THE BRAIN IN ECLAMPSIA

The occurrence of a convulsion marks the transition of preeclampsia to eclampsia. Although many women who experience eclamptic convulsions recover without neurologic sequelae including epilepsy, the mortality of eclampsia, much due to cerebral lesions, increases with the number of convulsions. A review of the character of the neurological manifestations of toxemia is followed by proposals for their pathogenesis. The author exposes that the neurologic manifestations of eclampsia are those of hypertensive encephalopathy in previously normotensive young women. Hypertensive encephalopathy occurs if sustained mean arterial blood pressure exceeds the upper limit of autoregulation of cerebral perfusion. Thus, the pathophysiological event which compromises the brain is not a convulsion but rather the point at which a preeclamptic woman's blood pressure exceeds her upper limit of the autoregulation of cerebral perfusion.