What Are Febrile Seizures?
Febrile
seizures are convulsions brought on by a fever in infants or small children. During a febrile
seizure, a child often loses consciousness and shakes, moving limbs on both sides of the body. Less commonly, the child becomes rigid or has twitches in only a portion of the body, such as an arm or a leg, or on the right or the left side only.
Most febrile seizures last a minute or two, although some can be as brief as a few seconds. Others can last for more than 15 minutes.
The majority of children who experience febrile seizures have rectal temperatures greater than 102 degrees Fahrenheit. Most febrile seizures occur during the first day of a child's fever. Children prone to febrile seizures are not considered to have
epilepsy, since epilepsy is characterized by recurrent seizures that are not triggered by fever.
Statistics on Febrile Seizures
Approximately one in every 25 children will have at least one febrile seizure, and more than one third of these children will have additional febrile seizures before they outgrow the tendency to have them.
Febrile seizures usually occur in children between the ages of six months and five years and are particularly common in toddlers. Children rarely develop their first febrile seizure before the age of six months or after three years of age. The older a child is when the first febrile seizure occurs, the less likely that child is to have more.
Risk Factors for Febrile Seizures
A few factors appear to boost a child's risk of having recurrent febrile
seizures, including the following:
- Being younger than 15 months old at the time of the first seizure
- Having frequent fevers
- Having immediate family members with a history of febrile seizures.
If the seizure occurs soon after a fever has begun or when the temperature is relatively low, the risk of recurrence is higher. A long initial febrile seizure does not substantially boost the risk of recurrent febrile seizures, either brief or long.
Are Febrile Seizures Harmful?
Although they can be frightening to parents, the vast majority of febrile seizures are harmless. During a seizure, there is a small chance that the child may be injured by falling or may choke from food or saliva in the mouth. Using proper
first aid for seizures can help avoid these hazards.
There is no evidence that febrile seizures cause brain damage. Large studies have found that children with febrile seizures have normal school achievement and perform as well on intellectual tests as their siblings who don't have seizures. Even in the rare instances of very prolonged seizures (more than one hour), most children recover completely.
Febrile Seizures and Epilepsy
Between 95 and 98 percent of children who have experienced febrile seizures do not go on to develop
epilepsy. However, although the absolute risk remains very small, certain children who have febrile seizures face an increased risk of developing epilepsy. Those at greatest risk for epilepsy include:
- Children whose febrile seizures affect only part of the body, are lengthy, or recur within 24 hours
- Children with cerebral palsy (or those exhibiting delayed development or other neurological abnormalities).
Among children who don't have any of these risk factors, only one in 100 develops epilepsy after a febrile seizure.
First Aid Techniques for Febrile Seizures
If a febrile
seizure occurs, parents should stay calm and carefully observe the child. To prevent accidental injury, the child should be placed on a protected surface such as the floor or ground. The child should not be held or restrained during a convulsion. To prevent choking, the child should be placed on his or her side or stomach. When possible, the parent should gently remove all objects in the child's mouth. The parent should never place anything in the child's mouth during a convulsion.
Objects placed in the mouth can be broken and obstruct the child's airway. If the
seizure lasts longer than 10 minutes, the child should be taken immediately to the nearest medical facility for further treatment. Once the seizure has ended, the child should be taken to his or her doctor to check for the source of the fever. This is especially urgent if the child shows symptoms of stiff neck, extreme lethargy, or abundant vomiting.
Diagnosing and Treating Febrile Seizures
Before diagnosing febrile seizures in infants and children, doctors sometimes perform tests to be sure that seizures are not caused by something other than simply the fever itself. For example, if a doctor suspects the child has
meningitis (an infection of the membranes surrounding the brain), a spinal tap may be needed to check for signs of the infection in the cerebrospinal fluid (fluid that bathes the brain and spinal cord). If there has been severe
diarrhea or vomiting, dehydration could be responsible for seizures. Also, doctors often perform other tests such as examining the blood and urine to pinpoint the cause of the child's fever.
A child who has a febrile seizure usually doesn't need to be hospitalized. If the seizure is prolonged or is accompanied by a serious infection, or if the source of the infection cannot be determined, a doctor may recommend that the child be hospitalized for observation.
Preventing Febrile Seizures
If a child has a fever, most parents will use fever-lowering drugs such as
acetaminophen or
ibuprofen to make the child more comfortable; however, there are no studies that prove that this will reduce the risk of a
seizure. Obviously, reducing the number of febrile illnesses would help with prevention of febrile
seizures, although this is often not a practical possibility.
Prolonged daily use of oral anticonvulsants, such as phenobarbital or valproate, to prevent febrile seizures is usually not recommended because of their potential for side effects and questionable effectiveness for preventing such seizures.
Children especially prone to febrile seizures may be treated with the drug
diazepam orally or rectally, whenever they have a fever. The majority of children with febrile seizures do not need to be treated with medication, but in some cases a doctor may decide that medicine given only while the child has a fever may be the best alternative. This medication may lower the risk of having another febrile seizure. It is usually well tolerated, although it occasionally can cause:
- Drowsiness
- A lack of coordination
- Hyperactivity.
Children vary widely in their susceptibility to such side effects.
Research on Febrile Seizures
Scientists are exploring what environmental and genetic risk factors make children susceptible to febrile seizures. Some studies suggest that women who smoke or drink alcohol during their pregnancies are more likely to have children with febrile seizures, but more research needs to be done before this link can be clearly established.
Scientists are also working to pinpoint factors that can help predict which children are likely to have recurrent or long-lasting febrile seizures.
Investigators continue to monitor the long-term impact that febrile seizures might have on intelligence, behavior, school achievement, and the development of
epilepsy. For example, scientists conducting studies in animals are assessing the effects of seizures and anticonvulsant drugs on brain development.
Investigators also continue to explore which drugs can effectively treat or prevent febrile seizures and to check for side effects of these medicines.
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