[Physiopathology of brain edema]

Cerebral edema is by definition an increase in the water content of the brain. Because of the rigidity of the skull, every increase in brain volume invariably causes intracranial hypertension which, in turn, has two major consequences: firstly, cerebral perfusion pressure is reduced, thus promoting ischemia; secondly, cerebral structures are displaced toward places of lesser resistance, thus causing brain herniation. In consequence, medical treatment of intracranial hypertension should be chiefly directed against brain edema. Recent research in the field demonstrates that there are different forms of edema, the underlying mechanisms of which are discussed.