The significance of febrile status epilepticus and complex febrile seizures

Febrile status epilepticus (FSE) occurs when febrile seizures (FS) are of at least 30 minutes duration. Since some complex FS (CFS) can be categorised as FSE, both are considered here. Of all FS, one-third are CFS and about 5% FSE. Important predisposing factors are positive family histories for epilepsy and young age. Previous neurodevelopmental anomalies, which can range from very mild to obvious, are frequently present. At presentation, the general physical well-being, and acute neurological status should be assessed. Lateralised features in the seizure and/or the physical examination are particularly important. The acute EEG cannot predict later epilepsy, but may show unexpected focal or lateralised changes. MRI is adding considerably to the understanding of FS: acute unilateral hippocampal swelling can be shown to be followed by atrophy. Prophylactic drug therapy may reduce the risk of prolonged recurrences, but does not prevent later epilepsy. At least one-third of those with prolonged lateralised FS have partial epilepsy later. Various types of neurological and learning difficulties have been identified after CFS and FSE. The pre-seizure state of the brain is crucial in the determination of the type of FS and of the ultimate outcome..