Emerging insights into the genesis of cerebral ischaemia and stroke

Abstract

Stroke is a global problem with increasing significance because of the ageing population. Except for age, hypertensionisbyfar themostimportantriskfactorfor stroke. Hypertensionpredisposes toanumberof intracerebral and extracerebral vascular lesions which may cause cerebrovascular events by different mechanisms. The high metabolic need and low energy reserve make the braiavery vulnerable to ischaemia. During the last decade a number of experimental studies - supported by PET studies in man - suggest the presence of a therapeutic window, i.e. the time during which the neurons can be saved. The penumbra is the zone surrounding the core of the infarct where the flow is decreased and the neurons are lethargic and may be electrically silent but still viable. The presumed role of calcium, excitatory amino acids, free radicals, platelet-activating factor, acidosis and brain temperature in the process of neuronal death is briefly reviewed.