ICD-10 Code G05.3 – Encephalitis and encephalomyelitis in diseases classified elsewhere (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G05.3 – Encephalitis and encephalomyelitis in diseases classified elsewhere
What it is
This code identifies inflammation of the brain, or brain and spinal cord, that occurs as a manifestation of another underlying disease. You use it when the neurologic condition is secondary to a separate classified illness.
Clinical signs
Clinical features vary; refer to documentation. Typical findings may include altered mental status, focal neurologic deficits, seizures, or signs of combined brain and spinal cord involvement.
When to use this code
Use G05.3 when the provider documents encephalitis or encephalomyelitis as due to another disease, and the underlying cause is coded elsewhere. Make sure the record links the neurologic inflammation to the causative condition. If the cause is not documented, check documentation before coding.
Do not use for
Do not use this code for primary encephalitis without an underlying disease, or for nonspecific neurologic symptoms alone. Check documentation if the provider describes a different inflammatory or infectious CNS disorder.
Coding tip
Always code the underlying disease first when documentation supports a secondary cause.