ICD-10 Code for Encephalomyelitis

The default ICD-10-CM 2027 code for encephalomyelitis is G04.90 – Encephalitis and encephalomyelitis, unspecified. More specific codes depend on the details documented, as listed in the official index (18 codes, 18 billable).

Main code: G04.90 – Encephalitis and encephalomyelitis, unspecified
Billable: Yes
See also: Encephalitis

Index entries for Encephalomyelitis

acute disseminated – G04.00
- infectious – G04.01
- noninfectious – G04.81
- postimmunization – G04.02
- postinfectious – G04.01
acute necrotizing hemorrhagic – G04.30
- postimmunization – G04.32
- postinfectious – G04.31
- specified NEC – G04.39
equine – A83.9
- Eastern – A83.2
- Venezuelan – A92.2
- Western – A83.1
in diseases classified elsewhere – G05.3
myalgic – G93.32
- chronic fatigue syndrome [ME/CFS] – G93.32
postchickenpox – B01.11
postinfectious NEC – G04.01
postmeasles – B05.0
postvaccinal – G04.02
postvaricella – B01.11
rubella – B06.01
specified NEC – G04.81
Venezuelan equine – A92.2

How to choose the right code

Start with the main term, then pick the indented subterm that matches the documentation (type, cause, site, laterality, episode of care). Always confirm the code in the tabular list: follow its Excludes1/Excludes2, “code first” and “use additional code” notes, and add a 7th character where required.

Source: CDC/NCHS ICD-10-CM FY2027 alphabetic index.