Abstracts

RATIONALE: Periodic lateralized epileptiform discharges (PLEDs) are an electroencephalographic (EEG) finding seen in patients who present with acute stroke, infections or hypoxic encephalopathy. However, in most case series on PLEDs, there were a group of patients who had chronic intractable epilepsy with no acute deterioration and persistent PLEDs on EEG. The etiology of PLEDs in this group of patients who presented with chronic epilepsy without any acute deterioration is not known. We studied the etiology, clinical and neuroimaging findings, and outcome of children who presented with chronic epilepsy and PLEDs on EEG but without any acute clinical deterioration.
At the end of this activity, the participant should be able to recognize the causes of chronic PLEDs in children under the age of two years.
METHODS: The EEG database at the Cleveland Clinic from 1990 to 2000 was searched for children under the age of two years with EEG diagnosis of PLEDs. Their medical charts, neuroimaging and EEG records were then retrospectively reviewed.
RESULTS: Nineteen patients, 6 days-23 months in age, were identified with EEG diagnosis of PLEDs. Seven had acute neurological illness and 12 patients had chronic epilepsy with no acute deterioration. All patients in the chronic group had brain MRI. Malformations of cortical development (MCD) were seen in seven; three had PLEDs following functional hemispherectomy (2 hemimegalencephaly, 1 Sturge-weber); and two patients had metabolic diseases with basal ganglia lesions in one and normal brain MRI in the other. Of the seven patients with MCD, two had unilateral fronto-parietal cortical dysplasia, two had hemimegalencephaly, one had tuberous sclerosis with bilateral cortical tubers, one had lissencephaly, and one patient had bilateral diffuse cortical dysplasia. Eleven of the 12 patients with chronic PLEDs had a long-term follow-up (5months [ndash] 9years). The two with metabolic diseases died, and nine remained stable with persistent PLEDs on EEGs.
CONCLUSIONS: PLEDs may be seen in the children under the age of two years who have chronic intractable epilepsy due to MCD and metabolic diseases. PLEDs may not always represent an acute neurological illness.