2021 ICD-10-CM Diagnosis Code G04.01

Postinfectious acute disseminated encephalitis and encephalomyelitis (postinfectious ADEM)

    2016 2017 2018 2019 2020 2021 Billable/Specific Code
  • G04.01 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes.
  • Short description: Postinfect acute dissem encephalitis and encephalomyelitis
  • The 2021 edition of ICD-10-CM G04.01 became effective on October 1, 2020.
  • This is the American ICD-10-CM version of G04.01 - other international versions of ICD-10 G04.01 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 G04.01. 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.
  • post chickenpox encephalitis (
    ICD-10-CM Diagnosis Code B01.1

    Varicella encephalitis, myelitis and encephalomyelitis

      2016 2017 2018 2019 2020 2021 Non-Billable/Non-Specific Code
    Applicable To
    • Postchickenpox encephalitis, myelitis and encephalomyelitis
    B01.1
    )
  • post measles encephalitis (
    ICD-10-CM Diagnosis Code B05.0

    Measles complicated by encephalitis

      2016 2017 2018 2019 2020 2021 Billable/Specific Code
    Applicable To
    • Postmeasles encephalitis
    B05.0
    )
  • post measles myelitis (
    ICD-10-CM Diagnosis Code B05.1

    Measles complicated by meningitis

      2016 2017 2018 2019 2020 2021 Billable/Specific Code
    Applicable To
    • Postmeasles meningitis
    B05.1
    )
The following code(s) above G04.01 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 G04.01:
  • G00-G99
    2021 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 2021 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 2021 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
  • Acute disseminated encephalomyelitis
  • Encephalitis following immunization
  • Encephalitis, acute disseminated
  • Encephalomyelitis, post infectious
  • Myelitis following immunization procedures
  • Post-infectious encephalitis
  • Post-infectious encephalomyelitis
  • Postinfectious encephalitis
ICD-10-CM G04.01 is grouped within Diagnostic Related Group(s) (MS-DRG v38.0):
  • 023 Craniotomy with major device implant or acute complex cns principal diagnosis with mcc or chemotherapy implant or epilepsy with neurostimulator
  • 024 Craniotomy with major device implant or acute complex cns principal diagnosis 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 G04.01 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
  • 2021 (effective 10/1/2020): No change
Code annotations containing back-references to G04.01:
  • Type 1 Excludes: G36
    ICD-10-CM Diagnosis Code G36

    Other acute disseminated demyelination

      2016 2017 2018 2019 2020 2021 Non-Billable/Non-Specific Code
    Type 1 Excludes
    • postinfectious encephalitis and encephalomyelitis NOS (G04.01)

Diagnosis Index entries containing back-references to G04.01:
  • 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 2021 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 2021 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 2021 Billable/Specific Code
        • infectious G04.01
        • postinfectious G04.01
    • postinfectious NEC G04.01
  • Encephalomyelitis G04.90
    - see also Encephalitis
    ICD-10-CM Diagnosis Code G04.90

    Encephalitis and encephalomyelitis, unspecified

      2016 2017 2018 2019 2020 2021 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 2021 Billable/Specific Code
      • infectious G04.01
      • postinfectious G04.01
    • postinfectious NEC G04.01
  • Leukoencephalitis G04.81
    ICD-10-CM Diagnosis Code G04.81

    Other encephalitis and encephalomyelitis

      2016 2017 2018 2019 2020 2021 Billable/Specific Code
    Applicable To
    • Noninfectious acute disseminated encephalomyelitis (noninfectious ADEM)
    • postinfectious G04.01
  • Meningoencephalomyelitis - see also Meningoencephalitis
    • acute NEC (viral) A86
      ICD-10-CM Diagnosis Code A86

      Unspecified viral encephalitis

        2016 2017 2018 2019 2020 2021 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 2021 Billable/Specific Code
        • postinfectious G04.01

ICD-10-CM Codes Adjacent To G04.01
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
G04.39 Other acute necrotizing hemorrhagic encephalopathy
G04.8 Other encephalitis, myelitis and encephalomyelitis
G04.81 Other encephalitis and encephalomyelitis

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