What is the appropriate emergency department workup for a patient with a history of seizures presenting after a seizure?

Emergency Department Workup for Patients with History of Seizures

For patients with a known seizure history presenting after a seizure, the emergency department workup should focus on identifying potential triggers, medication compliance, and ruling out acute complications, while avoiding unnecessary testing in patients who have returned to baseline. 1

Initial Assessment

• Immediate priorities:

  • Assess airway, breathing, and circulation
  • Evaluate neurological status and vital signs (including temperature, heart rate, blood pressure, oxygen saturation)
  • Determine if patient has returned to baseline mental status
  • Position patient in lateral safety position if actively seizing

• Focused history:

  • Timing and characteristics of current seizure
  • Comparison to typical seizure pattern
  • Medication compliance (critical as 58.5% of patients with known seizures are immediately noncompliant) 2
  • Recent medication changes
  • Potential triggers (alcohol, sleep deprivation, illness)
  • Associated symptoms (fever, headache, trauma)

Laboratory Evaluation

• Essential laboratory tests:

  • Serum glucose (most common metabolic abnormality) 3, 1
  • Electrolytes, especially sodium (hyponatremia is a common trigger) 3, 1
  • Antiepileptic drug levels (if on medication)
  • Pregnancy test for women of childbearing age 1

• Conditional laboratory tests (based on clinical suspicion):

  • Complete blood count (if infection suspected)
  • Toxicology screen (if substance abuse suspected, though routine use not supported) 1
  • Calcium, magnesium (if clinically indicated by history or exam findings) 3
  • Lumbar puncture (only if fever, immunocompromised state, or clinical suspicion of CNS infection) 1

Neuroimaging

• Neuroimaging is NOT routinely indicated for patients with known seizure disorder who have returned to baseline after a typical seizure 3

• Indications for emergent neuroimaging:

  • New focal neurological deficit
  • Persistent altered mental status
  • Fever or persistent headache
  • Recent trauma
  • Anticoagulant use
  • Immunocompromised state
  • Seizure pattern different from baseline 1

Management Considerations

• Medication management:

  • For patients with subtherapeutic antiepileptic levels, consider loading dose in the ED 3
  • Common loading strategies include:
    • Carbamazepine: 8 mg/kg oral suspension (single load)
    • Gabapentin: 900 mg/day oral (300 mg tid)
    • Phenytoin, valproate, and levetiracetam are most commonly used 2

• Risk factors for early seizure recurrence (within 24 hours):

  • Age ≥40 years
  • Alcoholism (highest risk in alcoholic patients with history of seizures - 25.2%)
  • Hyperglycemia
  • Glasgow Coma Scale score <15 3

Disposition Criteria

• Discharge criteria:

  • Return to neurological baseline
  • No recurrent seizures in ED
  • Normal or non-acute findings on neuroimaging (if performed)
  • Reliable follow-up available
  • Responsible adult to observe patient 1

• Admission criteria:

  • Status epilepticus or recurrent seizures in ED
  • Persistent altered mental status
  • Acute symptomatic seizure requiring treatment
  • Significant abnormality on neuroimaging
  • Inability to complete outpatient workup 1

Common Pitfalls to Avoid

1. Overreliance on routine laboratory testing - Studies show that clinical examination can accurately predict the need for most laboratory tests, with routine serum chemistries having extremely low yield in patients with known seizure disorders who return to baseline 4

2. Failure to check medication compliance - More than half of patients with known seizure disorders are noncompliant with medications, making this assessment critical 2

3. Unnecessary neuroimaging - Patients with known seizure disorders who return to baseline after a typical seizure rarely benefit from emergency neuroimaging 3

4. Missing early seizure recurrence - Most early seizure recurrences happen within 6 hours (median 90 minutes), with 85% occurring within 360 minutes 3

5. Overlooking alcohol as a trigger - Chronic alcohol consumption is a significant predictor of medication noncompliance (OR: 2.78) 2