Febrile Seizure

1. Definition
   1. Seizure with fever in neurologically healthy child
2. Epidemiology
   1. Ages affected: 6 months to 5 years
   2. Most common Seizures of childhood
3. Risk Factors: First Febrile Seizure
   1. Low grade fever
   2. Day care attendance
   3. Developmental delay
   4. Neonatal nursery hospitalization >30 days
   5. Viral infections
      1. Primary human herpes 6 Infection (most common association)
         1. Laina (2010) Pediatr Neurol 42(1): 28-31
      2. Other infections
         1. InfluenzaVirus
         2. Adenovirus
         3. Parainfluenza Virus
         4. Chung (2007) Arch Dis Child 92(7): 589-93
   6. Family History
      1. Febrile Seizure in parent or sibling (10% risk)
   7. Vitamin Deficiency
      1. Iron deficiency
         1. Hartfield (2009) Clin Pediatr 48(4): 420-6
      2. Zinc Deficiency
         1. Ganesh (2008) Clin Pediatr 47(2): 164-66
   8. Vaccinations
      1. Influenza Vaccine
         1. 2010 Southern Hemisphere seasonal trivalent vaccine (Fluvax)
      2. DTP vaccine
         1. Limited to within first 24 hours after Immunization
      3. MMR Vaccine
         1. Related to fever from vaccine (not vaccine itself)
         2. Risk was 1-2 per 1000
         3. Increased risk only in the first 2 weeks after vaccination
         4. Vestergaard (2004) JAMA 292(3): 351-7
4. Risk Factors: Recurrent Febrile Seizure
   1. Age of onset of first Seizure
      1. First Seizure age 1 to 3 years: 30% risk
      2. First Seizure any other age: 50% risk
   2. More than one prior Febrile Seizure
      1. Second Febrile Seizure: 50% risk
   3. Risk Scoring
      1. Criteria: One point for each
         1. Age <18 months
         2. Short interval between fever onset and Seizure (<1 hour)
         3. Lower peak fever (<104 F or 40 C)
         4. First degree relative with Febrile Seizure
      2. Risk of recurrence within 2 years
         1. Recurrence in 14% if 0 risk factors
         2. Recurrence in 20% if 1 risk factors
         3. Recurrence in 30% if 2 risk factors
         4. Recurrence in 60% if 3 risk factors
         5. Recurrence in 70% if 4 risk factors
      3. References
         1. Berg (1997) Arch Pediatr Adolesc Med 151(4): 371-8
5. Types: Febrile Seizure
   1. Simple Febrile Seizure (65-90%)
      1. Generalized Seizure
      2. Seizure duration <15 minutes
      3. Occurs once in 24 hour period
      4. No prior neurologic conditions
   2. Complex Febrile Seizure
      1. Focal Seizure
      2. Seizure duration >15 minutes
      3. Occurs more than once in a 24 hour period
      4. Known neurologic condition (e.g. Cerebral Palsy)
6. Differential Diagnosis
   1. See Seizure
   2. Meningitis
7. Exam: Identify source of fever
   1. Consider Meningitis (rare cause of Febrile Seizure)
   2. Consider Bacteremia in Children
      1. Streptococcal Bacteremia (Streptococcus Pneumoniae)
      2. Urinary Tract Infection
8. Evaluation: Red Flags
   1. Meningeal Signs
   2. Altered Level of Consciousness
      1. Patient should return to full alertness within one hour
      2. Altered Level of Consciousness is present in 93% of patients with Meningitis
      3. Green (1993) Pediatrics 92(4): 527-34
9. Labs
   1. Finger stick blood sugar (bedside glucose)
   2. Urinalysis
   3. Consider serum electrolytes if indicated by history
      1. Example: Diarrhea or Vomiting
      2. However lab testing is not routinely indicated
10. Diagnostics: Criteria for Lumbar Puncture (LP)
    1. No LP if otherwise normal history and exam
       1. Simple Febrile Seizures without other findings are not associated with Meningitis
       2. Kimia (2009) Pediatrics 123(1): 6-12
    2. Specific indications
       1. Children 6-12 months of age with unknown or incomplete vaccination series
          1. HaemophilusInfluenzae type B vaccine
          2. Streptococcus Pneumoniae vaccine (Prevnar)
       2. Lumbar Puncture is no longer routinely indicated for children under 18 months without other findings
    3. Atypical Seizure history
       1. Complex Febrile Seizure alone does not mandate Lumbar Puncture
          1. Risk of Bacterial Meningitis as cause of complex Febrile Seizure is <1%
          2. Kimia (2010) Pediatrics 126(1): 62-9
       2. Focal Seizure
       3. Prolonged Seizure exceeding 15 minutes
       4. Multiple Seizures
    4. Physical exam findings suggestive of intracranial abnormality
       1. Petechiae
       2. Nuchal Rigidity
       3. Decreased Level of Consciousness or Coma
       4. Hypotension
       5. Focal neurologic deficit
11. Imaging: Neuroimaging (CT or MRI) Indications
    1. General
       1. No imaging if otherwise normal history and exam
       2. MRI Head is the preferred modality if imaging is absolutely required (no radiation)
    2. Criteria
       1. Cerebral abscess risk
       2. Increased Intracranial Pressure
       3. Head Trauma
       4. Suspected structural defect (e.g. Microcephaly)
       5. Status Epilepticus
       6. Complex Febrile Seizure
          1. Only obtain imaging if associated with other neurologic findings
          2. Complex Febrile Seizure alone is not associated with intracranial abnormality
          3. Teng (2006) Pediatrics 117(2): 304-8
    3. References
       1. Offringa (2001) BMJ 323:1111-4
12. Management: General
    1. Lowering temperature with antipyretics (Tylenol and Ibuprofen) does not prevent Seizure
       1. Strengell (2009) Arch Pediatr Adolesc Med 163(9): 799-804
    2. Warn parents that recurrence is likely
       1. See recurrence risk factors above
       2. One third of children with febrile seziure will have another (75% within one year)
          1. Berg (1997) Arch Pediatr Adolesc Med 151(4): 371-8
    3. Offer reassurance (key)
       1. Children with Febrile Seizures have identical intellectual and behavioral development as with their peers
       2. Simple Febrile Seizures are not associated with increased morbidity or mortality
       3. Complex Febrile Seizures have a very rare mortality, nearly undetectable rate in the first 2 years after Seizure
       4. Verity (1998) N Engl J Med 338(24): 1723-8
       5. Vestergaard (2008) Lancet 372(9637): 457-63
13. Management: Prophylaxis
    1. May offer parent some sense of control
    2. Prophylaxis, however, is not recommended
       1. Significant adverse effects (lethargy, irritability)
       2. Does not effect future Seizure risk
       3. Agents taken continuously have adverse effects
       4. Agents taken intermittently (Diazepam) not protective
          1. Typically Seizure presents with fever onset
    3. Intermittent dose for fever >38.5
       1. Not recommended unless high risk of recurrence
       2. Diazepam (adjust dosing per age)
    4. Continuous Dosing (not recommended - adverse effects)
       1. Phenobarbital
          1. Age 2-24 months: 5-8 mg/kg/day
          2. Age >2 years: 3-5 mg/kg/day
       2. Valproic Acid 10-15 mg/kg/day (max 60 mg/kg) divided
14. Management: Seizure duration >15 minutes (Status Epilepticus)
    1. Emergency department
       1. Lorazepam
          1. Preferred agent for acute tonic-clonic pediatric Seizures
          2. Dose: 0.1 mg/kg IV up to 4 mg
       2. Diazepam
          1. Dose: 0.2 to 0.5 mg/kg IV q15 minutes
          2. Maximum cummulative dose: 5 mg for age <5 years
       3. Fosphenytoin (preferred over Phenytoin)
          1. Indicated for Seizure refractory to Benzodiazepine
    2. Home environment (emergency prescription)
       1. Agents
          1. Diazepam gel (buccal Diazepam) - preferred over rectal formulation
          2. Diazepam rectal suppository (Diastat)
       2. Dosing
          1. Diazepam 0.5 mg/kg for single dose (age 2-5 years)
       3. Protocol
          1. Parents would have available at home for prn use
          2. Give for Seizure lasting longer than 15 minutes
          3. Immediate ER evaluation for prolonged Seizure
    3. References
       1. Offringa (2001) BMJ 323:1111-4
15. Consultations: Neurology Indications
    1. Not recommended in simple Febrile Seizures
    2. Complex Febrile Seizure
    3. Abnormal findings on examination or diagnostics
    4. Electroencephologram (EEG) does not predict future Seizure disorder
       1. (2011) Pediatrics 127(2):389-94
16. Prognosis: Excellent
    1. Normal school progression expected
       1. Verity (1998) N Engl J Med 338(24): 1723-8
    2. Seizure remission expected
       1. No further Seizures after age 5 years in 98% children
17. Prognosis: Predictors of continued Epilepsy
    1. Neurodevelopmental disorder
       1. Developmental delay
       2. Cerebral Palsy
       3. Hydrocephalus
       4. Abnormal Neurologic Exam
    2. Fever duration less than 1 hour before Seizure onset
    3. Family History of Epilepsy in first degree relative
    4. Complex Febrile Seizure with multiple complex features (see type description above)
       1. Two complex features: 17-22% chance of future Epilepsy
       2. Three complex features: 49% chance of future Epilepsy
    5. References
       1. Shinnar (2002) J Child Neurol 17(suppl 1): S44-S52
18. References
    1. Graves (2012) Am Fam Physician 85(2): 149-53
    2. Hampers (2011) Emerg Med Clin North Am 29(1): 83-93
    3. Millar (2006) Am Fam Physician 73(10):1761-6
    4. Shinnar (2002) J Child Neurol 17:S44-52
    5. Warden (2003) Ann Emerg Med 41:215-22