Definition and Classification of Stroke
The term stroke is used synonymously with Cerebrovascular accident (CVA) or Cerebrovascular Disease (CVD). Stroke refers to neurological signs and symptoms, usually focal and acute that result from diseases involving blood vessels. The World Health Organisation (WHO) defined stroke as ‘rapidly developing clinical signs of focal disturbance of cerebral function, with symptoms lasting 24 hours or longer or leading to death, with no apparent cause other than vascular origin’ (WHO 1989).
Classification of stroke is based on underlying pathology. In general, there are two main types of stroke; ischaemic stroke and hemorrhagic stroke. Ischaemic stroke represents 80% of all strokes, and is caused either by an atheroma in the artery itself or secondary emboli from the heart or vessels in the neck (Bamford et al. 1988, cited in Stokes 2004). Hemorrhagic stroke, which is 20% of all stroke, can be sub-categorised into intracerebral hemorrhage or subarachnoid hemorrhagic, with intracerebral hemorrhage been the more frequent type (Stokes 2004). The most frequent cause of intracerebral hemorrhage is hypertension, while rupture of an aneurysm at or near circle of Willis is the main cause of subarachnoid hemorrhage (Stokes 2004).
Clinical presentations following stroke are determined by the anatomy of the brain affected, regardless of the cause (Stokes 2004). However, observation of stroke patients noticed a set of sign and symptoms which is similar in all types of stroke. Typical clinical presentations are hemiplegia or hemiparesis, hemianaesthesia, hemianopia, dysphasia, ataxia and cranial nerve palsies (Anderson & Stewart-Wynne 1991).