Febrile seizure

Background

• 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
• Returns to neurologic baseline and has normal neuro exam after brief post-ictal period

Complex Febrile Seizure

• As above, elements of one or more of the following:
  • Can be focal or generalized OR
  • Prolonged or multiple seizures in 24hr period OR
  • Not returned to baseline or abnormal neuro exam
• 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
  • Meningitis
  • Encephalitis
  • CNS abscess
  • Intracranial hemorrhage
  • Alcohol withdrawal
  • Benzodiazepine withdrawal
  • Metabolic abnormalities: hyponatremia, hypernatremia, hypocalcemia, hypomagnesemia, hypoglycemia, hyperglycemia
  • Pyridoxine responsive seizure
  • Eclampsia
  • Neurocysticercosis
  • Posterior reversible encephalopathy syndrome
  • Impact seizure (head trauma)
  • Seizure with VP shunt
  • Toxic ingestion
  • Psychogenic nonepileptic seizure (pseudoseizure)
• Hydrocephalus
• Intracranial mass
• Syncope
• Breath-holding spell
• Hyperventilation syndrome
• Migraine headache
• Movement disorders
• Narcolepsy/cataplexy
• Post-hypoxic myoclonus (Status myoclonicus)
• Infatile Spasms/West Syndrome

Pediatric fever

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

Evaluation

Work-Up

• 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

Diagnosis

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.

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

Simple versus Complex

• Simple
  • Generalized tonic-clonic seizure
  • <15 min in duration
  • Age 6mo - 5yr
  • Occurs only once in 24hr period
  • No focal features
• Complex
  • Any exception to above

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)