Benign Childhood Seizure Susceptibility Syndrome

Posted on August 22, 2009 by clinicalpediatric

Benign childhood focal seizures and related epileptic syndromes are the commonest and probably the most fascinating and rewarding topic in paediatric epileptology. They affect 25% of children with non-febrile seizures and form a significant part of the everyday practice of paediatricians, neurologists and clinical neurophysiologists who care for children with seizures. Rolandic seizures (RS) are widely recognised and are associated with an excellent prognosis thanks to appropriate research and publications. Paediatricians have been receptive to and have made excellent use of this knowledge. Panayiotopoulos syndrome (PS), a common disorder with dramatic clinical and EEG manifestations, eluded us until recently. PS has now been formally recognised in the new ILAE diagnostic scheme and is becoming more readily diagnosed by physicians. Less common phenotypes, such as the Gastaut type-idiopathic childhood occipital epilepsy (G-ICOE) and idiopathic photosensitive occipital lobe epilepsy have also been recognised and defined. Furthermore, there are also children who manifest with seizures of predominantly affective symptoms, and there are claims of other benign childhood seizures associated with certain interictal EEG foci, such as frontal, midline or parietal, with or without extreme somatosensory evoked spikes.

Considerations on Nomenclature

These are detailed in the individual description of each of these benign childhood focal syndromes. Overall, benign childhood focal syndromes and their main representatives, BCECTS and PS, do not fulfil the diagnostic criteria of ‘epilepsy’ defined as “chronic neurological condition characterised by recurrent epileptic seizures”. BCECTS and PS are age-limited (not “chronic”) and at least one-third of patients have a single (not “recurrent”) seizure. They should be classified among “Conditions with epileptic seizures that do not require a diagnosis of epilepsy”, which is a new concept in the ILAE diagnostic scheme to incorporate “febrile, benign neonatal, single seizures or isolated clusters of seizures and rarely repeated seizures (oligoepilepsy)” (Table 1.7).

Schematic presentation of benign childhood seizure (more…)

Figure 9.1

Schematic presentation of benign childhood seizure susceptibility syndrome.*

Top: Over 90% of functional spikes are clinically silent.

Middle: Prevalence of functional spikes by location. Centrotemporal spikes predominate followed by occipital spikes.

Bottom: Rolandic seizures (64%) are 2.5 times more common than PS (25%), but this figure may change with increasing awareness of PS and the inclusion of less typical cases.

* The percentages are approximate estimations from available relevant clinical and EEG data on the prevalence of clinical phenotypes of benign childhood focal seizures and functional spikes in childhood.¹^;⁴

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Figure 9.1

Schematic presentation of benign childhood seizure susceptibility syndrome.*

Top: Over 90% of functional spikes are clinically silent.

Middle: Prevalence of functional spikes by location. Centrotemporal spikes predominate followed by occipital spikes.

Bottom: Rolandic seizures (64%) are 2.5 times more common than PS (25%), but this figure may change with increasing awareness of PS and the inclusion of less typical cases.

Schematic presentation of benign childhood seizure susceptibility syndrome.*

Top: Over 90% of functional spikes are clinically silent.

Middle: Prevalence of functional spikes by location. Centrotemporal spikes predominate followed by occipital spikes.

Bottom: Rolandic seizures (64%) are 2.5 times more common than PS (25%), but this figure may change with increasing awareness of PS and the inclusion of less typical cases.

It should also be emphasised that functional spikes of whatever location occur in 2–4% of children with or without seizures including apparently normal children without seizures and even more often children with non-epileptic neurological or medical disorders.

All these conditions may be linked together in a broad age-related and age-limited benign childhood seizure susceptibility syndrome (BCSSS), which may also constitute a biological continuum with febrile seizures and benign infantile and neonatal seizures. It is my thesis that the clinical, EEG, pathophysiological and management aspects of BCSSS should be properly re-examined and redefined. The 1989 ILAE classification recognised three “age-related and localization-related (focal, local, partial) epilepsies and syndromes” (Table 1.5):

Benign childhood epilepsy with centrotemporal spikes (BCECTS)
Childhood epilepsy with occipital paroxysms (Gastaut type)
Primary reading epilepsy

The new diagnostic scheme rightly reclassified “reading epilepsy” as a reflex epileptic syndrome (Table 1.7) and recognised three syndromes of “idiopathic childhood focal epilepsy”:²