A febrile seizure is a convulsion (shaking, twitching, muscle tightness) or fainting associated with a fever. It occurs in infants or small children. This seizure is not associated with any other illness or medical condition except the fever.

There are two types of febrile seizures:

  • Simple febrile seizures:
    • Convulsions last between a few seconds to 15 minutes
    • Seizures are followed by a period of confusion and sleepiness which slowly goes away
  • Complex febrile seizures:
    • Last longer than 15 minutes
    • Occur more than once within 24 hours
    • Convulsions which affect only part the body

Febrile seizures can be alarming. Fortunately, children tend to outgrow these seizures. There is also a low risk for long term physical or mental disorders.

High body temperature due to a fever is believed to trigger the seizure. The fever is most often caused by common viral infections. Some febrile seizures may be caused by fever after routine immunizations.