ICD-10-CM Code A85.8

Other specified viral encephalitis

Version 2021 Billable Code

Valid for Submission

A85.8 is a billable code used to specify a medical diagnosis of other specified viral encephalitis. The code is valid for the fiscal year 2021 for the submission of HIPAA-covered transactions. The ICD-10-CM code A85.8 might also be used to specify conditions or terms like arbovirus encephalitis, cache valley virus infection, disease due to flaviviridae, disease due to nairovirus, encephalitis caused by alphavirus, encephalitis caused by hendra virus, etc

Short Description:Other specified viral encephalitis
Long Description:Other specified viral encephalitis

Tabular List of Diseases and Injuries

The Tabular List of Diseases and Injuries is a list of ICD-10 codes, organized "head to toe" into chapters and sections with guidance for inclusions, exclusions, descriptions and more. The following references are applicable to the code A85.8:

Inclusion Terms

Inclusion Terms
These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
  • Encephalitis lethargica
  • Von Economo-Cruchet disease

Index to Diseases and Injuries

The Index to Diseases and Injuries is an alphabetical listing of medical terms, with each term mapped to one or more ICD-10 code(s). The following references for the code A85.8 are found in the index:


The following clinical terms are approximate synonyms or lay terms that might be used to identify the correct diagnosis code:

  • Arbovirus encephalitis
  • Cache Valley virus infection
  • Disease due to Flaviviridae
  • Disease due to Nairovirus
  • Encephalitis caused by Alphavirus
  • Encephalitis caused by Hendra virus
  • Encephalitis caused by Nipah virus
  • Encephalitis caused by Polyoma virus
  • Encephalitis caused by Rubulavirus
  • Encephalitis caused by tick-borne encephalitis virus
  • Encephalitis due to European subtype of tick-borne encephalitis virus
  • Encephalitis due to Langat virus
  • Encephalitis lethargica
  • Hendra virus infection
  • Henipavirus encephalitis
  • Human immunodeficiency virus encephalitis
  • Infection caused by Henipavirus
  • Infection caused by Henipavirus
  • Infection caused by Henipavirus
  • Infection due to Nipah virus
  • Kumlinge virus encephalitis
  • Nairoviral encephalitis
  • Negishi encephalitis
  • Neuroinvasive Cache Valley encephalitis virus infection
  • Neuroinvasive Cache Valley virus disease
  • Rhabdovirus encephalitis
  • Rio Bravo fever
  • Rio Bravo viral encephalitis
  • Tensaw encephalitis
  • Tensaw virus disease
  • Thogoto virus disease

Convert A85.8 to ICD-9

  • 049.8 - Viral encephalitis NEC (Approximate Flag)

Code Classification

  • Certain infectious and parasitic diseases (A00–B99)
    • Viral and prion infections of the central nervous system (A80-A89)
      • Other viral encephalitis, not elsewhere classified (A85)

Code History

  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016
    (First year ICD-10-CM implemented into the HIPAA code set)
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
  • FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021

Information for Patients


Encephalitis is an inflammation of the brain. Usually the cause is a viral infection, but bacteria can also cause it. It can be mild or severe. Most cases are mild. You may have flu-like symptoms. With a mild case, you may just need rest, plenty of fluids, and a pain reliever.

Severe cases need immediate treatment. Symptoms of severe cases include

  • Severe headache
  • Sudden fever
  • Drowsiness
  • Vomiting
  • Confusion
  • Seizures

In babies, additional symptoms may include constant crying, poor feeding, body stiffness, and bulging in the soft spots of the skull.

Severe cases may require a stay in the hospital. Treatments include oral and intravenous (IV) medicines to reduce inflammation and treat infection. Patients with breathing difficulties may need artificial respiration. Some people may need physical, speech, and occupational therapy once the illness is under control.

NIH: National Institute of Neurological Disorders and Stroke

  • Cerebral spinal fluid (CSF) collection (Medical Encyclopedia)
  • CSF analysis (Medical Encyclopedia)
  • Encephalitis (Medical Encyclopedia)
  • Japanese Encephalitis Vaccine: What You Need to Know (Centers for Disease Control and Prevention)
  • Subacute sclerosing panencephalitis (Medical Encyclopedia)

[Learn More]

Viral Infections

Viruses are very tiny germs. They are made of genetic material inside of a protein coating. Viruses cause familiar infectious diseases such as the common cold, flu and warts. They also cause severe illnesses such as HIV/AIDS, smallpox, and Ebola.

Viruses are like hijackers. They invade living, normal cells and use those cells to multiply and produce other viruses like themselves. This can kill, damage, or change the cells and make you sick. Different viruses attack certain cells in your body such as your liver, respiratory system, or blood.

When you get a virus, you may not always get sick from it. Your immune system may be able to fight it off.

For most viral infections, treatments can only help with symptoms while you wait for your immune system to fight off the virus. Antibiotics do not work for viral infections. There are antiviral medicines to treat some viral infections. Vaccines can help prevent you from getting many viral diseases.

  • ECHO virus (Medical Encyclopedia)
  • Enterovirus D68 (Medical Encyclopedia)
  • Hand-foot-mouth disease (Medical Encyclopedia)
  • Herpangina (Medical Encyclopedia)
  • Molluscum contagiosum (Medical Encyclopedia)
  • Parainfluenza (Medical Encyclopedia)
  • Roseola (Medical Encyclopedia)
  • Zika virus disease (Medical Encyclopedia)

[Learn More]