Epilepsy MUSC

Comprehensive Epilepsy Center

A Febrile Seizure vs a Seizure with a Fever

Learn more about febrile seizures, when they occur and how to tell the difference between a febrile seizure and a seizure with a fever.

What are Febrile Seizures?

This is a very important question, because some physicians get it wrong. “Febrile” is a term that means fever. Some physicians make the diagnosis of febrile seizure for any childhood seizure that occurs in the context of fever. However, there are two particular features that characterize true febrile seizures.

  • First, the seizure must occur without any warning. Any indication of what is to follow (such as staring, distress, or jerking of the face or hand) suggests the possibility that the seizure has begun in one region of the brain and is spreading throughout the brain. This argues against the event being a febrile seizure.
  • The second characteristic feature is that the seizure must be “generalized”. That means the entire body is symmetrically involved in stiffening or jerking. Seizures that begin in one part of the body and seizures that are generalized from the outset have two different mechanisms of action. (This is important for deciding which medication to use.) The important point is that true febrile seizures must occur without warning and should not follow a period of staring.

When Do Febrile Seizures Occur?

Febrile seizures typically begin between 6 months and 2 years of age. They usually last only a few minutes, rarely over 10. Often one of the child’s parents had febrile seizures as a child. Febrile seizures typically have a good outcome, which means that most children with febrile seizures outgrow them by 6 years of age. For this reason many physicians elect not to treat febrile seizures, except to minimize the risk of fever which triggers them. This approach, with the reassurance that often comes with it, is misplaced if the seizure does not meet the basic criteria above. While true febrile seizures do not require as thorough an evaluation as do other seizures, it is important that any seizure that does not meet the above criteria be carefully evaluated.

Seizure with Fever vs. Febrile Seizures?

The problem becomes more confusing because any type of seizure is more likely to occur during fever, not just febrile seizures. Fever—like illness, sleep deprivation, and alcohol—can lower the seizure threshold, making it easier for a seizure to occur. The good outcome that is associated with febrile seizures is not necessary guaranteed in other seizure types that occur with illness and fever. Make sure both you and your pediatrician understand the difference between these two types of seizure disorders.


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