Should I be worried about a child with a febrile convulsion?

(Taken from the July Emergency Department edition of Paediatric Pearls)

‘A febrile seizure usually occurs between 3 months and 5 years of age, associated with fever but without evidence of intracranial infection or defined cause for the seizure’. NIH, USA
Most febrile seizures are generalised tonic clonic (GTCS), but fever can provoke other types of fits. Differential diagnoses include rigors and faints. At least 50% are caused by viruses, 1% of patients have meningitis or encephalitis instead.

Simple Febrile Convulsions (70%):

  • GTCS
  • Last < 10 minutes, usually < 2 minutes
  • Do not recur within same illness

Complex Febrile Convulsions (30%):

  • GTCS or focal
  • Last > 10 minutes
  • Recur within 24 hrs
  • Need referral to paediatric team

For families:

  • Febrile seizures are common – 3-4% of children by age 7 will have had one
  • Short febrile seizures are not dangerous, those lasting > 30mins can be
  • May have more febrile fits but does not mean that the child has epilepsy

Risk of recurrence is 30-40% overall. Depends on number of risk factors (low temperature, < 18/12 old, family history, short duration of illness) present. No risk factors = 4%, 1 = 23%, 2 = 32%, 3 = 62%, 4 = 72% risk of recurrence.

Risk of developing epilepsy also depends on risk factors (abnormal neurodevelopment, complex febrile seizures, family history of epilepsy).

No risk factors = 0.5% (same as background population risk), 1 = 6-8%, all 3 = almost 50% risk.

Reference: Paediatric Epilepsy Training (PET) Level 1 course guide. See

Taken from the July Emergency Department edition of Paediatric Pearls

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3 thoughts on “Should I be worried about a child with a febrile convulsion?

    1. 1% of children who fit with a fever have encephalitis or meningitis. 99% don’t. Any child who has a fit lasting over 30 minutes or who has multiple fits over 30 minutes without fully regaining consciousness (status epilepticus definition) is at risk of significant morbidity. 70% of febrile fits last less than 10 minutes, the vast majority less than 2 minutes. The statistics in this article come from the British Paediatric Neurology Association ( ) and I hoped they would provide some sort of evidence on which to base one’s clinical decision making / level of worry in an individual case. The majority of children who fit with a fever have a generalised tonic clonic convulsion for less than 2 minutes with a temperature of over 38 degrees C and come round again, pretty much back to their normal self, by about 20 minutes later. I suppose my own level of concern rises a bit if they don’t fit this picture. I have recently done a teaching session with our juniors on febrile convulsions and you can find the Powerpoint slides, which are just an expanded version of this article really, at NICE don’t say anything about febrile convulsions that I am aware of. Their guideline is on epilepsy and febrile convulsions are not epilepsy.

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