Long-term outcome and prognosis of patients with emergent periodic lateralized epileptiform discharges (ePLEDs)

Purpose: Emergent EEG (eEEG) is an EEG performed on a non-elective basis upon request from a clinician for a seemingly emergency indication. Little is known about the long-term prognosis of patients with emergent periodic lateralized epileptiform discharges (ePLEDs).

Methods: We analyzed the EEG and clinical records of patients with ePLEDs from January 2002 to December 2008.

Results: Out of 1948 eEEGs, 79 (4%) patients had ePLEDs. Sixty-three patients had ePLEDs and 16 had eBiPLEDs (emergent bilateral periodic lateralized epileptiform discharges). The etiology of ePLEDs was CNS infection and inflammation (35.4%), stroke (32.9%), and metabolic encephalopathy (11.4%). Of the surviving 52 (65.8%) patients with ePLEDs, 34 (65.4%) had persistent seizures during a mean follow-up of 28 months (range 12-72 months). Seizure as the initial presentation was more commonly seen in children as compared to adults (64% versus 31%, p=0.005). CNS infection and inflammation were also seen more frequently in the pediatric age group (50% versus 27%, p=0.04). At follow-up, patients with eBiPLEDs had more seizures than patients with ePLEDs (87.5% versus 61.3%).

Conclusion: ePLEDs is associated with significant morbidity and mortality. However, the etiology of ePLEDs and brain dysfunction will influence the long-term outcome. This information is invaluable for prognostication and underscores the importance of rigorous management of patients with ePLEDs.