Effects of steroids on behavior, electrophysiology, water content and intracranial pressure in cerebral cytotoxic edema.

The effect of therapy with methylprednisolone sodium succinate (5.33 mg/kg/day) and dexamethasone sodium phosphate (1 mg/kg/day) on grey matter of rabbits rendered edematous by a metabolic blocker, 6-aminonicotinamide, is presented. Methylprednisolone was observed to significantly reduce the water content of the grey matter (p less than 0.001), whereas dexamethasone had little effect. Both agents, however, were equally effective in reducing intracranial pressure (p less than 0.001) and improving intracranial elastance, when compared to untreated animals. However, in the dexamethasone-treated group, there was improved behavior and EEG findings in 50% of the animals when compared to the untreated controls, and similar improvement was present in less than 15% of the methylprednisolone group. The disparity between the effects on water content, behavior and EEG supports the thesis that in cerebral edema these agents have a metabolic effect out of proportion to their effect on tissue water.