Enterovirus meningitis without pleocytosis is not only a problem in children ; A retrospective observational study in adults.

Reverse-transcriptase polymerase chain reaction (RT-PCR)-confirmed Enterovirus (EV) meningitis without pleocytosis has reported in only children. We examined the frequency of EV meningitis without pleocytosis and compared clinical features in adults. We retrospectively analyzed the data of adult patients with EV meningitis confirmed by cerebrospinal fluid (CSF) RT-PCR. Among 17 patients finally included, 58.8% showed no pleocytosis. The median age and clinical symptoms were not different between the pleocytosis and the non-pleocytosis group. There were no statistically significant differences in terms of seasonal variation or time from the onset of meningitis symptoms to undergoing lumbar puncture. The peripheral white blood cell (WBC) count of the pleocytosis was significantly higher than in patients without pleocytosis. The median CSF pressure showed higher trend in the non-pleocytosis group. Patients with higher CSF pressure than the normal level were more common in the non-pleocytosis group. The median CSF protein values were higher than the normal values in both groups. We confirmed a high frequency of EV meningitis without pleocytosis in adults. An accurate diagnosis using RT-PCR is necessary when meningitis symptoms are prominent during an EV epidemic and CSF protein levels and pressure are high, even if the CSF WBC count is normal.