Febrile Seizures and Other Paroxysmal Events in Early Childhood
Seizures and epilepsy are relatively common disorders in childhood. Seizures are characterized by the occurrence of paroxysmal motor, sensory, autonomic and/ or psychic symptoms. Epilepsy is dei ned as the occurrence of two or more unprovoked epileptic seizures. There are also several other conditions in childhood that can manifest with periodically occurring paroxysmal events. It is important to distinguish these non-epileptic paroxysmal events from epileptic seizures. This can be challenging as they may partially share the same clinical manifestations.
NON-EPILEPTIC PAROXYSMAL EVENTS
Non-epileptic paroxysmal events can be due to physiological or exaggerated physiological responses, parasomnias, movement disorders, behavioural or psychiatric disturbances, or to hemodynamic, respiratory or gastro-intestinal dysfunction (Table 1). Knowledge of the occurrence of non-epileptic paroxysmal events is to a large part based on studies on children referred to tertiary clinics because of the suspicion of refractory seizures. In these settings, the diagnosis, often based on prolonged observation and video-EEG registrations, appears to be non-epileptic in 20-40%. In a small study on 22 children under the age of 1 year referred to a
paediatric neurologist because of possible seizures, 59% had non-epileptic paroxysmal events. Not much is known about the incidence of paroxysmal events, and the incidence of diferent types of events relative to each other, in the general population. In the only study we have found, they were reported in 25% of the children in the i rst 2 years of life. The majority of these events were innocent events often related to feeding9. In the UK National Child Development Study, 6.7% of all children had experienced at least one episode of altered consciousness at the age of 11 years.
In conclusion, the etiology of febrile seizures is largely unknown. Most cases of common febrile seizures are considered to be multifactorial, inl uenced by a variation in several susceptibility genes as well as several pre-, and postnatal environmental factors. Cognitive outcome in school-aged children appears to be good, perhaps with exception of children with recurrent and prolonged febrile seizures, or a first seizure at young age.