2026 ICD-10-CM Diagnosis Code G04Encephalitis, myelitis and encephalomyelitis
G04 is a non-billable ICD-10-CM category code for encephalitis, myelitis and encephalomyelitis, so it cannot be submitted on claims. Use a more specific code from this category instead, such as G04.00, G04.01, G04.02, and G04.1.
Code Identity
Code Classification
Specific Coding for Encephalitis, myelitis and encephalomyelitisOverview
Non-specific codes like G04 require more characters. Use one of these billable codes instead:
G04.0 for Acute disseminated encephalitis and encephalomyelitis (ADEM)
Use G04.00 for Acute disseminated encephalitis and encephalomyelitis, unspecified
Use G04.01 for Postinfectious acute disseminated encephalitis and encephalomyelitis (postinfectious ADEM)
Use G04.02 for Postimmunization acute disseminated encephalitis, myelitis and encephalomyelitis
Use G04.1 for Tropical spastic paraplegia
Use G04.2 for Bacterial meningoencephalitis and meningomyelitis, not elsewhere classified
G04.3 for Acute necrotizing hemorrhagic encephalopathy
Use G04.30 for Acute necrotizing hemorrhagic encephalopathy, unspecified
Use G04.31 for Postinfectious acute necrotizing hemorrhagic encephalopathy
Use G04.32 for Postimmunization acute necrotizing hemorrhagic encephalopathy
Use G04.39 for Other acute necrotizing hemorrhagic encephalopathy
G04.8 for Other encephalitis, myelitis and encephalomyelitis
Use G04.81 for Other encephalitis and encephalomyelitis
Use G04.82 for Acute flaccid myelitis
Use G04.89 for Other myelitis
G04.9 for Encephalitis, myelitis and encephalomyelitis, unspecified
Use G04.90 for Encephalitis and encephalomyelitis, unspecified
Use G04.91 for Myelitis, unspecified
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Includes
- acute ascending myelitis
- meningoencephalitis
- meningomyelitis
Type 1 Excludes
- encephalopathy NOS G93.40
Type 2 Excludes
- acute transverse myelitis G37.3
- alcoholic encephalopathy G31.2
- multiple sclerosis G35
- myalgic encephalomyelitis G93.32
- subacute necrotizing myelitis G37.4
- toxic encephalitis G92.8
- toxic encephalopathy G92.8
This note appears immediately under a three character code title to further define, or give examples of, the content of the category.
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
A type 2 excludes note represents "Not included here". An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.
Patient EducationClinical
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.
The full article covers:
- What is encephalitis?
- What causes encephalitis?
- Who is more likely to get encephalitis?
- What are the symptoms of encephalitis?
- How is encephalitis diagnosed?
- What are the treatments for encephalitis?
- Can encephalitis be prevented?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Code HistoryHistory
Questions About G04Overview
Is G04 (Encephalitis, myelitis and encephalomyelitis) a billable code?
No. This is a category header that groups the codes for encephalitis, myelitis and encephalomyelitis, and headers cannot be submitted on claims. Claims for encephalitis, myelitis and encephalomyelitis need a more specific code from this category, such as G04.00, G04.01, and G04.02.
