Aseptic meningitis

Aseptic meningitis is defined as meningeal inflammation, operationalized in the cited review as cerebrospinal fluid pleocytosis of at least 5 cells/mm³, when the process is not attributable to an infectious cause ^[1]. The literature summarized here also notes that the term is used across heterogeneous causes, including systemic diseases with meningeal involvement, drug-induced aseptic meningitis, and neoplastic meningitis ^[1]. Because of this breadth, the category is etiologically inclusive and does not denote one uniform agent or mechanism ^[1][2].

The clinical picture described in the viral meningitis review includes acute onset of meningeal symptoms and fever, with cerebrospinal fluid pleocytosis and no growth on routine bacterial culture ^[3]. Viral cases may be associated with encephalitis or meningoencephalitis ^[3]. The broader aseptic meningitis literature emphasizes that the syndrome can arise from infectious and noninfectious causes, which complicates clinical interpretation and can make distinguishing bacterial from nonbacterial meningitis difficult ^[2]. Source-backed detail on specific symptom frequencies, complications, or prognostic patterns is not yet available beyond these general features ^[2][3].

The available sources do not provide a single geographic distribution or incidence estimate for aseptic meningitis; instead, they emphasize heterogeneity in cause and case ascertainment ^[2][3]. One review notes that over half of cases remain without an identified etiology, even with advanced molecular diagnostics, indicating a substantial unresolved burden in clinical practice ^[2]. The viral review also states that etiology varies by age and country, and that enteroviruses remain the leading cause among viral cases, while Herpesviridae, arboviruses, fungi, and spirochetes are also reported contributors ^[2][3]. Source-backed detail on outbreak settings, seasonal pattern, or reservoir ecology is not yet available ^[2][3].

Transmission is not uniform because aseptic meningitis is an umbrella syndrome with noninfectious and infectious causes ^[1][2]. For viral meningitis, the cited review states that viruses reach the central nervous system hematogenously or in a retrograde manner from nerve endings ^[3]. Beyond this route to the CNS, source-backed detail on person-to-person spread or specific exposure pathways is not yet available in the provided material ^[3].

Source-backed detail on specific demographic or occupational risk groups is not yet available in the provided material. The viral review states only that viral etiology varies according to age and country, without naming discrete high-risk populations ^[3]. The broader review also identifies several etiologic categories, including systemic autoimmune disease, drug exposure, and neoplastic disease, but does not quantify risk groups for surveillance purposes ^[1][2].

Preventive measures are source-specific rather than syndrome-specific. The viral review states that many of the viruses discussed are preventable by vaccination and by proper skin protection against transmitting vectors ^[3]. However, the provided sources do not enumerate particular vaccines, schedules, or exposure-control protocols, and they also note that many cases are noninfectious or remain of unknown cause ^[1][2][3].

In surveillance and reporting, aseptic meningitis should be interpreted cautiously as a syndrome with mixed infectious and noninfectious etiologies, not as a single disease agent ^[1][2]. The literature highlights the importance of advanced molecular diagnostics such as multiplex PCR and metagenomic sequencing for improving pathogen identification and reducing misclassification between bacterial and nonbacterial meningitis ^[2][3]. Because more than half of cases may remain without an identified cause, surveillance summaries should distinguish confirmed etiologies from idiopathic or unresolved cases when such stratification is available ^[2].

1. 1 Tattevin P et al. Aseptic meningitis. Rev Neurol (Paris). 2019 Sep-Oct. PMID: 31375286. doi: 10.1016/j.neurol.2019.07.005. PubMed: https://pubmed.ncbi.nlm.nih.gov/31375286/
2. 2 Allos H et al. Aseptic meningitis: a foundation review. Curr Opin Infect Dis. 2025 Jun 1. PMID: 40152185. doi: 10.1097/QCO.0000000000001105. PubMed: https://pubmed.ncbi.nlm.nih.gov/40152185/
3. 3 Wright WF et al. Viral (aseptic) meningitis: A review. J Neurol Sci. 2019 Mar 15. PMID: 30731305. doi: 10.1016/j.jns.2019.01.050. PubMed: https://pubmed.ncbi.nlm.nih.gov/30731305/
4. 4 “ASEPTIC MENINGITIS.”. Medical Journal of Australia. 1943. doi: 10.5694/j.1326-5377.1943.tb51199.x. DOI: https://doi.org/10.5694/j.1326-5377.1943.tb51199.x
5. 5 Aseptic meningitis. Handbook of Clinical Neurology. 2013. doi: 10.1016/b978-0-444-52910-7.00035-0. DOI: https://doi.org/10.1016/b978-0-444-52910-7.00035-0
6. 6 Aseptic Meningitis. Encyclopedia of Pain. 2013. doi: 10.1007/978-3-642-28753-4_100137. DOI: https://doi.org/10.1007/978-3-642-28753-4_100137

ICD-10

ICD-11

Total cases

11K

Peak month

2013-08

Coverage

1 reporting countries · 2012-09-15 → 2026-06-20