A92.31 West Nile virus infection with encephalitis

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

Applicable to

• West Nile encephalitis
• West Nile encephalomyelitis

Applies from A92 Other mosquito-borne viral fevers

Excludes1 (never code together)

• Ross River disease (B33.1)

Applies from A92.3 West Nile virus infection

Applicable to

• West Nile fever

MS-DRG index

Defines the logic of DRG(s) 865-866 in MDC 18.

Approximate ICD-9-CM (GEMs)

• 066.41 West Nile Fever with encephalitis

Code annotations containing back-references to A92.31

Back-references to A92.31

• Type 1 Excludes: A85.2 Arthropod-borne viral encephalitis, unspecified ("West nile virus with encephalitis (A92.31)")

Back-references to A92.3

• Type 2 Excludes: A83 Mosquito-borne viral encephalitis ("West Nile fever (A92.3-)")
• Type 2 Excludes: A83 Mosquito-borne viral encephalitis ("West Nile virus (A92.3-)")

Diagnosis Index entries for A92.31

• Fever (inanition) (of unknown origin) (persistent) (with chills) (with rigor) › West › Nile (viral) › with › encephalitis
• Fever (inanition) (of unknown origin) (persistent) (with chills) (with rigor) › West › Nile (viral) › with › encephalomyelitis
• Virus, viral › West Nile (fever) › with › encephalitis
• Virus, viral › West Nile (fever) › with › encephalomyelitis

Nearby codes

• A92.0 Chikungunya virus disease
• A92.1 O'nyong-nyong fever
• A92.2 Venezuelan equine fever
• A92.3 West Nile virus infection
• A92.30 West Nile virus infection, unspecified
• A92.31 West Nile virus infection with encephalitis (this code)
• A92.32 West Nile virus infection with other neurologic manifestation
• A92.39 West Nile virus infection with other complications
• A92.4 Rift Valley fever
• A92.5 Zika virus disease
• A92.8 Other specified mosquito-borne viral fevers