Abstracts

Rationale: In adult series periodic lateralized epileptiform discharges (PLED) have usually been reported transiently during acute stroke, infection, or hypoxic encephalopathy. Data on PLEDs in children are limited to small case series. We report clinical and radiological features of 51 children (<18 years) with PLEDs on a scalp EEG. Methods: The EEG database at the Cleveland Clinic from 1990-2000 was searched using the key word PLED . Patients < 18 years were identified and their medical records and brain imaging were reviewed. Results: 89 EEGs on 51 children (6 days to 18 years, median 6.5 years) showed unilateral or bilateral PLEDs. In 14 of 51 (27%), PLEDs occurred after an acute or subacute neurological illness in previously healthy children (acute group) with acute infections and stroke being the most common etiologies. In the remaining 37 children (73%), PLEDs were seen in the setting of a pre-existing neurological illness (chronic group). All children in the chronic group had developmental delay and neurological deficits. In the chronic group, 14 (37%) developed new PLEDs (acute on chronic group) during seizure recurrence with or without status epilepticus while 23 (62%) had no acute worsening in their neurological status and PLEDs were a chronic finding in the setting of a malformation of cortical development (9), prior epilepsy surgery (7, no PLEDs before surgery), encephalomalacia from remote trauma (2) or stroke (2), and metabolic encephalopathy (2). Children with remote epilepsy surgery (n=7) were seizure free despite post-operative PLEDs. All other children in the chronic group had epilepsy. Mortality was high with 9 deaths out of 28 (32%) in acute and acute on chronic group compared to 2 out of 23 (8.5%) with chronically present PLEDs. Of 23 with chronically present PLEDs, 22 children had an EEG and clinical follow-up for 5 months to 9 years (median 4.5 years). 2 with metabolic disease died (both had BiPLEDs), 4 underwent hemispherectomy (3) or fronto-parietal resection (1) with disappearance of PLEDs and seizures after surgery, 7 with remote epilepsy surgery were seizure free, and 9 with inoperable MCD, remote head trauma and infarcts continued to have PLEDs or BiPLEDs and chronic persistent seizures on follow-up EEGs. Conclusions: While acute brain injury remains an important cause, PLEDs in children are more likely to be associated with preexisting chronic neurological condition with or without acute exacerbation. This recognition is important to avoid over emphasis on EEG, and relying on the clinical evaluation to guide further management in children.