ICD-10-CM Code G04.91

Myelitis, unspecified

Version 2021 Billable Code

Valid for Submission

G04.91 is a billable code used to specify a medical diagnosis of myelitis, unspecified. The code is valid for the fiscal year 2021 for the submission of HIPAA-covered transactions. The ICD-10-CM code G04.91 might also be used to specify conditions or terms like acute ascending myelitis, encephalitis, myelitis and encephalomyelitis, infection causing myelitis, myelitis, myelitis caused by bacterium, myelitis caused by virus, etc

Short Description:Myelitis, unspecified
Long Description:Myelitis, unspecified

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 G04.91 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:

  • Acute ascending myelitis
  • Encephalitis, myelitis and encephalomyelitis
  • Infection causing myelitis
  • Myelitis
  • Myelitis caused by bacterium
  • Myelitis caused by virus

Clinical Information

  • 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

Convert G04.91 to ICD-9

  • 323.9 - Encephalitis NOS (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
  • FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021

Information for Patients

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.

  • Epidural abscess (Medical Encyclopedia)
  • Spinal cord abscess (Medical Encyclopedia)
  • Spinal tumor (Medical Encyclopedia)
  • Subacute combined degeneration (Medical Encyclopedia)
  • Syphilitic myelopathy (Medical Encyclopedia)

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