Enteroviruses are the most common cause of meningitis in the United States, with an estimated 50000-75000 cases each year. Enteroviral meningitis (EVM) is frequently a diagnosis of exclusion, as viral cultures lack sensitivity and require prolonged incubation periods.
To develop a sensitive and rapid test for the diagnosis of EVM.
A rapid, one-step, reverse transcriptase-polymerase chain reaction (RT-PCR) was used in a prospective analysis of 160 patients who had cerebrospinal fluid (CSF) tested for enterovirus.
Of the 160 patients, 14 were excluded due to missing CSF viral culture data. A total of 14 were CSF culture positive (10 with pleocytosis) and 19 were PCR positive (15 with pleocytosis). The ability to detect enterovirus by either culture or PCR correlated significantly with the white blood cell count in the CSF (P=0.001). Based on a clinical definition of enterovirus culture positive and pleocylosis: ten had definite EVM and 12 had probable EVM (pleocytosis without any other cause). Four had possible EVM (CSF culture positive without pleocytosis) and 18 had pleocytosis due to other causes. PCR was positive in all ten patients with definite EVM. Five out of 12 patients with probable EVM and three out of four patients with possible EVM. No patients with pleocytosis due to other causes were PCR positive and one patient that was defined as EVM negative (culture negative and no pleocytosis) was PCR positive. Overall, PCR was positive in 18 out of the 26 patients with a likelihood of EVM, while CSF culture was positive in only 14 cases. Our results demonstrated that RT-PCR enhances the sensitivity of enterovirus detection in CSF (69 vs. 54% for culture).
The diagnosis of EVM is difficult to make clinically: the enhanced sensitivity and rapid turn around time of PCR will be of great clinical benefit.