The Facts on Febrile Seizures

Few events are as traumatic for a parent as watching your child have a seizure. Unfortunately, this is fairly common, as up to 5% of all children will have a seizure with a fever. The good news is that these episodes are usually benign, with no lasting consequences. The thought of a seizure can be horrifying to parents, so get the facts.

What is a Febrile Seizure?

The American Academy of Pediatrics defines a febrile seizure as a “seizure accompanied by fever (>100.4° F or 38° C by any method), without central nervous system infection, that occurs in infants and children 6 through 60 months of age.”

But what does that look like? To most parents, the scene is frightening, even if you have seen someone have a seizure before. Most children with a febrile seizure will have a brief period of looking strange or being “out of it,” followed by stiffening, then uncontrollable jerking of the arms, legs, and body. She will probably be unresponsive during this time, and for a short time afterwards. During the seizure, she may roll her eyes, as well.

Febrile seizures come in two types: simple and complex. A simple seizure lasts less than 15 minutes and does not recur within 24 hours. A complex seizure lasts longer than 15 minutes, or recurs within 24 hours, or is localized (not affecting the entire body, as described above, but limited to just one area of the body).

Most children will develop the febrile seizure within 24 hours of the illness, and up to 21% of febrile seizures occur within an hour of the fever’s onset. Seizures that occur 3 or more days after the onset of fever most likely are not febrile seizures.

Why Do Children Have Febrile Seizures?

Febrile seizures seem to be more dependent on the person and not solely on the height of the fever, though higher fevers are more likely to result in febrile seizures. Many people can get high fevers and never develop a seizure, but others will have a febrile seizure at much lower temperatures.

Part of the reason for this seems to be genetics. The more relatives with febrile seizures, the more likely it is for a person to have a febrile seizures. If a person has a sibling with febrile seizures, the risk is 10% to 45%, much higher than the 2% to 5% in the general population.

One large study from Korea identified other factors that increased the risk for febrile seizures, including male gender, preterm birth, and brain injury at birth.

What Should I Do If My Child Has A Febrile Seizure?

The short answer is, “Not much.” Many parents understandably become frantic when their child has a febrile seizure, and they feel like they have to do something. The reality is that most maneuvers parents try can do more harm than good. For example, it’s a myth that someone who seizes can “swallow their tongue.” This doesn’t happen, so don’t put anything in the child’s mouth to “prevent” this as this can cause further trauma to the teeth or mouth.

The most important thing to do is to keep the child safe until the seizure is over. Follow these tips:

  • Try to remain calm
  • Place her on the floor or bed away from any hard or sharp objects
  • Turn her head to the side to allow any saliva or vomit to drain from her mouth
  • Do not put anything in her mouth
  • Do not restrain her
  • Call 911 if the seizure lasts longer than 5 minutes

Watching a child have a febrile seizure can be a terrifying experience, and parents naturally want to do something, anything to help their child. But as a pediatrician, I often tell parents that if the child is in a safe position, it’s best to follow this rule of thumb: “Don’t just do something, stand there.”

After your child has stopped having the seizure, you should call your doctor. It is important to identify and possibly treat the source of infection.

What Are the Consequences of Febrile Seizures?

The good news is that if your child is safe (not falling down the stairs or riding a bike at the time of the seizure), then nothing bad will happen to her due to the febrile seizure. Febrile seizures do not cause brain damage, intellectual disability, paralysis, nervous system problems, or death.

Children younger than 1 year at the time of their first febrile seizure have a 50% chance of having another one, but children older than 1 year have a 30% chance of recurrence.

Over 97% of children who have a febrile seizure will not have epilepsy later in life, though the risk of this is higher in these children. The risk of developing epilepsy is 1%-2.4% following a simple febrile seizure, and 4%-6% after a complex febrile seizure (compared to 0.5% in the general population).

What Can I Do to Prevent a Febrile Seizure?

Again, the answer is, “Not much.” Remember that most fevers in infants are benign, and there can be serious consequences to being overly aggressive with anti-fever medications. Too much acetaminophen (Tylenol®) can lead to liver damage, which is far more dangerous than the febrile seizure. In addition, acetaminophen and ibuprofen can reduce fevers, but won’t prevent a febrile seizure. If your child has already had a febrile seizure, talk to your doctor about what to do the next time she has a fever. Don’t alternate medicines (acetaminophen and ibuprofen), and don’t put her in a cold water bath. Use a weight-appropriate dose of acetaminophen or ibuprofen (but not both), apply cool washcloths on forehead for comfort (also won’t prevent febrile seizures, but will help your child feel better), and call your doctor if you’re worried.

Ruben Rucoba
Dr. Rucoba has over 25 years of experience as a primary care pediatrician after completing medical school at the University of California, San Francisco. His clinical areas of expertise include caring for children with special health care needs and assisting families with international adoption. He has been a freelance medical writer since 2010, writing for health websites, continuing medical education providers, and various print outlets. He currently works at Wheaton Pediatrics in the suburbs of Chicago, where he lives with his wife and four daughters, including a set of twins.

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