Definition (Pediatrics 2008;121:1281; Pediatr Rev 2007;28:363)
• Simple febrile seizure: Brief (<15 min), generalized (nonfocal) occurring once in a 24-hr period in a febrile child. Usually limited and no further workup required.
• Complex febrile seizure: Prolonged (>15 min), focal component, and/or >1 episode within 24-hr period. Often requires ancillary workup/neuroimaging to r/o focal etiology.
Epidemiology (J Child Neurol 2002;17:S44)
• Most common szr disorder in children, affects ∼2–5% between ages 6–60 mo
• Risk factors: 1st-/2nd-degree relative h/o febrile szr, peak temp, & rate of rise
Pathophysiology (J Child Neurol 2002;17:S44; Trends Neurosci 2007;30:490)
• Mechanism unclear, may be related to rate of rise of fever or actual peak temp (usually >102). Possible cytokine & temp effect on ion channels & neuronal tissue
Diagnostic Studies (Pediatrics 2011;127:389)
• In general, focus should be on fever workup and not workup of seizure itself
• 1st simple febrile seizure: No workup
• Complex febrile seizure: CBC w/ diff, Chem 10, EEG; lumbar puncture (LP) (as below), neuroimaging if focal (MRI preferred)
• LP: Not routinely warranted for simple febrile szr but recommended for:
• Signs suggestive of meningitis or intracranial infection. Be aware that meningeal sx may be absent in infants <12 mo and subtle in pts 12–18 mo
• Infants 6–12 mo w/ unknown or deficient Hib or Strep pneumo vaccination status
• Current or recent antibiotics use (risk of partially rx’d meningitis, can mask sx)
• Febrile status epilepticus
• EEG: Not recommended in eval of neurologically healthy pts w/ 1st simple febrile szr
• No assoc btw abnl EEG & future febrile szr or development of epilepsy
• Neuroimaging: Not recommended in routine eval of first simple febrile seizure
• Laboratory studies: No evidence that routine blood studies (Chem7, Ca, Mg, Phos, CBC, or blood glucose) are of benefit in eval of first simple febrile seizure
Treatment (Pediatrics 2008;121:1281; Pediatr Rev 2007;28:405)
• Most febrile seizures require no intervention and end within <10 min
• Anticonvulsant therapy is not recommended for simple febrile seizures
• For prolonged or recurrent febrile szr, rx for home rectal diazepam (0.3–0.5 mg/kg) may be provided for outpt treatment of szr lasting >5 min
• Children w/ complex febrile seizures are candidates for trial of antiepileptic drug (AED) prophylaxis, such as phenobarbital, benzodiazepines, or valproate. However, there is no evidence associating a reduced risk of epilepsy with prophylactic AED use
• Antipyretics have not been shown to ↓ risk of recurrence of simple febrile seizures
Complications (Pediatrics 2008;121:1281; J Child Neurol 2002;17:S44)
• Almost all w/ excellent prognosis. No evidence that simple febrile szr causes IQ decline
• May progress to febrile status epilepticus. Usually focal and often the pts’ 1st febrile szr (Neurology 2008;7:170)
• Minimal ↑ risk of developing epilepsy. Simple febrile seizure carries 1% risk, same as compared to general pop. ↑ to 2.4% if multiple simple febrile seizures, <12 mo at the time of the 1st febrile seizure, or +family history of epilepsy
• Febrile szrs frequently recur. Risk ∼30% if 1st szr occurs >12 mo or ∼50% if 1st szr occurs <12 mo. Recurrence risk also ↑ if +FHx febrile szr, lower peak temp w/ 1st szr, and shorter duration of fever w/ 1st febrile szr