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Martin L. Kutscher, MD; Departments of Pediatrics and Neurology, New York Medical College, Valhalla, NY. © 2004, 2006
Febrile seizure are very common, and occur in 3-4% of all children. They have an average age of onset of 24 months, and are rare <6 months or >5-6 years of age. They usually occur within 24 hours of onset of fever to >39 degrees. Febrile seizures can be classified as simple, complex, or atypical.
"Simple febrile seizures" last <15 minutes, are generalized, and occur only once per 24 hours.
"Complex febrile seizures" last >15 minutes, have a focal onset, or occur more than once per 24 hours.
"Atypical febrile seizures" differ in some other way from the above, such as a lower temperature than usual, unusual age of the child, etc. The more the seizure diverges from the classical syndrome, the better it is to call the events "seizures with fever." Such a label reminds us that we do not yet have a diagnosis. Febrile seizures should rarely be diagnosed in children who have afebrile seizures.
Although usually benign, febrile seizures are very frightening to watch. It may not seem like a major deal to doctors--now that the child is better and there is the backup of all of hospital equipment and staff--but the parents were likely convinced that they just witnessed the impending death of their child.
Lumbar Puncture and blood tests may be indicated acutely
EEGs, CTs, and MRIs
EEGs, CTs, and MRIs are not recommended in a neurologically healthy child with a first simple febrile seizure. They are usually obtained if the seizures are complex or atypical, the child is neurologically abnormal, or if there are multiple febrile seizures. Even so, studies fail to show the usefulness of EEGs of predicting epilepsy in these cases.
Children with typical simple febrile seizures are usually not hospitalized, assuming they look well, do not need hospitalization for general pediatric reasons, have been observed for several hours, and have reliable caretakers who are comfortable watching the child at home. Atypical or complex features place the children at risk for underlying pathology, and usually indicate the need for in-patient observation or treatment.
Risks and Treatment Options
In order to make logical decisions about long term treatment, the caregiver and parents need some underlying information. Although febrile seizures may well recur, even prolonged ones are unlikely to cause damage or epilepsy. The data underlying these issues are discussed in Table 4.
Armed with this information, we can make logical choices with the family regarding appropriate long term treatment options. Since the risk of developing epilepsy after febrile seizures is low, it does not make sense to treat a child with long term anticonvulsants just in case a few percent might develop epilepsy years into the future. Thus, most treatment options are aimed at preventing recurrent febrile seizures--events which we have seen are unlikely to cause damage. Options include rectal diazepam (Diastat) (table 5) and phenobarbital prophylaxis (table 6). Valproate (Depakane (TM)) prophylaxis is also effective for febrile seizure prophylaxis, but is rarely used in this setting because of its risks in this age range. Phenytoin (Dilantin (TM)) is not felt to be effective in the treatment of febrile seizures. Treatment should also include instruction on first aid for seizures and agressive temperature control.
Risks of Febrile Seizures
Take Home Message
for Families and Caregivers
|Febrile seizures recur in 1/3 of children who have had a febrile seizure. [Nelson]||The risk ranges from 50% recurrence if they
start before 1 year of age, to 10% if they start after age 3 years.
Berg identified 4 risk factors for recurrence of febrile seizures:
14% of children with no risk factors will recur, vs. a risk of 64% with with 3 or 4 risk factors [Berg].
|Epilepsy is uncommon after febrile seizures.||Children with febrile seizures have only a 0.9%
chance of developing epilepsy (compared to 0.5% in the general population).
Even children with a risk factors such abnormal neurological status, complex febrile seizures, or family history of epilepsy have only a 2-4% chance of developing epilepsy.
|Febrile seizures are unlikely to cause mental retardation or death.||Even febrile status is associated with a 98%
chance of no identifiable long term neurological damage. [Shinnar]
Other studies have shown a higher incidence of neurological sequelae of febrile status up to 24% .[Van Esch]
|Febrile status epilepticus has only a 3% chance
of recurring as status in a normal child.
The risk rises to 1/3 for children with neurological abnormalities. [Freeman].
|Berg showed that children with 3-4 of the
following risk factors have a 72% chance of febrile status epilepticus
recurring as status:
Indication for rectal diazepam in febrile seizures
Commonly used indications:
May be offered to any child with febrile seizures.
Children with prolonged febrile seizures.
Children with multiple febrile seizures.
Children with high risk of recurrent seizures.
Indication for phenobarbital prophylaxis
in febrile seizures
Neurologically abnormal children with prolonged febrile seizures.
Many practitioners would also prophylax neurologically normal children with prolonged febrile seizures for several weeks to several months.
Rarely, children with multiple febrile seizures or with high risk of recurrent seizures.
Phenobarbital given orally at the time of fever or seizure is not effective.
Most common side effects are hyperactivity, sedation, or rash.
1AAP, "Practice Parameter: The Neurodiagnostic Evaluation of the Child with a First Simple Febrile Seizure." Pediatrics 97 (5) 769-75. May 1996.
2Green S, "Can Seizures Be the Sole Manifestation of Meningitis in Febrile Children?" Pediatrics. 92 (4) 527-34. Oct. 1993.
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Disclaimer: This web site is presented as a resource to patients by Pediatric Neurological Associates. There are no commercial sponsors. This information does not constitute medical advice; nor is it a substitute for discussion between patients and their doctors. The views of cited references do not necessarily represent the views of our staff. This information was last modified 06/10/06.
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