| G04 | Encephalitis, myelitis and encephalomyelitis | NON-BILLABLE CODE |
| G04.0 | Acute disseminated encephalitis and encephalomyelitis (ADEM) | NON-BILLABLE CODE |
| G04.00 | Acute disseminated encephalitis and encephalomyelitis, unspecified | BILLABLE CODE |
| G04.01 | Postinfectious acute disseminated encephalitis and encephalomyelitis (postinfectious ADEM) | BILLABLE CODE |
| G04.02 | Postimmunization acute disseminated encephalitis, myelitis and encephalomyelitis | BILLABLE CODE |
| G04.2 | Bacterial meningoencephalitis and meningomyelitis, not elsewhere classified | BILLABLE CODE |
| G04.3 | Acute necrotizing hemorrhagic encephalopathy | NON-BILLABLE CODE |
| G04.30 | Acute necrotizing hemorrhagic encephalopathy, unspecified | BILLABLE CODE |
| G04.31 | Postinfectious acute necrotizing hemorrhagic encephalopathy | BILLABLE CODE |
| G04.32 | Postimmunization acute necrotizing hemorrhagic encephalopathy | BILLABLE CODE |
| G04.39 | Other acute necrotizing hemorrhagic encephalopathy | BILLABLE CODE |
| G04.8 | Other encephalitis, myelitis and encephalomyelitis | NON-BILLABLE CODE |
| G04.81 | Other encephalitis and encephalomyelitis | BILLABLE CODE |
| G04.82 | Acute flaccid myelitis | BILLABLE CODE |
| G04.89 | Other myelitis | BILLABLE CODE |
| G04.9 | Encephalitis, myelitis and encephalomyelitis, unspecified | NON-BILLABLE CODE |
| G04.90 | Encephalitis and encephalomyelitis, unspecified | BILLABLE CODE |
| G04.91 | Myelitis, unspecified | BILLABLE CODE |
