Febrile Convulsions in Children: Clinical Framework

Diagnostic Categories

It is clinically imperative to rapidly categorize a febrile convulsion as either 'simple' or 'complex,' as this classification directs the entire investigative algorithm and long-term prognostic counseling for the parents.

• Simple Febrile Seizures: These comprise the vast majority of cases. They are characterized by a generalized tonic-clonic motor pattern (involving both sides of the body simultaneously), a short duration of less than 15 minutes, and no recurrence within a 24-hour period.
• Complex Febrile Seizures: These are defined by the presence of any one of three distinct features: a focal onset (involving only one limb or one side of the face), a prolonged duration exceeding 15 minutes, or multiple recurrent seizures clustering within a single 24-hour illness window. Complex seizures carry a slightly higher statistical risk of future afebrile epilepsy development.

Investigative Approach and Reassurance

Extensive neurological workup is typically unnecessary and invasive for the vast majority of simple presentations.

• Neuroimaging: Routine CT or MRI of the brain is not indicated for simple febrile seizures following a rapid return to an ordinary baseline neurological state. Imaging is reserved exclusively for complex seizures accompanied by persistent abnormal neurological signs.
• Electroencephalogram (EEG): Routine EEG testing after a simple febrile seizure is not recommended because the tracing is usually normal and does not accurately predict the chance of future recurrence.
• Lumbar Puncture: The threshold for performing a lumbar puncture should remain low in infants strictly under 12 months of age, or if there is incomplete vaccination for Haemophilus influenzae type B or Streptococcus pneumoniae, to definitively rule out bacterial meningitis.