A85.8 Other specified viral encephalitis
The ICD-10-CM code for Other specified viral encephalitis is A85.8 (FY2026). It is a billable, claim-ready diagnosis code.
Classification
- Section
- A80-A89: Viral and prion infections of the central nervous system (A80-A89)
- Category A85
- 5 codes (4 billable)
- FY2026 Status
- Stable since FY2024
Also Known As
ICD-10-CM Alphabetic Index entries that lead to A85.8:
- Von Economo-Cruchet disease
- Cruchet's disease
- Economo's disease
- Encephalitis (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute) › lethargica (acute) (infectious)
- Encephalitis (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute) › Rio Bravo
- Encephalitis (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute) › Vienna
- Encephalitis (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute) › Mengo
- Encephalitis (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute) › acute › inclusion body
Inclusion Terms
- Encephalitis lethargica
- Von Economo-Cruchet disease
U.S. Hospital Utilization
- An estimated 620 U.S. inpatient stays in 2023 included A85.8 among the documented diagnoses.
- 175 stays listed it as the principal diagnosis.
Source: National Inpatient Sample (NIS), Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality, 2016–2023. National survey-weighted estimates.
Official Coding Guidelines
HIV Infections (TOC entry)a. Human Immunodeficiency Virus (HIV) Infections .............................................................. 19
Infectious agents causing diseases in other chapters (TOC)b. Infectious agents as the cause of diseases classified to other chapters ................................. 22
Source: CMS — ICD-10-CM Official Guidelines for Coding and Reporting, FY2026