What is the best course of treatment for a patient with a known history of seizures (epilepsy) who presents to the emergency room (ER) after a seizure?

Management of ER Visit After Seizure in Patient with Known Epilepsy

For patients with known epilepsy who present to the ER after a seizure and have returned to baseline, focus on identifying precipitating factors (medication noncompliance, subtherapeutic drug levels, acute illness), resume or optimize their baseline antiepileptic regimen, and discharge home with close neurology follow-up if no concerning features are present. 1, 2

Initial Assessment and Stabilization

Immediate laboratory evaluation:

• Check serum glucose and sodium immediately, as these are the only laboratory abnormalities that consistently alter acute management 2, 3
• Obtain antiepileptic drug levels if the patient takes phenytoin, valproate, carbamazepine, or phenobarbital to identify subtherapeutic levels as the seizure trigger 2
• Assess whether the patient has returned to neurological baseline, as this is the critical determinant of disposition and workup intensity 1, 2

Key clinical questions to address:

• Was this a breakthrough seizure due to medication noncompliance or subtherapeutic levels? 2
• Is there an acute precipitating factor (provoked seizure) such as infection, electrolyte disturbance, alcohol withdrawal, or new medication? 1
• Has the patient fully returned to their neurological baseline? 2, 3

Neuroimaging Decision Algorithm

Perform emergent CT head without contrast if ANY of the following high-risk features are present: 2, 3

• Recent head trauma
• Persistent altered mental status beyond the expected post-ictal period
• New focal neurological deficits
• Fever suggesting CNS infection
• History of cancer or immunocompromised state
• Anticoagulation use

For patients without high-risk features who have returned to baseline, neuroimaging can be deferred to outpatient follow-up. 3

Antiepileptic Drug Management

For Patients with Subtherapeutic Drug Levels

Route of administration options (both equally effective for preventing recurrence): 1

Intravenous loading (if patient cannot tolerate oral):

• Fosphenytoin: 18 PE/kg IV at maximum rate of 150 PE/min 2
• Valproate: up to 30 mg/kg IV at maximum rate of 10 mg/kg/min 2
• Levetiracetam: 1,500 mg IV load 2

Oral loading (for stable patients at baseline):

• Phenytoin: 20 mg/kg divided in maximum doses of 400 mg every 2 hours 2
• Levetiracetam: 1,500 mg oral load 2

The American College of Emergency Physicians found no significant difference in seizure recurrence rates between oral and intravenous routes when resuming antiepileptic medications in patients with known seizure disorders. 1

Management of Active or Recurrent Seizures

If seizure activity persists or recurs in the ED:

• Administer benzodiazepines immediately for any seizure lasting >5 minutes: midazolam 0.2 mg/kg IM (maximum 6 mg per dose), may repeat every 10-15 minutes 2
• If seizures persist after optimal benzodiazepine dosing, administer additional antiepileptic medication such as IV valproate, fosphenytoin, or levetiracetam 1, 2

Critical Observation Period

Patients should remain under observation for at least 6 hours, as 85% of early seizure recurrences occur within this timeframe. 2, 3, 4

The overall 24-hour recurrence rate in patients with known epilepsy presenting after a seizure is 9.4%, with mean time to first recurrence of 121 minutes (median 90 minutes). 2, 4

Disposition Decision Algorithm

Criteria for Hospital Admission: 2, 3

• Persistent abnormal neurological examination
• Failure to return to baseline within several hours
• Status epilepticus requiring ongoing treatment
• Concern for underlying acute process (infection, stroke, intracranial hemorrhage)
• Abnormal investigation results requiring inpatient management
• Inability to ensure medication compliance or follow-up

Criteria for Safe Discharge: 2, 3

• Patient has returned to clinical baseline
• Normal neurological examination
• No persistent altered mental status
• No abnormal investigation results requiring inpatient management
• Reliable neurology follow-up arrangements established
• Patient or caregiver can ensure medication compliance

Common Pitfalls to Avoid

Do not assume alcohol withdrawal as the cause in first-time presentations without excluding other symptomatic causes. 3 Alcohol withdrawal seizures should be a diagnosis of exclusion, especially in patients with known epilepsy presenting with breakthrough seizures.

Do not discharge patients who have not returned to baseline. 2, 3 Persistent altered mental status beyond the expected post-ictal period warrants further investigation and observation.

Do not miss acute precipitating factors. 1 Provoked seizures occur within 7 days of acute neurologic, systemic, metabolic, or toxic insults including hyponatremia, hypoglycemia, withdrawal, toxic ingestions, encephalitis, or CNS mass lesions.

Do not forget to check for medication interactions. 5 Carbapenem antibiotics (ertapenem, imipenem, meropenem) can reduce valproic acid concentrations to subtherapeutic levels, resulting in loss of seizure control.