Stroke

Stroke (cerebral infarction) is the acute development of a focal neurological deficit caused by disruption of the blood supply to an area of the brain, lasting more than 24 hours.

Classification:

• Ischaemic (87%) - hypoperfusion due to occlusion of a blood vessel, or other cause
  • TOAST classification of aetiology
    • Cardioembolic
    • Large vessel disease
    • Small vessel disease
    • Unusual causes
    • Undetermined aetiology
  • Around 20% are probably related to carotid atherosclerosis
  • Lacunar infarcts:
    • Small subcortical infarcts that result from presumed occlusion of a single penetrating artery of the brain
• Haemorrhagic - rupture of a blood vessel
  • Intra-cerebral haemorrhage (bleeding within brain parenchyma)
  • Subarachnoid haemorrhage
• Stroke: >24 hours
• TIA: <24 hours of symptoms
  • Note that many patients, although functionally back to baseline, do have neurological cell death (25% demonstrable on CT)
  • Consider it a warning sign for future stroke - 30% go on to have a stroke in five years
    • Risk factors for future stroke would be age >60 years, DM, presence of focal symptoms, and TIAs lasting longer than 10 minutes

Ischaemic stroke

Risk factors:

• Male sex
• Age - for each decade >55, risk of stroke doubles
• Race - black
• HTN
• FHx
• AF
• Smoking
• Hchol
• Physical activity
• Diabetes
• Obesity
• Diet
• Alcohol heavy
• Renal insufficiency

Outcome of stroke

• Recurrence:
  • 2% at 7 days
  • 4% at 30 days
  • 12% at one year
  • 29% at five years
• Recurrence in setting of symptomatic carotid disease:
  • 26% over two years

Craniotomes:

• Carotid (anterior circulation):
  • Contralateral sensorimotor loss
    • Can range from mild hemiparesis to complete hemiparesis
    • Sensory deficits can be mild numbness or complete paraesthesia
  • Speech deficit
    • Dysarthria - deficiency in muscles for speech
    • Dysphasia - deficiency in generation of speech
    • Aphasia
  • Ipsilateral monocular blindness
    • Amaurosis fugax (emboli to retinal artery via ophthalmic artery) is the classic sign of TIA related to carotid lesions
• Posterior circulation (vertebral arteries):
  • Dizziness
  • Difficulty focusing visually
  • Loss of balance
• Cerebellum:
  • Vertigo
  • Vomiting
  • Blurred vision
  • Difficulty walking
• Lacunar infarcts can present as one of the following:
  • Pure motor hemiparesis
  • Pure sensory syndrome
  • Sensorimotor syndrome
  • Ataxic hemiparesis
  • Dysarthria-clumsy hand syndrome

Prevention:

• Statins for:
  • LDL >4.1
  • Males >45 and females >55 with following risk factors:
    • Positive family history
    • Smoking
    • HTN
    • LVH

Treatment of acute stroke

• Most often supportive and medical