Current Practice Febrile

Febrile seizures (FS) are the most common seizure disorder in childhood. Studies from the developed world report 2-5 % of all children between the ages of 6 months to 5 years being affected. Although 6 months is considered as the lower age limit by many paediatricians, the National Institute of Health (NIH) and International League Against Epilepsy (ILAE) definitions on febrile seizures use a lower age limit of 3 months and 1 month respectively 1,2. It is defined as a seizure occurring in the context of a febrile illness, not secondary to a central nervous system (CNS) infection or an altered metabolic state in children who have not had neonatal or previous afebrile seizures. There are two main clinical forms: simple febrile seizures which are a single episode of generalised tonic clonic seizures lasting less than 10-15 minutes, occurring during the first 24 hours of a febrile illness. Majority (70-75 %) of FS are of this type. Those lasting longer or occurring after the first 24 hours or having multiple seizures during the same febrile illness or convulsions affecting one side of the body or occurrence of focal neurological deficits are called complex febrile seizures (9-35%). There is a third form which is febrile status epilepticus (FSE) and this constitutes 5 % of all FS. The phenotype of FS is not well defined; though in the NIH and ILAE definitions they are called an ‘event’, classically FS are generalised tonic clonic convulsions. Two conditions that may mimic FS in this age group are convulsions with gastroenteritis and febrile myoclonus. The first initially described amongst Asian children comprises convulsions that occur during gastroenteritis. These show similar presentation and characteristics to FS such as age of presentation, associated family history and recurrences 3. However, they tend to cluster more often, are less associated with a family history and have a lower rate of recurrence compared to FS. Febrile myoclonus is myoclonic seizures occurring during a febrile illness in a neurologically norma