From the Guidelines
The most common causes of aseptic meningitis are viral infections, particularly enteroviruses, which account for a significant proportion of cases with an identifiable cause. These include coxsackieviruses, echoviruses, and other enteroviruses, as well as other viral causes such as herpes simplex virus (HSV), varicella-zoster virus (VZV), HIV, mumps virus, and arboviruses 1. Non-infectious causes include certain medications (NSAIDs, antibiotics like trimethoprim-sulfamethoxazole, intravenous immunoglobulin), autoimmune conditions (lupus, sarcoidosis), and cancers (lymphoma, leukemia) 1.
Key Considerations
- The term "aseptic" indicates that routine bacterial cultures are negative, distinguishing it from bacterial meningitis.
- Patients typically present with headache, fever, neck stiffness, and photophobia.
- Diagnosis involves lumbar puncture showing increased white blood cells (predominantly lymphocytes), normal glucose, and normal to slightly elevated protein levels.
- Treatment focuses on the underlying cause, with most viral cases resolving spontaneously within 7-10 days with supportive care including rest, hydration, and analgesics for pain and fever.
- Specific antiviral therapy is indicated for certain causes like HSV and VZV meningitis, where acyclovir is the treatment of choice, although its use in herpes meningitis is not supported by strong evidence 1.
Management Approach
- CSF PCR is the gold standard for confirmation of viral meningitis, and most laboratories will test for enterovirus, HSV-1, HSV-2, and VZV 1.
- If a viral cause is suspected, viral pathogens should be looked for, normally by CSF PCR, to allow for a diagnosis and to stop unnecessary antibiotics.
- Treatment should be supportive, with priority given to expediting discharge from hospital once a viral diagnosis is made.
- For recurrent episodes of lymphocytic meningitis, such as Mollaret’s meningitis, which is most often caused by HSV-2, the use of oral valaciclovir has not been shown to reduce recurrences 1.
From the Research
Causes of Aseptic Meningitis
- Enteroviruses are the most common cause of aseptic meningitis, as stated in studies 2, 3, 4, 5
- Specific enteroviruses such as coxsackie B5, echovirus 6,9, and 30 are more likely to cause meningitis outbreaks 2
- Other causes of aseptic meningitis include:
Diagnosis and Clinical Characteristics
- Nucleic acid tests are more sensitive than cultures in diagnosing enteroviral infections 2
- Serum and stool specimens are important adjunct samples for diagnosing enteroviral infections in children 2
- Cerebrospinal fluid (CSF) protein and serum procalcitonin can be useful laboratory markers for distinguishing between bacterial and aseptic meningitis 2
- Clinical characteristics such as younger age and lower percentage of lymphocytes in CSF analysis may be suggestive of enterovirus meningitis 4