G04.81 Other encephalitis and encephalomyelitis

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

Applicable to

• Noninfectious acute disseminated encephalomyelitis (noninfectious ADEM)

Applies from G04 Encephalitis, myelitis and encephalomyelitis

Includes

• acute ascending myelitis
• meningoencephalitis
• meningomyelitis

Excludes1 (never code together)

• encephalopathy NOS (G93.40)

Excludes2 (not included here)

• 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)

Applies from G04.8 Other encephalitis, myelitis and encephalomyelitis

Code also

• any associated seizure (G40.-, R56.9)

MS-DRG index

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

Approximate ICD-9-CM (GEMs)

• 323.81 Other causes of encephalitis and encephalomyelitis (approximate)

Code annotations containing back-references to G04.81

Back-references to G04.81

• Type 1 Excludes: G04.0 Acute disseminated encephalitis and encephalomyelitis (ADEM) ("other noninfectious acute disseminated encephalomyelitis (noninfectious ADEM) (G04.81)")
• Code Also: G37.81 Myelin oligodendrocyte glycoprotein antibody disease ("noninfectious acute disseminated encephalomyelitis (G04.81)")

Back-references to G04

• Type 1 Excludes: G03 Meningitis due to other and unspecified causes ("meningoencephalitis (G04.-)")
• Type 1 Excludes: G03 Meningitis due to other and unspecified causes ("meningomyelitis (G04.-)")
• Type 2 Excludes: G95 Other and unspecified diseases of spinal cord ("myelitis (G04.-)")

Diagnosis Index entries for G04.81

• Encephalitis (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute) › acute › disseminated › noninfectious
• Encephalitis (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute) › Rasmussen
• Encephalitis (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute) › specified NEC
• Encephalitis (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute) › suppurative
• Encephalomyelitis › acute disseminated › noninfectious
• Encephalomyelitis › specified NEC
• Leukoencephalitis
• Meningoencephalitis › specified organism NEC
• Rasmussen encephalitis
• Syndrome › Rasmussen

Nearby codes

• G04.30 Acute necrotizing hemorrhagic encephalopathy, unspecified
• G04.31 Postinfectious acute necrotizing hemorrhagic encephalopathy
• G04.32 Postimmunization acute necrotizing hemorrhagic encephalopathy
• G04.39 Other acute necrotizing hemorrhagic encephalopathy
• G04.8 Other encephalitis, myelitis and encephalomyelitis
• G04.81 Other encephalitis and encephalomyelitis (this code)
• G04.82 Acute flaccid myelitis
• G04.89 Other myelitis
• G04.9 Encephalitis, myelitis and encephalomyelitis, unspecified
• G04.90 Encephalitis and encephalomyelitis, unspecified
• G04.91 Myelitis, unspecified