Aseptic meningitis

Aseptic meningitis is defined as inflammation of the meninges—the protective membranes covering the brain and spinal cord—in which the cerebrospinal fluid (CSF) shows evidence of infection (e.g., elevated white cell count and protein) but lacks detectable bacteria via standard culture methods. The term 'aseptic' reflects the absence of bacterial pathogens in routine testing, not the absence of infection; many cases are due to viruses or other non-bacterial agents. This condition is distinct from bacterial meningitis primarily by its microbiological profile, although clinical presentation may overlap significantly.

Symptoms typically include fever (often 38–40°C), headache, neck stiffness, nausea or vomiting, and anorexia. In pediatric patients, additional manifestations may include hepatic necrosis, myocarditis, seizures, and focal neurological deficits. While generally self-limiting and less severe than bacterial meningitis, serious complications—including multi-organ failure—can occur, especially in immunocompromised individuals or infants. The course and severity vary depending on the underlying etiology, with viral causes often resolving within 7–14 days without sequelae.

Aseptic meningitis is a globally distributed condition, with seasonal variation noted in some regions, particularly during summer and early fall when enterovirus circulation peaks. Enteroviruses account for approximately 90% of viral cases, with mumps, varicella-zoster, and herpesviruses representing less common but clinically significant causes. The incidence is higher in children and young adults, though it can affect all age groups. Vaccination programs have reduced mumps-associated cases in high-income settings, while drug-induced forms remain relatively stable across populations. Surveillance data are limited, and no standardized ICD-10/11 codes exist for this entity, reflecting its classification as a syndrome rather than a discrete disease.

Transmission depends on the etiological agent: enteroviruses spread via fecal-oral route and respiratory secretions; varicella-zoster and herpesviruses reactivate from latent infection; drug-induced forms are not transmissible; and infectious causes like mycobacteria or fungi require exposure through environmental or hematogenous routes. No person-to-person transmission has been documented for non-infectious causes such as medication-related or autoimmune forms.

Children and young adults are at highest risk for viral causes, particularly enteroviral infections. Immunocompromised individuals face increased risk of fungal, mycobacterial, or opportunistic viral etiologies. Patients on certain medications—including NSAIDs, sulfonamides, and antiepileptics—are susceptible to drug-induced forms. Infants and elderly persons may experience more severe presentations, including organ involvement or delayed recovery, though source-backed details on age-specific outcomes remain limited.

Preventive strategies are etiology-specific: vaccination against mumps, measles, and varicella reduces certain viral causes; hygiene measures (e.g., handwashing) help limit enterovirus spread; and careful pharmacovigilance may reduce drug-induced cases. There is no universal prophylaxis for aseptic meningitis, and no targeted public health interventions exist beyond general infection control and immunization programs for preventable viral etiologies.

In surveillance contexts, aseptic meningitis should be reported as a syndrome with detailed etiological attribution where possible, given its heterogeneous causes and lack of formal coding. Monitoring should include case counts stratified by suspected cause (e.g., viral vs. drug-induced), age group, and seasonality. Because it shares symptoms with bacterial meningitis, differential diagnosis remains critical; laboratory confirmation via CSF analysis is essential for accurate classification and appropriate resource allocation.

1. 1 Wikidata. aseptic meningitis.
2. 2 Wikipedia. Aseptic meningitis - Wikipedia.

ICD-10

ICD-11

Total cases

11K

Peak month

2013-08

Coverage

1 reporting countries · 2012-09-15 → 2026-05-02