A86 Unspecified viral encephalitis

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

Applicable to

• Viral encephalomyelitis NOS
• Viral meningoencephalitis NOS

Applies from A86 Unspecified viral encephalitis

Applicable to

• Viral encephalomyelitis NOS
• Viral meningoencephalitis NOS

MS-DRG index

Defines the logic of DRG(s) 097-099 in MDC 01.

Approximate ICD-9-CM (GEMs)

• 049.9 Unspecified non-arthropod-borne viral diseases of central nervous system (approximate)

Code annotations containing back-references to A86

Back-references to A86

• Type 1 Excludes: A88 Other viral infections of central nervous system, not elsewhere classified ("viral encephalitis NOS (A86)")

Back-references to A86

• Type 1 Excludes: A88 Other viral infections of central nervous system, not elsewhere classified ("viral encephalitis NOS (A86)")

Diagnosis Index entries for A86

• Encephalitis (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute) › acute
• Encephalitis (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute) › endemic (viral)
• Encephalitis (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute) › epidemic NEC (viral)
• Encephalitis (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute) › infectious (acute) (virus) NEC
• Encephalitis (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute) › postviral NEC
• Encephalitis (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute) › viral, virus
• Meningoencephalitis › acute NEC
• Meningoencephalitis › infectious (acute) (viral)
• Meningoencephalitis › virus NEC
• Meningoencephalomyelitis › acute NEC (viral)

Nearby codes

• A86 Unspecified viral encephalitis (this code)