2024 ICD-10-CM Diagnosis Code A83.3

by

St Louis encephalitis

  • A83.3 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes.
  • The 2024 edition of ICD-10-CM A83.3 became effective on October 1, 2023.
  • This is the American ICD-10-CM version of A83.3 – other international versions of ICD-10 A83.3 may differ.

The following code(s) above A83.3 contain annotation back-references

 that may be applicable to A83.3:

  • A00-B99  Certain infectious and parasitic diseases
  • A80-A89  Viral and prion infections of the central nervous system
  • A83  Mosquito-borne viral encephalitis

Approximate Synonyms

  • St. Louis encephalitis virus infection

Clinical Information

  • A viral encephalitis caused by the st. Louis encephalitis virus (encephalitis virus, st. Louis), a flavivirus. It is transmitted to humans and other vertebrates primarily by mosquitoes of the genus culex. The primary animal vectors are wild birds and the disorder is endemic to the midwestern and southeastern United States. Infections may be limited to an influenza-like illness or present as an aseptic meningitis or encephalitis. Clinical manifestations of the encephalitic presentation may include seizures, lethargy, myoclonus, focal neurologic signs, coma, and death. (from Adams et al., Principles of Neurology, 6th ed, p750)
  • Brain infection caused by the st. Louis encephalitis virus

ICD-10-CM A83.3 is grouped within Diagnostic Related Group(s) (MS-DRG v41.0):

  • 023 Craniotomy with major device implant or acute complex cns principal diagnosis with mcc or chemotherapy implant or epilepsy with neurostimulator
  • 024 Craniotomy with major device implant or acute complex cns principal diagnosis without mcc
  • 097 Non-bacterial infection of nervous system except viral meningitis with mcc
  • 098 Non-bacterial infection of nervous system except viral meningitis with cc
  • 099 Non-bacterial infection of nervous system except viral meningitis without cc/mcc

Convert A83.3 to ICD-9-CMCode 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

Diagnosis Index entries containing back-references to A83.3: