Coding and coverage · ICD-10-CM

G04 Encephalitis, myelitis and encephalomyelitis

Not billable (header)Chapter 6

Report one of the more specific codes below.

Check coverage with this diagnosis

Codes under this one

  • G04.0 Acute disseminated encephalitis and encephalomyelitis (ADEM)Header
  • G04.1 Tropical spastic paraplegia
  • G04.2 Bacterial meningoencephalitis and meningomyelitis, not elsewhere classified
  • G04.3 Acute necrotizing hemorrhagic encephalopathyHeader
  • G04.8 Other encephalitis, myelitis and encephalomyelitisHeader
  • G04.9 Encephalitis, myelitis and encephalomyelitis, unspecifiedHeader

Instructional notes

Chapter 6

Excludes2Not included here: the patient may have both; report both when both are present.
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)

This code

Excludes1Not coded here: never report with this code, except when the two conditions are unrelated.
Excludes2Not included here: the patient may have both; report both when both are present.
  • 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)
Includes
  • acute ascending myelitis
  • meningoencephalitis
  • meningomyelitis

Chapter 6: Diseases of the nervous system · G00-G09 Inflammatory diseases of the central nervous system (G00-G09)

Source: ICD-10-CM FY 2027 code descriptions and tabular list (CMS and CDC National Center for Health Statistics), effective 2026-10-01 through 2027-09-30 · CMS ICD-10 files. HCC mapping: CMS-HCC V28, payment year 2027. As of 2026-11-04.

Coverage and payment depend on the claim details; confirm with the Medicare Administrative Contractor.