Febrile Seizure

What is a Febrile Seizure?

A seizure is described as an involuntary spasm of muscles. Febrile seizures occur
in developmentally and neurologically normal children between ages 6 months to 5
years of age who are also experiencing a fever and who are without an infection
of the central nervous system. Febrile seizures occur in 2-5% of all children under
5 years of age. While frightening, they are generally benign events.

Two classifications exist:

  1. The simple febrile seizure is a single, brief episode associated with a fever
    and it resolves within 15 minutes.
  2. The complex febrile seizure lasts longer than 15 minutes and/or it recurs
    within a 24 hour period.

Who is at Risk for Febrile Seizures?

Three risks have been identified as possible predisposing factors for febrile seizures:
height and duration of the temperature, a first degree relative with a history of
febrile seizures, and if it occurs in association with vomiting and diarrhea.

One third of children will have a recurrence of a febrile seizure, more commonly
between 12 – 24 months of age.

Four risks have been identified for recurrence of febrile seizures:

  1. First degree relative with a history of febrile seizures,
  2. Age of onset less than 18 months of age,
  3. Temperature greater than 104 degrees Fahrenheit (40 degrees Celsius), and
  4. Rapid onset (less than one hour between the onset of the fever and occurrence of a seizure).

How are Febrile Seizures Diagnosed?

A practitioner will perform a history and physical exam and determine if any other
tests would be helpful to assess the problem. No routine blood tests are necessary
to diagnose a febrile seizure.

Lumbar puncture should be performed if an infection of the nervous system is suspected
or if a child is under 18 months of age and your practitioner has a concern for
a nervous system infection. An electroencephalogram (EEG) is not indicated unless
a complex febrile seizure occurs or if a child has a neurological abnormality. An
MRI is reserved for difficult cases; for example, seizures with neurological changes
and/or changes on an EEG exist.

How is a Febrile Seizure Treated?

A fever is best treated with antipyretic medication (Acetaminophen and/or Ibuprofen)
and administered prior to an event. If the seizure occurs, avoid danger to the child
by assuring safe placement of the head and avoiding choking. Parents should activate
their local emergency medical system (i.e. call 911) if the child has a loss of
consciousness for greater than 1 minute. Treatment of a single febrile seizure is
not indicated since only one third of children will have a second febrile seizure.

Typically an anticonvulsant medication is chosen for children with a known underlying
neurological abnormality or if a recurrent febrile seizure is prolonged. The onset
of a febrile seizure does not occur with every fever; therefore, treatment is specific
to the case and chosen by the practitioner and parents. Intermittent therapy has
been used. Most of the medications that have been studied do have side effects (including
sedation, aggressiveness, euphoria, cognitive changes, weight changes, blood abnormalities
etc.). The medications include diazepam, phenobarbital, and valproate. Diazepam
has been the most favorable and can be administered orally or rectally, Two drugs
are ineffective in preventing recurrent febrile seizures phenytoin and carbamazepine.

What are the Complications of Febrile Seizures?

Febrile seizures do not result in serious complications, including mental retardation,
a decrease in IQ, cerebral palsy, neurological damage, epilepsy or learning difficulties.
Thus the simple febrile seizure has no long or short term effect. No recommendation
to restrict activities exists.

Can a Febrile Seizure be Prevented?

Acetaminophen and Ibuprofen are used to treat fever but have not been proven to
prevent a seizure or its recurrence. Nothing has been guaranteed to prevent an initial
febrile seizure.


Baumann RJ, Duffner PK: Treatment of Children with Simple Febrile Seizures: The
AAP Practice Parameter. Pediatric Neurology 2000;23 (1):11-17.

Shinnar S, Glauser TA: Febrile Seizures. Journal of Child Neurology 2002;17:S44-S52.

Provisional committee on Quality Improvement Subcommittee on Febrile Seizures: Practice
Parameter: The Neurodiagnostic Evaluation of the Child with a First Simple Febrile
Seizure. Pediatrics/AAP 1996:71-74.

Hampers L: Diagnosis and Management of Febrile Seizures. Pediatric Emergency Medicine
at The Children’s Hospital, Denver Colorado p 1-8.

Reviewed by: Sunit Gill MD

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