Febrile seizures are the most common convulsive event in children, affecting 2–5% of children aged 6 months to 5 years, defined as a seizure accompanied by fever ≥38°C (100.4°F) without CNS infection. [1-2] They are classified as simple (generalized, <15 min, no recurrence within 24 hrs) or complex (focal, ≥15 min, or recurrent within 24 hrs). [1-2] Most are benign and self-limiting, with an excellent long-term prognosis. [1-2]
1. History
- Seizure characterization: Type of movements (generalized tonic-clonic vs. focal), duration, eye deviation, body part involved, level of consciousness
- Timing: Onset relative to fever, whether seizure was the first sign of illness or occurred during a known febrile illness
- Duration: Critical to classify as simple (<15 min) vs. complex (≥15 min) [1-2]
- Recurrence: Any additional seizures within the same 24-hour period
- Postictal state: Duration of drowsiness/confusion; prolonged postictal unresponsiveness is a red flag [3]
- Fever details: Peak temperature, duration of fever before seizure, source of fever (URI, AOM, GI illness)
- Prior episodes: Number of previous febrile seizures, age at first episode
- Important negatives: No preceding trauma, no toxic ingestion, no rash/petechiae, no recent travel, no vomiting/headache/neck stiffness
2. Alarm Features
- Seizure duration >5 minutes (requires acute benzodiazepine treatment) [1]
- Seizure duration ≥30 minutes (febrile status epilepticus — risk of acute encephalitis in 25% of this subgroup) [4]
- Focal features (unilateral jerking, eye deviation to one side, Todd's paralysis)
- Multiple seizures within 24 hours
- Prolonged postictal unresponsiveness or focal neurologic deficits postictally [3]
- Meningeal signs: Nuchal rigidity, bulging fontanelle, Kernig/Brudzinski signs
- Ill-appearing child who does not return to baseline
- Age <6 months (not a typical febrile seizure — consider other etiologies)
- Seizure requiring ≥2 IV anticonvulsants to terminate (67% had acute encephalitis in one study) [4]
3. Medications
- Acute seizure management (>5 min):
- Midazolam intranasal (0.2 mg/kg) or IM (0.2 mg/kg) — preferred prehospital/office route [5]
- Diazepam rectal (0.5 mg/kg) — well-established option [3][5]
- Lorazepam IV (0.1 mg/kg) — first-line if IV access available [6]
- Antipyretics: Acetaminophen (15 mg/kg PO/PR) and ibuprofen (10 mg/kg PO) for comfort; do not prevent febrile seizures [1][7]
- Prophylactic antiepileptics are NOT routinely recommended — risks/side effects outweigh benefits for this benign condition [1][7-8]
- Intermittent rectal diazepam at seizure onset may be considered for recurrent prolonged febrile seizures, but routine intermittent prophylaxis at times of fever is discouraged [3][9]
- Contraindicated approach: Continuous phenobarbital or valproic acid for simple febrile seizures — adverse effects (cognitive, hepatotoxic) outweigh any benefit [7-8]
4. Diet
- No specific dietary triggers or restrictions
- Maintain adequate hydration during febrile illness
- Encourage oral fluids; consider oral rehydration solution if poor intake
- No evidence that dietary interventions prevent febrile seizures
5. Review of Systems
- HEENT: Ear pain (AOM), rhinorrhea, pharyngitis (common fever sources)
- Respiratory: Cough, tachypnea, respiratory distress
- GI: Vomiting, diarrhea (gastroenteritis as fever source; also assess hydration)
- GU: Dysuria, foul-smelling urine (UTI — common occult fever source in young children)
- Neuro: Headache, irritability, lethargy, neck stiffness, photophobia
- Skin: Rash (viral exanthem vs. petechiae/purpura suggesting meningococcemia)
- MSK: Joint swelling, limp (septic arthritis/osteomyelitis)
6. Collateral History and Family History
- Witness account of the seizure is essential — parents, daycare providers
- Family history of febrile seizures — present in ~25–50% of cases; significantly increases recurrence risk [10-11]
- Family history of epilepsy — first-degree relative with epilepsy increases risk of later epilepsy and recurrence [10-11]
- Vaccination history: Recent DPT (within 24 hrs) or MMR (8–14 days) vaccination can trigger febrile seizures [3]
- Immunization status: Incomplete Hib or pneumococcal vaccination lowers threshold for LP [2]
- Developmental history: Any pre-existing neurodevelopmental abnormalities (increases risk of complex FS and later epilepsy) [12]
7. Risk Factors
- Age: Peak incidence at 18 months; younger age at first episode (<12–18 months) increases recurrence risk [8][11]
- Genetic predisposition: Autosomal dominant and polygenic inheritance patterns; SCN1A and PCDH19 variants identified in ~16% of FS patients [3][13]
- Viral illness: Most common trigger; respiratory tract infections predominate [3]
- Recent vaccination: DPT (within 24 hrs), MMR (8–14 days post-vaccination) [3]
- Frequent febrile illnesses [11]
- Lower temperature at seizure onset and shorter duration of fever before seizure increase recurrence risk [6]
- Metabolic: Lower serum sodium, vitamin D, and zinc levels have been associated with FS occurrence [13]
8. Differential Diagnosis
- Bacterial meningitis — cannot-miss diagnosis; incidence in well-appearing children with simple FS is extremely low (~0.003%), but must be considered if ill-appearing or meningeal signs present [14]
- Viral encephalitis — prolonged seizures (≥30 min), altered mental status, focal deficits [4]
- Epilepsy (unprovoked seizure coinciding with fever) — consider if afebrile seizures also occur
- Dravet syndrome — prolonged febrile seizures in infancy, especially if recurrent and refractory; SCN1A mutation [11]
- Electrolyte abnormalities — hyponatremia, hypoglycemia, hypocalcemia
- Toxic ingestion — accidental medication/substance exposure
- Intracranial pathology — tumor, hemorrhage, abscess (rare; consider if focal features or persistent deficits)
- Shaking injury/non-accidental trauma — consider in infants with unexplained seizures
- Febrile myoclonus/rigors — mimics seizure but no loss of consciousness, no postictal state
9. Past Medical History
- Prior febrile seizures (number, type, duration)
- Prior afebrile seizures (suggests epilepsy rather than febrile seizure)
- Neurodevelopmental abnormalities (increases risk of complex FS and epilepsy) [12]
- Neonatal seizures (excludes diagnosis of febrile seizure per ILAE definition) [8]
- Birth history: Prematurity, perinatal complications
- Chronic illnesses: Immunodeficiency (lowers threshold for infectious workup)
10. Physical Exam
- Vitals: Temperature (≥38°C required), HR, RR, BP, SpO2; assess for hemodynamic instability
- General: Toxicity assessment — well-appearing vs. ill-appearing is the single most important determination [1-2]
- Neuro: Mental status (should return to baseline), fontanelle (bulging?), tone, strength, reflexes, focal deficits (Todd's paralysis vs. structural lesion)
- Meningeal signs: Nuchal rigidity, Kernig sign, Brudzinski sign (unreliable in children <18 months)
- HEENT: TMs (AOM), pharynx (pharyngitis), fontanelle assessment
- Skin: Rash (viral exanthem, petechiae/purpura), signs of trauma, neurocutaneous stigmata
- Respiratory: Lung auscultation for pneumonia
- Abdomen: Tenderness, organomegaly
11. Lab Studies
Simple febrile seizure in a well-appearing child
- No routine labs recommended per AAP guidelines [2][14]
- Labs should be directed at identifying the source of fever (e.g., urinalysis if UTI suspected)
Consider labs when clinically indicated
- Glucose — if prolonged seizure, altered mental status, or diabetic
- BMP — if concern for dehydration, electrolyte abnormality, or prolonged seizure
- CBC, blood culture — if ill-appearing or concern for bacteremia/sepsis
- Lumbar puncture — if meningeal signs, ill-appearing, or child 6–12 months with incomplete Hib/pneumococcal immunization; also consider if pretreated with antibiotics [2]
12. Imaging
- Neuroimaging is NOT recommended for simple febrile seizures [1-2]
- Head CT rates have declined from 10.6% to 1.6% following AAP guideline publication, without missed diagnoses [14]
- Consider neuroimaging (CT or MRI) only if:
- Prolonged postictal unresponsiveness
- Focal neurologic deficits
- Signs of increased intracranial pressure
- Concern for intracranial pathology or non-accidental trauma
- MRI is preferred over CT when non-emergent imaging is needed (avoids radiation)
13. Special Tests
- EEG is NOT recommended for simple febrile seizures — does not predict recurrence or epilepsy [2][15]
- EEG may be considered in complex febrile seizures with recurrent episodes, though a Cochrane review found insufficient evidence to support routine use [12]
- Point-of-care glucose — should be checked in any actively seizing child or prolonged postictal state
- Rapid viral testing (RSV, influenza) — may help identify fever source and guide disposition
14. ECG
- Not routinely indicated for febrile seizures
- Consider ECG only if the event description is atypical and cardiac syncope (e.g., long QT syndrome with convulsive syncope) is in the differential
15. Assessment
Classification is the key clinical decision point
- Prognosis is excellent: No increased long-term mortality, no negative effects on academic progress, intellect, or behavior [1-2]
- Recurrence risk: 30–40% overall; highest in the first 1–2 years after initial episode [3][6]
- Consider Dravet syndrome if recurrent prolonged febrile seizures begin in infancy, especially with refractory seizures or developmental regression [11]
16. Treatment Plan
Acute management
- Seizure <5 min: Supportive care — position safely, protect airway, do not restrain, time the seizure
- Seizure ≥5 min: Administer benzodiazepine: [1][5]
- Midazolam IN 0.2 mg/kg (max 10 mg) or IM 0.2 mg/kg
- Diazepam PR 0.5 mg/kg (max 20 mg)
- Lorazepam IV 0.1 mg/kg (max 4 mg)
- Seizure ≥30 min (febrile status epilepticus): Second-line agents (fosphenytoin, levetiracetam, or valproate IV); admit to ICU [5]
- Treat the fever source: Appropriate antibiotics if bacterial infection identified
- Antipyretics for comfort: Acetaminophen or ibuprofen; these do not prevent recurrent febrile seizures [1][7]
Prophylaxis (generally NOT recommended)
- Routine continuous or intermittent antiepileptic prophylaxis is not indicated for simple febrile seizures [1][7-8]
- For children with recurrent prolonged febrile seizures, rescue rectal diazepam at seizure onset may be prescribed for home use [3][9]
17. Disposition
Discharge criteria (simple febrile seizure)
- Child has returned to neurologic baseline
- Fever source identified or no concerning features
- Well-appearing, tolerating PO
- Adequate caregiver understanding and follow-up plan
- Most children with simple FS can be safely discharged; hospitalization rates have appropriately declined to ~5% [14]
- Short-term recurrence is low (1.9%) and occurs within the first 3 hours; extended observation may not be necessary once the child returns to baseline [16]
Admission criteria
- Seizure duration ≥30 minutes or requiring ≥2 IV anticonvulsants [4]
- Ill-appearing child or concern for serious bacterial infection/meningitis
- Persistent altered mental status or focal neurologic deficits
- Age <18 months with complex features (lower threshold per some guidelines) [17]
- Inability to identify fever source in a young infant
- Inadequate follow-up or caregiver concerns
Specialist consultation
- Pediatric neurology: Complex febrile seizures, recurrent febrile seizures, concern for epilepsy or Dravet syndrome
- Pediatric infectious disease: If meningitis/encephalitis suspected
18. Follow Up / Return Precautions
- Follow-up with PCP within 24–48 hours after discharge
- Neurology referral if complex features, recurrent episodes, or developmental concerns
Return precautions — instruct caregivers to return immediately for:
- Another seizure lasting >5 minutes
- Multiple seizures in 24 hours
- Child does not return to normal behavior after seizure
- Stiff neck, bulging fontanelle, persistent vomiting
- New rash (especially petechiae/purpura)
- Increasing lethargy, poor feeding, inconsolability
Parent counseling points
- Febrile seizures are common and benign — no increased risk of brain damage, intellectual disability, or death [1-2]
- Recurrence risk is 30–40%, highest in the first 2 years [3][6]
- Antipyretics treat discomfort but do not prevent febrile seizures [1][7]
- During a seizure at home: Place child on side, do not put anything in the mouth, time the seizure, call 911 if >5 minutes
- Vaccinations should not be withheld — the benefit far outweighs the small risk of vaccine-associated febrile seizure [3]
References
1. Febrile Seizures: Risks, Evaluation, and Prognosis. — Smith DK, Sadler KP, Benedum M. American Family Physician. 2019.
2. Neurodiagnostic Evaluation of the Child With a Simple Febrile Seizure. — Pediatrics. 2011.
3. Epilepsy in Children. — Guerrini R. Lancet. 2006.
4. Risk Factors for Acute Encephalitis and Early Seizure Recurrence in Complex Febrile Seizures. — Kajiwara K, Koga H. European Journal of Pediatrics. 2022.
5. Preparation for Pediatric Emergencies in the Office: Technical Report. — Cantrell P, Hoffmann J, Yuknis M, et al. Pediatrics. 2026.
6. Febrile Seizures: Risks, Evaluation, and Prognosis. — Graves RC, Oehler K, Tingle LE. American Family Physician. 2012.
7. Technical Report: Treatment of the Child With Simple Febrile Seizures. — Baumann RJ. Pediatrics. 1999.
8. Prophylactic Drug Management for Febrile Seizures in Children. — Offringa M, Newton R, Nevitt SJ, Vraka K. The Cochrane Database of Systematic Reviews. 2021.
9. Febrile Seizures: Treatment and Prognosis. — Knudsen FU. Epilepsia. 2000.
10. Evaluation of the Risk Factors for Recurrence in Patients With Febrile Seizures. — Sadık ZZT, Uyur E, Güder D, Bıkmazer B, Hacıfazlıoğlu NE. Journal of Paediatrics and Child Health. 2026.
11. Childhood Epilepsy. — Menon RN, Helen Cross J. Lancet. 2025.
12. EEG for Children With Complex Febrile Seizures. — Shah PB, James S, Elayaraja S. The Cochrane Database of Systematic Reviews. 2020.
13. A Comprehensive Perspective on Febrile Seizures in Children: A Prospective Cohort Study With Evaluation of Clinical, Laboratory, and Genetic Features. — Yalçın G, Yıldırım R, Unal E, et al. Journal of Clinical Medicine. 2025.
14. Trends in Management of Simple Febrile Seizures at US Children's Hospitals. — Raghavan VR, Porter JJ, Neuman MI, Lyons TW. Pediatrics. 2021.
15. Establishment of Achievable Benchmarks of Care in the Neurodiagnostic Evaluation of Simple Febrile Seizures. — Stephens JR, Hall M, Molloy MJ, et al. Journal of Hospital Medicine. 2022.
16. Beyond the Seizure: The Role of Post-Event Observation in Febrile Seizure Management. — Test G, Zigman AL, Pasternak D, et al. European Journal of Pediatrics. 2025.
17. Febrile Seizures: A Systematic Review of Different Guidelines. — Corsello A, Marangoni MB, Macchi M, et al. Pediatric Neurology. 2024.