G04: Encephalitis, myelitis and encephalomyelitis
Codes under G04 (Encephalitis, myelitis and encephalomyelitis). A ✓ marks a billable (fully specified) code; category codes without a ✓ are not billable on their own.
| Code | Description | Billable |
|---|---|---|
| G04.0 | Acute disseminated encephalitis and encephalomyelitis (ADEM) | — |
| G04.0 | Acute disseminated encephalitis and encephalomyelitis (ADEM) | — |
| G04.00 | Acute disseminated encephalitis and encephalomyelitis, unspecified | ✓ |
| G04.00 | Acute disseminated encephalitis and encephalomyelitis, unspecified | ✓ |
| G04.01 | Postinfectious acute disseminated encephalitis and encephalomyelitis (postinfectious ADEM) | ✓ |
| G04.01 | Postinfectious acute disseminated encephalitis and encephalomyelitis (postinfectious ADEM) | ✓ |
| G04.1 | Tropical spastic paraplegia | ✓ |
| G04.1 | Tropical spastic paraplegia | ✓ |
| G04.02 | Postimmunization acute disseminated encephalitis, myelitis and encephalomyelitis | ✓ |
| G04.02 | Postimmunization acute disseminated encephalitis, myelitis and encephalomyelitis | ✓ |
| G04.2 | Bacterial meningoencephalitis and meningomyelitis, not elsewhere classified | ✓ |
| G04.2 | Bacterial meningoencephalitis and meningomyelitis, not elsewhere classified | ✓ |
| G04.3 | Acute necrotizing hemorrhagic encephalopathy | — |
| G04.3 | Acute necrotizing hemorrhagic encephalopathy | — |
| G04.8 | Other encephalitis, myelitis and encephalomyelitis | — |
| G04.8 | Other encephalitis, myelitis and encephalomyelitis | — |
| G04.9 | Encephalitis, myelitis and encephalomyelitis, unspecified | — |
| G04.9 | Encephalitis, myelitis and encephalomyelitis, unspecified | — |
| G04.30 | Acute necrotizing hemorrhagic encephalopathy, unspecified | ✓ |
| G04.30 | Acute necrotizing hemorrhagic encephalopathy, unspecified | ✓ |
| G04.31 | Postinfectious acute necrotizing hemorrhagic encephalopathy | ✓ |
| G04.31 | Postinfectious acute necrotizing hemorrhagic encephalopathy | ✓ |
| G04.32 | Postimmunization acute necrotizing hemorrhagic encephalopathy | ✓ |
| G04.32 | Postimmunization acute necrotizing hemorrhagic encephalopathy | ✓ |
| G04.39 | Other acute necrotizing hemorrhagic encephalopathy | ✓ |
| G04.39 | Other acute necrotizing hemorrhagic encephalopathy | ✓ |
| G04.81 | Other encephalitis and encephalomyelitis | ✓ |
| G04.81 | Other encephalitis and encephalomyelitis | ✓ |
| G04.82 | Acute flaccid myelitis | ✓ |
| G04.82 | Acute flaccid myelitis | ✓ |
| G04.89 | Other myelitis | ✓ |
| G04.89 | Other myelitis | ✓ |
| G04.90 | Encephalitis and encephalomyelitis, unspecified | ✓ |
| G04.90 | Encephalitis and encephalomyelitis, unspecified | ✓ |
| G04.91 | Myelitis, unspecified | ✓ |
| G04.91 | Myelitis, unspecified | ✓ |
Frequently asked questions
What is ICD-10-CM code G04?
G04 is an ICD-10-CM category covering Encephalitis, myelitis and encephalomyelitis. It contains 36 more specific diagnosis codes, 28 of which are billable.
Is G04 a billable code?
No — G04 is a category header and isn't billable on its own. Code to the highest level of specificity using one of its subcodes (for example G04.0 — Acute disseminated encephalitis and encephalomyelitis (ADEM)). 28 of the 36 codes under G04 are billable.
What codes fall under G04?
G04 includes G04.0, G04.0, G04.00, G04.00, G04.01, plus 31 more. See the full list with descriptions and billable status above.
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Informational only, not coding or medical advice. Verify against the official ICD-10-CM (FY2026) and your payer's guidelines.
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