2024 ICD-10-CM Diagnosis Code A84

Tick-borne viral encephalitis

  • A84 should not be used for reimbursement purposes as there are multiple codes below it that contain a greater level of detail.
  • The 2024 edition of ICD-10-CM A84 became effective on October 1, 2023.
  • This is the American ICD-10-CM version of A84 – other international versions of ICD-10 A84 may differ.

Includes

  • tick-borne viral meningoencephalitis

The following code(s) above A84 contain annotation back-references

 that may be applicable to A84:

  • A00-B99  Certain infectious and parasitic diseases
  • A80-A89  Viral and prion infections of the central nervous system

Clinical Information

  • Encephalitis caused by neurotropic viruses that are transmitted via the bite of ticks. In europe, the diseases are caused by encephalitis viruses, tick-borne, which give rise to russian spring-summer encephalitis, central european encephalitis, louping ill encephalitis, and related disorders. Powassan encephalitis occurs in north america and russia and is caused by the powassan virus. Aseptic meningitis and rarely encephalitis may complicate colorado tick fever which is endemic to mountainous regions of the western United States. (from Joynt, Clinical Neurology, 1996, ch26, pp14-5)

Code History

  • 2016 (effective 10/1/2015): New code (first year of non-draft ICD-10-CM)
  • 2017 (effective 10/1/2016): No change
  • 2018 (effective 10/1/2017): No change
  • 2019 (effective 10/1/2018): No change
  • 2020 (effective 10/1/2019): No change
  • 2021 (effective 10/1/2020): No change
  • 2022 (effective 10/1/2021): No change
  • 2023 (effective 10/1/2022): No change
  • 2024 (effective 10/1/2023): No change