2026 ICD-10-CM Diagnosis Code G05.4Myelitis in diseases classified elsewhere

ICD-10-CM Codes›G00–G99›G00-G09›G05

ICD-10-CM G05.4
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

G05.4 is a billable ICD-10-CM diagnosis code for myelitis in diseases classified elsewhere. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). The code is a manifestation code that cannot be reported as the principal diagnosis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Encephalitis.

Code Identity

ICD-10-CM Code
G05.4
Billable Status
Yes — Valid for Submission
Code Describes
Myelitis in diseases classified elsewhere
Short Description
Myelitis in diseases classified elsewhere
Same as the full description in the CMS dataset.
Parent Code
G05
Encephalitis, myelitis and encephalomyelitis in diseases classified elsewhere

Code Classification

ChapterG00–G99Diseases of the nervous system
SectionG00-G09Inflammatory diseases of the central nervous system
CategoryG05Encephalitis, myelitis and encephalomyelitis in diseases classified elsewhere
This CodeG05.4Myelitis in diseases classified elsewhere

Code EditsBilling

Medicare Code Editor checks that affect claim validity for G05.4.

Manifestation diagnoses
Manifestation codes describe the manifestation of an underlying disease, not the disease itself, and therefore should not be used as a principal diagnosis.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Borrelia infection of central nervous system
  • Central nervous system disorder due to Sjögren's syndrome
  • Coccidioides infection of the central nervous system
  • Coenurosis
  • Cysticercosis myelitis
  • Dengue
  • Disorder of spinal cord co-occurrent with human immunodeficiency virus infection
  • Epstein Barr virus infection of the central nervous system
  • Histoplasma infection of central nervous system
  • Infection by Coenurosis cerebralis
  • Infection by Multiceps multiceps
  • Infection caused by Roseolovirus
  • Infection of central nervous system caused by Borrelia burgdorferi
  • Infection of central nervous system caused by Cytomegalovirus
  • Infection of spinal cord caused by Histoplasma
  • Lyme neuroborreliosis
  • Myelitis caused by Actinomyces
  • Myelitis caused by Aspergillus
  • Myelitis caused by bacterium
  • Myelitis caused by Borrelia burgdorferi
  • Myelitis caused by Coccidioides
  • Myelitis caused by Coenurus cerebralis
  • Myelitis caused by Cytomegalovirus
  • Myelitis caused by Dengue virus
  • Myelitis caused by Enterovirus
  • Myelitis caused by Epstein-Barr virus
  • Myelitis caused by fungus
  • Myelitis caused by Human herpes virus
  • Myelitis caused by human poliovirus
  • Myelitis caused by Influenza A virus
  • Myelitis caused by Plasmodium
  • Myelitis caused by Roseolovirus
  • Myelitis caused by Schistosoma
  • Myelitis caused by Schistosoma haematobium
  • Myelitis caused by Schistosoma japonicum
  • Myelitis caused by Schistosoma mansoni
  • Myelitis caused by Toxoplasma gondii
  • Myelitis caused by Treponema pallidum
  • Myelitis co-occurrent with human immunodeficiency virus infection
  • Myelitis due to anti-phospholipid syndrome
  • Myelitis due to Behcet disease
  • Myelitis due to multiple sclerosis
  • Myelitis due to sarcoidosis
  • Myelitis due to Sjogren syndrome
  • Myelitis due to systemic lupus erythematosus
  • Myelitis due to vasculitis
  • Myelitis with AIDS
  • Myelopathy with AIDS
  • Parasitic infection causing myelitis
  • Protozoal myelitis
  • Schistosoma haematobium infection
  • Schistosoma japonicum infection
  • Schistosoma mansoni infection

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Meningomyelitis in diseases classified elsewhere

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Meningomyelitis
      • in diseases classified elsewhere
    • Myelitis(acute) (ascending) (childhood) (chronic) (descending) (diffuse) (disseminated) (idiopathic) (pressure) (progressive) (spinal cord) (subacute)
      • in diseases classified elsewhere

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR NVS002
Encephalitis
Default principal diagnosis: inpatient No · outpatient No

Clinical InformationClinical

  • Lyme Neuroborreliosis

    nervous system infections caused by tick-borne spirochetes of the borrelia burgdorferi group. the disease may affect elements of the central or peripheral nervous system in isolation or in combination. common clinical manifestations include a lymphocytic meningitis, cranial neuropathy (most often a facial neuropathy), polyradiculopathy, and a mild loss of memory and other cognitive functions. less often more extensive inflammation involving the central nervous system (encephalomyelitis) may occur. in the peripheral nervous system, b. burgdorferi infection is associated with mononeuritis multiplex and polyradiculoneuritis. (from j neurol sci 1998 jan 8;153(2):182-91)

  • Dengue

    an acute febrile disease transmitted by the bite of aedes mosquitoes infected with dengue virus. it is self-limiting and characterized by fever, myalgia, headache, and rash. severe dengue is a more virulent form of dengue.

  • Dengue Vaccines

    vaccines or candidate vaccines used to prevent infection with dengue virus. these include live-attenuated, subunit, dna, and inactivated vaccines.

  • Dengue Virus

    a species of the genus flavivirus which causes an acute febrile and sometimes hemorrhagic disease in man. dengue is mosquito-borne and four serotypes are known.

  • Severe Dengue

    a virulent form of dengue characterized by thrombocytopenia and an increase in vascular permeability (grades i and ii) and distinguished by a positive pain test (e.g., tourniquet pain test). when accompanied by shock (grades iii and iv), it is called dengue shock syndrome.

  • Flavivirus

    a genus of flaviviridae containing several subgroups and many species. most are arboviruses transmitted by mosquitoes or ticks. the type species is yellow fever virus.

  • Schistosoma Japonicum Infection

    an infection that is caused by schistosoma japonicum.

  • Schistosoma Mansoni Infection

    an infection that is caused by schistosoma mansoni.

Patient EducationClinical

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.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert G05.4 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
323.42 Oth myelitis ot inf else
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About G05.4Overview

Is G05.4 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report myelitis in diseases classified elsewhere on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

Can G05.4 be a principal diagnosis?

No. This is a manifestation code: myelitis in diseases classified elsewhere describes the manifestation of an underlying disease rather than the disease itself, so the underlying condition is sequenced first.

What is the ICD-9 equivalent of G05.4?

Under the General Equivalence Mappings, myelitis in diseases classified elsewhere converts to ICD-9-CM 323.42 (oth myelitis ot inf else). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.