Benign childhood focal epilepsies: assessment of established and newly recognized syndromes

Abstract

A big advance in epileptology has been the recognition of syndromes with distinct aetiology, clinical and EEG features, treatment and prognosis. A prime and common example of this is rolandic epilepsy that is well known by the general paediatricians for over 50 years, thus allowing a precise diagnosis that predicts an excellent prognosis. However, rolandic is not the only benign childhood epileptic syndrome. Converging evidence from multiple and independent clinical, EEG and magnetoencephalographic studies has documented Panayiotopoulos syndrome (PS) as a model of childhood autonomic epilepsy, which is also common and benign. Despite high prevalence, lengthy and dramatic features, PS as well as autonomic status epilepticus had eluded recognition because emetic and other ictal autonomic manifestations were dismissed as non-epileptic events of other diseases. Furthermore, PS because of frequent EEG occipital spikes has been erroneously considered as occipital epilepsy and thus confused with the idiopathic childhood occipital epilepsy of Gastaut (ICOE-G), which is another age-related but rarer and of unpredictable prognosis syndrome. Encephalitis is a common misdiagnosis for PS and migraine with visual aura for ICOE-G. Pathophysiologically, the symptomatogenic zone appears to correspond to the epileptogenic zone in rolandic epilepsy (sensory-motor symptomatology of the rolandic cortex) and the ICOE-G (occipital lobe symptomatology), while the autonomic clinical manifestations of PS are likely to be generated by variable and widely spread epileptogenic foci acting upon a temporarily hyperexcitable central autonomic network. Rolandic epilepsy, PS, ICOE-G and other possible clinical phenotypes of benign childhood focal seizures are likely to be linked together by a genetically determined, functional derangement of the systemic brain maturation that is age related (benign childhood seizure susceptibility syndrome). This is usually mild but exceptionally it may diverge to serious epileptic disorders such as epileptic encephalopathy with continuous spike and wave during sleep. Links with other benign and age-related seizures in early life such as febrile seizures, benign focal neonatal and infantile seizures is possible. Overlap with idiopathic generalized epilepsies is limited and of uncertain genetic significance. Taking all these into account, benign childhood focal seizures and related epileptic syndromes would need proper multi-disciplinary re-assessment in an evidence-based manner.