Stroke is a sudden onset of brain dysfunction, caused by an alteration in cerebrovascular blood supply. It is characterised by:
  • Rapid, acute onset – within a few minutes
  • Focal neurological defect – almost always some sort of hemiplegia, with/without other focal neurological signs
    • If these two instances are true, then there is a 95% chance there is a vascular cause. Be wary if the symptoms get worse over hours/days, as this points to another cause.
Stroke can be a clinical diagnosis – but it is easier to confirm with tests


  • Haemorrhage – 10-20%
  • Brain Ischaemia (Infarct) – 80-90%
    • Thrombus
    • Other type of embolism
    • Systemic hypoperfusion
  • TIA – Transient Ischaemic Attack
  • This is essentially a ‘minor’ stroke. It may present with stroke like symptoms (limb weakness, dysphagia, visual defects), but the clinical effects will completely resolve within 24 hoursThey are usually the result of micro emboli, (80%)but not always. Sometimes a mass lesion may mimic a TIA, and other times, they are the result of a temporary reduced blood flow – e.g. with massive postural hypotension, or decreased blood flow through a stenosed artery – which is later compensated for by autoregulation mechanisms.
  • Completed Stroke
  • The clinical effects have reached their maximum – usually within 6 hours of the onset.
  • Stroke in evolution
  • Describes the progress of a stroke in the first 24 hours.
  • Cerebrovascular accident (CVA)– avoid using this term! Used to be synonymous with ‘Stroke’ but should be no longer used.


  • Mortality – 20% in first 2 months, then roughly 10%/year
  • <40% of stroke (not TIA) patients make a full recovery
  • Drowsyness at presentation has a poor prognosis

Mechanisms of Stroke

  • Arterial embolism – from a distant site; e.g. carotids, vertebral or basilar arteries. The embolus will occlude an artery of the brain resulting in infarction. May also come from heart valves in endocarditis.
  • Haemorrhage – can be in the cerebrum itself, or also a subarachnoid haemorrhage may cause a similar effect

Uncommon causes

  • Venous infarct
  • Carotid/vertebral dissection
  • Polycythemia
  • Fat / air embolism – e.g. in divers
  • MS – a demyelinating plaque may act as an embolus
  • Mass lesions (e.g. tumour)
  • Migraine
  • Thrombocythaemia and thrombophilia
  • Vasculitis
  • Amyloidosis
  • Drugs – particularly cocaine and OTC cold remedies that contain vasoconstrictors.
Damage will occur when the blood flow to brain tissue drops below 50% of the normal value. Remember in some (probably elderly patients) there will already be reduced blood flow, e.g. to due stenosis/ $(function(){ var pertama = $('#herb-dict .herblist li:first-child').attr('class'); $('#herb-dict .herblist li.'+pertama).show(); $('#herb-dict .alphlist li#'+pertama+' a').addClass('active'); $('#herb-dict .alphlist li a').click(function(){ var target = $(this).attr('rel') $('#herb-dict .herblist li').hide(); $('#herb-dict .herblist li.'+target).show(); $('#herb-dict .alphlist li a').removeClass('active'); $(this).addClass('active'); }); });