What are the diagnostic criteria and treatment for eclampsia in a pregnant woman?

Diagnosis and Treatment of Eclampsia

Eclampsia is diagnosed when a pregnant woman with preeclampsia develops seizures that cannot be attributed to other causes, and immediate treatment with magnesium sulfate, blood pressure control, and preparation for delivery is essential to prevent maternal and fetal mortality. 1

Diagnostic Criteria for Eclampsia

Eclampsia is characterized by:

1. Seizures in a pregnant woman (or within 10 days postpartum) 2
2. Presence of preeclampsia features:
   • New-onset hypertension (≥140/90 mmHg) after 20 weeks' gestation 1
   • Proteinuria (≥30 mg/mmol or 0.3 mg/mg protein/creatinine ratio) 1
   • One or more of the following maternal organ dysfunctions:
     • Thrombocytopenia (<100,000/μL)
     • Elevated liver enzymes
     • Renal insufficiency
     • Pulmonary edema
     • Cerebral or visual disturbances 1, 3

Important clinical note: Up to 38% of eclamptic seizures can occur without premonitory signs of preeclampsia, and 44% occur postpartum, with some cases occurring more than a week after delivery 2.

Immediate Management of Eclamptic Seizures

1. Airway, Breathing, Circulation:

   • Ensure patent airway and adequate oxygenation
   • Position patient in left lateral position to prevent aspiration and improve uteroplacental perfusion 3, 4

2. Seizure Control:

   • Magnesium sulfate is the anticonvulsant of choice 1, 3, 5, 6:
     • Loading dose: 4-6 g IV over 15-20 minutes
     • Maintenance: 1-2 g/hour continuous infusion
     • Continue for at least 24 hours post-delivery 3, 5
   • If seizures persist despite magnesium sulfate:
     • Consider diazepam as supplementary treatment 7

3. Blood Pressure Management (for BP ≥160/110 mmHg):

   • First-line IV antihypertensives 3:
     • IV hydralazine: 5-10 mg every 15-30 minutes
     • IV labetalol: 10-20 mg initially, then 20-80 mg every 10-30 minutes (maximum 220 mg)
     • IV nicardipine: Start at 5 mg/h, increase by 2.5 mg/h every 5-15 minutes (maximum 15 mg/h)
   • Target BP: <160/110 mmHg but maintain diastolic BP ≥85 mmHg to preserve uteroplacental perfusion 3

Monitoring and Assessment

1. Maternal Monitoring:

   • Continuous vital signs monitoring (BP, heart rate, respiratory rate, oxygen saturation)
   • Neurological assessment (headache, visual disturbances, hyperreflexia, clonus, level of consciousness)
   • Laboratory tests (twice weekly minimum) 1, 3:
     • Complete blood count with platelets
     • Liver function tests
     • Renal function tests
     • Uric acid levels
   • Strict fluid balance monitoring with urinary catheter (aim for output >30 mL/hour) 3
   • Monitor for magnesium toxicity:
     • Loss of patellar reflexes (early sign)
     • Respiratory depression (<16 breaths/min)
     • Keep calcium gluconate immediately available as antidote 5

2. Fetal Assessment:

   • Continuous fetal heart rate monitoring
   • Ultrasound for fetal biometry, amniotic fluid, and umbilical artery Doppler 1

Definitive Treatment: Delivery

Delivery is indicated in eclampsia regardless of gestational age 1, 3, 4. Additional indications for immediate delivery include:

• Uncontrolled severe hypertension despite treatment with 3 classes of antihypertensives
• Progressive thrombocytopenia
• Progressively abnormal renal or liver enzyme tests
• Pulmonary edema
• Persistent neurological symptoms
• Non-reassuring fetal status 1

Delivery considerations:

• Vaginal delivery is preferable when possible
• Cesarean section if maternal condition is deteriorating rapidly, fetal distress is present, or expedited delivery is needed 3

Postpartum Management

1. Continue close monitoring for at least 72 hours postpartum 3
2. Continue magnesium sulfate for at least 24 hours post-delivery 3
3. Continue antihypertensive therapy as needed 1, 3
4. Avoid NSAIDs for postpartum analgesia unless other analgesics are ineffective 1
5. Important: Eclamptic seizures may develop for the first time in the early postpartum period 1

Common Pitfalls and Caveats

1. Failure to recognize atypical presentations: Eclampsia can occur without prior signs of preeclampsia and up to several weeks postpartum 6, 2

2. Magnesium sulfate administration risks:

   • Monitor for toxicity (loss of reflexes, respiratory depression)
   • Use with caution in renal impairment (maximum 20g/48h) 5
   • Avoid abrupt cessation of therapy 5
   • Enhanced CNS depression when combined with other CNS depressants 5

3. Fluid management challenges:

   • Avoid fluid overload which can worsen cerebral edema and cause pulmonary edema
   • No plasma volume expansion is recommended 3

4. Long-term follow-up:

   • Review at 3 months postpartum to ensure BP, proteinuria, and laboratory abnormalities have normalized 1
   • Women with history of eclampsia have increased risk of recurrence (1-2%) and preeclampsia (22-35%) in subsequent pregnancies 6

By following this algorithmic approach to diagnosis and management, maternal and fetal outcomes in eclampsia can be significantly improved.