La ponction lombaire (PL) est classiquement indiquée devant une convulsion fébrile (CF) avant l’âge de 18 mois pour éliminer une méningite. Suite à plusieurs études récentes, l’American Academy of Pediatrics (AAP) a actualisé en 2011 les recommandations de prise en charge des premières CF simples : le critère d’âge seul n’est plus une indication de PL. L’objectif de ce travail était d’évaluer si ces nouvelles recommandations peuvent s’appliquer en France.

Étude rétrospective monocentrique incluant 157 enfants de moins de 18 mois vus dans un service d’urgences pour une première CF entre 2009 et 2010.

Trois méningites bactériennes et 2 méningo-encéphalites virales non herpétiques ont été diagnostiquées. Le risque était majoré en cas de CF complexe (prolongées, focalisées ou répétées) (14 % versus 0 % en cas de CF simple, p=0,06) et de signes cliniques évocateurs (trouble de conscience, hypotonie, fontanelle bombée, trouble du comportement, purpura, aspect septique) (36 % contre 0 % en l’absence d’orientation clinique, p<0,01). La probabilité d’une méningite bactérienne ou d’une encéphalite devant une CF simple sans aucun autre signe est extrêmement faible, quel que soit l’âge de l’enfant.

Devant une CF simple sans aucun signe évocateur de méningite ou d’encéphalite, la PL n’est pas nécessaire, même avant 18 mois. Elle reste formellement indiquée en présence de signes évocateurs et doit être discutée en cas de CF complexe, d’antibiothérapie préalable ou de vaccination incomplète.

Because meningitis symptoms are not very specific under the age of 18 months, lumbar puncture (LP) was widely recommended in children presenting a febrile seizure (FS). Recent retrospective studies have challenged this age criterion. In 2011, the American Academy of Pediatrics updated its guidelines for the first episode of simple FS: LP is indicated if signs suggestive of meningitis are present and remains “an option” in case of prior antibiotic treatment or between the age of 6 and 12 months if the child is not properly vaccinated against Haemophilus and Streptococcus pneumoniae. Because the meningitis epidemiology and the vaccination coverage are different, the objective of this study was to evaluate whether these new guidelines were applicable in France.

Between 2009 and 2010, we conducted a retrospective single-center study including 157 children aged less than 18 months admitted to the pediatric emergency department (Children's Hospital, Toulouse, France) for their first febrile seizure. The data collected were: type of seizure, knowledge of prior antibiotic treatment, neurological status, signs of central nervous system infection, and biological results (LP, blood cultures).

Lumbar puncture was performed in 40% of cases (n=63). The diagnosis of meningitis/encephalitis was selected in eight cases: three cases of viral meningitis, three bacterial meningitis (Streptococcus pneumoniae), and two non-herpetic viral encephalitis. The incidence of bacterial meningitis in our study was 1.9%. The risk of serious infection, bacterial meningitis or encephalitis, was increased when there was a complex FS (14% versus 0% with a simple FS, P=0.06). The presence of other suggestive clinical symptoms was strongly associated with a risk of bacterial meningitis/encephalitis (36% in case of clinical orientation versus 0% in the absence of such signs, P<0.001).

All severe clinical presentations were associated with complex FS (prolonged, focal, and/or repeated seizures) and the presence of other suggestive clinical signs (impaired consciousness lasting longer than 1h after the seizure, septic aspect, behavior disorders, hypotonia, bulging fontanel, neck stiffness, petechial purpura). The risk of bacterial meningitis or encephalitis associated with a simple FS and followed by a strictly normal clinical examination is extremely low.

After a simple febrile seizure without any other suggestive signs of meningitis, systematic lumbar puncture is not necessary even in children younger than 18 months. LP remains absolutely indicated if clinical symptoms concentrate on central nervous system infection and should be discussed in case of complex seizures, prior antibiotic treatment, or incomplete vaccination.