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Stroke

Definition

Damage or dysfunction to part of the brain, as a result of ischaemia (clot or haemorrhage)

 

Risk factors

  • Hypertension
  • Age
  • Atherosclerosis
  • AF
  • Structural cardiac abnormalities (eg septal defect – allows clots easy access from body to brain, without passing through ‘filter’ of pulmonary capillaries
  • Diabetes
  • Genetic predisposition (family members with stroke or CVD at young age)
  • Overweight/obesity
  • Smoking
  • Inactivity
  • Excess alcohol (low/moderate intake may be protective)
  • Previous stroke or TIA
  • Low SES
  • Recreational drugs – cocaine and amphetamines
  • COCP, HRT
  • Migraine (even higher risk if have aura: 6x)
  • Thrombophilia

 

Differential diagnoses

  • TIA
  • Haemorrhage
  • Dementia
  • Migraine (hemiplegic or not)
  • Headache disorder (eg cluster headache)
  • Brain tumour
  • Epilepsy
  • Aortic dissection
  • Spinal cord injury
  • Brain trauma
  • MS
  • Encephalopathy
    • Hepatitis
    • Accelerated hypertension

 

Epidemiology

  • One of the leading causes of death, especially in western countries
  • Increased incidence with age
  • Slightly more common in men, but more severe and disabling in women
  • More common in Black and Hispanic people
  • Worldwide

 

Aetiology

  • Ischaemic stroke – account for about 85% of strokes:
    • Thrombus occludes an artery supplying part of the brain
      • Could be arterial in origin
      • Cardiac in origin
      • Result of different disease process
    • Ischemia and hypoxic damage from lack of blood supply
    • Most common artery = middle cranial artery
  • Haemorrhagic stroke – accounts for about 15% of strokes:
    • Intercerebral haemorrhage of cerebral arteries or their branches
    • Results in ischaemia to downstream areas, and damage to surrounding areas by compression from haematoma

 

Clinical features

  • Sudden onset
  • Focal neurological deficits
    • Hemiparesis/motor deficit
    • Paraesthesia/sensory deficit
  • Homonymous hemianopia
  • Higher cognitive dysfunction
    • Aphasia
    • Confusion
  • Loss of consciousness
  • Headache is rare, more common in haemorrhagic
  • Bamford/Oxford stroke classification:
    • TACS (Total Anterior Circulation Stroke), ACA or MCA = all 3 of:
      • Unilateral weakness and/or sensory deficit in arm, leg AND face
      • Homonymous hemianopia
      • Higher cerebral dysfunction (eg dysphasia, visuospatial disorder)
    • PACS (Partial Anterior Circulation Syndrome), ACA or MCA = 2 of:
      • Unilateral weakness and/or sensory deficit in arm, leg AND face
      • Homonymous hemianopia
      • Higher cerebral dysfunction (eg dysphasia, visuospatial disorder)
    • POCS (POsterior Circulation Syndrome), PCA = At least one of:
      • Cerebellar (ataxia, dysarthria, reduced muscle coordination) or brainstem (vertigo, reduced consciousness, diplopia, respiratory depression, dizziness) syndrome
      • Homonymous hemianopia
      • Loss of consciousness
    • LACS (LACunar Syndrome), small subcortical haemorrhage = No higher cerebral dysfunction + 1 of:
      • Unilateral weakness and/or sensory deficit in >=2 of arm, leg or face
      • Pure sensory stroke
      • Ataxic hemiparesis (contralateral loss of muscle control, worse in legs)
  • Long term features of stroke/UMN lesion:
    • Hypertonicity, increased reflexes
    • Weakness: especially flexors of lower limb, extensors of upper limb
    • Extensor Babinski reflex (plantar response)
    • Muscle wasting

 

Pathophysiology

  • Neural dysfunction as a result of ischaemia

 

Investigations

  • Neurological exam
  • History
  • Rule out alternative causes of symptoms (FBC, glucose, U&Es, ECG [also tells you if they have AF], cardiac enzymes, CXR)
  • CT scan
    • Within 1 hour if eligible for thrombolysis
    • Within 24 hours if not eligible
    • Won’t show acute infarction, unless actual thrombus can be visualised
    • Rule out haemorrhage
  • Diffusion weighted MRI
    • Shows areas of infarction
  • Clotting studies if considering thrombolysis

 

Management

  • Thrombolysis, using altepase or streptokinase
    • Exclusion criteria = >3 hours since symptom onset (some sources say 4.5h), INR < 1.7 on warfarin, recent or current haemorrhage, surgery in last 2 weeks, serious head trauma
    • Extra caution: pregnancy, recent/current lumbar or arterial puncture, GI bleed, symptoms are improving
  • Antiplatelet therapy if not suitable for thrombolysis
  • Don’t generally treat haemorrhage initially unless deepening coma or coning
  • Mechanical clot retrieval is a new procedure – clot is surgically removed (like PCI in MIs)
  • Decompressive craniotomy – surgical procedure to remove piece of skull to prevent intercranial pressure rise. Is risky and likely to best possible outcomes still involve brain damage. Must be:
    • <60 (older people have brain atrophy, and therefore enough space in brain to accommodate oedema/inflammation)
    • Large MCA infarct
    • Severe and extensive damage
    • Reduced consciousness
  • Longer term:
    • Antiplatelet therapy (aspirin or clopidogrel)
    • Statins
    • Heparin or warfarin if AF
    • Hypertension control
    • Carotid angiography – if bilateral carotid stenosis >50%, carotid endarterectomy to remove thrombus
    • Rehabilitation – eg physiotherapy, speech and language
    • Medical devices eg wheelchair, splints

 

Prognosis

  • Mortality of ischaemic stroke = 8-12%
  • Long-term disability = further 15-30%, increased with age, comorbidities and previous stroke
Stroke.docx
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