G05

Encephalitis, myelitis and encephalomyelitis in diseases classified elsewhere

FY2027Chapter 6: Diseases of the nervous system/G00–G09 Inflammatory diseases of the central nervous system

Non-billable headerNot valid on its own. Use one of the more specific codes under it.

G05 is a non-billable ICD-10-CM code category for encephalitis, myelitis and encephalomyelitis in diseases classified elsewhere. Report a more specific code from it instead. It is part of the FY2027 code set, effective October 1, 2026. The more specific codes under it are G05.3 Encephalitis and encephalomyelitis in diseases classified elsewhere and G05.4 Myelitis in diseases classified elsewhere. Its coding notes include a Code first instruction, 11 Excludes1 entries and 8 Excludes2 entries.

Code first

If the underlying condition listed here is present and known, sequence it first.

This code
  • underlying disease, such as:
    • congenital toxoplasmosis encephalitis, myelitis and encephalomyelitis (P37.1)
    • cytomegaloviral encephalitis, myelitis and encephalomyelitis (B25.8)
    • encephalitis, myelitis and encephalomyelitis (in) systemic lupus erythematosus (M32.19)
    • eosinophilic meningoencephalitis (B83.2)
    • human immunodeficiency virus [HIV] disease (B20)
    • poliovirus (A80.-)
    • suppurative otitis media (H66.01-H66.4)
    • systemic lupus erythematosus (M32.19)
    • trichinellosis (B75)

Excludes1

Not coded here. The listed conditions generally should not be reported together.

This code
  • adenoviral encephalitis, myelitis and encephalomyelitis (A85.1)
  • encephalitis, myelitis and encephalomyelitis (in) measles (B05.0)
  • enteroviral encephalitis, myelitis and encephalomyelitis (A85.0)
  • herpesviral [herpes simplex] encephalitis, myelitis and encephalomyelitis (B00.4)
  • listerial encephalitis, myelitis and encephalomyelitis (A32.12)
  • meningococcal encephalitis, myelitis and encephalomyelitis (A39.81)
  • mumps encephalitis, myelitis and encephalomyelitis (B26.2)
  • postchickenpox encephalitis, myelitis and encephalomyelitis (B01.1-)
  • rubella encephalitis, myelitis and encephalomyelitis (B06.01)
  • toxoplasmosis encephalitis, myelitis and encephalomyelitis (B58.2)
  • zoster encephalitis, myelitis and encephalomyelitis (B02.0)

Excludes2

Not included here. Both codes may be reported if the patient has both conditions.

Also from chapter/block level (8 notes)
Inherited from Chapter 6 Diseases of the nervous system
  • 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)

More specific codes under G05 2