Version 2024

2024 ICD-10-CM Diagnosis Code G04

Encephalitis, myelitis and encephalomyelitis

ICD-10-CM Code:
ICD-10 Code for:
Encephalitis, myelitis and encephalomyelitis
Is Billable?
Not Valid for Submission
Code Navigator:

Code Classification

  • Diseases of the nervous system
    • Inflammatory diseases of the central nervous system
      • Encephalitis, myelitis and encephalomyelitis

G04 is a non-specific and non-billable diagnosis code code, consider using a code with a higher level of specificity for a diagnosis of encephalitis, myelitis and encephalomyelitis. The code is not specific and is NOT valid for the year 2024 for the submission of HIPAA-covered transactions. Category or Header define the heading of a category of codes that may be further subdivided by the use of 4th, 5th, 6th or 7th characters.

Specific Coding Applicable to Encephalitis, myelitis and encephalomyelitis

Non-specific codes like G04 require more digits to indicate the appropriate level of specificity. Consider using any of the following ICD-10-CM codes with a higher level of specificity when coding for encephalitis, myelitis and encephalomyelitis:

  • G04.0 for Acute disseminated encephalitis and encephalomyelitis (ADEM) - NON-BILLABLE CODE

  • Use G04.00 for Acute disseminated encephalitis and encephalomyelitis, unspecified - BILLABLE CODE

  • Use G04.01 for Postinfectious acute disseminated encephalitis and encephalomyelitis (postinfectious ADEM) - BILLABLE CODE

  • Use G04.02 for Postimmunization acute disseminated encephalitis, myelitis and encephalomyelitis - BILLABLE CODE

  • Use G04.1 for Tropical spastic paraplegia - BILLABLE CODE

  • Use G04.2 for Bacterial meningoencephalitis and meningomyelitis, not elsewhere classified - BILLABLE CODE

  • G04.3 for Acute necrotizing hemorrhagic encephalopathy - NON-BILLABLE CODE

  • Use G04.30 for Acute necrotizing hemorrhagic encephalopathy, unspecified - BILLABLE CODE

  • Use G04.31 for Postinfectious acute necrotizing hemorrhagic encephalopathy - BILLABLE CODE

  • Use G04.32 for Postimmunization acute necrotizing hemorrhagic encephalopathy - BILLABLE CODE

  • Use G04.39 for Other acute necrotizing hemorrhagic encephalopathy - BILLABLE CODE

  • G04.8 for Other encephalitis, myelitis and encephalomyelitis - NON-BILLABLE CODE

  • Use G04.81 for Other encephalitis and encephalomyelitis - BILLABLE CODE

  • Use G04.82 for Acute flaccid myelitis - BILLABLE CODE

  • Use G04.89 for Other myelitis - BILLABLE CODE

  • G04.9 for Encephalitis, myelitis and encephalomyelitis, unspecified - NON-BILLABLE CODE

  • Use G04.90 for Encephalitis and encephalomyelitis, unspecified - BILLABLE CODE

  • Use G04.91 for Myelitis, unspecified - BILLABLE CODE

Tabular List of Diseases and Injuries

The following annotation back-references are applicable to this diagnosis code. The Tabular List of Diseases and Injuries is a list of ICD-10-CM codes, organized "head to toe" into chapters and sections with coding notes and guidance for inclusions, exclusions, descriptions and more.


This note appears immediately under a three character code title to further define, or give examples of, the content of the category.
  • acute ascending myelitis
  • meningoencephalitis
  • meningomyelitis

Type 1 Excludes

Type 1 Excludes
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.

Type 2 Excludes

Type 2 Excludes
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.
  • 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

Patient Education


Encephalitis is an inflammation of the brain. Usually the cause is a viral infection, but bacteria can also cause it. It can be mild or severe. Most cases are mild. You may have flu-like symptoms. With a mild case, you may just need rest, plenty of fluids, and a pain reliever.

Severe cases need immediate treatment. Symptoms of severe cases include:

  • Severe headache
  • Sudden fever
  • Drowsiness
  • Vomiting
  • Confusion
  • Seizures

In babies, additional symptoms may include constant crying, poor feeding, body stiffness, and bulging in the soft spots of the skull.

Severe cases may require a stay in the hospital. Treatments include oral and intravenous (IV) medicines to reduce inflammation and treat infection. Patients with breathing difficulties may need artificial respiration. Some people may need physical, speech, and occupational therapy once the illness is under control.

NIH: National Institute of Neurological Disorders and Stroke

[Learn More in MedlinePlus]

Spinal Cord Diseases

Your spinal cord is a bundle of nerves that runs down the middle of your back. It carries signals back and forth between your body and your brain. It is protected by your vertebrae, which are the bone disks that make up your spine. If you have an accident that damages the vertebrae or other parts of the spine, this can also injure the spinal cord. Other spinal cord problems include:

  • Tumors
  • Infections such as meningitis and polio
  • Inflammatory diseases
  • Autoimmune diseases
  • Degenerative diseases such as amyotrophic lateral sclerosis and spinal muscular atrophy

Symptoms vary but might include pain, numbness, loss of sensation and muscle weakness. These symptoms can occur around the spinal cord, and also in other areas such as your arms and legs. Treatments often include medicines and surgery.

[Learn More in MedlinePlus]

Code History

  • FY 2024 - No Change, effective from 10/1/2023 through 9/30/2024
  • FY 2023 - No Change, effective from 10/1/2022 through 9/30/2023
  • FY 2022 - No Change, effective from 10/1/2021 through 9/30/2022
  • FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016. This was the first year ICD-10-CM was implemented into the HIPAA code set.