face, arm and leg • Lack of impairment of consciousness, aphasia, or visual disturbances • More common in blacks and hx of HTN, DM • 60% of patients with lacunar infarctions will be independent at one year following stroke

47. Case • 85 yr old female • In ICU, post AAA rupture repair • GCS 15/15 • Complaining of difficulty moving her leg and that it feels numb

48. Watershed Infarction • occurs in vulnerable areas supplied by distal distribution cerebral arteries during periods of hypotension • infarction between the anterior and middle cerebral arteries presents with hemiparesis and hemianesthesia, predominantly in the leg • dominant hemisphere infarctions: decrease in verbal ability with preserved comprehension • Infarction involving the posterior watershed area presents with homonymous hemianopia +/- hypoesthesia in the face and legs

49. Case • 77 yr old male • Sudden onset headache, vomiting • went unresponsive • GCS 3/15, elevated BP • What has happened?

50. Hemorrhagic Stroke • Classic: sudden onset HA, vomiting, elevated BP • Focal neurologic deficits that progress over minutes • May present with agitation and lethargy but progresses to stupor or coma