Anatomy and patho

• Cerebrovascular accident (stroke or brain attack) is the 5th most common cause of death in Canada. The most effective way to decrease this burden is with prevention
• Stroke occurs when there is ischemia to a part of the brain OR hemorrhage into the brain that results in death of brain cells
• Functions controlled by the part of the brain with tissue death (left or right) are lost or impaired (eg: movement, sensation, emotions). The severity of the loss varies according to location and extent of the brain involved
• The most common location for stroke is the middle cerebral artery. Other locations include the internal carotid artery or the vertebral artery.
• Non modifiable factors

  • advanced age
  • gender
  • ethnicity
  • family history
  • prior TIA or stroke
• Modifiable risk factors:

  • HTN
  • diabetes mellitus
  • atrial fibrillation
  • dyslipidemia
  • carotid stenosis
  • oral contraceptive use
  • smoking
• Transient ischemic attack (TIA) is a transient episode of neurological dysfunction without acute infarction (cell death) of the brain. Symptoms typically last less than an hour but is a big risk factor for strokes
• Types of stroke

  1. ischemic: can be thrombotic (clot formed in brain) or embolic (clot travels to brain)
  2. hemorrhagic (bleeding in brain)
• Thrombotic strokes occur when a thrombus (blood clot) forms in diseased and narrowed blood vessel in the brain. It is often associated with HTN or diabetes
• Embolic strokes occur when an embolus lodges in and occludes a cerebral artery. Heart conditions associated with emboli are atrial fibrillation and valvular prostheses
• Hemorrhagic strokes result from bleeding into the brain tissue itself or into the subarachnoid space or ventricles. This happens through a cerebral artery aneurysm that bursts and releases blood
• Hemorrhagic strokes are classified according to where the bleed is located. For examples a subarachnoid stroke is a bleed over the arachnoid meninge.
• Stroke clinical manifestations

  • hemiplegia (paralysis) or hemiparesis (weakness)
  • impaired swallowing or gag reflex = dysphagia
  • numbness of face, arm or leg
  • visual disturbance = hemianopsia (loss of half the visual field)
• The left side of the brain sees te right side of the world meaning that if the left side of the brain is damaged, your right visual field is affected
• Stroke patients may experience aphasia (understanding) or dysarthria (speech) when a stroke damages the dominant hemisphere of the brain
• Impaired communication

  • Broca’s aphasia: difficulty in expressing thoughts
  • Wernicke’s aphasia: difficulty understanding language
  • Dysarthria: disturbance of muscular control of speech
• Intellectual clinical manifestations

  • difficulty controlling their emotions
  • exaggerated or unpredictable emotional responses
  • impaired memory or judgement
  • spatial perceptual: difficulty judging distances or neglect
• Stroke pts may initially have urinary and bowel elimination problems
• Motor deficits are contralateral (opposite) because motor pathways cross at the brain stem. A stroke affecting the left side of the brain will lead to motor deficits on the right side
• Right brain damage manifestations

  • left side hemiplegia or neglect
  • spatial perceptual deficits
  • deny or minimize problems
  • rapid performance and short attention span
  • impulsive and impaired judgement
  • impaired time concepts
• Left brain damage manifestations

  • right side hemiplegia
  • aphasias
  • slow performance, cautious
  • aware of deficits = depression and anxiety
  • impaired math and language comprehension
  • impaired right left discrimination