Atypical Evolutions of Idiopathic Focal Epilepsies in Childhood

The recognition of epilepsies in children associating focal clinical manifestations andelectroencelphographic (EEG) discharges with the features of functional epilepsies and a benign outcome has been one of the most interesting contributions to pediatric epileptology in the past 50 years.

Absence of structural lesions and genetic predisposition in the presence of age-related seizures prompted the use of the term benign. But, can we denominate as benign an epilepsy syndrome in which some cases may not show at all a benign evolution?

The most recent International League Against Epilepsy (ILAE) report lists three well-defined syndromes of idiopathic focal epilepsies in childhood (IFEC): benign childhood epilepsy with centrotemporal spikes, Panayiotopoulos syndrome, and idiopathic childhood occipital epilepsy of Gastaut.

The concept of epileptic syndromes was constructed on the bases of recognizing particular aggregations of types of seizures and EEG epileptiform abnormalities. As is natural, each patient may present typical or atypical features guiding to diagnosis. The aim of this review is to update the identification of patients who are first diagnosed as one of the IFEC and later evolve into epileptic encephalopathies within the spectrum of continuous spike-and-wave during slow sleep (CSWS) or electrical status epilepticus during sleep (ESES). These four subsyndromes are: atypical benign focal epilepsy of childhood, status of IFEC, Landau-Kleffner syndrome, and CSWS/ESES syndromes. We disclose a small group of children who present each of these atypical evolutions alternate in variable sequences.

It is true that the majority of cases with Landau-Kleffner syndrome are not clearly related to previous IFEC, as that many patients with CSWS/ESES syndrome belong to the category of symptomatic epileptic encephalopathies.

Pathophysiologic mechanisms of these atypical evolutions and genetic studies in IFEC are specially focused, while treatment of classic syndromes and of atypical evolutions of IFEC are also detailed.

We present our new series with a significant number of patients diagnosed as epileptic encephalopathies appearing in the course of IFEC and include criteria to prevent these complications and to treat them once they are recognized.

We appreciate very much the collaboration in this special issue of a group of international well-known leaders of opinion in the subject.