Febrile Convulsions

Typical febrile convulsions are:

  • age 6 months to 6 years
  • Normal neurodevelopment
  • generalized, tonic-clonic

Most important differential is CNS infection eg encephalitis, meningitis.  These tend to present with posturing, impaired conscious level, or focal seizures. 15% of patients presenting with status epilepticus with fever have meningitis (observational study) – although low rate of LP so underestimate? I suspect there would have been other features to suggest meningitis beforehand.  Stiff neck? Fear of doing LP due to RICP from fit and/or meningitis, so do CT first if in ICU or abnormal neurology else as soon as no contraindication. If in doubt, treat empirically for meningitis (+/- herpes encephalitis, although risk unknown) with antibiotics and steroids. [Chin RFM, Arch Dis Child 2005;90:66-9.(Ed by Kneen)]

About 30-35% of febrile seizures in the absence of CNS infection however have one or more complex features:

  • focal onset,
  • duration >10 minutes,
  • or multiple seizures during the illness episode

Febrile status epilepticus, a subgroup of complex febrile seizures with seizures lasting more than 30 minutes, occur in about 5% of cases.  [BMJ 2015; 351 doi: http://dx.doi.org/10.1136/bmj.h4240 ]


One third of children with febrile convulsion/seizure (FS) will experience further FS; age would appear to be the single, strongest, and most consistent risk factor. Most recurrences will occur during the first year after the initial FS and over 90% recur within two years. Other risk factors for recurrence are –

  • family history of febrile seizures (but not epilepsy) in a first degree relative,
  • children whose initial FS occurred with a relatively low fever,
  • multiple initial seizures occurring during the same febrile episode.

Surprisingly, status in an otherwise normal child does not appear to significantly increase the risk for further febrile seizures or the development of epilepsy.

Information for Families

From European Journal of Pediatrics 2021: