Eclampsia

Life-threatening generalised tonic-clonic seizure and coma occurring in a woman with pre-eclampsia or gestational hypertension.

This covers eclampsia. Pregnancy induced hypertension and pre-eclampsia is covered at Hypertensive Diseases of Pregnancy.

Epidemiology and Risk Factors

Eclampsia:

  • Occurs in ~0.05% of pregnancies
  • Timing is variable:
    • 60% of cases occur antepartum
      • 50% pre-term
      • 20% 20-30 weeks
    • 20% intrapartum
    • 20% post-partum
      90% within 1 week of delivery.
  • Recurrent seizure in 10%

Pathophysiology

Mechanisms are not well understood but may include the following apparently mutually exclusive hypotheses:

  • Loss of cerebral autoregulation
    • Hyperperfusion
    • Endothelial dysfunction
    • Vasogenic oedema
  • Maintenance of autoregulation leading to extreme vasoconstriction
    • Hypoperfusion
    • Localised ischaemia

Clinical Manifestations

Generalised tonic-clonic seizure with unconsciousness with a post-ictal period lasting 10-20 minutes, preceded in most cases by:

Despite this, 25% of cases have no precipitating signs or symptoms.

  • Hypertension
  • Headache
  • Visual disturbances
  • Abdominal pain
    • Epigastric
    • RUQ

Other features of pre-eclampsia may also be evident, including:

  • Hyperreflexia/clonus
  • Visual deficits
  • Altered mental status
  • Cranial nerve deficits

Diagnostic Approach and DDx

Investigations

Bedside:

Laboratory:

Imaging:

  • CTB
    Evaluate for intracranial complications.

Other:

Management

  • Airway protection and aspiration prevention
  • Terminate seizure with magnesium
  • Correct hypertension
  • Prevent recurrent seizure
  • Expedite delivery

Management of co-existing pre-eclampsia is crucial, and is covered at Hypertensive Diseases of Pregnancy.

Resuscitation:

  • A
    • Airway protection
      Prevention of aspiration.
  • B
    • Supplemental oxygen
  • C
    • Control of blood pressure
      • Target SBP 140-150mmHg and DBP 90-100mmHg
      • Strategy depends on severity of hypertension
        • Hypertensive crisis:
          • Labetalol
            • 20-80mg IV over 2 minutes
              Can repeat every 10 minutes.
          • Nifedipine
            • 10-20mg PO IR
          • Hydralazine
            • 10mg IV Q20 minutes
          • GTN
            For hypertension and APO
  • D
    • Seizure treatment and prophylaxis
      • Magnesium Sulphate
        • Prophylaxis and treatment for eclampsia in women with severe pre-eclampsia
          Not recommended for use as an antihypertensive agent.
        • Multifactorial mechanism of action:
          • ↑ Prostacyclin synthesis
          • ↓ Calcium influx
            Thereby ↓ ATP-consuming Ca2+-dependent processes.
          • NMDA antagonism
        • Give 4g over 20 minutes, and then 1g/hr thereafter
        • Target level is 1.7-3.5mmol/L
        • Blood levels should be performed:
          • Q6H in women with renal impairment
          • If any of:
            • RR < 12
            • UO < 100ml over 4 hours
            • Loss of patella reflexes
            • Seizures
              Including repeat seizures.
        • Magnesium toxicity
          • Associated with muscular weakness, rarely respiratory arrest
          • Unlikely if deep tendon reflexes present
          • Treated with:
            • Calcium
            • RRT
      • Anticonvulsants
        • Conventional anticonvulsants are only indicated for:
          • Persistent seizures (>5 minutes) with therapeutic magnesium levels
          • Magnesium contraindication
        • Benzodiazepines
          • Lorazepam 4mg IV
          • Midazolam 1-2mg IV

Specific therapy:

  • Pharmacological
    • Blood pressure control
  • Procedural
    • Expedite delivery

Disposition:

  • ICU Admission
    • Following seizure
    • Commonly required after delivery

Marginal and Ineffective Therapies

Anaesthetic Considerations

Complications

  • Death
  • A
    • Aspiration
  • D
    • Intracranial haemorrhage
    • Cerebral oedema
    • Cerebral venous thrombosis

Prognosis

Key Studies

References

  1. Bersten, A. D., & Handy, J. M. (2018). Oh’s Intensive Care Manual. Elsevier Gezondheidszorg.