Definition of stroke
A stroke or cerebrovascular accident (CVA) is typically an event of sudden onset (although it can occur over hours in some patients where a major vessel is slowly thrombosing). It is due to an interruption of blood supply to an area of the central nervous system (CNS) that causes irreversible loss of tissue at the core with a penumbra of compromised tissue around the area that may still be salvageable. If the disturbance in blood flow is temporary it causes a transient ischaemic attack or TIA. This is often a harbinger of a stroke. Stroke is common and its consequences depend on the vessel that has been occluded.
Investigation of stroke
· History and examination
· Computed tomography (CT)/magnetic resonance imaging (MRI)
· Blood tests including full blood count, erythrocyte sedimentation rate, renal function, glucose and lipids
· Electrocardiogram (ECG) which may be repeated and prolonged if a cardiac source for the stroke is suspected
Other investigation may include an ECHO cardiogram and imaging of the blood vessels and/or a CSF examination and this depends on the type of stroke (see Table 64.1).
Rare causes of stroke
The most common causes of stroke are atherosclerosis and embolic disease from the blood vessels to the brain and the heart. The other causes are quite rare. Other syndromes that resemble stroke include mitochondrial disease (see Chapter 63), where there can be a sudden onset of neurological deficits due to problems in the mitochondria and not in the vasculature. Such events in the brain typically do not obey vascular territories when investigated with MRI for example.
Treatment of stroke
· Consider local thrombolysis if a single major vessel is involved: e.g. basilar artery/venous sinus
• Acutely (if <3–4 hours) and no contraindication thrombolysis
• Treat any risk factors eg stop smoking, lower-cholesterol etc and start aspirin/perindopril/statin
• Heparin if major venous sinus thrombosis
• Surgery, if recognizable lesion causing stroke is identified e.g. >70% carotid artery stenosis/aneurysm
• Rehabilitation therapy