II. Definitions
- Febrile Seizure
- Seizure with fever (Temperature >100.4 F) in neurologically healthy child without CNS Infection
III. Epidemiology
- Ages affected: 6 months to 5 years (peaks at age 2 years)
- Most common Seizures of childhood
- Occurs in 3-5% of children before age 5 years
- Gender: 66% are male
- Most common in winter and early spring
- Corresponding to increased frequency of respiratory and gastrointestinal infections
IV. Risk Factors: First Febrile Seizure
- Low grade fever
- Day care attendance (OR 3.1)
- Developmental Delay (OR 4.9)
- Neonatal nursery hospitalization >28 days (OR 5.6)
-
Viral Infections (esp. those associated with high fever)
- Primary human herpes 6 Infection (most common association)
- Other infections
-
Family History
- Up to 25-49% of those with Febrile Seizures have a Family History
- Febrile Seizure in parent or sibling (10% risk, OR 4.5)
- Febrile Seizure in second degree relative (OR 3.6)
- Vitamin Deficiency
-
Vaccinations
- Background
- Prophylactic antipyretics did not reduce Seizure risk and may reduce immune response to Vaccination
- Prymula (2009) Lancet 374(9698): 1339-50 [PubMed]
- Influenza Vaccine
- 2010 Southern Hemisphere seasonal trivalent Vaccine (Fluvax)
- Over the longterm, Influenza Vaccine has not been consistently associated with Febrile Seizures
- DTP Vaccine
- Limited to within first 24 hours after Immunization
- DTaP is not associated with significantly increased risk
- MMR Vaccine
- Related to fever from Vaccine (not Vaccine itself)
- Risk was 1 per 1000 if MMR given at age 16-23 months
- However risk drops to 4 in 10,000 (less than half), if Vaccine given at 12-15 months
- Increased risk only in the first 2 weeks after Vaccination
- Vestergaard (2004) JAMA 292(3): 351-7 [PubMed]
- Background
V. Risk Factors: Recurrent Febrile Seizure
- Age of onset of first Seizure
- High risk recurrence factors
- Complex Febrile Seizure
- Febrile Status Epilepticus
- Recurrence Febrile Seizure in 43%
- Recurrent febrile Status Epilepticus in 10%
- Timing of recurrence
- When Febrile Seizures recur, they do so in the first year in 75% of cases
- Risk Scoring
- Criteria: One point for each
- Age <18 months
- Short interval between fever onset and Seizure (<1 hour)
- Lower peak fever (<104 F or 40 C)
- First degree relative with Febrile Seizure
- Risk of recurrence within 2 years
- Recurrence in 14% if 0 risk factors
- Recurrence in 24% if 1 risk factors
- Recurrence in 32% if 2 risk factors
- Recurrence in 63% if 3 risk factors
- Recurrence in 75% if 4 risk factors
- References
- Criteria: One point for each
VI. Types: Febrile Seizure
- Simple Febrile Seizure (65-90%)
- Generalized Seizure
- Seizure duration <15 minutes
- Occurs once in 24 hour period
- No prior neurologic conditions
- Normal Neurologic Exam
- Complex Febrile Seizure (20-25%)
- Focal Seizure (most common reason for classifying as complex Seizure)
- Seizure duration >15 minutes
- Occurs more than once in a 24 hour period
- Known neurologic condition (e.g. Cerebral Palsy)
- Postictal neurologic abnormality (Todd's Paralysis)
- May also be associated with prolonged postictal state
- Febrile Status Epilepticus (5%)
- Generalized Febrile Seizure lasting >30 minutes
VII. Differential Diagnosis
- See Seizure
- Meningitis
- Generalized Epilepsy with Febrile Seizure Plus (GEFS+)
- Dravet Syndrome
- Severe myoclonic Epilepsy
- Rare, but severe degenerative neurologic condition
VIII. History
-
Seizure episode
- Duration of Seizure (most Febrile Seizures last <7-8 minutes, typically much less than this)
- Characteristics (generalized or focal findings)
- Postictal signs and duration
- Recurrence
- Past medical history
- Recent Infections or Antibiotic use
- Recent head injuries
- Prior Seizures
-
Immunization status
- Recent Vaccinations (e.g. MMR)
- HaemophilusInfluenzae Type B Vaccine (Hib Vaccine)
- Streptococcus PneumoniaeVaccine (Prevnar)
-
Family History
- Febrile Seizures
- Seizure Disorder
IX. Exam
- Complete Neurologic Exam
- Focal neurologic deficit (e.g. Todd Paralysis)
- Identify source of fever
- Simple Febrile Seizures are not associated with an increased risk of serious infection
- Well appearing children are not at higher risk of UTI, Pneumonia or Bacterial Meningitis
- Consider Meningitis (for ill appearing children or those with complex Seizures)
- However, Meningitis rarely presents as Febrile Seizures (especially not simple Febrile Seizures)
- Those with Meningitis and Seizure, had other abnormalities (e.g. ALOC, Nuchal Rigidity, petechial rash)
- Green (1993) Pediatrics 92(4): 527-34 [PubMed]
- Consider Bacteremia in Children (for ill appearing children or those with complex Seizures)
- Simple Febrile Seizures are not associated with an increased risk of serious infection
X. Evaluation: Red Flags
- Meningeal Signs
- Complex Febrile Seizure
-
Altered Level of Consciousness
- Patient should return to full alertness within one hour
- Altered Level of Consciousness is present in 93% of patients with Meningitis
- Green (1993) Pediatrics 92(4): 527-34 [PubMed]
- Additional risks for serious Bacterial Infection cause
- Age <6 months or >60 months with first-time Febrile Seizure
- Age <12 months with inadequate or unknown Immunization history
- Febrile Status Epilepticus
XI. Labs
- Well appearing children with simple Febrile Seizures do not require lab testing
- In addition, well appearing children even with complex Febrile Seizures are unlikely to have abnormal labs
- Finger stick Blood Sugar (bedside Glucose)
- Consider Urinalysis
- Consider serum Electrolytes if indicated by history
- Example: Diarrhea or Vomiting
- However lab testing is not routinely indicated (not recommended by AAP)
- Consider basic chemistry panel (Serum Glucose, Serum Sodium, Serum Calcium, Serum Magnesium)
XII. Diagnostics: Criteria for Lumbar Puncture (LP)
- No LP if otherwise normal history and exam
- Simple Febrile Seizures without other findings are not associated with Meningitis
- Kimia (2009) Pediatrics 123(1): 6-12 [PubMed]
- Guedj (2015) Acad Emerg Med 22(11): 1290-7 +PMID:26468690 [PubMed]
- Atypical Seizure history
- Complex Febrile Seizure alone does not mandate Lumbar Puncture
- Risk of Bacterial Meningitis as cause of complex Febrile Seizure is <1%
- Kimia (2010) Pediatrics 126(1): 62-9 [PubMed]
- Focal Seizure
- Prolonged Seizure exceeding 15 minutes
- Multiple Seizures
- Complex Febrile Seizure alone does not mandate Lumbar Puncture
- Physical exam findings suggestive of intracranial abnormality or findings suggestive of Meningitis
- Petechiae
- Nuchal Rigidity (or Kernig Sign or Brudzinksi Sign)
- Decreased Level of Consciousness or Coma
- Hypotension
- Focal neurologic deficit
- Other possible indications
- Pretreatment with Antibiotics or
- Children 6-12 months of age with unknown or incomplete Vaccination series
- Lumbar Puncture is no longer routinely indicated for children under 18 months without other findings
XIII. Imaging: Neuroimaging (MRI or CT) Indications
- See Neuroimaging after First Seizure
-
General
- No imaging is needed if otherwise normal history and exam
- MRI Head is the preferred modality if imaging is absolutely required (no radiation)
- MRI in young children requires sedation and increased resource use
- Consult pediatric neurology if imaging may be deferred to follow-up or tertiary transfer
- Larger, tertiary facilities have T3 MRI allowing rapid sequences and shorter MRI time
- Imaging Indications
- Persistent neurologic deficits or Altered Mental Status
- Cerebral Abscess risk
- Increased Intracranial Pressure signs
- Head Trauma
- Suspected structural defect (e.g. Microcephaly)
- Status Epilepticus
- Complex Febrile Seizure
- Only obtain imaging if associated with other neurologic findings
- Complex Febrile Seizure alone is not associated with intracranial abnormality
- Teng (2006) Pediatrics 117(2): 304-8 [PubMed]
- References
XIV. Management: Seizure duration >15 minutes (Status Epilepticus)
- See Status Epilepticus
- Approach
- Treated the same regardless of fever presence
- Consider initiating Benzodiazepines for Seizure >5 minutes (as these are unlike to stop spontaneously)
- ABC Management
- Supplemental Oxygen, monitor and airway management
- Benzodiazepines (Lorazepam, Diazepam, Midazolam) followed by Fosphenytoin, Levetiracetam or Phenobarbital
- Emergency department
- Lorazepam
- Preferred agent for acute tonic-clonic pediatric Seizures
- Dose: 0.1 mg/kg IV up to 4 mg
- Diazepam
- Consider rectal form (diastat) when no IV Access available
- Dose: 0.2 to 0.5 mg/kg IV (or rectally) q15 minutes
- Maximum cummulative dose: 5 mg for age <5 years
- Midazolam
- Consider when no IV Access available (use IM)
- Dose: 0.2 mg/kg IM of the IV formulation up to 10 mg
- Fosphenytoin (preferred over Phenytoin)
- Indicated for Seizure refractory to Benzodiazepine
- Lorazepam
- Home environment (emergency prescription)
- Agents
- Dosing
- Diazepam 0.5 mg/kg for single dose (age 2-5 years)
- Protocol
- References
XV. Management: General
- Disposition to home criteria
- Simple Febrile Seizure
- Return to baseline status, tolerating oral fluids, non-toxic in appearance
- Complex Febrile Seizure
- Return to baseline with no persistent neurologic deficits
- Simple Febrile Seizure
- Plan follow-up
- All children discharged from Emergency Department after Febrile Seizure in 1-2 days in clinic
- Lowering Temperature with antipyretics (Tylenol and Ibuprofen)
- Some stuides showed no reduced risk of Seizure (although may aid comfort)
- Other studies showed Acetaminophen reduced Seizure recurrence in first 24 hours
- Warn parents that recurrence is likely
- See recurrence risk factors above
- One third of children with febrile seziure will have another (75% within one year)
- Discuss with parents general home measures during recurrent Seizure
- Place child in safe position in left lateral decubitus position
- Ensure unobstructed airway
- Give emergency Seizure abortive medication (e.g. rectal Diazepam) if prescribed
- Call 911 for prolonged Seizure or at parental discretion
- Re-evaluation for new complex Seizure features, Seizure recurrence in 24 hours
- Offer reassurance (key)
- Children with Febrile Seizures have identical intellectual and behavioral development as with their peers
- Simple Febrile Seizures are not associated with increased morbidity or mortality
- Complex Febrile Seizures have a very rare mortality, nearly undetectable rate in the first 2 years after Seizure
- Verity (1998) N Engl J Med 338(24): 1723-8 [PubMed]
- Vestergaard (2008) Lancet 372(9637): 457-63 [PubMed]
XVI. Management: Prophylaxis
- May offer parent some sense of control
- Prophylaxis, however, is not recommended
- Intermittent dose for fever >38.5
- Not recommended unless high risk of recurrence
- Diazepam (adjust dosing per age)
- Continuous Dosing (not recommended - adverse effects)
- Phenobarbital
- Age 2-24 months: 5-8 mg/kg/day
- Age >2 years: 3-5 mg/kg/day
- Valproic Acid 10-15 mg/kg/day (max 60 mg/kg) divided
- Phenobarbital
XVII. Management: Neurology Consultation Indications
- Not recommended in simple Febrile Seizures
- Complex Febrile Seizure
- Abnormal findings on examination or diagnostics
XVIII. Management: Outpatient EEG
- Precautions
- AAP does not recommend for simple Febrile Seizures in neurologically healthy children
- Electroencephologram (EEG) does not predict future Seizure Disorder
- Indications
- History of neurologic or Developmental Disorders
- Family History of Seizure Disorder
- More than one feature characterizing Febrile Seizure as complex
XIX. Prognosis: Excellent
XX. Prognosis: Predictors of continued Epilepsy
- Neurodevelopmental disorder
- Fever duration less than 1 hour before Seizure onset
- Age >3 years at time of Febrile Seizure
- Multiple Febrile Seizures at age <1 year
- Febrile Seizure with Eye Deviation, lip smacking or prolonged motor movement >15 min
- Family History of Epilepsy in first degree relative
- Complex Febrile Seizure with multiple complex features (see type description above)
- References
XXI. References
- Homme (2017) Febrile Seizures, Mayo Clinical Reviews, Rochester, MN
- Ruest et al (2016) Crit Dec Emerg Med 30(12): 13-9
- Graves (2012) Am Fam Physician 85(2): 149-53 [PubMed]
- Hampers (2011) Emerg Med Clin North Am 29(1): 83-93 [PubMed]
- Millar (2006) Am Fam Physician 73(10):1761-6 [PubMed]
- Smith (2019) Am Fam Physician 99(7): 445-50 [PubMed]
- Shinnar (2002) J Child Neurol 17:S44-52 [PubMed]
- Warden (2003) Ann Emerg Med 41:215-22 [PubMed]