ED EEGs for Uncomplicated First-Time Seizure
The First-Time Seizure Emergency Department Electroencephalogram Study. Wyman et al. (2017) Annals of Emergency Medicine. 69(2):184-191.
To determine whether obtaining an EEG in the ED after first time uncomplicated seizure could identify patients with epilepsy as candidates for immediate initiation of an antiepileptic drug (AED) on discharge.
A prospective trial of a convenience sample of patients presenting with an uncomplicated first time seizure at a single tertiary care center in North Carolina. Inclusion criteria included all patients over age 18 who presented with first time generalized tonic-clonic seizure (GTC) or recurrent GTC without prior EEG, who have clinically returned to baseline and are eligible for discharge home, and who have some prior neuroimaging (CT or MRI) available for review. Exclusion criteria included patients who were to receive an AED regardless of EEG result or patients whose lab studies or neuroimaging revealed an obvious cause for the seizure.
Patients included in the study received a 30 minute bedside EEG performed by in-house EEG technicians. The tech contacted an epileptologist on completion of the EEG for immediate remote interpretation and recommendations for AED initiation. All patients were scheduled for outpatient epilepsy clinic follow up 2 weeks after discharge. EEG reads were categorized as epileptiform, abnormal nonepileptiform or normal, and were reviewed by a second epileptologist at a later time for evaluation of interobserver agreement. ED physicians were asked to obtain a seizure activity history focusing on focal symptoms, possible provocation and historical risk factors.
The primary outcome was clinical diagnosis of epilepsy and initiation of AED on ED discharge. Secondary outcomes included interobserver agreement for EEG interpretation and the association between seizure features and abnormal EEG results.
Sevety-one patients enrolled in the study received EEGs. Twenty-four percent (17/71) were discharged on AEDs, 88% (15/17) of those patients were diagnosed with epilepsy based on EEG findings. Four patients included in the study had abnormal findings on CT that correlated with an epilepsy focus on EEG. Twenty-seven percent (19/71) patients had abnormal nonepileptiform EEG findings and 52% (37/71) had normal EEG reads. The average time from seizure to EEG was 3.85 hours. They found sufficient agreement between 2 epileptologists (k = 0.69). There was no association between clinical or historical factors and abnormal EEG result. Forty-eight percent (34/71) of patients returned at 2 weeks for follow up and no changes in drug regimens were made at that time.
Bedside EEG in the ED diagnosed epilepsy in 21% of patients with uncomplicated first-time seizure and resulted in AED initiation in 24% of patients at ED discharge. Limitations of the study included availability of EEG techs, cost and effects on ED length of stay.