A database study identifies the most common pathogens in patients with viral meningitis.

Viruses are probably the most common cause of meningitis, with enteroviruses (EV), herpes simplex type 2 (HVS-2) and varicella zoster (VZ) the most common causative pathogens. In about half of patients with presumed viral meningitis, the aetiology remains unidentified. Although viral meningitis is often considered a benign disease, incomplete recovery is frequently seen in these patients. A benefit of antiviral treatment with acyclovir in meningitis caused by HSV-2 or VZV is unproven.

In this Danish nationwide, population-based, prospective, observational cohort study, researchers analysed a total of 1066 episodes of viral meningitis in 1045 patients identified from the Danish Study Group of Infections of the Brain database. EV were detected in 419 (39%), HSV-2 in 171 (16%), and VZV in 162 (15%) of episodes. Miscellaneous viruses were detected in 31 (3%), and pathogens were not identified in 283 (27%). The median age was 33 years, and females had 576 (54%) of all 1066 episodes. At admission, headache was one of the most frequent symptoms (95% of episodes), followed by history or presence of fever (71%), hyperacusis or photophobia (67%) and neck stiffness (36%) of patients. Only 28% had the triad of headache, neck stiffness, and hyperacusis or photophobia. Women had a higher risk for unfavourable outcome on the Glasgow Outcome Scale at 30 days (adjusted relative risk, 1.34). Neither pathogen type nor timing of antiviral treatment (aciclovir or valaciclovir) was associated with 30-day functional outcome.

Comment: This clinical study has interesting conclusions: most patients did not have the classic triad of headache, neck stiffness and hyperacusis or photophobia. Females had an increased risk for unfavourable outcome. However, the outcome was similar among patients with different aetiologies, including those without an identified pathogen, and early antiviral treatment in patients with HSV-2 or varicella zoster did not improve the outcome.

Note to readers: At the time we reviewed this paper, its publisher noted that it was not in final form and that subsequent changes might be made.

Jaime Toro, MD, Chief, Section of Neurology, Fundación Santa Fe de Bogotá; Professor and Director of the Program of Neurology, University of El Bosque, Santa Fe de Bogotá, Colombia.

Petersen PT, et al. Clinical features and prognostic factors in adults with viral meningitis. Brain 2023 Mar 16; e-pub (https://doi.org/10.1093/brain/awad089).

This summary is taken from the following Journal Watch titles: Neurology, Infectious Diseases.