Febrile seizure

Revision as of 00:04, 15 September 2019 by ClaireLewis (talk | contribs) (Clinical Features)


  • 50% of patients never have temperature >39
  • Febrile seizures do not increase the risk of serious bacterial illness


  • 2-3% chance of developing epilepsy (1% for general population)
  • 50% of patients <12 mo will have another simple febrile seizure
  • 30% of patients >12 mo will have another simple febrile seizure

Clinical Features

Simple Febrile Seizure

  • Age 6mo-5yr
  • Single seizure in 24hr
  • Duration <15min
  • Generalized
  • Returns to neurologic baseline and has normal neuro exam after brief post-ictal period

Complex Febrile Seizure

  • As above, elements of one or more of the following:
    • Can be focal or generalized OR
    • Prolonged or multiple seizures in 24hr period OR
    • Not returned to baseline or abnormal neuro exam
  • May indicate more serious disease process

Differential Diagnosis

Pediatric seizure

Pediatric fever



  • Glucose in all patients

Simple febrile seizure

Complex febrile seizure


The key is to distinguish between simple febrile seizure secondary to minor illness vs. seizure from serious central nervous system infection, which may also present with fever and seizure.

Algorithm for the differentiation between simple and complex febrile seizures. Guidelines for evaluation of each.

Simple versus Complex

  • Simple
    • Generalized tonic-clonic seizure
    • <15 min in duration
    • Age 6mo - 5yr
    • Occurs only once in 24hr period
    • No focal features
  • Complex
    • Any exception to above


Ongoing Seizure

See Seizure (peds)

Seizure Stopped



  • Simple febrile seizure if patient at baseline
    • Follow-up in 1-2d
    • Around-the-clock acetaminophen may prevent seizure recurrence in the same febrile episode[2]
  • Complex febrile seizure if patient well-appearing, work-up normal
    • Follow-up in 24hr


  • Ill-appearing
  • Lethargy beyond postictal period

See Also


  1. Baxter P. et al. Pyridoxine‐dependent and pyridoxine‐responsive seizures. Developmental Medicine & Child Neurology 2001, 43: 416–42
  2. Murata et al. Acetaminophen and Febrile Seizure Recurrences During the Same Fever Episode. Pediatrics. November 2018, VOLUME 142 / ISSUE 5