ICD-10 Code A39.81 – Meningococcal encephalitis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code A39.81 – Meningococcal encephalitis
What it is
A39.81 identifies encephalitis caused by meningococcal infection. Use it when documentation states inflammation of the brain due to Neisseria meningitidis.
Clinical signs
Clinical features vary; refer to documentation. Typical encephalitis findings may include altered mental status, confusion, seizures, or focal neurologic deficits, with meningococcal infection confirmed or strongly linked in the record.
When to use this code
Use this code when the provider documents meningococcal encephalitis, meningococcal brain inflammation, or encephalitis due to Neisseria meningitidis. It may apply whether the diagnosis is principal or secondary, depending on the encounter focus. Check documentation for the causal link.
Do not use for
Do not use this code for meningitis without encephalitis, or for encephalitis from another organism. If the record only says meningococcal infection or sepsis, code the documented condition instead.
Coding tip
Confirm that both encephalitis and meningococcal cause are documented before assigning A39.81.