STROKE

1. STROKE a.k.a. Cerebrovascular Accident (CVA) & Brain Attack

2. Stroke • Ischemia is inadequate blood flow • Occurs when ischemia to part of the brain results in death of brain cells

3. Stroke • Movement, sensation, or emotions controlled by affected area are lost or impaired • Loss of function varies with location and extent of damage

4. Stroke • Brain attack • Term increasingly being used to describe stroke and communicate urgency of recognizing stroke symptoms and treating their onset as a medical emergency

5. Risk FactorsNonmodifiable • Age • Gender (women more likely to die) • Race (African Americans) • Heredity

6. Risk FactorsModifiable • Asymptomatic carotid stenosis • Diabetes mellitus • Heart disease, atrial fibrillation • Heavy alcohol consumption • Hypercoagulability • Hyperlipidemia

7. Risk FactorsModifiable • Hypertension • Obesity • Oral contraceptive use • Physical inactivity • Sickle cell disease • Smoking

8. Etiology and Pathophysiology • Brain requires continuous supply of O2 and glucose for neurons to function • If blood flow is interrupted • Neurologic metabolism is altered in 30 seconds • Metabolism stops in 2 minutes • Cell death occurs in 5 minutes

9. Etiology and Pathophysiology • Atherosclerosis is a major cause of stroke • Can lead to thrombus formation and contribute to emboli

10. Sites for Atherosclerosis Fig. 56-2

11. Etiology and Pathophysiology • Around the core area of ischemia is a border zone of reduced blood flow where ischemia is potentially reversible • If adequate blood flow can be restored early (<3 hours) and the ischemic cascade can be interrupted • less brain damage and less neurologic function lost

12. Transient Ischemic Attacks (TIA) • Temporary focal loss of neurologic function caused by ischemia (analogous to angina in CAD) • Most resolve within 3 hours • May be due to micro-emboli that temporarily block blood flow • A warning sign of progressive cerebrovascular disease

13. Types of Stroke • Classification based on underlying pathophysiologic findings • Ischemic • Thrombotic • Embolic • Hemorrhagic

14. Major Types of Stroke Fig. 56-3

15. Ischemic Stroke • Result of inadequate blood flow to brain due to partial or complete occlusion of an artery • Constitute 85% of all strokes • Most patients with ischemic stroke do not have a decreased level of consciousness in the first 24 hours • Symptoms often worsen during first 72 hours d/t cerebral edema

16. Ischemic Stroke • Thrombotic stroke • Thrombosis occurs in relation to injury to a blood vessel wall → blood clot • Result of thrombosis or narrowing of the blood vessel • Most common cause of stroke

17. Ischemic Stroke • Thrombotic stroke • Two-thirds are associated with HTN and diabetes • Often preceded by a TIA

18. Ischemic Stroke • Embolic stroke • Embolus lodges in and occludes a cerebral artery • Results in infarction and edema of the area supplied by the vessel • Second most common cause of stroke

19. Ischemic Stroke • Embolic stroke • Majority of emboli originate in heart, with plaque breaking off from the endocardium and entering circulation • Associated with sudden, rapid occurrence of severe clinical symptoms

20. Ischemic Stroke • Embolic stroke • Patient usually remains conscious although may have a headache • Recurrence is common unless the underlying cause is aggressively treated

21. Hemorrhagic Stroke • Account for approximately 15% of all strokes • Result from bleeding into the brain tissue itself or into the subarachnoid space or ventricles

22. Hemorrhagic Stroke • Intracerebral hemorrhage • Bleeding within the brain caused by a rupture of a vessel • Hypertension is the most important cause • Commonly occurs during activity

23. Hemorrhagic Stroke • Intracerebral hemorrhage • Often a sudden onset of symptoms that progress over minutes to hours b/c of ongoing bleeding • Manifestations include neurologic deficits, headache, N & V, decreased levels of consciousness, and HTN

24. Hemorrhagic Stroke • Subarachnoid hemorrhage • Bleeding into cerebrospinal space between the arachnoid and pia mater • Commonly caused by rupture of a cerebral aneurysm

25. Clinical Manifestations of Stroke • Affects many body functions • Motor activity • Elimination • Intellectual function • Spatial-perceptual alterations • Personality • Affect • Sensation • Communication

26. Clinical ManifestationsMotor Function • Most obvious effect of stroke • Can include impairment of • Mobility • Respiratory function • Swallowing and speech • Gag reflex • Self-care abilities

27. Clinical ManifestationsMotor Function • Characteristic motor deficits (contra-lateral) • Loss of skilled voluntary movement • Impairment of integration of movements • Alterations in muscle tone (flaccid → spastic) • Alterations in reflexes (hypo → hyper)

28. Clinical ManifestationsCommunication • Patient may experience aphasia when stroke damages the dominant hemisphere of the brain • Aphasia: total loss of comprehension and use of language • Dysphasia: difficulty with comprehension and use of language • Classified as nonfluent or fluent

29. Clinical ManifestationsCommunication • Dysarthria • Disturbance in the muscular control of speech • Impairments in pronunciation, articulation, and phonation; NOT meaning or comprehension

30. Clinical ManifestationsAffect • May have difficulty controlling their emotions • Emotional responses may be exaggerated or unpredictable • Depression , impaired body image and loss of function can make this worse • May be frustrated by mobility and communication problems

31. Clinical ManifestationsIntellectual Function • Memory and judgment may be impaired • Left-brain stroke: more likely to result in memory problems related to language

32. Manifestations of Right-Brain and Left-Brain Stroke Fig. 56-6

33. Clinical ManifestationsSpatial-Perceptual Alterations • Stroke on the right side of the brain is more likely to cause problems in spatial-perceptual orientation • However, this may occur with left-brain stroke

34. Clinical ManifestationsSpatial-Perceptual Alterations • Spatial-perceptual problems may be divided into four categories • Incorrect perception of self and illness (may deny illness or body parts) • Erroneous perception of self in space (e.g., neglect all input from affected side; distance judgement)

35. Clinical ManifestationsSpatial-Perceptual Alterations • Inability to recognize an object by sight, touch, or hearing • Inability to carry out learned sequential movements on command

36. Clinical ManifestationsElimination • Most problems with elimination occur initially and are temporary • Prognosis for normal bladder function is excellent when only one hemisphere of brain is affected.

37. Diagnostic Studies • When symptoms of a stroke occur, diagnostic studies are done to • Confirm that it is a stroke • Identify the likely cause of the stroke • CT is the primary diagnostic test used after a stroke

38. Collaborative CarePrevention • Education and management of modifiable risk factors to prevent a stroke • Close management of patients with known risk factors

39. Collaborative CarePrevention • Antiplatelet drugs (usually Aspirin) to prevent stroke in those with history of TIA

40. Collaborative CarePrevention • Surgical interventions for those with TIAs from carotid disease: • Carotid endarterectomy • Transluminal angioplasty • Stenting • Extracranial-intracranial bypass

41. Add Figure 56-7, p. 1533

42. Collaborative CareAcute Care • Assessment findings • Altered level of consciousness (See GCS, p. 1500) • Weakness, numbness, or paralysis • Speech or visual disturbances • Severe headache • ↑ or ↓ heart rate • Respiratory distress • Unequal pupils

43. Collaborative CareAcute Care • Assessment findings • Hypertension • Facial drooping on affected side • Difficulty swallowing • Seizures • Bladder or bowel incontinence • Nausea and vomiting • Vertigo

44. Collaborative CareAcute Care • Interventions – Initial: ABC • Ensure patient airway • Remove dentures • Perform pulse oximetry • Maintain adequate oxygenation • IV access • Maintain BP according to guidelines • (treat if SBP > 220 or MAP > 130)

45. Collaborative CareAcute Care • Interventions – Initial • Immediate CT scan to determine cause (ischemic vs hemorrhagic) • Measures to control ICP • Head & neck in alignment (avoid flexion) • Elevate HOB 30 ° if no symptoms of shock or injury • Avoid hip, knee flexion • Pain management, euvolemia, diuretics if needed

46. Collaborative CareAcute Care • Interventions – Initial • Institute seizure precautions • Avoid hyperthermia ( ↑s cerebral metabolism) • Anticipate thrombolytic/fibrinolytic therapy for ischemic stroke

47. Collaborative CareAcute Care • Thrombolytic/fibrinolytic therapy with recombinant tissue plasminogen activator (tPA) is used to • Reestablish blood flow and prevent cell death in patients of ischemic stroke

48. Collaborative CareAcute Care • Thrombolytic/fibrinolytic therapy given within 3 hours of the onset of symptoms • ↓ disability • But at the expense of ↑ in deaths within the first 7 to 10 days and ↑ in intracranial hemorrhage

49. Collaborative CareAcute Care • For ischemic strokes (24 hr after tPA): • Antiplatelets • Anticoagulants (Heparin, coumadin) • Must maintain therapeutic levels • PTT, INR

50. Collaborative CareAcute Care • Interventions – Ongoing • Monitor vital signs and neurologic status • Level of consciousness • Motor and sensory function • Pupil size and reactivity • O2 saturation • Cardiac rhythm