ICD-10-CM Code G04.81

Other encephalitis and encephalomyelitis

Version 2020 Billable Code

Valid for Submission

G04.81 is a billable code used to specify a medical diagnosis of other encephalitis and encephalomyelitis. The code is valid for the year 2020 for the submission of HIPAA-covered transactions. The ICD-10-CM code G04.81 might also be used to specify conditions or terms like allergic encephalitis, allergic encephalitis, allergic encephalomyelitis, autoimmune encephalitis, autoimmune encephalitis, autoimmune encephalitis, etc

Short Description:Other encephalitis and encephalomyelitis
Long Description:Other encephalitis and encephalomyelitis

Tabular List of Diseases and Injuries

The Tabular List of Diseases and Injuries is a list of ICD-10 codes, organized "head to toe" into chapters and sections with guidance for inclusions, exclusions, descriptions and more. The following references are applicable to the code G04.81:

Inclusion Terms

Inclusion Terms
These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
  • Noninfectious acute disseminated encephalomyelitis (noninfectious ADEM)

Index to Diseases and Injuries

The Index to Diseases and Injuries is an alphabetical listing of medical terms, with each term mapped to one or more ICD-10 code(s). The following references for the code G04.81 are found in the index:


The following clinical terms are approximate synonyms or lay terms that might be used to identify the correct diagnosis code:

  • Allergic encephalitis
  • Allergic encephalitis
  • Allergic encephalomyelitis
  • Autoimmune encephalitis
  • Autoimmune encephalitis
  • Autoimmune encephalitis
  • Autoimmune encephalitis
  • Autoimmune encephalitis caused by N-methyl D-aspartate receptor antibody
  • Bickerstaff's brainstem encephalitis
  • Brainstem encephalitis
  • Brainstem encephalitis
  • Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids
  • Encephalitis due to Herpesviridae
  • Epstein Barr virus infection of the central nervous system
  • Experimental allergic encephalomyelitis
  • Focal encephalitis
  • Granulomatous meningoencephalomyelitis
  • Infectious mononucleosis encephalitis
  • Limbic encephalitis
  • Limbic encephalitis with contactin-associated protein-like 2 antibodies
  • Limbic encephalitis with dipeptidyl-peptidase 6 antibodies
  • Limbic encephalitis with leucine-rich glioma-inactivated 1 antibodies
  • Limbic encephalitis with N-methyl-D-aspartate receptor antibodies
  • Meningoencephalomyelitis
  • Meningoencephalomyelitis
  • Non-herpetic acute limbic encephalitis
  • Post-transplant acute limbic encephalitis
  • Pyogranulomatous meningoencephalomyelitis
  • Rasmussen syndrome
  • Rasmussen syndrome, refractory

Convert G04.81 to ICD-9

  • 323.81 - Enceph & encephlalo NEC (Approximate Flag)

Code Classification

  • Diseases of the nervous system (G00–G99)
    • Inflammatory diseases of the central nervous system (G00-G09)
      • Encephalitis, myelitis and encephalomyelitis (G04)

Code History

  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016
    (First year ICD-10-CM implemented into the HIPAA code set)
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020

Information for Patients


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

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