Seizures in Women with Preeclampsia: Mechanisms and Management.

Abstract

Eclampsia is currently defined in the obstetrical literature as the occurrence of unexplained seizure during pregnancy in a woman with preeclampsia.1,2 In the Western world, the incidence of eclampsia is ~1 in 2000 to 1 in 3000 pregnancies3–5, but the incidence is 10-fold higher than that in tertiary referral centers and undeveloped countries where there is poor prenatal care, and in multi-fetal gestations.6,7 Eclampsia is associated with high maternal and fetal mortality and morbidity.3,8,9 Nearly 1 in 50 women with eclampsia die as do 1 in 14 of their offspring, and mortality rates are considerably higher in undeveloped countries.3,8,9 Eclampsia is also associated with significant life-threatening complications, including neurological events. In the brain, seizure can cause stroke, hemorrhage, edema and brain herniation acutely,10–13 but also predisposes to epilepsy and cognitive impairment later in life.13,14 Preeclampsia by definition is a prodrome for eclampsia, making hypertension and proteinuria prerequisite for seizure during pregnancy. However, women who develop eclampsia exhibit a wide spectrum of signs and symptoms ranging from severe hypertension and proteinuria to mild or absent hypertension with no proteinuria.6,9,15 In a study of 53 pregnancies complicated by eclampsia, only 7 women (13%) could be considered to have severe preeclampsia prior to seizure.15 A similar result was found in a study in the United Kingdom in which high blood pressure (≥120 mmHg diastolic) was recorded in only 20% of patients with eclampsia.3 The findings that a fair number of women with eclampsia do not have the clinical definition of hypertension or proteinuria suggests that eclampsia is not always a progression from severe preeclamptic disease to seizure (eclampsia). While this alternative view of the eclamptic seizure was presented over 10 years ago, there has been little progress in understanding the underlying cause of eclampsia.3 Eclampsia remains a significant life-threatening complication of pregnancy, yet there are no reliable tests or symptoms for predicting the development of seizure. In addition, while magnesium sulfate (MgSO4) is the primary treatment of preeclamptic women for prevention of eclampsia, its use is controversial because of potential serious side effects including areflexia and respiratory distress.16–19 Thus, eclampsia is difficult to predict and treat likely because of our lack of understanding of its underlying cause. This review will highlight our current understanding of how pregnancy and preeclampsia affect the brain and cerebral circulation that could promote neuronal excitability (seizure) and ways in which to manage seizure in preeclamptic women during pregnancy and preeclampsia.