ICD-10-CM Codes
G00-G99
G00-G09
G04-
2023 ICD-10-CM Diagnosis Code G04

2023 ICD-10-CM Diagnosis Code G04

Encephalitis, myelitis and encephalomyelitis

2016

2017

2018

2019

2020

2021

2022

2023

Non-Billable/Non-Specific Code

G04 should not be used for reimbursement purposes as there are multiple codes below it that contain a greater level of detail.
The 2023 edition of ICD-10-CM G04 became effective on October 1, 2022.
This is the American ICD-10-CM version of G04 - other international versions of ICD-10 G04 may differ.

Type 1 Excludes

Type 1 Excludes Help

A type 1 excludes note is a pure excludes. It means "not coded here". A type 1 excludes note indicates that the code excluded should never be used at the same time as G04. A type 1 excludes note is for used for when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.

encephalopathy NOS (
ICD-10-CM Diagnosis Code G93.40
Encephalopathy, unspecified
G93.40
)

Type 2 Excludes

Type 2 Excludes Help

A type 2 excludes note represents "not included here". A type 2 excludes note indicates that the condition excluded is not part of the condition it is excluded from but a patient may have both conditions at the same time. When a type 2 excludes note appears under a code it is acceptable to use both the code (G04) and the excluded code together.

acute transverse myelitis (
ICD-10-CM Diagnosis Code G37.3
Acute transverse myelitis in demyelinating disease of central nervous system
Applicable To
- Acute transverse myelitis NOS
- Acute transverse myelopathy
Type 1 Excludes
- acute flaccid myelitis (G04.82)
- multiple sclerosis (G35)
- neuromyelitis optica [Devic] (G36.0)
G37.3-
)
alcoholic encephalopathy (
ICD-10-CM Diagnosis Code G31.2
Degeneration of nervous system due to alcohol
Applicable To
- Alcoholic cerebellar ataxia
- Alcoholic cerebellar degeneration
- Alcoholic cerebral degeneration
- Alcoholic encephalopathy
- Dysfunction of the autonomic nervous system due to alcohol
Code Also
- associated alcoholism (F10.-)
G31.2
)
multiple sclerosis (
ICD-10-CM Diagnosis Code G35
Multiple sclerosis
Applicable To
- Disseminated multiple sclerosis
- Generalized multiple sclerosis
- Multiple sclerosis NOS
- Multiple sclerosis of brain stem
- Multiple sclerosis of cord
G35
)
myalgic encephalomyelitis (
ICD-10-CM Diagnosis Code G93.32
Myalgic encephalomyelitis/chronic fatigue syndrome
Applicable To
- Chronic fatigue syndrome
- ME/CFS
- Myalgic encephalomyelitis
G93.32
)
subacute necrotizing myelitis (
ICD-10-CM Diagnosis Code G37.4
Subacute necrotizing myelitis of central nervous system
G37.4
)
toxic encephalitis (
ICD-10-CM Diagnosis Code G92.8
Other toxic encephalopathy
Applicable To
- Toxic encephalitis
- Toxic metabolic encephalopathy
Code First
- poisoning due to drug or toxin, if applicable, (T36-T65 with fifth or sixth character 1-4 or 6)
Use Additional
- code for adverse effect, if applicable, to identify drug (T36-T50 with fifth or sixth character 5)
G92.8
)
toxic encephalopathy (
ICD-10-CM Diagnosis Code G92.8
Other toxic encephalopathy
Applicable To
- Toxic encephalitis
- Toxic metabolic encephalopathy
Code First
- poisoning due to drug or toxin, if applicable, (T36-T65 with fifth or sixth character 1-4 or 6)
Use Additional
- code for adverse effect, if applicable, to identify drug (T36-T50 with fifth or sixth character 5)
G92.8
)

Includes

Includes Help

"Includes" further defines, or give examples of, the content of the code or category.

acute ascending myelitis
meningoencephalitis
meningomyelitis

The following code(s) above G04 contain annotation back-references

Annotation Back-References

In this context, annotation back-references refer to codes that contain:

Applicable To annotations, or
Code Also annotations, or
Code First annotations, or
Excludes1 annotations, or
Excludes2 annotations, or
Includes annotations, or
Note annotations, or
Use Additional annotations

that may be applicable to G04:

G00-G99
2023 ICD-10-CM Range G00-G99
Diseases of the nervous system
Type 2 Excludes
- certain conditions originating in the perinatal period (P04-P96)
- certain infectious and parasitic diseases (A00-B99)
- complications of pregnancy, childbirth and the puerperium (O00-O9A)
- congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
- endocrine, nutritional and metabolic diseases (E00-E88)
- injury, poisoning and certain other consequences of external causes (S00-T88)
- neoplasms (C00-D49)
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
Diseases of the nervous system

Clinical Information

An inflammatory process involving the brain (encephalitis) and meninges (meningitis), most often produced by pathogenic organisms which invade the central nervous system, and occasionally by toxins, autoimmune disorders, and other conditions.

Code History

2016 (effective 10/1/2015): New code (first year of non-draft ICD-10-CM)
2017 (effective 10/1/2016): No change
2018 (effective 10/1/2017): No change
2019 (effective 10/1/2018): No change
2020 (effective 10/1/2019): No change
2021 (effective 10/1/2020): No change
2022 (effective 10/1/2021): No change
2023 (effective 10/1/2022): No change

Code annotations containing back-references to G04:

Type 1 Excludes: G03
, G03

ICD-10-CM Diagnosis Code G03
Meningitis due to other and unspecified causes
Includes
- arachnoiditis NOS
- leptomeningitis NOS
- meningitis NOS
- pachymeningitis NOS
Type 1 Excludes
- meningoencephalitis (G04.-)
- meningomyelitis (G04.-)
ICD-10-CM Diagnosis Code G03
Meningitis due to other and unspecified causes
Includes
- arachnoiditis NOS
- leptomeningitis NOS
- meningitis NOS
- pachymeningitis NOS
Type 1 Excludes
- meningoencephalitis (G04.-)
- meningomyelitis (G04.-)
Type 2 Excludes: G95

ICD-10-CM Diagnosis Code G95
Other and unspecified diseases of spinal cord
Type 2 Excludes
- myelitis (G04.-)

ICD-10-CM Codes Adjacent To G04

G00.8 Other bacterial meningitis

G00.9 Bacterial meningitis, unspecified

G01 Meningitis in bacterial diseases classified elsewhere

G02 Meningitis in other infectious and parasitic diseases classified elsewhere

G03 Meningitis due to other and unspecified causes

G03.0 Nonpyogenic meningitis

G03.1 Chronic meningitis

G03.2 Benign recurrent meningitis [Mollaret]

G03.8 Meningitis due to other specified causes

G03.9 Meningitis, unspecified

G04 Encephalitis, myelitis and encephalomyelitis

G04.0 Acute disseminated encephalitis and encephalomyelitis (ADEM)

G04.00 Acute disseminated encephalitis and encephalomyelitis, unspecified

G04.01 Postinfectious acute disseminated encephalitis and encephalomyelitis (postinfectious ADEM)

G04.02 Postimmunization acute disseminated encephalitis, myelitis and encephalomyelitis

G04.1 Tropical spastic paraplegia

G04.2 Bacterial meningoencephalitis and meningomyelitis, not elsewhere classified

G04.3 Acute necrotizing hemorrhagic encephalopathy

G04.30 …… unspecified

G04.31 Postinfectious acute necrotizing hemorrhagic encephalopathy

G04.32 Postimmunization acute necrotizing hemorrhagic encephalopathy

Reimbursement claims with a date of service on or after October 1, 2015 require the use of ICD-10-CM codes.

2023 ICD-10-CM Diagnosis Code G04

Encephalitis, myelitis and encephalomyelitis

Encephalopathy, unspecified

Acute transverse myelitis in demyelinating disease of central nervous system

Degeneration of nervous system due to alcohol

Multiple sclerosis

Myalgic encephalomyelitis/chronic fatigue syndrome

Subacute necrotizing myelitis of central nervous system

Other toxic encephalopathy

Other toxic encephalopathy

Diseases of the nervous system

Meningitis due to other and unspecified causes

Meningitis due to other and unspecified causes

Other and unspecified diseases of spinal cord