ICD-10 Code A83.2 – Eastern equine encephalitis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code A83.2 – Eastern equine encephalitis
What it is
A83.2 identifies Eastern equine encephalitis, a rare viral infection that affects the brain and surrounding tissues. Use it when documentation confirms this specific mosquito-borne encephalitis.
Clinical signs
Clinical features vary; refer to documentation. Common findings can include fever, headache, confusion, seizures, and signs of encephalitis or meningoencephalitis.
When to use this code
Use A83.2 when the provider documents Eastern equine encephalitis as the confirmed diagnosis. It may also apply when the record clearly states EEE, Eastern equine encephalitis virus infection, or encephalitis due to this agent. Check documentation if the note only says viral encephalitis without naming the organism.
Do not use for
Do not use this code for other arboviral or unspecified viral encephalitides. If the diagnosis is not clearly Eastern equine encephalitis, check documentation.
Coding tip
Assign A83.2 only when the organism is specifically identified; otherwise, choose the most accurate unspecified or alternative encephalitis code.