How do preeclampsia and eclampsia differ?

Difference Between Eclampsia and Preeclampsia

Eclampsia is preeclampsia plus seizures—it represents the progression of preeclampsia to include convulsions that cannot be attributed to other causes. 1

Core Distinction

Preeclampsia is a multisystem syndrome of pregnancy characterized by:

• New-onset hypertension (≥140/90 mmHg) after 20 weeks of gestation 1
• Plus proteinuria (≥300 mg/24 hours) or evidence of maternal organ dysfunction (renal insufficiency, liver involvement, thrombocytopenia, pulmonary edema, or cerebral/visual disturbances) 1
• The underlying pathophysiology involves placental dysfunction leading to widespread maternal endothelial dysfunction 1

Eclampsia is defined as:

• The occurrence of seizures in a woman with preeclampsia that cannot be attributed to other causes 1, 2
• Historically described since 100 AD as "seizures during pregnancy that abated with delivery" 1
• Occurs in approximately 0.2% of preeclamptic patients 2
• Can develop antepartum, intrapartum, or postpartum (even after delivery) 3, 4

Clinical Implications for Morbidity and Mortality

The progression from preeclampsia to eclampsia dramatically escalates maternal and fetal risk:

• Preeclampsia alone presents acute risks to mother and baby, including growth restriction, preterm delivery, placental abruption, and maternal organ damage 1
• Eclampsia adds the life-threatening complication of seizures with associated risks of maternal cerebral hemorrhage, aspiration, hypoxia, and fetal compromise 1
• Both conditions resolve after delivery of the placenta, confirming the placenta as the essential driver of disease 1, 3

Warning Signs of Progression to Eclampsia

Symptoms indicating severe preeclampsia at risk of progressing to eclampsia include:

• Persistent severe headache unresponsive to treatment 1, 5
• Visual disturbances (scotomata, blurred vision, photophobia) 1, 5
• Right upper quadrant or epigastric pain (from hepatic edema/hemorrhage) 5, 3
• Hyperreflexia and clonus (though nonspecific) 5, 3

Management Differences

For preeclampsia:

• Magnesium sulfate is used for seizure prophylaxis in women with severe features or neurological symptoms 4, 2
• Antihypertensive therapy targets severe hypertension (≥160/110 mmHg) 4
• Delivery timing depends on gestational age, maternal condition, and fetal status 4

For eclampsia:

• Magnesium sulfate becomes therapeutic (not just prophylactic) to control active seizures 2
• Loading dose of 4 g IV or 10 g IM, followed by maintenance infusion 4
• Immediate delivery is typically indicated once maternal condition is stabilized 4
• Diazepam may supplement magnesium sulfate if seizures persist 2

Common Pitfalls to Avoid

• Do not assume preeclampsia is "mild" based on blood pressure alone—all preeclampsia can progress unpredictably to eclampsia or other life-threatening complications 4, 6
• Do not delay magnesium sulfate prophylaxis in women with severe features or neurological symptoms, as eclampsia can develop rapidly 4, 2
• Do not discontinue monitoring immediately after delivery—eclampsia can occur postpartum, requiring continued vigilance for at least 72 hours 3, 4
• Do not use serum uric acid or degree of proteinuria to predict eclampsia risk; clinical features (headache, visual changes) are more relevant 4

Long-term Cardiovascular Implications

Both conditions increase lifetime cardiovascular risk, though the data primarily address preeclampsia history:

• Women with preeclampsia history have 75% increased cardiovascular mortality risk (OR 1.75) 5
• The risk is amplified with severe preeclampsia (OR 2.74 vs. 2.24 for moderate disease) 5
• Mandatory 3-month postpartum follow-up is required to confirm resolution and initiate cardiovascular screening 5, 3
• Annual lifelong follow-up is recommended for all women with preeclampsia or eclampsia history 5, 3