Febrile Seizures



Febrile seizures are a common cause of convulsion in pediatric populations. The diagnosis is one of exclusion, as the child should no signs of CNS infection, metabolic abnormality nor have a history of seizures. The seizure is associated with temps above 38 C and ages less than 6 years.



  1. It is not entirely understood why febrile illness is associated with seizures but some fever induced cytokines may increase the risk for convulsions in pediatric populations with developing CNS and genetic susceptability.
  2. Both viral and bacterial infections provide an impetus for fever and subsequently febrile seizures.


Clinical Features

  1. Incidence of 3-4 %
  2. 6 mo-5 years with greatest incidence between 14-18 months. Unusual < 9 months
  3. Most are generalized seizures and last between 1-2 minutes.
  4. Usually occur early in the course of an illness or may be the presenting symptom of the illness
  5. Frequently there is a positive family history of febrile seizures
  6. Often associated with otitis media and HHV 6 infection 
  7. If seizures lasts longer than 15 minutes, must treat like an afebrile seizure and start usual first aid measures and give anticonvulsants 
  8. Must rule out intracranial infection, intracranial abnormality, endo or exotoxin such as Salmonella or Shigella infection, or first seizure of an idiopathic seizure disorder
  9. There is a 30% incidence of recurrence and this is increased the earlier in life the first seizure occurs, the lower the temperature, and the shorter the duration of the fever prior to the seizure
  10. is an increased rate of afebrile seizures. The rate is increased by
    1. Complex seizure- greater than 15 minutes, focal, and recurrence within 24 hours
    2. Positive family history of afebrile seizures
    3. Previous neurologic disorder
    4. Recurrent seizures with fevers
    5. First seizure < 1 year of age


Differential Diagnosis

  1. Meningitis and encephalitis are major concerns when a child presents with fever and convulsions
  2. Metabolic abnormality
  3. Electrolyte imbalance
  4. Epiliepsy


Laboratory Evaluation

  1. Dependent on the condition and underlying illness of the child
    1. LP should always be considered, but standardized use in febrile seizures is disputed. If LP is conducted, seurm cultures and blood glucose should also be collected.
    2. CBC and serum electrolytes should also be considered
  2. EEG- not usually indicated because will not predict the incidence of future afebrile seizures even if abnormal
  3. CT and MRI- only indicated if suspect intracranial pathology


Disposition of the Child

  1. If the child looks well and the parent are comfortable, the child may be sent home. 
  2. Usually anticonvulsants are not necessary at the time of the first seizure . 
  3. Explain the chances of recurrences, 
  4. Treat the fever aggressively
  5. to do if the child has another seizure 
  6. Reassure the family that seizures usually will not cause death, mental deficiency, and neurologic sequelae.


Treatment to Prevent Recurrent Febrile Seizures

  1. Opinion is divided on whether to treat prophylactically daily. Drugs that have been used are Phenobarbital, Valproic acid, and Primidone
  2. Pro
    1. Seizures are scary and upsetting to the families
    2. Patient may injure themselves during the seizure
    3. have increased risk of afebrile seizures if there are recurrences
  3. Con
    1. No deaths or neurologic sequelae
    2. medications have side effects and compliance usually poor
    3. Child treated differently because has had seizure and treatment will enhance these feelings and increase anxiety
  4. therapy at the time of the febrile illness
    1. Oral and rectal diazepam (if seizure lasts longer than 5 minutes)
    2. Aggressive antipyretics
  5. Most important treatment is to discuss febrile seizures with the families and reassure them.



  1. Rosman NP et al, A Controlled Trial of Diazepam Administered During Febrile Illness to Prevent Recurrence of Febrile Seizures NEJM July 8, 1993.
  2. Hirtz D.G. Febrile Seizures. Pediatrics in Review. 1997
  3. Baumann R.J. Technical Report: Treatment of the Child with Simple Febrile Seizures. Pediatrics. 1999
  4. Duffner P.K. and Baumann R.J. A Synopsis of the American Academy of Pediatrics' Practice Parameters on the Evaluation and Treatment of Children with Febrile Seizures. Pediatrics in Review. 1999
  5. AAP Febrile Seizures: Clinicl Practice Guideline for the Long-Term Management of the Child with Simple Febrile Seizures.  Pediatrics June 2008
  6. Kimia A. et al. Utility of Lumbar Puncture for First Simple Febrile Seizure among Patients 6-18 Months of Age.  Pediatrics Jan 2009
  7. Kimnia A. Yield of LP with First Complex Febrile Seizure.  Pediatrics July 2010
  8. AAP Report. Febrile Seizures: Clinical Practice Guideline for the Neurodiagnositic Evaluation of the Child with a Simple Febrile Seizure.  Pediatrics Feb 2011