G05.4 Myelitis in diseases classified elsewhere

Billable ICD-10-CM code, FY2026. Acts as a Major Complication or Comorbidity (MCC) as a secondary diagnosis.

Applicable to

• Meningomyelitis in diseases classified elsewhere

Applies from G05 Encephalitis, myelitis and encephalomyelitis in diseases classified elsewhere

Excludes1 (never code together)

• 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)

Code first

• 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)

Risk adjustment (HCC)

• CMS-HCC V28: HCC 182 — Spinal Cord Disorders/Injuries
• CMS-HCC V22: HCC 72 — Spinal Cord Disorders/Injuries
• RxHCC V08: HCC 155 — Spinal Cord Disorders
• ESRD V24: HCC 72

MS-DRG index

Defines the logic of DRG(s) 023-024 in MDC 01.

Approximate ICD-9-CM (GEMs)

• 323.42 Other myelitis due to other infections classified elsewhere (approximate)

Medicare Code Edits (MCE v43.1 (April 2026))

• Manifestation codes as principal diagnosis: Manifestation codes describe the manifestation of an underlying disease, not the disease itself, and are not allowed as principal diagnosis.

Code annotations containing back-references to G05.4

Back-references to G05

• Type 1 Excludes: G01 Meningitis in bacterial diseases classified elsewhere ("meningoencephalitis and meningomyelitis in bacterial diseases classified elsewhere (G05)")
• Type 1 Excludes: G02 Meningitis in other infectious and parasitic diseases classified elsewhere ("meningoencephalitis and meningomyelitis in other infectious and parasitic diseases classified elsewhere (G05)")

Diagnosis Index entries for G05.4

• Meningomyelitis › in diseases classified elsewhere
• Myelitis (acute) (ascending) (childhood) (chronic) (descending) (diffuse) (disseminated) (idiopathic) (pressure) (progressive) (spinal cord) (subacute) › in diseases classified elsewhere

Nearby codes

• G05 Encephalitis, myelitis and encephalomyelitis in diseases classified elsewhere
• G05.3 Encephalitis and encephalomyelitis in diseases classified elsewhere
• G05.4 Myelitis in diseases classified elsewhere (this code)