Febrile Seizures: A Convulsion Caused By Fever
Posted May. 1, 2014, 8:16 am
Special To The Mirror
By Kiarash Sadrieh, MD
CHLA Pediatric Neurologist
Children with fevers are usually miserable. Their bodies can ache, they are listless, and they just don’t feel well. While fever is a part of our natural response to infection, the fever itself can lead to complications. One rare, but particularly frightening, complication is a febrile seizure.
As a father, I can’t imagine too many things more distressing than seeing my already-ill child suffer through a seizure; but as a pediatric neurologist, I recognize that febrile seizures are usually benign and self-limited.
Typically, the child will lose consciousness, stiffen and have full-body shaking. Usually, a seizure lasts only a minute or two, but can go on longer. Febrile seizures rarely require medication. The majority of the cases we see at Children’s Hospital Los Angeles do not require hospital admission.
Febrile seizures are convulsions that occur in the setting of a fever in children between six months and six years of age. The majority occur between 12 and 18 months of age. Children who suffer a febrile seizure do not have epilepsy. That diagnosis requires the presence of two or more seizures that were not caused by a fever. Seizures due to an infection of the brain and its protective lining (meninges) or seizures associated with metabolic problems are not febrile seizures.
A Common Occurrence
Febrile seizures are the most common type of seizure in childhood, affecting 2 to 5 percent of children (one in 20). They are a frequent reason that children are referred to the Children’s Hospital Los Angeles Emergency Department and pediatric clinics. Although the exact mechanism by which a fever provokes a seizure in this susceptible age group is not fully understood, genetic predisposition is a factor.
Febrile seizures are generally divided into two categories: simple febrile seizures and complex febrile seizures. Simple febrile seizures are more common. They involve full-body shaking and last less than 15 minutes. A febrile seizure is considered complex if it affects only a part of the body, lasts longer than 15 minutes or recurs within 24 hours. Complex febrile seizures have a slightly higher rate of future complications.
Although febrile seizures are scary, they are usually not associated with significant health problems. Short febrile seizures do not cause brain damage, and studies show that simple febrile seizures do not affect future school performance or intelligence. The chances of epilepsy developing in a healthy developmentally typical child who has had a simple febrile seizure are estimated to be 2 to 4 percent, while the rate in the general population is about 1 to 2 percent.
How To React
If a child has a seizure, febrile or otherwise, it is important to stay calm. The child should be placed on his or her side to prevent choking. There is no need to restrain the child or try to stop the shaking; the seizure will run its course regardless. Never put anything in the child’s mouth. This can lead to chipped teeth, damaged gums or even a blocked airway.
The next thing to do is to time the seizure. We recommend parents call 911 for seizures that last more than five minutes, as medication may be needed to end the seizure. While brief seizures don’t require emergency services, parents should have the child evaluated that day, mainly to check for the cause of the fever.
In addition to routine tests to evaluate fever, certain situations require further diagnostic testing. For example, a lumbar puncture is indicated if meningitis is suspected. A lumbar puncture, or spinal tap, involves the insertion of a small needle in the lower back in order to remove a sample of cerebrospinal fluid for analysis. A well-appearing and fully immunized child with a simple febrile seizure does not require a lumbar puncture. However, depending on a child’s age, immunization status, recent illnesses or physical examination, a spinal tap may be required to assess the brain and meninges for infection. Electroencephalography (EEG) and imaging such as a CT scan or an MRI are not required for simple febrile seizures. Children with simple febrile seizures usually do not need to be hospitalized once the fever evaluation is complete. Blood and urine tests are only performed if needed to evaluate the fever.
Treatment is usually limited to fever-lowering agents such as acetaminophen or ibuprofen. Daily anti-seizure drugs are not recommended. Sometimes, children who have a prolonged febrile seizure are given a medication to use only if they have another long seizure. The chance of recurrence is generally 30 to 35 percent. Factors such as young age (less than 12 months) or a family history of seizures can increase the recurrence rate. Treating fevers aggressively with fever-lowering drugs does not decrease the chance of having another febrile seizure, but it will make the child more comfortable.
Seizures are frightening, but knowing what to do if one occurs is important. If your child has a febrile seizure, make sure he or she sees your pediatrician or an emergency department physician as soon as possible. While simple febrile seizures are not harmful, we need to make sure they are not a symptom of a more serious illness. Talk with your pediatrician to determine if a consultation with a pediatric neurology specialist is appropriate for your child.
Kiarash Sadrieh, MD, is a CHLA pediatric neurologist with office hours at Children’s Hospital Los Angeles – Santa Monica, our outpatient care center, at 1301 20th St., Ste. 460, Santa Monica, CA 90404. For appointments call 310.820.8608. For information, go to CHLA.org/SantaMonica. Kiarash Sadrieh is the co-program director of the Child Neurology Residency at CHLA and also serves as an assistant professor of Clinical Neurology and Pediatrics at the Keck School of Medicine of the University of Southern California.