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Stroke is defined by the World Health Organization as a clinical syndrome consisting
of 'rapidly developing clinical signs of focal (at times global) disturbance
of cerebral function, lasting more than 24 h or leading to death with no apparent
cause other than that of vascular origin' (1).
- a transient ischaemic attack (TIA) is defined as stroke symptoms and signs
that resolve within 24 hours
- strokes result from:
- cerebral infarction (84%):
- secondary to thrombosis (53%); or
- embolus (31%)
- primary intracerebral haemorrhage (10%)
- subarachnoid haemorrhage (6%)
- a non-disabling stroke is defined as a stroke with symptoms that last for
more than 24 hours but later resolve, leaving no permanent disability
Notes:
- there are limitations to these definitions of stroke and TIA outlined
- for example, they do not include retinal symptoms (sudden onset of monocular
visual loss), which should be considered as part of the definition of stroke
and TIA. The symptoms of a TIA usually resolve within minutes or a few hours
at most, and anyone with continuing neurological signs when first assessed
should be assumed to have had a stroke
- definition of stroke excludes transient ischaemic attacks, subdural haematomas,
and infarction or haemorrhage due to infection or tumour. However, practically
it is often difficult to discriminate between a small stroke and a transient
ischaemic attack
- the term 'brain attack' is sometimes used to describe any neurovascular
event and may be a clearer and less ambiguous term to use
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Reference:
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