Childhood Absence Epilepsy evolving to Eyelid Myoclonia with Absence Epilepsy

Abstract

Purpose: Children with Childhood Absence Epilepsy (CAE) may develop generalized tonic-clonic seizure or juvenile myoclonic epilepsy. A possible evolution to Eyelid Myoclonia with Absence Epilepsy (EMA) hasn't been documented yet. We report the electroclinical features of a case series of children with CAE that evolved to EMA after therapy withdrawal.

Method: Of 108 patients with CAE referred at our Epilepsy Center in the last ten years, 5 satisfied the inclusion criteria: CAE diagnosis, a minimum of 3 years follow-up, a progression to EMA after therapy withdrawal.

Results: All the six subjects were females. CAE was characterized by typical absences induced by hyperventilation; intermittent photic stimulation (IPS) was negative. All subjects were treated successfully with valproate. After drug withdrawal, all the six girls presented EMA. EMA was characterized by eyelid myoclonia with or without brief absences related to generalized spike/polyspike-waves discharges induced by IPS and less frequently by eye-closure.

Conclusions: Our study documented another possible evolution of CAE into EMA. These results support the hypothesis that these two epileptic conditions are dynamic processes evolving into one another. CAE and EMA could be considered "system epilepsy" characterized by a high susceptibility to changes in the brain networks during specific life periods such as childhood and puberty.