G04.9
Non-billableEncephalitis, myelitis and encephalomyelitis, unspecified
G04.9 is the ICD-10-CM code for Encephalitis, myelitis and encephalomyelitis, unspecified. It is a non-billable category code — use a more specific child code such as G04.90 for billing.
G00-G99 Diseases of the nervous system
What this means — in plain language
MedlinePlus · NIHWhat is encephalitis? Encephalitis is inflammation (swelling) of the brain. It can happen when an infection or medical condition that affects the brain activates your immune system. The inflammation can cause a wide range of symptoms. In extreme cases, it can lead to brain damage, stroke , or even death. What causes encephalitis? There are different types of encephalitis, based on what the cause is. The two main…
Read more about Encephalitis at MedlinePlus ↗Source: U.S. National Library of Medicine (MedlinePlus). Informational only — not medical advice.
Conditions mapped to this code
MedlinePlus · NIHPlain-language health-topic references grounded in MedlinePlus (NIH/NLM).
Frequently asked questions
Source: CMS ICD-10-CM FY2026. For informational purposes only — not medical advice. See our medical disclaimer.
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