G04.9 – Encephalitis, myelitis and encephalomyelitis, unspecified
ICD-10-CM 2027 diagnosis code · Inflammatory diseases of the central nervous system
- Code
G04.9(claims format:G049)- Description
- Encephalitis, myelitis and encephalomyelitis, unspecified
- Billable
- No – use a more specific code below
- Valid for
- Dates of service October 1, 2026 – September 30, 2027 (FY2027)
- Chapter
- 6. Diseases of the nervous system (G00-G99)
- Block
- G00-G09 Inflammatory diseases of the central nervous system
- Parent codes
- G04
Billable codes under G04.9
G04.9 is a header code and cannot be used on claims. Choose the most specific code:
Notes inherited from parent codes
Instructional notes at a category or block level apply to every code below it.
G04 – Encephalitis, myelitis and encephalomyelitis
- acute ascending myelitis
- meningoencephalitis
- meningomyelitis
- encephalopathy NOS (G93.40)
Related codes in G04
- G04.0 – Acute disseminated encephalitis and encephalomyelitis (ADEM)Header
- G04.1 – Tropical spastic paraplegiaBillable
- G04.2 – Bacterial meningoencephalitis and meningomyelitis, not elsewhere classifiedBillable
- G04.3 – Acute necrotizing hemorrhagic encephalopathyHeader
- G04.8 – Other encephalitis, myelitis and encephalomyelitisHeader
Frequently asked questions
What is ICD-10 code G04.9?
G04.9 is the ICD-10-CM code for encephalitis, myelitis and encephalomyelitis, unspecified, in the block G00-G09 (Inflammatory diseases of the central nervous system).
Is G04.9 a billable code?
No. G04.9 is a header code with more specific child codes; report one of the billable codes listed above.
What category does G04.9 belong to?
It belongs to category G04 – Encephalitis, myelitis and encephalomyelitis.
Source: CDC/NCHS ICD-10-CM FY2027 code files, tabular list and index. Reference only – code assignment must follow the official ICD-10-CM guidelines and documentation in the medical record.