2026 ICD-10-CM Diagnosis Code G04.89Other myelitis

ICD-10-CM Codes›G00–G99›G00-G09›G04

ICD-10-CM G04.89
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

G04.89 is a billable ICD-10-CM diagnosis code for other myelitis. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 974 through 976. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Encephalitis.

Code Identity

ICD-10-CM Code
G04.89
Billable Status
Yes — Valid for Submission
Code Describes
Other myelitis
Short Description
Other myelitis
Same as the full description in the CMS dataset.
Parent Code
G04.8
Other encephalitis, myelitis and encephalomyelitis

Code Classification

ChapterG00–G99Diseases of the nervous system
SectionG00-G09Inflammatory diseases of the central nervous system
CategoryG04Encephalitis, myelitis and encephalomyelitis
This CodeG04.89Other myelitis

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Coxsackievirus infection of the central nervous system
  • Disease caused by Deltaretrovirus
  • Disorder of spinal cord due to and following radiotherapy
  • Enteroviral neurological disease
  • Human T-lymphotropic virus 1 infection
  • Infection caused by Human T-lymphotropic virus
  • Infection caused by Mycoplasma pneumoniae
  • Myelitis caused by bacterium
  • Myelitis caused by Enterovirus
  • Myelitis caused by Human coxsackievirus A
  • Myelitis caused by Human coxsackievirus B
  • Myelitis caused by Human echovirus
  • Myelitis caused by human T-lymphotropic virus type 1
  • Myelitis caused by Mycoplasma pneumoniae
  • Myelitis caused by Retroviridae
  • Post-infective myelitis
  • Radiation myelitis

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.

    • Infection, infected, infective(opportunistic)
      • spinal cord NOS
        • streptococcal
    • Myelitis(acute) (ascending) (childhood) (chronic) (descending) (diffuse) (disseminated) (idiopathic) (pressure) (progressive) (spinal cord) (subacute)
      • postinfectious NEC
    • Myelitis(acute) (ascending) (childhood) (chronic) (descending) (diffuse) (disseminated) (idiopathic) (pressure) (progressive) (spinal cord) (subacute)
      • specified NEC

Clinical ClassificationClinical

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

CCSR NVS002
Encephalitis
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Myelitis

    inflammation of the spinal cord. relatively common etiologies include infections; autoimmune diseases; spinal cord; and ischemia (see also spinal cord vascular diseases). clinical features generally include weakness, sensory loss, localized pain, incontinence, and other signs of autonomic dysfunction.

  • Myelitis, Transverse

    inflammation of a transverse portion of the spinal cord characterized by acute or subacute segmental demyelination or necrosis. the condition may occur sporadically, follow an infection or vaccination, or present as a paraneoplastic syndrome (see also encephalomyelitis, acute disseminated). clinical manifestations include motor weakness, sensory loss, and incontinence. (adams et al., principles of neurology, 6th ed, pp1242-6)

  • Neuroschistosomiasis

    schistosomiasis of the brain, spinal cord, or meninges caused by infections with trematodes of the genus schistosoma (primarily schistosoma japonicum; schistosoma mansoni; and schistosoma haematobium in humans). s. japonicum infections of the nervous system may cause an acute meningoencephalitis or a chronic encephalopathy. s. mansoni and s. haematobium nervous system infections are associated with acute transverse myelitis involving the lower portions of the spinal cord. (from joynt, clinical neurology, 1998, ch27, pp61-2)

  • Encephalomyelitis, CTCAE

    a disorder characterized by an infectious or inflammatory process involving the brain and spinal cord tissues.

  • Grade 2 Myelitis, CTCAE|Grade 2 Myelitis|Grade 2 Myelitis

    moderate weakness or sensory loss; limiting instrumental adl or mild/moderate impact on age-appropriate normal daily activity (pediatric)

  • Grade 3 Encephalomyelitis, CTCAE

    iv antibiotic, antifungal, or antiviral intervention indicated; steroid therapy indicated; severe changes in mental status; self-limited seizure activity; neurologic abnormalities

  • Grade 3 Myelitis, CTCAE|Grade 3 Myelitis|Grade 3 Myelitis

    severe weakness or sensory loss; limiting self-care adl or severe impact on age-appropriate normal daily activity (pediatric)

  • Grade 4 Encephalomyelitis, CTCAE

    life-threatening consequences; urgent intervention indicated

  • Grade 5 Encephalomyelitis, CTCAE

    death

  • Acute Disseminated Encephalomyelitis|ADEM|ADEM

    an inflammatory process affecting the central nervous system. it is characterized by perivascular demyelination. symptoms usually follow an acute viral infection or immunization and include fever, confusion, somnolence and involuntary movements. it may lead to coma and death.

  • Acute Flaccid Myelitis

    an acute onset of focal limb weakness that is associated mainly with gray matter abnormalities or csf pleocytosis, but which is without an apparent cause.

  • Acute Poliomyelitis|Polia|Polio|Polio|Poliomyelitis

    an acute infectious disorder that affects the nervous system. it is caused by the poliovirus. the virus spreads by direct contact, and can be prevented by prophylaxis with the polio vaccine.

  • Acute Transverse Myelitis

    a neurologic disorder that is caused by inflammation across both sides of one level, or segment, of the spinal cord. (from ninds)

  • Acute Transverse Myelitis in Demyelinating Disease of Central Nervous System|Acute transverse myelitis in demyelinating disease of central nervous system

    evidence of acute transverse myelitis in demyelinating disease of the central nervous system.

  • Chronic Fatigue Syndrome|Myalgic Encephalomyelitis|Myalgic encephalomyelitis/chronic fatigue syndrome|chronic fatigue syndrome

    a syndrome of unknown etiology. chronic fatigue syndrome (cfs) is a clinical diagnosis characterized by an unexplained persistent or relapsing chronic fatigue that is of at least six months' duration, is not the result of ongoing exertion, is not substantially alleviated by rest, and results in substantial reduction of previous levels of occupational, educational, social, or personal activities. common concurrent symptoms of at least six months duration include impairment of memory or concentration, diffuse pain, sore throat, tender lymph nodes, headaches of a new type, pattern, or severity, and nonrestorative sleep. the etiology of cfs may be viral or immunologic. neurasthenia and fibromyalgia may represent related disorders. also known as myalgic encephalomyelitis.

  • Chronic Recurrent Multifocal Osteomyelitis|CRMO|CRMO|NBO|NBO|Non-bacterial Osteomyelitis|Non-bacterial Osteomyelitis

    an autoinflammatory disease characterized by sterile bone lesions which are multifocal and/or recurrent.

  • Diphtheria-Tetanus-Acellular Pertussis-Inactivated Poliomyelitis-Haemophilus influenzae Type B Vaccine|DTaP(5)-IPV-Hib|DTaP-IPV-Hib|Pediacel

    a vaccine consisting of detoxified diphtheria toxoid (d), detoxified tetanus toxoid (t), acellular pertussis (ap) antigens, inactivated poliovirus (ipv) types 1, 2 and 3, and haemophilus influenzae type b (hib) capsular polysaccharide (polyribosylribitol phosphate; prp) covalently bound to tetanus protein, suspended in water for injection and with active immunizing activity against diphtheria, tetanus, pertussis, poliomyelitis and h. influenzae type b. the five purified pertussis antigens in this vaccine are pertussis toxin (pt), filamentous hemagglutinin (fha), pertactin (prn) and fimbriae types 2 and 3 (fim). upon intramuscular injection of the diphtheria-tetanus-acellular pertussis-inactivated poliomyelitis-haemophilus influenzae type b vaccine (dtap-ipv-hib), this vaccine activates the immune system to develop antibodies against diphtheria toxin, tetanus toxin, b. pertussis antigens, polioviruses and hib, thereby providing active immunization against these diseases. the diphtheria and tetanus toxoids and pertussis antigens (inactivated pt, fha, prn and fim) are adsorbed separately onto aluminum phosphate and then combined with ipv and prp.

  • Encephalomyelitis

    inflammation of the brain and the spinal cord.

  • Encephalomyelitis Infection, CTCAE|Encephalomyelitis Infection|Encephalomyelitis infection

    a disorder characterized by an infectious process involving the brain and spinal cord tissues.

  • Experimental Allergic Encephalomyelitis|EAE|Experimental Autoimmune Encephalomyelitis

    an autoimmune demyelinating disease of the central nervous system that is produced experimentally in animals by the injection of homogenized brain or spinal cord in freund's adjuvant. myelin basic protein appears to be the antigen that elicits the hypersensitivity immune response which is characterized by focal areas of lymphocyte and macrophage infiltration into the brain, associated with demyelination and destruction of the blood-brain barrier. experimental allergic encephalomyelitis (eae) is used as an animal model for demyelinating diseases of the human central nervous system such as multiple sclerosis.

  • Grade 1 Myelitis, CTCAE|Grade 1 Myelitis|Grade 1 Myelitis

    asymptomatic; mild signs (e.g., babinski's reflex or lhermitte's sign)

  • Grade 2 Myelitis, CTCAE|Grade 2 Myelitis|Grade 2 Myelitis

    moderate weakness or sensory loss; limiting instrumental adl

  • Grade 3 Encephalomyelitis Infection, CTCAE|Grade 3 Encephalomyelitis infection

    iv antibiotic, antifungal, or antiviral intervention indicated; invasive intervention indicated

  • Grade 3 Myelitis, CTCAE|Grade 3 Myelitis|Grade 3 Myelitis

    severe weakness or sensory loss; limiting self care adl

  • Grade 4 Encephalomyelitis Infection, CTCAE|Grade 4 Encephalomyelitis infection

    life-threatening consequences; urgent intervention indicated

  • Grade 4 Myelitis, CTCAE|Grade 4 Myelitis|Grade 4 Myelitis

    life-threatening consequences; urgent intervention indicated

  • Grade 5 Encephalomyelitis Infection, CTCAE|Grade 5 Encephalomyelitis infection

    death

  • Grade 5 Myelitis, CTCAE|Grade 5 Myelitis|Grade 5 Myelitis

    death

  • Infectious Encephalomyelitis|Encephalomyelitis infection

    an infectious process that affects the brain and spinal cord tissues. it is usually caused by viruses.

  • Myelitis

    an inflammatory process affecting the spinal cord. causes include viral infections, autoimmune disorders, vascular disorders, and toxic agents. symptoms include weakness, paresthesia, sensory loss, pain, and incontinence.

  • Myelitis, CTCAE|Myelitis|Myelitis|Myelitis

    a disorder characterized by inflammation involving the spinal cord. symptoms include weakness, paresthesia, sensory loss, marked discomfort and incontinence.

  • Neuromyelitis Optica|Devic Syndrome|Neuromyelitis optica [Devic]

    an autoimmune inflammatory syndrome characterized by optic neuritis and myelitis. signs and symptoms include loss of vision, weakness and paralysis of the extremities, and loss of sensation.

  • Osteomyelitis|osteomyelitis

    an acute or chronic inflammation of the bone and its structures due to infection with pyogenic bacteria.

  • Staphylococcal Osteomyelitis|Staph Osteomyelitis|Staph Osteomyelitis

    osteomyelitis resulting from an infection with staphylococcus.

  • Subacute Necrotizing Myelitis of Central Nervous System|Subacute necrotizing myelitis of central nervous system

    evidence of subacute necrotizing myelitis of central nervous system.

  • Vaccine-Associated Paralytic Poliomyelitis|OPV associated Paralytic Poliomyelitis|VAPP|VAPP

    a rare, paralytic poliomyelitis associated with the orally administered live attenuated strain of the poliovirus, opv.

  • Western Equine Encephalomyelitis

    a mosquito-born viral infection caused by the western equine encephalitis virus. the signs and symptoms range from flu-like illness to permanent central nervous system damage, coma, and death.

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 G04.89 to ICD-9-CMHistory

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

ICD-9-CM
323.82 Myelitis cause NEC
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 G04.89Overview

Is G04.89 (Other encephalitis, myelitis and encephalomyelitis) a billable code?

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

What MS-DRG does G04.89 group to?

When other myelitis is the principal diagnosis on an inpatient stay, it groups to MS-DRG 974, 975, 976, with relative weights from 0.8945 to 2.8860 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of G04.89?

Under the General Equivalence Mappings, other myelitis converts to ICD-9-CM 323.82 (myelitis cause NEC). 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.