Separating the wheat from the chaff - Optimizing the diagnosis of enterovirus-associated meningitis.

BACKGROUND

Enteroviruses (EV) comprise the single most common cause of aseptic meningitis with variable geographical and temporal epidemiology. While EV-PCR in CSF is considered a gold standard for diagnosis, it is not-uncommon to use stool EV as a surrogate. Our aim was to assess the clinical significance of EV-PCR-positive CSF and stool in the investigation of patients with neurological symptoms.

METHODS

In this retrospective study from Sheba Medical centre, the largest tertiary hospital in Israel, we collected demographic, clinical and laboratory data of patients with EV-PCR-positive between 2016 and 2020. A comparison between various combinations of EV-PCR-positive CSF and stool was conducted. Data regarding EV strain-type and cycle threshold (Ct) were crossed with clinical symptoms and temporal kinetics.

RESULTS

Between 2016-2020, 448 CSF samples with positive EV-PCR were recorded from unique patients, the vast majority of which were diagnosed with meningitis (98%, 443/448). Unlike the diverse strain types of EV background activity, meningitis-related EV showed a clear epidemic pattern. In comparison with the EV CSF+/Stool+ group, the EV CSF-/Stool+ group had frequently more alternative pathogens detected and a higher stool Ct-value. Clinically, EV CSF-/Stool+ patients were less febrile and more lethargic and convulsive.

DISCUSSION: The comparison of the EV CSF+/Stool+ and CSF-/Stool+ groups suggests that putative diagnosis of EV meningitis is prudent in the febrile, non-lethargic non-convulsive patients with an EV-PCR-positive stool. Otherwise, the detection of stool EV only, in a non-epidemic setup, especially with a high Ct-value, may be incidental and mandate a continuous diagnostic effort for an alternative culprit.