Febrile seizure

Background

• Occur in 2-5% of American children before age 5
• 50% of patients never have temperature >39
• Febrile seizures do not increase the risk of serious bacterial illness

Prognosis

• 2-3% chance of developing epilepsy (1% for general population)
• 50% of patients <12 mo will have another simple febrile seizure
• 30% of patients >12 mo will have another simple febrile seizure

Clinical Features

• Seizure + fever

Simple Febrile Seizure

• Age 6mo-5yr
• Single seizure in 24hr
• Duration <15min
• Generalized with no focal features
• Returns to neurologic baseline and has normal neuro exam after brief post-ictal period

Complex Febrile Seizure

• Any exception to above
• May indicate more serious disease process

Differential Diagnosis

Pediatric seizure

• Epileptic seizure
  • First-time seizure
  • Seizure with known seizure disorder
  • Status epilepticus
  • Temporal lobe epilepsy
  • Non-compliance with or "outgrowing" AEDs
• Non-epileptic seizure
  • Febrile seizure
  • Brain inflammation
    • Meningitis
    • Encephalitis
    • CNS abscess
    • Intracranial hemorrhage
    • Neurocysticercosis
  • Increased ICP
    • Seizure with VP shunt
    • Hydrocephalus
    • Intracranial mass
  • Toxicologic
    • Alcohol withdrawal
    • Benzodiazepine withdrawal
    • Toxic ingestion
  • Metabolic abnormalities: hyponatremia, hypernatremia, hypocalcemia, hypomagnesemia, hypoglycemia, hyperglycemia
  • Pyridoxine responsive seizure
  • Eclampsia
  • Posterior reversible encephalopathy syndrome
  • Impact seizure (head trauma)
• Other mimics
  • Psychogenic nonepileptic seizure (pseudoseizure)
  • Syncope (peds)
  • Breath-holding spell
  • Hyperventilation syndrome
  • Migraine headache
  • Movement disorders
  • Narcolepsy/cataplexy
  • Post-hypoxic myoclonus (Status myoclonicus)
  • Infantile Spasms/West Syndrome

Pediatric fever

• Upper respiratory infection (URI)
• UTI
• Sepsis
• Meningitis
• Febrile seizure
• Juvenile Rheumatoid Arthritis
• Pneumonia
• Acute otitis media
• Whooping cough
• Unclear source
• Kawasaki disease
• Neonatal HSV
• Specific virus
  • COVID-19 (peds)
    • MIS-C

Evaluation

• The key is to distinguish between simple febrile seizure secondary to minor illness vs. seizure from serious central nervous system infection, which may also present with fever and seizure.
• Glucose in all patients

Simple febrile seizure

• Neither labs nor neuroimaging are absolutely necessary
• Normal pediatric fever workup

Complex febrile seizure

• Consider CBC, blood culture, UA, urine culture, CSF studies
• Consider CT if:
  • Persistently abnormal neuro exam (especially with focality)
  • Signs/symptoms of increased ICP
  • Patient has VP shunt
• Consider ECG if:
  • Family history of long QT, Brugada, sudden death
• Routine EEG not indicated
  • Consider only if developmental delay or for focal symptoms
• Causes amenable to specific treatment
  • Hypoglycemia
  • Hyponatremia (water intoxication, dilution of formula)
  • Hypocalcemia
  • Hypomagnesemia
  • INH ingestion

Algorithm for the differentiation between simple and complex febrile seizures. Guidelines for evaluation of each.

Management

Ongoing Seizure

See Seizure (peds)

Seizure Stopped

• Treat underlying infection if indicated
  • See pediatric fever of uncertain source

Disposition

Discharge

• Simple febrile seizure if patient at baseline
  • Follow-up in 1-2d
  • Around-the-clock acetaminophen may prevent seizure recurrence in the same febrile episode
• Complex febrile seizure if patient well-appearing, work-up normal
  • Follow-up in 24hr

Admit

• Ill-appearing
• Lethargy beyond postictal period

See Also

• Seizure
• Fever (Peds)