Eclamptic Seizure Pathophysiology

Initiating Events

• Abnormal placentation, characterized by shallow cytotrophoblast invasion of maternal spiral arteries, is the initiating event in eclamptic seizures, according to the American Heart Association, and is associated with reduced placental perfusion and placental ischemia 1, 2
• Spiral arteries fail to undergo normal remodeling, remaining small muscular vessels instead of becoming distended, low-resistance channels, leading to placental dysfunction 1

Systemic Endothelial Dysfunction

• The ischemic placenta releases soluble factors, including excess sFlt-1, into maternal blood, causing systemic endothelial dysfunction throughout maternal vasculature, including cerebral vessels, as stated by the European Society of Cardiology 1, 2
• These circulating factors antagonize vascular endothelial growth factor (VEGF) and placental growth factor (PlGF), contributing to endothelial dysfunction 2

Cerebral Autoregulation Failure

• Cerebral autoregulation fails when severe hypertension exceeds the upper limit of autoregulation, causing forced vasodilation and further endothelial injury, according to the European Heart Journal 3
• The result is vasogenic cerebral edema, predominantly in posterior circulation territories, which lowers the seizure threshold 3, 4

Clinical Context and Risk Factors

• Eclampsia occurs in women with severe preeclampsia who do not receive magnesium sulfate prophylaxis, with a higher incidence in those without prophylaxis, as reported by the American College of Obstetricians and Gynecologists 5, 6
• Warning signs of impending seizures include occipital lobe blindness, hyperreflexia, and clonus, indicating severe cerebrovascular involvement and high seizure risk, according to the European Society of Cardiology 3, 4

Treatment and Prevention

• The only definitive treatment is delivery of the placenta, which removes the source of circulating pathogenic factors, as stated by the American Heart Association 1, 5, 6
• Continuous maternal magnesium sulfate administration can prevent seizures, but its use beyond 5-7 days requires careful consideration of potential fetal effects, as recommended by the American College of Obstetricians and Gynecologists 3, 4