Febrile Seizures
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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 while
others last for more than 15 minutes.
The majority of children with febrile seizures have rectal temperatures
greater than 102 degrees F. 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.
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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 6 months and 5 years and are particularly
common in toddlers. Children rarely develop their first febrile seizure
before the age of 6 months or after 3 years of age. The older a child is
when the first febrile seizure occurs, the less likely that child is to
have more.
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A few factors appear to boost a child's risk of having recurrent febrile
seizures, including young age (less than 15 months) during the first seizure,
frequent fevers, and 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.
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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
(see section entitled "What should be done for a child having a febrile
seizure?").
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
1 hour), most children recover completely.
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. These children include those who have febrile
seizures that are lengthy, that affect only part of the body, or that recur
within 24 hours, and children with cerebral palsy, 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.
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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.
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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.
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If a child has a fever most parents will use fever-lowering drugs such
as acetominophen or ibuprofen to make the child more comfortable, although
there are no studies that prove that this will reduce the risk of a seizure.
One preventive measure would be to try to reduce the number of febrile illnesses,
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, or
hyperactivity. Children vary widely in their susceptibility to such side
effects.
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The National Institute of Neurological Disorders and Stroke (NINDS), a
part of the National Institutes of Health (NIH), sponsors research on febrile
seizures in medical centers throughout the country. NINDS-supported 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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Epilepsy Foundation
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