Eclampsia: additional seizure mechanisms and timing of fits
THE CONTEXT
The passage continues the proposed causes of cerebral irritation and classifies eclamptic fits by their onset relative to labor and delivery.
Additional proposed mechanisms
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Excessive release of excitatory neurotransmitters, particularly glutamate, may contribute to convulsions.
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Loss of cerebrovascular autoregulation with forced dilatation and vasospasm is another proposed mechanism.
Timing of onset
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Fits occur most commonly in the third trimester, which accounts for more than 50% of cases. Rarely, convulsions occur in the early months, as in hydatidiform mole.
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Antepartum fits account for 50% and begin before labor. Labor often starts soon afterward, sometimes making distinction from intrapartum fits difficult.
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Intrapartum fits account for 30% and occur for the first time during labor.
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Postpartum fits account for 20% and first occur in the puerperium, usually within 48–72 hours of delivery.