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G04 ICD-10-CA category: Encephalitis, myelitis and encephalomyelitis

G04 isn’t a code on its own. Choose one of the 5 codes beneath it, the one the documentation supports.

Official description

G04

Encephalitis, myelitis and encephalomyelitis

ICD-10-CA · Canada

Codes in G04

G04 isn’t a code on its own. Open the code that matches what the note documents.

G04.0Acute disseminated encephalitisG04.1Human T-cell lymphotropic virus associated myelopathyG04.2Bacterial meningoencephalitis and meningomyelitis, not elsewhere classifiedG04.8Other encephalitis, myelitis and encephalomyelitisG04.9Encephalitis, myelitis and encephalomyelitis, unspecified

Notes for G04

As CIHI prints them, with any note G04 takes from the headings above it.

Includes

  • Acute ascending myelitismeningoencephalitismeningomyelitis

Excludes

Conditions classified elsewhere.

  • Encephalopathy:• NOS (G93.4)• alcoholic (G31.2)• toxic (G92)multiple sclerosis (G35)myalgic encephalomyelitis (G93.3)myelitis:• acute transverse (G37.3)• subacute necrotizing (G37.4)West Nile encephalitis (A92.3)West Nile encephalomyelitis (A92.3)
  • Certain:• conditions originating in the perinatal period (P00-P96)• infectious and parasitic diseases (A00-B99)complications of pregnancy, childbirth and the puerperium (O00-O99)congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)endocrine, nutritional and metabolic diseases (E00-E90)injury, poisoning and certain other consequences of external causes (S00-T98)neoplasms (C00-D48)symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R99)From Chapter 6: Diseases of the nervous system (G00-G99)

Where G04 sits

  1. 1ChapterChapter 6: Diseases of the nervous system (G00-G99)
  2. 2Block G00-G09Inflammatory diseases of the central nervous system
  3. 3Category G04Encephalitis, myelitis and encephalomyelitis

Source and release

Data release
ICD-10-CA · FY 2026–2027
Effective date
Apr 1, 2026
Publisher
CIHI

This page is built from the ICD-10-CA catalog that Vero Codes reads when it suggests codes: Canadian Institute for Health Information’s FY 2026–2027 release, imported from the publisher’s file and checked against it. The description, notes and structured data come from the same record.

See G04 in the CIHI source

Frequently asked questions

Is G04 a valid ICD-10-CA code?

No. G04 (Encephalitis, myelitis and encephalomyelitis) is a category heading in CIHI’s ICD-10-CA FY 2026–2027 release. It holds 5 codes; record the one the documentation supports.

Where is G04 in ICD-10-CA?

G04 sits under G00-G09 Inflammatory diseases of the central nervous system, within Chapter 6: Diseases of the nervous system (G00-G99).

What coding notes apply to G04?

ICD-10-CA lists Includes, Excludes notes for G04, including those from the headings it sits under. They are listed on this page with where each one comes from.

Which ICD-10-CA release does this page use?

It uses CIHI’s FY 2026–2027 release, in effect from Apr 1, 2026 to Mar 31, 2027. It is a reference: confirm the code against the current list and the payer’s rules before you submit it.

Codes beside G04

G00Bacterial meningitis, not elsewhere classifiedG01Meningitis in bacterial diseases classified elsewhereG02Meningitis in other infectious and parasitic diseases classified elsewhereG03Meningitis due to other and unspecified causesG05Encephalitis, myelitis and encephalomyelitis in diseases classified elsewhereG06Intracranial and intraspinal abscess and granulomaG07Intracranial and intraspinal abscess and granuloma in diseases classified elsewhereG08Intracranial and intraspinal phlebitis and thrombophlebitisG09Sequelae of inflammatory diseases of central nervous system