Stroke occurs when there is inadequate blood flow to the brain resulting in cell death. It is a leading cause of death and disability. There are two main types - ischemic caused by clots or blockages cutting off blood flow, and hemorrhagic caused by bleeding within or around the brain. Strokes cause deficits varying by location but often involve motor, communication, cognitive and emotional impairments. Risk factors include hypertension, smoking, obesity, age, and heredity.

1. Stroke

2. Stroke Ischaemia is inadequate blood flow Stroke occurs when there is ischaemia to a part of the brain that results in death of brain cells

3. Stroke Functions, such as movement, sensation, or emotions, that were controlled by the affected area of the brain are lost or impaired Severity of the loss of function varies according to the location and extent of the brain involved

4. Stroke Third on list of top killers of New Zealanders behind heart disease and cancer Approx 1/3 of those who have a stroke die as a result Further 1/3 are left with disabilities Predicted rise in number of strokes attributed to population that is growing & ageing

5. Risk Factors Most effective way to decrease the burden of stroke is prevention Risk factors can be divided into non-modifiable and modifiable risks

6. Risk Factors Modifiable Hypertension Obesity Oral contraceptive use Physical inactivity Smoking

7. Risk Factors Nonmodifiable Modifiable Age Gender Race Heredity Asymptomatic carotid stenosis Diabetes mellitus Heart disease, atrial fibrillation Heavy alcohol consumption Hypercoagulability Hyperlipidemia

8. Etiology and Pathophysiology Blood is supplied to the brain by 2 major pairs of arteries Internal carotid arteries Vertebral arteries

9. Etiology and Pathophysiology Carotid arteries branch to supply most of the Frontal, parietal, and temporal lobes Basal ganglia Part of the diencephalon Thalamus Hypothalamus

10. Etiology and Pathophysiology Vertebral arteries join to form the basilar artery, which supply the Middle and lower temporal lobes Occipital lobes Cerebellum Brainstem Part of the diencephalon

11. Etiology and Pathophysiology Cerebral arteries and the Circle of Willis

12. Etiology and Pathophysiology Brain requires a continuous supply of blood to provide the oxygen and glucose that neurons need to function If blood flow to the brain is totally interrupted Neurologic metabolism is altered in 30 seconds Metabolism stops in 2 minutes Cellular death occurs in 5 minutes

13. Etiology and Pathophysiology Brain is normally well protected from changes in mean systemic arterial blood pressure by a mechanism known as cerebral autoregulation

14. Etiology and Pathophysiology Cerebral autoregulation involves Changes in the diameter of cerebral blood vessels in response to changes in pressure so that the blood flow to the brain stays constant

15. Etiology and Pathophysiology Factors that affect blood flow to the brain Systemic blood pressure Cardiac output Blood viscosity

16. Etiology and Pathophysiology Collateral circulation may develop to compensate for a decrease in cerebral blood flow An area of the brain can potentially receive blood supply from another blood vessel if its original blood supply is cut off

17. Etiology and Pathophysiology Atherosclerosis is the hardening and thickening of arteries and is a major cause of stroke It can lead to thrombus formation and contribute to emboli

18. Etiology and Pathophysiology Around the core area of ischemia is a border zone of reduced blood flow where ischemia is potentially reversible

19. Etiology and Pathophysiology 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

20. Etiology and Pathophysiology Transient ischemic attack (TIA) is a temporary focal loss of neurologic function caused by ischemia Most TIAs resolve within 3 hours

21. Etiology and Pathophysiology TIAs may be due to microemboli that temporarily block the blood flow TIAs are a warning sign of progressive cerebrovascular disease

22. Types of Stroke Strokes are classified based on the underlying pathophysiologic findings Ischaemic Haemorrhagic

23. Ischaemic Stroke Ischaemic strokes result from inadequate blood flow to the brain from partial or complete occlusion of an artery 85% of all strokes are ischaemic strokes

24. Ischemic Stroke Ischaemic strokes can be Thrombotic Embolic Most patients with ischaemic stroke do not have a decreased level of consciousness in the first 24 hours May progress in the first 72 hours

25. Ischaemic Stroke Thrombotic stroke Thrombosis occurs in relation to injury to a blood vessel wall and formation of a blood clot Result of thrombosis or narrowing of the blood vessel Most common cause of stroke

26. Ischaemic Stroke

27. Ischaemic Stroke

28. Ischaemic Stroke Thrombotic stroke Two-thirds are associated with hypertension and diabetes mellitus Often preceded by a TIA

29. Ischaemic Stroke Embolic stroke Occur when an embolus lodges in and occludes a cerebral artery Results in infarction and oedema of the area supplied by the involved vessel Second most common cause of stroke

30. Ischaemic Stroke Embolic stroke Majority of emboli originate in the inside layer of the heart, with plaque breaking off from the endocardium and entering the circulation Patient with an embolic stroke commonly has a rapid occurrence of severe clinical symptoms

31. Embolic Stroke

32. Ischaemic Stroke Embolic stroke Onset of an embolic stroke is usually sudden and may or may not be related to activity Patient usually remains conscious although may have a headache

33. Ischaemic Stroke Embolic stroke Often occurs rapidly Recurrence is common unless the underlying cause is aggressively treated

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

35. Hemorrhagic Stroke Intracerebral hemorrhage Bleeding within the brain caused by a rupture of a vessel Hypertension is the most important cause Haemorrhage commonly occurs during periods of activity

36. Intracerebral Haemorrhage

37. Hemorrhagic Stroke Intracerebral haemorrhage Often a sudden onset of symptoms, with progression over minutes to hours because of ongoing bleeding

38. Hemorrhagic Stroke Intracerebral haemorrhage Manifestations include neurologic deficits, headache, nausea, vomiting, decreased levels of consciousness, and hypertension

39. Hemorrhagic Stroke Subarachnoid haemorrhage Occurs when there is intracranial bleeding into cerebrospinal fluid-filled space between the arachnoid and pia mater Commonly caused by rupture of a cerebral aneurysm

40. Subarachnoid Stroke

41. Stroke – Part B

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

43. Clinical Manifestations Brain attack Term increasingly being used to describe stroke and communicate urgency of recognizing stroke symptoms and treating their onset as a medical emergency

44. Clinical Manifestations Motor Function Most obvious effect of stroke Include impairment of Mobility Respiratory function Swallowing and speech Gag reflex Self-care abilities

45. Clinical Manifestations Motor Function Characteristic motor deficits Loss of skilled voluntary movement Impairment of integration of movements Alterations in muscle tone Alterations in reflexes

46. Clinical Manifestations Motor Function An initial period of flaccidity may last from days to several weeks and is related to nerve damage Spasticity of the muscles follows the flaccid stage and is related to interruption of upper motor neuron influence

47. Clinical Manifestations Communication Patient may experience aphasia when a stroke damages the dominant hemisphere of the brain Aphasia is a total loss of comprehension and use of language

48. Clinical Manifestations Communication Dysphasia refers to difficulty related to the comprehension or use of language and is due to partial disruption or loss Dysphasia can be classified as nonfluent or fluent

49. Clinical Manifestations Communication Many patients also experience dysarthria Disturbance in the muscular control of speech Impairments may involve pronunciation, articulation, and phonation

50. Clinical Manifestations Communication Dysarthria does not affect the meaning of communication or the comprehension of language It does affect the mechanics of speech

51. Clinical Manifestations Affect Patients who suffer a stroke may have difficulty controlling their emotions Emotional responses may be exaggerated or unpredictable

52. Clinical Manifestations Affect Depression and feelings associated with changes in body image and loss of function can make this worse Patients may also be frustrated by mobility and communication problems

53. Clinical Manifestations Intellectual Function Both memory and judgment may be impaired as a result of stroke A left-brain stroke is more likely to result in memory problems related to language

54. Clinical Manifestations Spatial-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

55. Spatial & Perceptual Deficits in stroke Food on the left side is not seen and thus is ignored

56. Clinical Manifestations Spatial-Perceptual Alterations Spatial-perceptual problems may be divided into 4 categories Incorrect perception of self and illness Erroneous perception of self in space Inability to recognize an object by sight, touch, or hearing (agnosia) 4. Inability to carry out learned sequential movements on command (apraxia)

57. Clinical Manifestations Elimination Most problems with urinary and bowel elimination occur initially and are temporary When a stroke affects one hemisphere of the brain, the prognosis for normal bladder function is excellent

58. Clinical Manifestations Right and Left Brain Damage

59. Aphasia http://www.strokecenter.org/pat/aphasia.html