What is the immediate management of a patient presenting with pre-eclampsia in the emergency department?

Pre-Eclampsia Emergency Department Presentation

Definition and Recognition

Pre-eclampsia is a hypertensive disorder of pregnancy occurring after 20 weeks' gestation, characterized by new-onset hypertension (≥140/90 mmHg) with proteinuria or end-organ dysfunction, requiring immediate ED recognition and aggressive management to prevent maternal mortality from cerebral hemorrhage, eclampsia, and multi-organ failure. 1

Severe Pre-eclampsia Criteria

• Blood pressure ≥160/110 mmHg persisting for >15 minutes defines severe hypertension requiring urgent treatment 1, 2
• Neurological symptoms: severe headache, visual disturbances (scotomata), altered mental status 1, 3
• Epigastric or right upper quadrant pain (suggests hepatic capsule distension or HELLP syndrome) 4
• Pulmonary edema or oxygen saturation <90% 2
• Renal dysfunction: oliguria (<400 mL/24h), elevated creatinine 4, 2
• Thrombocytopenia and elevated liver enzymes (HELLP syndrome) 4

Critical pitfall: 34% of eclamptic seizures occur with diastolic BP ≤100 mmHg, so do not be falsely reassured by "moderate" hypertension 4

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Immediate ED Management Algorithm

Step 1: Simultaneous Stabilization (First 15 Minutes)

Administer magnesium sulfate immediately for seizure prophylaxis in all patients with severe pre-eclampsia—this is the single most important intervention to prevent eclampsia and maternal death. 1, 2

Magnesium Sulfate Protocol

• Loading dose: 4-5g IV over 5 minutes 1
• Maintenance: 1-2g/hour continuous IV infusion 1
• Continue until 24 hours postpartum 2
• Monitor: Patellar reflexes (absent at toxic levels), respiratory rate (≥16/min required), urine output (≥100 mL/4 hours) 4, 5
• Antidote: Have IV calcium gluconate immediately available at bedside 4, 5

FDA Warning: Do not administer magnesium sulfate beyond 5-7 days due to risk of fetal skeletal demineralization and fractures 5

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Step 2: Blood Pressure Control (Within 15 Minutes)

Initiate IV antihypertensive therapy immediately when BP ≥160/110 mmHg persists >15 minutes to prevent maternal cerebral hemorrhage. 1, 2

Target Blood Pressure

• Systolic: 110-140 mmHg 1, 2
• Diastolic: 85 mmHg 1, 2
• Do not reduce diastolic <80 mmHg (risks placental hypoperfusion) 2

First-Line IV Antihypertensives (Choose One)

• Labetalol: 20mg IV bolus, then 40-80mg every 10 minutes (max 300mg) 1, 6
• Hydralazine: 5mg IV bolus, then 5-10mg every 20 minutes 1, 6, 7
• Nicardipine: 5mg/hour IV infusion, titrate by 2.5mg/hour every 5-15 minutes 1
• Nifedipine (oral): 10mg immediate-release, repeat in 30 minutes if needed 2, 6

Critical pitfall: Never use ACE inhibitors, ARBs, or diuretics—these are absolutely contraindicated due to fetotoxicity and volume depletion 1

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Step 3: Monitoring and Assessment

Continuous Maternal Monitoring

• Blood pressure every 15 minutes until stable, then hourly 3
• Continuous pulse oximetry (target >90%) 2
• Hourly urine output via Foley catheter (target ≥100 mL/4 hours) 4, 2
• Deep tendon reflexes before each magnesium dose 4, 5
• Respiratory rate (magnesium toxicity causes respiratory depression) 4, 5

Immediate Laboratory Testing

• Complete blood count (platelets, hemoglobin for HELLP) 4, 2
• Comprehensive metabolic panel (creatinine, liver enzymes) 1, 2
• Coagulation studies (PT/PTT, fibrinogen) 4
• Lactate dehydrogenase (hemolysis marker) 4, 8
• Urine protein/creatinine ratio (≥30 mg/mmol confirms significant proteinuria) 1, 2

Do not delay treatment while awaiting laboratory results 8, 7

Fetal Monitoring

• Continuous fetal heart rate monitoring 1, 2
• Ultrasound assessment: fetal biometry, amniotic fluid volume, umbilical artery Doppler 2

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Step 4: Obstetric Consultation and Transfer

Contact obstetric and maternal-fetal medicine specialists immediately—delivery is the definitive treatment and timing depends on gestational age and maternal/fetal status. 1, 2

Indications for IMMEDIATE Delivery (Regardless of Gestational Age)

• Inability to control BP despite ≥3 antihypertensive classes 2
• Eclamptic seizure 2, 8
• Maternal oxygen saturation <90% 2
• Progressive deterioration: worsening liver/renal function, falling platelets, hemolysis 2
• Persistent severe neurological symptoms (intractable headache, visual changes) 2
• Placental abruption 4, 2
• Non-reassuring fetal status (reversed end-diastolic flow, Category III tracing) 2

Gestational Age-Based Delivery Timing

• ≥37 weeks: Immediate delivery after stabilization 2
• 34-37 weeks: Expectant management with close monitoring OR delivery based on severity 2
• <34 weeks: Transfer to tertiary center with NICU; consider corticosteroids for fetal lung maturity 2

Critical consideration: Average interval from diagnosis to delivery at <32 weeks is 14 days, but substantial numbers require delivery within 72 hours 4

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Step 5: Transfer Protocol (If Delivering Facility Not Available)

Arrange medicalized transport to specialized obstetric center with maternal-fetal medicine and NICU capabilities. 1, 3

Pre-Transfer Checklist

• Initiate magnesium sulfate and achieve BP control BEFORE transport 3
• Coordinate via phone with receiving obstetric and anesthesia teams 1, 3
• Involve emergency medical services regulating physician 3
• Provide pre-arrival notification: patient condition, treatments given, ETA 3
• Continue monitoring during transport: vital signs every 15 minutes, level of consciousness 3

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Management of Eclamptic Seizure

If seizure occurs, magnesium sulfate is the first-line agent—NOT benzodiazepines or phenytoin. 8, 7, 9

Acute Seizure Management

• Protect airway: Position patient left lateral, suction as needed 10, 9
• Supplemental oxygen: Maintain maternal SpO2 >95% 10, 9
• Magnesium sulfate: 4-5g IV bolus over 5 minutes if not already on maintenance 1, 7
• If seizure persists: Additional 2g IV magnesium bolus 7
• If still seizing: Consider lorazepam 2-4mg IV as second-line 7

Maternal mortality from eclampsia is 5-20%, and 23% require mechanical ventilation 10, 9

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HELLP Syndrome Recognition

HELLP syndrome (Hemolysis, Elevated Liver enzymes, Low Platelets) represents the severe end of the pre-eclampsia spectrum with 3.4% maternal mortality. 4

Diagnostic Criteria

• Hemolysis: Elevated LDH, decreased haptoglobin, peripheral smear showing schistocytes 4, 1
• Elevated liver enzymes: AST/ALT >2x normal 4
• Low platelets: <100,000/mm³ (consider transfusion if <50,000 for cesarean) 4

Additional HELLP Considerations

• Epigastric/RUQ pain is the hallmark symptom 4
• Severe hypoglycemia can occur—monitor glucose intraoperatively 4
• Platelet transfusion if count <50,000/mm³ and cesarean planned 4
• Fresh whole blood if hemoglobin <10 g/dL 4

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Critical Pitfalls to Avoid

• Do not wait for proteinuria to diagnose severe pre-eclampsia—hypertension with symptoms is sufficient 1, 8
• Do not use diuretics for oliguria—these patients are intravascularly depleted despite edema 1
• Do not perform lumbar puncture before treating as eclampsia—other diagnoses can be considered after stabilization 8
• Do not delay magnesium for laboratory confirmation—clinical diagnosis is adequate 1, 7
• 38% of eclampsia occurs WITHOUT premonitory signs of pre-eclampsia 10
• 44% of eclamptic seizures occur postpartum—maintain vigilance up to 10 days after delivery 10
• Do not use routine invasive hemodynamic monitoring or aggressive volume expansion—these increase pulmonary edema risk 7

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Medications Absolutely Contraindicated

• ACE inhibitors and ARBs: Severe fetotoxicity 1
• Diuretics: Worsen intravascular volume depletion 1
• Direct renin inhibitors: Fetal harm 1
• Magnesium sulfate >5-7 days: Fetal skeletal demineralization and fractures 5

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Key Monitoring Parameters for Magnesium Toxicity

• Therapeutic range: 3-6 mg/dL (2.5-5 mEq/L) 4, 5
• Loss of deep tendon reflexes: >4 mEq/L 4, 5
• Respiratory depression: ~10 mEq/L 4, 5
• Cardiac arrest: >12 mEq/L 5
• Antidote: Calcium gluconate 1g IV over 3 minutes 4, 5