Clinical characteristics of enteroviral meningitis without pleocytosis in children: a retrospective single center observational study in the Republic of Korea

BACKGROUND: We aimed to study the prevalence of enterovirus (EV) meningitis without the presence of cerebrospinal fluid (CSF) pleocytosis and identify patient factors and clinical features associated with it. METHODS: This was a retrospective analysis of patients aged < 18 years old who were diagnosed with EV meningitis by CSF reverse-transcriptase polymerase chain reaction (RT-PCR) testing between January 2015 and December 2016. Clinical variables were compared with regard to the presence of CSF pleocytosis. RESULTS: A total of 305 patients were enrolled in study; 169 (55.4%) had no pleocytosis. Patients without pleocytosis were younger (median age 2 months vs. 67.0 months, p < 0.01) and had lower white blood cell (WBC) count (median, 8600/mm(3) vs. 10,300/mm(3), p < 0.01). Also absolute neutrophil (ANC) count were lower than pleocytosis group (median, 4674/mm(3) vs. 7600/mm(3), p < 0.01). Comparing three age groups, CSF apleocytosis was present in 106 of 128 patients (82.8%) aged ≤3 months, 7 of 13 patients (53.8%) aged 3 months–3 years and 56 of 164 patients (34.1%) aged > 3 years. Younger age groups had higher prevalence of CSF apleocytosis (p < 0.01). In patients aged ≤3 months, 94.5% underwent lumbar puncture within 24 h of symptom onset. The frequency of not having pleocytosis was higher than the frequency of having pleocytosis during peak EV infection prevalent months (summer and fall) (p < 0.01). CONCLUSION: This study shows that EV meningitis in young infants, with early lumbar puncture, or occurring during peak EV meningitis prevalent seasons cannot be solely excluded by pleocytosis. Also, a confirmation test for EV meningitis should be performed using RT-PCR.