No UpToDate eles colocam a idade entre 6-12 meses apenas se for relacionada com déficit de vacinação, mas como padrão <6m para punção lombar. Na aula do Medcurso 2023 também é da mesma forma

Referência: https://www.uptodate.com/contents/clinical-features-and-evaluation-of-febrile-seizures?search=convuls%C3%A3o%20febril&source=search_result&selectedTitle=1%7E150&usage_type=default&display_rank=1#H91723942

Trecho retirado do site:

LP is unnecessary in most well-appearing children who have returned to a normal baseline after a febrile seizure [3,4]. We agree with the American Academy of Pediatrics (AAP) recommendations regarding the performance of LP in the setting of febrile seizures, which include the following [3]:

●LP should be performed when there are meningeal signs or symptoms or other clinical features that suggest a possible meningitis or intracranial infection

●LP should be considered in infants between 6 and 12 months if the immunization status for Hib or Streptococcus pneumoniae is deficient or undetermined

●LP should be considered when the patient is on antibiotics because antibiotic treatment can mask the signs and symptoms of meningitis