What is the emergency management of a patient with a history of seizures presenting with another seizure?

Emergency Management of Seizures in Patients with Known Seizure History

For patients with a history of seizures presenting with another seizure in the emergency department, benzodiazepines should be administered as first-line treatment, followed by fosphenytoin, levetiracetam, or valproate as second-line agents if seizures persist despite optimal benzodiazepine dosing. 1

Initial Assessment and Management

Immediate Stabilization

• Ensure patent airway, adequate breathing, and circulatory support
• Position patient to prevent aspiration
• Administer supplemental oxygen if needed
• Obtain IV access promptly
• Monitor vital signs continuously

First-Line Treatment: Benzodiazepines

Lorazepam is the preferred benzodiazepine:

• Dosing: 4 mg IV given slowly (2 mg/min) for adults 2
• If seizures continue after 10-15 minutes, an additional 4 mg IV dose may be administered 2
• Underdosing of lorazepam is common and associated with progression to refractory status epilepticus 3

Alternative benzodiazepine options if IV access is challenging:

• Intranasal lorazepam (0.1 mg/kg, max 4 mg) has similar efficacy to IV administration 4
• IM lorazepam can be used when IV access is unavailable, though it has slower onset 2

Second-Line Treatment (if seizures persist after benzodiazepines)

According to the most recent ACEP guidelines (2024), the following agents have similar efficacy for refractory seizures 1:

1. Fosphenytoin

   • Dosing: 18-20 PE/kg IV at maximum rate of 150 PE/min
   • Advantages: Can be administered IM if IV access is difficult
   • Monitor for: Hypotension, cardiac arrhythmias

2. Levetiracetam

   • Dosing: 60 mg/kg IV (maximum 4500 mg)
   • Advantages: Fewer drug interactions, minimal hemodynamic effects
   • Well-tolerated in most patients

3. Valproate

   • Dosing: Up to 30 mg/kg IV at maximum rate of 10 mg/kg/min
   • Advantages: Potentially fewer adverse effects than phenytoin
   • Contraindicated in liver disease and certain metabolic disorders

Concurrent Diagnostic Workup

While treating the seizure, investigate potential causes:

• Obtain basic labs: Electrolytes, glucose, calcium, magnesium, BUN/creatinine, CBC
• Check anticonvulsant drug levels if patient is on medication
• Screen for toxins/drugs that lower seizure threshold
• Consider neuroimaging if there are new focal neurologic findings or altered mental status persists

Common Pitfalls to Avoid

1. Inadequate benzodiazepine dosing: Using less than the recommended dose of lorazepam (4 mg in adults) is associated with progression to refractory status epilepticus 3

2. Delayed administration of second-line agents: Don't wait too long to initiate second-line therapy if seizures persist after benzodiazepines

3. Failure to identify and treat underlying causes: Always search for treatable causes including hypoglycemia, hyponatremia, hypoxia, drug toxicity, and CNS infections 1

4. Missing non-convulsive status epilepticus: Consider this in patients with persistent altered mental status after apparent seizure resolution

5. Inappropriate medication selection: Phenytoin may be ineffective for seizures due to alcohol withdrawal, theophylline toxicity, or isoniazid toxicity 5

Special Considerations

• For patients with known seizure disorder who have missed their regular medications, resuming their antiepileptic medication is appropriate, though evidence doesn't favor oral versus parenteral administration 1

• Status epilepticus (seizure lasting >5 minutes or multiple seizures without return to baseline) requires aggressive management as it carries significant mortality and morbidity risk 1

• Consider early involvement of neurology for patients with refractory seizures not responding to second-line therapy

• Equipment for airway management should always be immediately available when administering benzodiazepines 2