Eclampsia
Summary
Eclampsia is defined as the occurrence of generalised tonic-clonic seizures in a woman with pre-eclampsia, not attributable to other causes (e.g., Epilepsy). It represents the most severe manifestation of the pre-eclampsia spectrum and is an obstetric emergency. Pre-eclampsia is a multisystem disorder of pregnancy characterised by new-onset hypertension (>140/90 mmHg after 20 weeks' gestation) and proteinuria (Or other end-organ dysfunction). Eclampsia can occur antepartum (44%), intrapartum (20%), or postpartum (36%) – most commonly within 48 hours of delivery but up to 6 weeks. Warning signs often precede seizures: Severe headache, Visual disturbances (Flashing lights, Blurred vision), Epigastric/RUQ pain, Hyperreflexia/Clonus. Management involves Magnesium Sulphate (MgSO4) – First-line for seizure control and prophylaxis, BP control (Labetalol, Hydralazine), Delivery (The only definitive cure), and supportive care (Airway, Left lateral tilt). Eclampsia remains a major cause of maternal mortality worldwide.
Key Facts
- Definition: Seizures in a woman with pre-eclampsia (Or developed postpartum).
- Timing: 44% Antenatal, 20% Intrapartum, 36% Postpartum.
- Warning Signs (Imminent Eclampsia): Severe headache, Visual disturbances, Epigastric pain, Hyperreflexia/Clonus.
- Treatment of Seizures: Magnesium Sulphate (4g IV Loading -> 1g/hr Infusion).
- BP Control: Labetalol IV (First-line). Hydralazine. Nifedipine PO.
- Definitive Treatment: Delivery.
- Mortality: Major cause of maternal death. ~1.8% in developed countries. Higher worldwide.
Clinical Pearls
"Magnesium Sulphate is the Drug of Choice": Superior to Diazepam/Phenytoin for both treatment and prophylaxis of eclamptic seizures (MAGPIE trial).
"Pre-Eclampsia Can Occur Postpartum": Up to 6 weeks. Don't discount eclampsia because the baby has been delivered.
"HELLP Syndrome May Accompany Eclampsia": Haemolysis, Elevated Liver enzymes, Low Platelets. Severe complication.
"Epigastric Pain = Liver Capsule Stretch = Red Flag": Indicates severe pre-eclampsia/HELLP.
Why This Matters Clinically
Eclampsia is a leading cause of maternal mortality. Prompt recognition and treatment with Magnesium Sulphate saves lives.
Incidence
- Eclampsia: ~1 in 2,000-3,500 pregnancies (UK). Higher in low-resource settings.
- Pre-Eclampsia: 3-5% of pregnancies.
- Timing: ~44% Antenatal, ~20% Intrapartum, ~36% Postpartum (Mostly within 48 hours).
Risk Factors for Pre-Eclampsia/Eclampsia
| Factor | Notes |
|---|---|
| Nulliparity | |
| Previous Pre-Eclampsia | |
| Family History | Mother/Sister with pre-eclampsia. |
| Multiple Pregnancy | |
| Obesity (BMI >0) | |
| Advanced Maternal Age (>0) | |
| Pre-Existing Hypertension | |
| Pre-Existing Diabetes | |
| Chronic Kidney Disease | |
| Autoimmune Disease (SLE, APS) | |
| IVF Pregnancy | |
| Long Interval Since Last Pregnancy |
Pre-Eclampsia Spectrum
| Stage | Detail |
|---|---|
| Abnormal Placentation | Failure of trophoblast invasion of spiral arteries. Inadequate remodelling. |
| Placental Ischaemia | Reduced uteroplacental blood flow. |
| Release of Factors | Anti-angiogenic factors (sFlt-1, sEng), Inflammatory cytokines, Oxidative stress. |
| Systemic Endothelial Dysfunction | Widespread endothelial damage. |
| Multi-Organ Effects | Hypertension, Proteinuria, Hepatic dysfunction, Thrombocytopenia, Renal impairment, Cerebral oedema. |
Eclampsia
- Cerebral Oedema / Posterior Reversible Encephalopathy Syndrome (PRES).
- Loss of cerebral autoregulation -> Vasogenic oedema.
- Seizure activity.
Pre-Eclampsia (Preceding Eclampsia)
| Feature | Notes |
|---|---|
| Hypertension | >140/90 mmHg (Or rise from baseline). Severe: >60/110. |
| Proteinuria | >300mg/24hr. Or PCR >0. |
| Oedema | Non-specific but may be significant. |
| Symptoms | May be asymptomatic. |
Imminent Eclampsia (Warning Signs)
| Sign/Symptom | Notes |
|---|---|
| Severe Headache | Frontal. Throbbing. Unrelieved by simple analgesia. |
| Visual Disturbances | Flashing lights. Blurred vision. Scotomata. |
| Epigastric / RUQ Pain | Liver capsule stretch (HELLP). |
| Hyperreflexia | Brisk tendon reflexes. |
| Clonus | Sustained ankle clonus (> beats). |
| Nausea / Vomiting | |
| Confusion / Agitation |
Eclamptic Seizure
| Feature | Notes |
|---|---|
| Type | Generalised tonic-clonic. |
| Duration | Usually 60-90 seconds. |
| Post-Ictal | Confusion. May recover or have further seizures. |
| Complications | Aspiration. Hypoxia. Placental abruption. Cerebral haemorrhage. |
HELLP Syndrome
| H | Haemolysis (Raised LDH, Bilirubin, Low Haptoglobin, Schistocytes). | | EL | Elevated Liver Enzymes (AST, ALT). | | LP | Low Platelets (<100 x10^9/L). |
Can occur with or without severe hypertension/proteinuria. Requires delivery.
Baseline
| Test | Purpose |
|---|---|
| Blood Pressure | Hypertension. Severity. |
| Urinalysis / PCR | Proteinuria. |
| FBC | Platelets (HELLP). |
| U&E | Renal function. |
| LFTs | Liver dysfunction (HELLP). |
| LDH | Haemolysis (HELLP). |
| Clotting Screen | DIC risk. |
| Uric Acid | Elevated in pre-eclampsia. |
Additional
| Test | Purpose |
|---|---|
| CTG (Cardiotocography) | Fetal wellbeing. |
| USS (Fetal Growth / Doppler) | IUGR. Placental assessment. |
| CT/MRI Head | If atypical features or prolonged post-ictal state. Rule out ICH, PRES. |
Principles (ABCDE)
- Airway / Breathing: Secure airway. Oxygen. Left lateral tilt.
- Call for Help: Obstetric emergency. Senior Obstetrician, Anaesthetist, Midwife.
- Control Seizures: Magnesium Sulphate.
- Control Blood Pressure: Target <150/100 (Avoid sudden drops).
- Deliver: The only definitive cure.
- Continuous Monitoring: CTG, Observations, Bloods.
Immediate Actions During Seizure
| Action | Detail |
|---|---|
| Left Lateral Position | Prevents aortocaval compression. Protects airway. |
| Protect from Injury | Move objects. |
| Oxygen 15L via Mask | |
| Do NOT restrain or put anything in mouth | |
| Time the Seizure |
Magnesium Sulphate Protocol
| Dose | Regimen |
|---|---|
| Loading Dose | 4g IV over 5-15 minutes. |
| Maintenance Infusion | 1g/hr IV for 24 hours (Post-last seizure or post-delivery). |
| Recurrent Seizure | Further 2g bolus IV. |
Continue for 24 hours after last seizure or 24 hours post-delivery.
Magnesium Toxicity Monitoring
| Parameter | Check | Toxicity Signs |
|---|---|---|
| Patellar Reflexes | Hourly | Absent reflexes = Early toxicity. |
| Respiratory Rate | Hourly | RR <12 = Stop infusion. |
| Urine Output | Hourly | <100ml/4hr = Reduce infusion. |
| Serum Magnesium | If concerned | Therapeutic 2-4 mmol/L. Toxic > mmol/L. |
Magnesium Toxicity Antidote
| Drug | Dose | Indication |
|---|---|---|
| Calcium Gluconate | 10ml of 10% IV over 10 minutes. | Respiratory depression. Loss of reflexes. Cardiac arrhythmia. |
Blood Pressure Control
| Target | <150/100 mmHg (Or MAP reduction ~25%). Avoid rapid drops (Placental hypoperfusion). |
| Drug | Dose | Notes |
|---|---|---|
| Labetalol IV | 20-50mg bolus. Then 20-160mg/hr infusion. | First-line. Avoid in asthma. |
| Hydralazine IV | 5-10mg boluses. Repeat every 20-30 min. | Alternative. |
| Nifedipine PO | 10-20mg PO. | If IV access difficult. Modified-release for maintenance. |
Delivery
- The Only Definitive Cure for Pre-Eclampsia/Eclampsia.
- Stabilise Mother FIRST (Seizures, BP).
- Do NOT delay delivery if stable.
- Mode: Depends on gestation, Fetal condition, Cervical favourability. Often expedited.
- Steroids: If preterm (<34 weeks), give Betamethasone for fetal lung maturity if time allows.
Maternal
| Complication | Notes |
|---|---|
| Recurrent Seizures | |
| Cerebral Haemorrhage (ICH) / Stroke | May be fatal. |
| HELLP Syndrome | Liver rupture risk. |
| Liver Rupture / Haematoma | Rare but catastrophic. |
| Pulmonary Oedema | Fluid overload. Capillary leak. |
| Acute Kidney Injury | |
| DIC | Coagulopathy. |
| Placental Abruption | |
| Aspiration Pneumonia | During seizure. |
| Death | ~1.8% in developed countries. Higher globally. |
Fetal
| Complication | Notes |
|---|---|
| Fetal Distress | Hypoxia during seizure. |
| IUGR | From placental insufficiency. |
| Prematurity | Iatrogenic (Early delivery). |
| Stillbirth |
| Consideration | Detail |
|---|---|
| Continue Magnesium | For 24 hours post-delivery or post-last seizure. |
| Antihypertensives | Often needed postpartum. Usually Labetalol/Nifedipine PO. |
| Fluid Balance | Careful monitoring. Risk of pulmonary oedema. |
| Debriefing | Explain events to patient/family. |
| Follow-Up | BP monitoring. Postnatal review. Counsel about future pregnancy risk. |
| Outcome | Notes |
|---|---|
| Maternal Mortality | ~1.8% (UK). Higher in resource-limited settings. |
| Recurrence Risk | ~25% risk of pre-eclampsia in subsequent pregnancy. |
| Long-Term CV Risk | Increased risk of hypertension, Stroke, IHD in later life. |
| Intervention | Who | Notes |
|---|---|---|
| Aspirin 150mg ON | High-risk women. | From 12 weeks to 36 weeks. Reduces pre-eclampsia risk. |
| Calcium Supplementation | Low dietary calcium. | May reduce risk. |
Key Guidelines
| Guideline | Organisation | Notes |
|---|---|---|
| NICE NG133 | NICE | Hypertension in Pregnancy. |
| RCOG Green-Top GTG 10A | RCOG | Management of Severe Pre-Eclampsia/Eclampsia. |
| MAGPIE Trial (2002) | Lancet | MgSO4 halves risk of eclampsia. Reduces maternal death. |
Scenario 1:
- Stem: A 32-week pregnant woman with known pre-eclampsia has a generalised seizure on the ward. What is the immediate management?
- Answer: Eclampsia. Left lateral position. Oxygen. Call for help. Give Magnesium Sulphate 4g IV Loading, then 1g/hr infusion.
Scenario 2:
- Stem: What is the antidote for Magnesium Sulphate toxicity?
- Answer: Calcium Gluconate 10% 10ml IV.
Scenario 3:
- Stem: A woman develops severe headache, visual disturbances, and epigastric pain with hypertension at 36 weeks. What is the concern?
- Answer: Severe Pre-Eclampsia / Imminent Eclampsia (Or HELLP Syndrome). Requires urgent assessment and consideration of delivery.
| Scenario | Urgency | Action |
|---|---|---|
| New Hypertension in Pregnancy | Urgent | Obstetric assessment. |
| Features of Severe Pre-Eclampsia | Emergency | Admit. Stabilise. Consider delivery. |
| Seizure in Pregnancy/Postpartum | Emergency | ABC. Magnesium Sulphate. Deliver. |
What is Eclampsia?
Eclampsia is a serious complication of pregnancy where a woman with high blood pressure (pre-eclampsia) has a seizure (fit). It is dangerous for both mother and baby.
What are the warning signs?
- Severe headache.
- Visual disturbances (flashing lights, blurred vision).
- Pain in the upper tummy.
- Swelling of face and hands. Seek medical attention immediately if you have these symptoms.
How is it treated?
- A medicine called Magnesium Sulphate to stop and prevent seizures.
- Medicines to control blood pressure.
- Delivery of the baby (the only cure for pre-eclampsia).
Key Counselling Points
- Attend Antenatal Appointments: "Regular checks can detect pre-eclampsia early."
- Report Warning Symptoms: "Come to hospital urgently if you get severe headache, visual changes, or upper tummy pain."
- Take Aspirin If Prescribed: "If you are high-risk, low-dose aspirin can reduce your risk."
| Standard | Target |
|---|---|
| Magnesium Sulphate given within 15 minutes of eclamptic seizure | 100% |
| BP controlled to <150/100 | >0% within 1 hour |
| Magnesium toxicity monitoring documented | 100% |
| Delivery within appropriate timeframe | As clinically indicated |
- Eclampsia: Greek "Eklampsis" = "Sudden flashing out" (Referring to seizures).
- MAGPIE Trial (2002): Landmark RCT proving Magnesium Sulphate halves eclampsia risk and reduces maternal mortality. Changed global practice.
- NICE NG133. Hypertension in Pregnancy: Diagnosis and Management. nice.org.uk
- RCOG GTG 10A. Management of Severe Pre-Eclampsia/Eclampsia. rcog.org.uk
- MAGPIE Trial Collaborative Group. Do women with pre-eclampsia, and their babies, benefit from magnesium sulphate? Lancet. 2002. PMID: 12049878
Last Reviewed: 2025-12-24 | MedVellum Editorial Team
Medical Disclaimer: MedVellum content is for educational purposes and clinical reference. Eclampsia is a medical emergency – seek immediate medical attention if suspected.