We aimed to describe cases of acute bacterial meningitis (ABM) without cerebrospinal fluid (CSF) pleocytosis and clinical and biological characteristics of children.
We analyzed results of a nation-wide population-based prospective surveillance study of acute ABM in children aged 3 months to 15 years in France. Absence of CSF pleocytosis was defined as CSF leukocyte count ≤5/mm.
4,754 cases of acute ABM from 2001 to 2022: 173 patients (3.6%) did not have CSF pleocytosis. ABM cases without CSF pleocytosis were mainly related to meningococcus (70% vs 44% with CSF pleocytosis, p<0.001). When performed in CSF with normal leukocyte count, Gram staining was positive for 33%, culture for 80%, PCR results for 41%, and antigen detection for 20% of cases. Case fatality rate was higher for cases without than with CSF pleocytosis (18% vs 6%, p<0.001). On multivariate analysis, absence of CSF pleocytosis was only associated with seizures before hospital arrival (adjusted odds ratio 2.3, 95% confidence interval 1.2-4.6, p<0.01).
ABM without CSF pleocytosis is infrequent but not exceptional, particularly in children with seizures before hospital arrival. Extended vaccination against meningococcus could prevent this clinical form with a high case fatality rate.