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Febrile Seizures
Febrile seizures are the most common convulsive disorder of
childhood. A febrile seizure is defined as a seizure associated with fever in
infancy or early childhood (usually between 3 months and 5 years of age),
without evidence of intracranial infection or other cause.
Febrile seizures are a benign syndrome
caused primarily by genetic factors, manifest as an age-related susceptibility
to seizures, which eventually is outgrown. The problem almost always resolves
without sequelae. Only a small minority will develop non-febrile seizures later.
Unless seizures are exceedingly long, there is no risk of brain damage.
Epidemiology
Febrile seizures occur in 2-4% of young
children. The most common age of onset is in the second year
Higher temperature and a history of febrile
seizures in a close relative are risk factors for the development.
Recurrence
After the first febrile seizure, 33% of
children will experience one or more recurrences, and 9% of children who have
febrile seizures.
The younger the child’s age when the first
febrile seizure occurs, the greater the likelihood.
Family history of febrile seizures is a risk
factor.
Short duration of fever before the initial
seizure and relatively lower fever at the time of the initial seizure.
Epilepsy.
Fewer than 5% of children who have febrile seizures actually develop epilepsy.
Genetics
Febrile seizures tend to occur in families. The risk of febrile seizures in younger siblings of children who have febrile convulsions is 10-20%, and the risk is higher if the parents have a history of febrile convulsions.
Risk factors for the development of epilepsy following febrile seizures include suspicious or abnormal development before the first seizure, family history of afebrile seizures, and complex first febrile seizure.
Pathophysiology
Most febrile illnesses associated with
febrile seizures are caused by common infections (tonsillitis, upper respiratory
infections.
Children of preschool age are subject to
frequent infections and high fevers. These children have a relatively low
seizure threshold, resulting in febrile seizures.
Clinical Evaluation
Febrile seizures usually occur early in
the course of a febrile illness, often as the first sign. The seizure may be of
any type, but the most common is tonic-clonic. Initially there may be a cry,
followed by loss of consciousness and muscular rigidity. During this tonic
phase, apnea and incontinence may occur. The tonic phase is followed by the
clonic phase of repetitive, rhythmic jerking movements, which is then followed
by postictal lethargy.
Treatment of Febrile Seizures
The child should be kept in the emergency
department or physician’s office for at least several hours and re-evaluated.
Most children will have improved and be alert, and the child may be sent home if
the cause of the fever has been diagnosed and treated. Hospital admission is
necessary if the child is unstable.
Parental Counseling
Parents are advised that febrile seizures
do not cause brain damage, and the likelihood of developing epilepsy or
recurrent non-febrile seizures.
There is a risk of further febrile seizures
during the current.
If another seizure occurs, the parent should place the child on his side or abdomen with the face downward. Nothing should be forced between the teeth. If the seizure does not stop after 10 minutes, the child should be brought to the hospital.
Control of fever with antipyretics (acetaminophen) and sponging is recommended, but this practice has not been proven to lower the risk of recurrent febrile seizures.
Childhood Immunizations.
Febrile seizures occur most commonly following a pertussis or DPT immunization
because pertussis provokes fever. The advantages of vaccines must be weighed
against the risk of pertussis if immunization is postponed. The greatest risk
for febrile seizure recurrences occurs in the 48 hours following a DPT
immunization and 7 to 10 days.
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