Febrile seizure

Background

Criteria: Seizure + temp >38 in pt age 6 mo - 6 yr without previous afebrile seizure

Diagnosis

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

1. Family history (2-4x higher)
2. Infection (viral and bacterial)
3. Recent vaccinations
4. Recurrence

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

Prognosis

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:

1. Young age at onset
2. Family history of febrile seizures
3. Low-degree of fever in the ED
4. Brief duration between onset of fever and initial seizure
5. Complex febrile seizure does not increase risk of recurrent seizures

See Also

Seizure (Peds)

Fever (Peds)

Source

Adapted from Gausche, Mistry, Donaldson, Pani, UpToDate