Generalized periodic epileptiform discharges in critically ill children: a continuum of status epilepticus or an epiphenomenon?

PURPOSE: Generalized periodic epileptiform discharges (GPEDs) are a specific periodic EEG pattern, reported with status epilepticus (SE) or a metabolic or an anoxic encephalopathy in critically ill patients. In this study, we examined the clinical course and evolution of EEG findings associated with GPEDs in children with refractory convulsive SE.

METHODS: The EEG reports of 279 children with SE diagnosed between 2002 and 2010 were reviewed to detect GPEDs. Ten children were identified with GPEDs on continuous EEG recording. The entire EEG recording was available for review in only six children. In the clinical course, seizure characteristics and evolution of EEG findings were analyzed.

RESULTS: Six children (age, 5 to 17 years) were admitted to the intensive care unit with refractory convulsive SE. All had acute symptomatic SE except for one child with a history of epilepsy and developmental delay. Intravenous anesthetic agents were used to treat convulsive SE in five children. After tapering the intravenous anesthetic agents, GPEDs were seen on the continuous EEG recording, nonconvulsive seizures occurred in five, and nonconvulsive SE in four children. None of the children returned to baseline, and three children died.

CONCLUSIONS: Generalized periodic epileptiform discharges are seen during the treatment course of convulsive SE in children and heralded seizure recurrence. We found a sequential evolution of the EEG patterns after the control of convulsive SE, with GPEDs occurring in a dynamic fashion in a continuum along with burst suppression and electrographic seizures. Recognizing that GPEDs represent a still active epileptic state after the control of convulsive SE with intravenous anesthetic agents and modifying the treatment regimen to control GPEDs may prevent immediate seizure recurrence.