Febrile seizure

Background

• Criteria: Seizure + temp >38 in pt age 6 mo - 6 yr without previous afebrile seizure
• Simple versus complex:
• Simple
• <15 min in duration
• No focal features
• Only a single episode in 24 hours
• Complex
• Any exception to above
• Risk Factors
• Family history (2-4x higher)
• Infection (viral and bacterial)
• Recent vaccinations
• Recurrence
• Risk of recurrence:
• If first seizure occurs in age <1yr = 50%
• If first seizure occurs in age 1-3yr = 25%
• If first seizure occurs in age >3yr = 12%
• Majority of recurrences occur within 1st year; almost all occur within 2 years
• Risk factors for recurrence include:
• Young age at onset
• Family history of febrile seizures
• Low-degree of fever in the ED
• Brief duration between onset of fever and initial seizure
• Complex febrile seizure does not increase risk of recurrent seizures

Diagnosis/Work-Up

• Consider trauma, toxidromes, infection/ petechiae
• Glucose check
• if sz >5 min tx with IM, IV, IN Versed
• Consider trauma or toxic cause
• Classifly as simple or comple
• Search for devel delay, fam hx,
• Physical exam should focus on source of fever
• Routine lab tests other than blood glucose not needed unless searching for cause of fever (UA, CBC, CXR, etc)
• Consider LP if:
• Age <12 mo (AAP guidelines)
• However, bacterial meningitis is rarely the diagnosis if it not clinically suspected
• Seizure occurs after the second day of illness
• Concern for CNS infection
• Febrile status epilepticus
• Pmd visit w/ in 48 hrs
• Sz in ED
• Focal sz
• Abnormal neuro/ phys exam
• Irritable, poor feeding
• Complex features
• Slow postictal clearance
• Pretreated with abx (consider partially tx meningitis if already on abx)
• CT if:
• Persistently abnormal neuro exam (especially with focal features)
• Signs/symptoms of increased ICP
• Consider for presence of VP shunt
• Routine EEG not indicated
• Consider only if developmental delay or for focal symptoms

DDx

• Meningitis
• More likely in patients with status epilepticus
• Seizure due to identifiable cause (e.g. intracranial mass, trauma)
• Epidural/subdural infection or hematoma

Treatment

• Treat if initial seizure persists >5 min or for subsequent seizures
• Benzodiapazines
• Lorazepam (0.05 - 0.1mg/kg)
• If seizure persists try one additional dose (risk of resp. depression incr if >2 doses)
• Effective duration of action is up to 4-6 hours
• Midazolam (0.1-0.3mg/kg)
• Diazepam
• Compared to lorazepam, less effective and more respiratory depression
• Fosphenytoin (15-20 mg/kg)
• Treat if seizure persists despite benzo tx
• Onset of action may take as long as 30 minutes
• Can cause hypotension and dysrhythmias
• Barbituates
• Consider only if benzos and phenytoin have failed
• May lead to respiratory depression, especially when preceded by a benzo
• Valproic acid
• Has been shown to be effective when benzos, phenytoin, and barbituates have failed
• Can be used as 2nd or 3rd-line treatment
• Propofol
• Treat underlying infection

Disposition

• Home: Simple febrile seizure and patient back at baseline with follow up in 1-2 days
• Admit: Complex febrile seizures, lethargy beyond postictal period, uncertain home situation

See Also

Seizure (Peds)

Fever (Peds)

Source

Adapted from Gausche, Mistry, Donaldson, Pani, UpToDate