ICD-10 Code A85.8 – Other specified viral encephalitis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code A85.8 – Other specified viral encephalitis
What it is
A85.8 identifies viral encephalitis that does not fit a more specific code. It is used when the provider documents a viral brain inflammation caused by an identified or suspected virus, but not one of the named categories.
Clinical signs
Clinical features vary; refer to documentation. Typical encephalitis findings may include altered mental status, fever, headache, seizures, or focal neurologic deficits, but you should code only when the record supports viral encephalitis.
When to use this code
Use A85.8 when the clinician documents other specified viral encephalitis and the case does not match a more specific ICD-10-CM code. It may also apply when the virus is identified, but the diagnosis remains in this residual category. Check documentation for the exact organism and wording.
Do not use for
Do not use this code for encephalitis with a more specific viral cause already assigned to another code. Do not use it for nonspecific viral illness, meningitis alone, or encephalopathy without documented encephalitis.
Coding tip
Match the code to the provider’s exact diagnosis wording and confirm that encephalitis, not meningitis or encephalopathy, is documented.