ICD-10 Code A88 – Other Viral Infections of Central Nervous System, Not Elsewhere Classified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code A88 – Other viral infections of central nervous system, not elsewhere classified
What it is
This code covers viral infections affecting the central nervous system that do not fit a more specific ICD-10-CM category. Use it when documentation identifies a viral CNS infection but does not name a more exact diagnosis.
Clinical signs
Clinical features vary; refer to documentation. Common CNS infection findings may include headache, fever, altered mental status, or meningeal or neurologic symptoms, but the record should support a viral cause.
When to use this code
Use A88 when the provider documents an unspecified or other viral infection of the brain, spinal cord, or meninges and no more specific code is available. It may apply when the organism is not identified or the note groups the illness under “other viral CNS infection.”
Choose the documented diagnosis only; do not infer encephalitis, meningitis, or myelitis without support in the chart. If the record gives a more precise viral CNS diagnosis, code that instead.
Do not use for
Do not use this code for bacterial, fungal, or parasitic CNS infections, or for viral infections outside the central nervous system. Check documentation if the provider names a specific viral syndrome.
Coding tip
Code the most specific viral CNS diagnosis documented, and use A88 only when the record truly supports an “other” or unspecified viral CNS infection.