2020 ICD-10-CM Diagnosis Code G04.02

Postimmunization acute disseminated encephalitis, myelitis and encephalomyelitis

    2016 2017 2018 2019 2020 Billable/Specific Code
  • G04.02 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes.
  • Short description: Postimmun ac dissem encphlts, myelitis and encephalomyelitis
  • The 2020 edition of ICD-10-CM G04.02 became effective on October 1, 2019.
  • This is the American ICD-10-CM version of G04.02 - other international versions of ICD-10 G04.02 may differ.
Applicable To
  • Encephalitis, post immunization
  • Encephalomyelitis, post immunization
Use Additional
Use Additional Help
Certain conditions have both an underlying etiology and multiple body system manifestations due to the underlying etiology. For such conditions the ICD-10-CM has a coding convention that requires the underlying condition be sequenced first followed by the manifestation. Wherever such a combination exists there is a "use additional code" note at the etiology code, and a "code first" note at the manifestation code. These instructional notes indicate the proper sequencing order of the codes, etiology followed by manifestation. In most cases the manifestation codes will have in the code title, "in diseases classified elsewhere." Codes with this title are a component of the etiology/manifestation convention. The code title indicates that it is a manifestation code. "In diseases classified elsewhere" codes are never permitted to be used as first listed or principle diagnosis codes. They must be used in conjunction with an underlying condition code and they must be listed following the underlying condition.
  • code to identify the vaccine (
    ICD-10-CM Diagnosis Code T50.A

    Poisoning by, adverse effect of and underdosing of bacterial vaccines

      2016 2017 2018 2019 2020 Non-Billable/Non-Specific Code
    T50.A-
    ,
    ICD-10-CM Diagnosis Code T50.B

    Poisoning by, adverse effect of and underdosing of viral vaccines

      2016 2017 2018 2019 2020 Non-Billable/Non-Specific Code
    T50.B-
    ,
    ICD-10-CM Diagnosis Code T50.Z

    Poisoning by, adverse effect of and underdosing of other vaccines and biological substances

      2016 2017 2018 2019 2020 Non-Billable/Non-Specific Code
    T50.Z-
    )
The following code(s) above G04.02 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 G04.02:
  • G00-G99
    2020 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
  • G04
    ICD-10-CM Diagnosis Code G04

    Encephalitis, myelitis and encephalomyelitis

      2016 2017 2018 2019 2020 Non-Billable/Non-Specific Code
    Includes
    • acute ascending myelitis
    • meningoencephalitis
    • meningomyelitis
    Type 1 Excludes
    Type 2 Excludes
    • acute transverse myelitis (G37.3-)
    • alcoholic encephalopathy (G31.2)
    • benign myalgic encephalomyelitis (G93.3)
    • multiple sclerosis (G35)
    • subacute necrotizing myelitis (G37.4)
    • toxic encephalitis (G92)
    • toxic encephalopathy (G92)
    Encephalitis, myelitis and encephalomyelitis
  • G04.0
    ICD-10-CM Diagnosis Code G04.0

    Acute disseminated encephalitis and encephalomyelitis (ADEM)

      2016 2017 2018 2019 2020 Non-Billable/Non-Specific Code
    Type 1 Excludes
    • acute necrotizing hemorrhagic encephalopathy (G04.3-)
    • other noninfectious acute disseminated encephalomyelitis (noninfectious ADEM) (G04.81)
    Acute disseminated encephalitis and encephalomyelitis (ADEM)
Approximate Synonyms
  • Encephalitis following immunization
  • Myelitis following immunization procedures
  • Post-immunization encephalitis
  • Post-immunization myelitis
ICD-10-CM G04.02 is grouped within Diagnostic Related Group(s) (MS-DRG v37.0):
  • 023 Craniotomy with major device implant or acute complex cns pdx with mcc or chemotherapy implant or epilepsy with neurostimulator
  • 024 Craniotomy with major device implant or acute complex cns pdx without mcc
  • 097 Non-bacterial infection of nervous system except viral meningitis with mcc
  • 098 Non-bacterial infection of nervous system except viral meningitis with cc
  • 099 Non-bacterial infection of nervous system except viral meningitis without cc/mcc

Convert G04.02 to ICD-9-CM

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
Code annotations containing back-references to G04.02:
  • Type 2 Excludes: T88.1
    ICD-10-CM Diagnosis Code T88.1

    Other complications following immunization, not elsewhere classified

      2016 2017 2018 2019 2020 Non-Billable/Non-Specific Code
    Applicable To
    • Generalized vaccinia
    • Rash following immunization
    Type 1 Excludes
    • vaccinia not from vaccine (B08.011)
    Type 2 Excludes
    • anaphylactic shock due to serum (T80.5-)
    • other serum reactions (T80.6-)
    • postimmunization arthropathy (M02.2)
    • postimmunization encephalitis (G04.02)
    • postimmunization fever (R50.83)

Diagnosis Index entries containing back-references to G04.02:
  • Complication(s) (from) (of)
    • vaccination T88.1
      ICD-10-CM Diagnosis Code T88.1

      Other complications following immunization, not elsewhere classified

        2016 2017 2018 2019 2020 Non-Billable/Non-Specific Code
      Applicable To
      • Generalized vaccinia
      • Rash following immunization
      Type 1 Excludes
      • vaccinia not from vaccine (B08.011)
      Type 2 Excludes
      • anaphylactic shock due to serum (T80.5-)
      • other serum reactions (T80.6-)
      • postimmunization arthropathy (M02.2)
      • postimmunization encephalitis (G04.02)
      • postimmunization fever (R50.83)
      • encephalitis or encephalomyelitis G04.02
      • myelitis G04.02
  • Encephalitis (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute) G04.90
    ICD-10-CM Diagnosis Code G04.90

    Encephalitis and encephalomyelitis, unspecified

      2016 2017 2018 2019 2020 Billable/Specific Code
    Applicable To
    • Ventriculitis (cerebral) NOS
    • acute A86
      - see also Encephalitis, viral
      ICD-10-CM Diagnosis Code A86

      Unspecified viral encephalitis

        2016 2017 2018 2019 2020 Billable/Specific Code
      Applicable To
      • Viral encephalomyelitis NOS
      • Viral meningoencephalitis NOS
      • disseminated G04.00
        ICD-10-CM Diagnosis Code G04.00

        Acute disseminated encephalitis and encephalomyelitis, unspecified

          2016 2017 2018 2019 2020 Billable/Specific Code
        • postimmunization G04.02 (postvaccination)
    • due to
      • smallpox inoculation G04.02
    • following vaccination or other immunization procedure G04.02
    • postimmunization G04.02
    • postvaccinal G04.02
  • Encephalomyelitis G04.90
    - see also Encephalitis
    ICD-10-CM Diagnosis Code G04.90

    Encephalitis and encephalomyelitis, unspecified

      2016 2017 2018 2019 2020 Billable/Specific Code
    Applicable To
    • Ventriculitis (cerebral) NOS
    • acute disseminated G04.00
      ICD-10-CM Diagnosis Code G04.00

      Acute disseminated encephalitis and encephalomyelitis, unspecified

        2016 2017 2018 2019 2020 Billable/Specific Code
      • postimmunization G04.02
    • postvaccinal G04.02
  • Encephalopathy (acute) G93.40
    ICD-10-CM Diagnosis Code G93.40

    Encephalopathy, unspecified

      2016 2017 2018 2019 2020 Billable/Specific Code
    • in (due to) (with)
      • vaccination G04.02
  • Leukoencephalitis G04.81
    ICD-10-CM Diagnosis Code G04.81

    Other encephalitis and encephalomyelitis

      2016 2017 2018 2019 2020 Billable/Specific Code
    Applicable To
    • Noninfectious acute disseminated encephalomyelitis (noninfectious ADEM)
    • acute (subacute) G36.1
      ICD-10-CM Diagnosis Code G36.1

      Acute and subacute hemorrhagic leukoencephalitis [Hurst]

        2016 2017 2018 2019 2020 Billable/Specific Code
      • postimmunization or postvaccinal G04.02
  • Leukoencephalopathy G93.49
    - see also Encephalopathy
    ICD-10-CM Diagnosis Code G93.49

    Other encephalopathy

      2016 2017 2018 2019 2020 Billable/Specific Code
    Applicable To
    • Encephalopathy NEC
    • postimmunization and postvaccinal G04.02
  • Meningoencephalomyelitis - see also Meningoencephalitis
    • acute NEC (viral) A86
      ICD-10-CM Diagnosis Code A86

      Unspecified viral encephalitis

        2016 2017 2018 2019 2020 Billable/Specific Code
      Applicable To
      • Viral encephalomyelitis NOS
      • Viral meningoencephalitis NOS
      • disseminated G04.00
        ICD-10-CM Diagnosis Code G04.00

        Acute disseminated encephalitis and encephalomyelitis, unspecified

          2016 2017 2018 2019 2020 Billable/Specific Code
        • postimmunization or postvaccination G04.02
    • postimmunization or postvaccination G04.02
  • Myelitis (acute) (ascending) (childhood) (chronic) (descending) (diffuse) (disseminated) (idiopathic) (pressure) (progressive) (spinal cord) (subacute) G04.91
    - see also Encephalitis
    ICD-10-CM Diagnosis Code G04.91

    Myelitis, unspecified

      2016 2017 2018 2019 2020 Billable/Specific Code
    • postimmunization G04.02
    • postvaccinal G04.02

ICD-10-CM Codes Adjacent To G04.02
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
G04.39 Other acute necrotizing hemorrhagic encephalopathy
G04.8 Other encephalitis, myelitis and encephalomyelitis
G04.81 Other encephalitis and encephalomyelitis
G04.89 Other myelitis

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