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 called simple and complex. They are determined by the length of seizure, how often they recur and recovery characteristics:

  • 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 very 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.