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.