Stroke 2010


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Stroke 2010

  1. 1. Stroke
  2. 2. Stroke <ul><li>Ischaemia is inadequate blood flow </li></ul><ul><li>Stroke occurs when there is ischaemia to a part of the brain that results in death of brain cells </li></ul>
  3. 3. Stroke <ul><li>Functions, such as movement, sensation, or emotions, that were controlled by the affected area of the brain are lost or impaired </li></ul><ul><li>Severity of the loss of function varies according to the location and extent of the brain involved </li></ul>
  4. 4. Stroke <ul><li>Third on list of top killers of New Zealanders behind heart disease and cancer </li></ul><ul><li>Approx 1/3 of those who have a stroke die as a result </li></ul><ul><li>Further 1/3 are left with disabilities </li></ul><ul><li>Predicted rise in number of strokes attributed to population that is growing & ageing </li></ul>
  5. 5. Risk Factors <ul><li>Most effective way to decrease the burden of stroke is prevention </li></ul><ul><li>Risk factors can be divided into non-modifiable and modifiable risks </li></ul>
  6. 6. Risk Factors Modifiable <ul><li>Hypertension </li></ul><ul><li>Obesity </li></ul><ul><li>Oral contraceptive use </li></ul><ul><li>Physical inactivity </li></ul><ul><li>Smoking </li></ul>
  7. 7. Risk Factors Nonmodifiable Modifiable <ul><li>Age </li></ul><ul><li>Gender </li></ul><ul><li>Race </li></ul><ul><li>Heredity </li></ul><ul><li>Asymptomatic carotid stenosis </li></ul><ul><li>Diabetes mellitus </li></ul><ul><li>Heart disease, atrial fibrillation </li></ul><ul><li>Heavy alcohol consumption </li></ul><ul><li>Hypercoagulability </li></ul><ul><li>Hyperlipidemia </li></ul>
  8. 8. Etiology and Pathophysiology <ul><li>Blood is supplied to the brain by 2 major pairs of arteries </li></ul><ul><ul><li>Internal carotid arteries </li></ul></ul><ul><ul><li>Vertebral arteries </li></ul></ul>
  9. 9. Etiology and Pathophysiology <ul><li>Carotid arteries branch to supply most of the </li></ul><ul><ul><li>Frontal, parietal, and temporal lobes </li></ul></ul><ul><ul><li>Basal ganglia </li></ul></ul><ul><ul><li>Part of the diencephalon </li></ul></ul><ul><ul><ul><li>Thalamus </li></ul></ul></ul><ul><ul><ul><li>Hypothalamus </li></ul></ul></ul>
  10. 10. Etiology and Pathophysiology <ul><li>Vertebral arteries join to form the basilar artery, which supply the </li></ul><ul><ul><li>Middle and lower temporal lobes </li></ul></ul><ul><ul><li>Occipital lobes </li></ul></ul><ul><ul><li>Cerebellum </li></ul></ul><ul><ul><li>Brainstem </li></ul></ul><ul><ul><li>Part of the diencephalon </li></ul></ul>
  11. 11. Etiology and Pathophysiology <ul><li>Cerebral arteries and the Circle of Willis </li></ul>
  12. 12. Etiology and Pathophysiology <ul><li>Brain requires a continuous supply of blood to provide the oxygen and glucose that neurons need to function </li></ul><ul><li>If blood flow to the brain is totally interrupted </li></ul><ul><ul><li>Neurologic metabolism is altered in 30 seconds </li></ul></ul><ul><ul><li>Metabolism stops in 2 minutes </li></ul></ul><ul><ul><li>Cellular death occurs in 5 minutes </li></ul></ul>
  13. 13. Etiology and Pathophysiology <ul><li>Brain is normally well protected from changes in mean systemic arterial blood pressure by a mechanism known as cerebral autoregulation </li></ul>
  14. 14. Etiology and Pathophysiology <ul><li>Cerebral autoregulation involves </li></ul><ul><ul><li>Changes in the diameter of cerebral blood vessels in response to changes in pressure so that the blood flow to the brain stays constant </li></ul></ul>
  15. 15. Etiology and Pathophysiology <ul><li>Factors that affect blood flow to the brain </li></ul><ul><ul><li>Systemic blood pressure </li></ul></ul><ul><ul><li>Cardiac output </li></ul></ul><ul><ul><li>Blood viscosity </li></ul></ul>
  16. 16. Etiology and Pathophysiology <ul><li>Collateral circulation may develop to compensate for a decrease in cerebral blood flow </li></ul><ul><li>An area of the brain can potentially receive blood supply from another blood vessel if its original blood supply is cut off </li></ul>
  17. 17. Etiology and Pathophysiology <ul><li>Atherosclerosis is the hardening and thickening of arteries and is a major cause of stroke </li></ul><ul><li>It can lead to thrombus formation and contribute to emboli </li></ul>
  18. 18. Etiology and Pathophysiology <ul><li>Around the core area of ischemia is a border zone of reduced blood flow where ischemia is potentially reversible </li></ul>
  19. 19. Etiology and Pathophysiology <ul><li>If adequate blood flow can be restored early (<3 hours) and the ischemic cascade can be interrupted, </li></ul><ul><ul><li>less brain damage and less neurologic function lost </li></ul></ul>
  20. 20. Etiology and Pathophysiology <ul><li>Transient ischemic attack (TIA) is a temporary focal loss of neurologic function caused by ischemia </li></ul><ul><li>Most TIAs resolve within 3 hours </li></ul>
  21. 21. Etiology and Pathophysiology <ul><li>TIAs may be due to microemboli that temporarily block the blood flow </li></ul><ul><li>TIAs are a warning sign of progressive cerebrovascular disease </li></ul>
  22. 22. Types of Stroke <ul><li>Strokes are classified based on the underlying pathophysiologic findings </li></ul><ul><ul><li>Ischaemic </li></ul></ul><ul><ul><li>Haemorrhagic </li></ul></ul>
  23. 23. Ischaemic Stroke <ul><li>Ischaemic strokes result from inadequate blood flow to the brain from partial or complete occlusion of an artery </li></ul><ul><li>85% of all strokes are ischaemic strokes </li></ul>
  24. 24. Ischemic Stroke <ul><li>Ischaemic strokes can be </li></ul><ul><ul><li>Thrombotic </li></ul></ul><ul><ul><li>Embolic </li></ul></ul><ul><li>Most patients with ischaemic stroke do not have a decreased level of consciousness in the first 24 hours </li></ul><ul><li>May progress in the first 72 hours </li></ul>
  25. 25. Ischaemic Stroke <ul><li>Thrombotic stroke </li></ul><ul><ul><li>Thrombosis occurs in relation to injury to a blood vessel wall and formation of a blood clot </li></ul></ul><ul><ul><li>Result of thrombosis or narrowing of the blood vessel </li></ul></ul><ul><ul><li>Most common cause of stroke </li></ul></ul>
  26. 26. Ischaemic Stroke
  27. 27. Ischaemic Stroke
  28. 28. Ischaemic Stroke <ul><li>Thrombotic stroke </li></ul><ul><ul><li>Two-thirds are associated with hypertension and diabetes mellitus </li></ul></ul><ul><ul><li>Often preceded by a TIA </li></ul></ul>
  29. 29. Ischaemic Stroke <ul><li>Embolic stroke </li></ul><ul><ul><li>Occur when an embolus lodges in and occludes a cerebral artery </li></ul></ul><ul><ul><li>Results in infarction and oedema of the area supplied by the involved vessel </li></ul></ul><ul><ul><li>Second most common cause of stroke </li></ul></ul>
  30. 30. Ischaemic Stroke <ul><li>Embolic stroke </li></ul><ul><ul><li>Majority of emboli originate in the inside layer of the heart, with plaque breaking off from the endocardium and entering the circulation </li></ul></ul><ul><ul><li>Patient with an embolic stroke commonly has a rapid occurrence of severe clinical symptoms </li></ul></ul>
  31. 31. Embolic Stroke
  32. 32. Ischaemic Stroke <ul><li>Embolic stroke </li></ul><ul><ul><li>Onset of an embolic stroke is usually sudden and may or may not be related to activity </li></ul></ul><ul><ul><li>Patient usually remains conscious although may have a headache </li></ul></ul>
  33. 33. Ischaemic Stroke <ul><li>Embolic stroke </li></ul><ul><ul><li>Often occurs rapidly </li></ul></ul><ul><ul><li>Recurrence is common unless the underlying cause is aggressively treated </li></ul></ul>
  34. 34. Hemorrhagic Stroke <ul><li>Account for approximately 15% of all strokes </li></ul><ul><li>Result from bleeding into the brain tissue itself or into the subarachnoid space or ventricles </li></ul>
  35. 35. Hemorrhagic Stroke <ul><li>Intracerebral hemorrhage </li></ul><ul><ul><li>Bleeding within the brain caused by a rupture of a vessel </li></ul></ul><ul><ul><li>Hypertension is the most important cause </li></ul></ul><ul><ul><li>Haemorrhage commonly occurs during periods of activity </li></ul></ul>
  36. 36. Intracerebral Haemorrhage
  37. 37. Hemorrhagic Stroke <ul><li>Intracerebral haemorrhage </li></ul><ul><ul><li>Often a sudden onset of symptoms, with progression over minutes to hours because of ongoing bleeding </li></ul></ul>
  38. 38. Hemorrhagic Stroke <ul><li>Intracerebral haemorrhage </li></ul><ul><ul><li>Manifestations include neurologic deficits, headache, nausea, vomiting, decreased levels of consciousness, and hypertension </li></ul></ul>
  39. 39. Hemorrhagic Stroke <ul><li>Subarachnoid haemorrhage </li></ul><ul><ul><li>Occurs when there is intracranial bleeding into cerebrospinal fluid-filled space between the arachnoid and pia mater </li></ul></ul><ul><ul><li>Commonly caused by rupture of a cerebral aneurysm </li></ul></ul>
  40. 40. Subarachnoid Stroke
  41. 41. Stroke – Part B
  42. 42. Clinical Manifestations <ul><li>Affects many body functions </li></ul><ul><ul><ul><li>Motor activity </li></ul></ul></ul><ul><ul><ul><li>Elimination </li></ul></ul></ul><ul><ul><ul><li>Intellectual function </li></ul></ul></ul><ul><ul><ul><li>Spatial-perceptual alterations </li></ul></ul></ul><ul><ul><ul><li>Personality </li></ul></ul></ul><ul><ul><ul><li>Affect </li></ul></ul></ul><ul><ul><ul><li>Sensation </li></ul></ul></ul><ul><ul><ul><li>Communication </li></ul></ul></ul>
  43. 43. Clinical Manifestations <ul><li>Brain attack </li></ul><ul><ul><li>Term increasingly being used to describe stroke and communicate urgency of recognizing stroke symptoms and treating their onset as a medical emergency </li></ul></ul>
  44. 44. Clinical Manifestations Motor Function <ul><li>Most obvious effect of stroke </li></ul><ul><li>Include impairment of </li></ul><ul><ul><li>Mobility </li></ul></ul><ul><ul><li>Respiratory function </li></ul></ul><ul><ul><li>Swallowing and speech </li></ul></ul><ul><ul><li>Gag reflex </li></ul></ul><ul><ul><li>Self-care abilities </li></ul></ul>
  45. 45. Clinical Manifestations Motor Function <ul><li>Characteristic motor deficits </li></ul><ul><ul><li>Loss of skilled voluntary movement </li></ul></ul><ul><ul><li>Impairment of integration of movements </li></ul></ul><ul><ul><li>Alterations in muscle tone </li></ul></ul><ul><ul><li>Alterations in reflexes </li></ul></ul>
  46. 46. Clinical Manifestations Motor Function <ul><li>An initial period of flaccidity may last from days to several weeks and is related to nerve damage </li></ul><ul><li>Spasticity of the muscles follows the flaccid stage and is related to interruption of upper motor neuron influence </li></ul>
  47. 47. Clinical Manifestations Communication <ul><li>Patient may experience aphasia when a stroke damages the dominant hemisphere of the brain </li></ul><ul><ul><li>Aphasia is a total loss of comprehension and use of language </li></ul></ul>
  48. 48. Clinical Manifestations Communication <ul><li>Dysphasia refers to difficulty related to the comprehension or use of language and is due to partial disruption or loss </li></ul><ul><li>Dysphasia can be classified as nonfluent or fluent </li></ul>
  49. 49. Clinical Manifestations Communication <ul><li>Many patients also experience dysarthria </li></ul><ul><ul><li>Disturbance in the muscular control of speech </li></ul></ul><ul><li>Impairments may involve pronunciation, articulation, and phonation </li></ul>
  50. 50. Clinical Manifestations Communication <ul><li>Dysarthria does not affect the meaning of communication or the comprehension of language </li></ul><ul><li>It does affect the mechanics of speech </li></ul>
  51. 51. Clinical Manifestations Affect <ul><li>Patients who suffer a stroke may have difficulty controlling their emotions </li></ul><ul><li>Emotional responses may be exaggerated or unpredictable </li></ul>
  52. 52. Clinical Manifestations Affect <ul><li>Depression and feelings associated with changes in body image and loss of function can make this worse </li></ul><ul><li>Patients may also be frustrated by mobility and communication problems </li></ul>
  53. 53. Clinical Manifestations Intellectual Function <ul><li>Both memory and judgment may be impaired as a result of stroke </li></ul><ul><li>A left-brain stroke is more likely to result in memory problems related to language </li></ul>
  54. 54. Clinical Manifestations Spatial-Perceptual Alterations <ul><li>Stroke on the right side of the brain is more likely to cause problems in spatial-perceptual orientation </li></ul><ul><li>However, this may occur with left-brain stroke </li></ul>
  55. 55. Spatial & Perceptual Deficits in stroke <ul><li>Food on the left side is not seen and thus is ignored </li></ul>
  56. 56. Clinical Manifestations Spatial-Perceptual Alterations <ul><li>Spatial-perceptual problems may be divided into 4 categories </li></ul><ul><ul><li>Incorrect perception of self and illness </li></ul></ul><ul><ul><li>Erroneous perception of self in space </li></ul></ul><ul><ul><li>Inability to recognize an object by sight, touch, or hearing (agnosia) </li></ul></ul><ul><ul><li>4. Inability to carry out learned sequential movements on command (apraxia) </li></ul></ul>
  57. 57. Clinical Manifestations Elimination <ul><li>Most problems with urinary and bowel elimination occur initially and are temporary </li></ul><ul><li>When a stroke affects one hemisphere of the brain, the prognosis for normal bladder function is excellent </li></ul>
  58. 58. Clinical Manifestations Right and Left Brain Damage
  59. 59. <ul><li>Aphasia </li></ul>