A practice parameter recommends that a lumbar puncture (LP) be performed following a febrile seizure if meningeal signs are present.
The same parameter recommends that LP be strongly considered if the child is younger than 12 months of age or has received antibiotics prior to the seizure, and LP be considered if the child is younger than 18 months.
Bacterial meningitis has been found in 1.8% to 5.4% of children presenting with a febrile seizure.