Febrile Seizures
What Are Febrile Seizures & Who Do They Affect?
These are seizures that are triggered when a child has a high fever (usually due to a urinary tract infection, Influenza, Roseola, or an ear infection). They’re not super common (affecting <5% of children), though happen enough that it’s good to know that they exist in case it happens to your child. They occur in children 6 months to 5 years of age and are more common in those with a family history of epilepsy. The fever is usually in the range of 103F-105F.
What Do They Look Like & How Long Do They Last?
They can be really scary to witness, especially if it’s the first time its happened. You’ll notice stiffening and rhythmic jerking of the arms and legs, the eyes rolling backwards, and loss of consciousness. Most last <15 minutes. There will typically be a short duration where the child is “out of it,” and can’t remember what happened, after which they should slowly return to their normal selves (albeit fatigued).
What Do I Do If It Happens?
Safety: Make sure your child is on a protected surface (if they are on a chair, the couch, or the bed, slowly move them to the floor so they can’t fall off and hurt themselves). Move away any nearby objects or furniture and position them on their side to prevent choking. It’s not recommend to hold them down, since this can cause injuries. If there’s anything near their mouth, gently remove it so they don’t choke.
Time The Seizure: This is the last thing most parents are thinking about when witnessing something so terrifying. However, it’s really helpful for the medical team to know, since longer seizures (>15 minutes) may qualify for further workup or need additional interventions. I recommend taking a video if you’re able to think clearly enough, since it helps us recognize the seizure type and verify the length (often, when something scary like this is happening, it feels a lot longer than it actually is).
Call Your PCP / 911:
If this is your child’s first febrile seizure, the CDC recommends going to the ER. This is to make sure that we’re not dealing with another (more scary) cause of seizures, like meningitis.
If the seizure lasts >5 minutes, involves focal shaking (e.g., of a single arm rather than the entire body), is associated with difficulty breathing, or there are multiple seizures within a 24-hour period, call 911.
If there is also neck stiffness, headache, or vomiting or if you have an infant with a bulging fontanelle (soft spot), since this is concerning for meningitis.
If your child isn’t returning to their baseline after the seizure finishes.
If your child is <6 months or >5 years, since this is outside of the range for febrile seizure and implies another cause.
If your child has a known history of febrile seizures, and they have a short (<5 minutes) seizure that looks like their normal type, you shouldn’t need to go to the ER, though I still advise calling your PCP to at minimum make an appointment for evaluation for the cause of the fever.
While febrile seizures are scary, the vast majority aren’t harmful and don’t cause any permanent damage.
Is Workup Needed?
There should be workup to identify and treat the cause of the fever. This often includes a full exam, urine sample, and viral testing to rule out the most common suspects. There may or may not be labs, depending on dehydration concerns or if they still can’t find a source of the fever. Once the cause is found, additional investigations aren’t usually needed. We don’t do head imaging (such as a CT or MRI), since it doesn’t tell us much about the cause and comes with radiation exposure. A lumbar puncture (sample of spinal fluid) will only be done if there’s concerns about meningitis. In some cases (e.g., seizures >15 minutes, or those with focal rather than full-body shaking), an EEG may be ordered to rule out epilepsy. This is typically ordered on an outpatient basis by your PCP.
Can You Prevent Febrile Seizures?
If only! Unfortunately, the research right now says that you can’t, even if you give Tylenol or Motrin to try and keep the fever down.
Can They Happen Again?
Yes. About 40% of children with a febrile seizure will have future recurrences, so it’s good to work out a plan with your PCP for when they occur, including when to call 911. They should space out as your child gets older, and should disappear entirely at 5 years of age.
Does This Mean My Child Has Epilepsy?
Not necessarily! A febrile seizure is a separate category of seizures, and doesn’t indicate epilepsy on its own. However, there is a slightly higher risk of epilepsy in these children compared to those that haven’t had febrile seizures.
Additional Notes:
If your child is in daycare, inform the staff of this medical diagnosis and of appropriate safety precautions in case one occurs at the facility. While most daycare staff should be CPR-trained, it helps them to know to keep an extra eye on your child if they’re sick, and reminds them to refresh their seizure first aid skills.
While febrile seizures can occur after certain vaccinations (specifically MMR and Varicella, especially the combination MMRV vaccine), it’s important to note that the vaccine isn’t what causes the seizures - it’s the fever! I try to counsel all my families receiving these vaccines on the risk of febrile seizure so they know what to expect, and emphasize that it’s still safe and recommended to continue the series even if one has occurred.
