Cerebral edema
21 July, 2008
Cerebral edema (cerebral oedema in British English) is an excess accumulation of water in the intracellular and/or extracellular spaces of the brain.
Vasogenic “cerebral edema”
Due to a breakdown of tight endothelial junctions which make up the blood-brain barrier (BBB). This allows normally excluded intravascular proteins and fluid to penetrate into cerebral parenchymal extracellular space. Once plasma constituents cross the BBB, the edema spreads; this may be quite fast and widespread. As water enters white matter it moves extracellularly along fiber tracts and can also affect the gray matter. This type of edema is seen in response to trauma, tumors, focal inflammation, late stages of cerebral ischemia and hypertensive encephalopathy.
Cytotoxic cerebral edema
In this type of edema the BBB remains intact. This edema is due to the derangement in cellular metabolism resulting in inadequate functioning of the sodium and potassium pump in the glial cell membrane. As a result there is cellular retention of sodium and water. There are swollen astrocytes in gray and white matter. Cytoxotic edema is seen with various intoxications (dinitrophenol, triethyltin, hexachlorophene, isoniazid), in Reye’s syndrome, severe hypothermia, early ischemia, encephalopathy, early stroke or hypoxia, cardiac arrest, pseudotumor cerebri, and cerebral toxins.
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