2024 ICD-10-CM Diagnosis Code A81.9

Atypical virus infection of central nervous system, unspecified

ICD-10-CM Code:
A81.9
ICD-10 Code for:
Atypical virus infection of central nervous system, unsp
Is Billable?
Yes - Valid for Submission
Chronic Condition Indicator: [1]
Chronic
Code Navigator:

Code Classification

  • Certain infectious and parasitic diseases
    (A00–B99)
    • Viral and prion infections of the central nervous system
      (A80-A89)
      • Atypical virus infections of central nervous system
        (A81)

A81.9 is a billable diagnosis code used to specify a medical diagnosis of atypical virus infection of central nervous system, unspecified. The code is valid during the current fiscal year for the submission of HIPAA-covered transactions from October 01, 2023 through September 30, 2024.

Unspecified diagnosis codes like A81.9 are acceptable when clinical information is unknown or not available about a particular condition. Although a more specific code is preferable, unspecified codes should be used when such codes most accurately reflect what is known about a patient's condition. Specific diagnosis codes should not be used if not supported by the patient's medical record.

Approximate Synonyms

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

  • Acquired prion disease
  • Autonomic disorder due to prion disease
  • Chorea due to prion disease
  • Dementia due to prion disease
  • Disorder of autonomic nervous system due to infectious disease
  • Familial Alzheimer-like prion disease
  • Parkinsonism due to prion disease
  • Prion disease
  • Secondary tic disorder
  • Slow viral central nervous system infection
  • Tic disorder due to prion disease

Clinical Classification

Clinical CategoryCCSR Category CodeInpatient Default CCSROutpatient Default CCSR
Other specified CNS infection and poliomyelitisNVS003Y - Yes, default inpatient assignment for principal diagnosis or first-listed diagnosis.Y - Yes, default outpatient assignment for principal diagnosis or first-listed diagnosis.
Viral infectionINF008N - Not default inpatient assignment for principal diagnosis or first-listed diagnosis.N - Not default outpatient assignment for principal diagnosis or first-listed diagnosis.

Tabular List of Diseases and Injuries

The following annotation back-references are applicable to this diagnosis code. The Tabular List of Diseases and Injuries is a list of ICD-10-CM codes, organized "head to toe" into chapters and sections with coding notes and guidance for inclusions, exclusions, descriptions and more.


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.
  • Prion diseases of the central nervous system NOS

Index to Diseases and Injuries References

The following annotation back-references for this diagnosis code are found in the injuries and diseases index. The Index to Diseases and Injuries is an alphabetical listing of medical terms, with each term mapped to one or more ICD-10-CM code(s).

Convert A81.9 to ICD-9-CM

  • ICD-9-CM Code: 046.9 - Cns slow virus infec NOS

Patient Education


Neurologic Diseases

The brain, spinal cord, and nerves make up the nervous system. Together they control all the workings of the body. When something goes wrong with a part of your nervous system, you can have trouble moving, speaking, swallowing, breathing, or learning. You can also have problems with your memory, senses, or mood.

There are more than 600 neurologic diseases. Major types include:

  • Diseases caused by faulty genes, such as Huntington's disease and muscular dystrophy
  • Problems with the way the nervous system develops, such as spina bifida
  • Degenerative diseases, where nerve cells are damaged or die, such as Parkinson's disease and Alzheimer's disease
  • Diseases of the blood vessels that supply the brain, such as stroke
  • Injuries to the spinal cord and brain
  • Seizure disorders, such as epilepsy
  • Cancer, such as brain tumors
  • infections, such as meningitis

[Learn More in MedlinePlus]

Viral Infections

What are viruses?

Viruses are very tiny germs. They are made of genetic material (either DNA or RNA) inside of a protein coating. There are a huge number of viruses on earth. Only a small number of them can infect humans. Those viruses can infect our cells, which may cause disease. Some of the diseases that viruses can cause include the common cold, the flu, COVID-19, and HIV.

How are viruses spread?

Viruses can be spread in different ways:

  • Through droplets and particles that are breathed out by someone who has the infection. You might breathe in the droplets or particles, or they could land on your mouth, nose, or eyes.
  • By touching surfaces or objects that have the virus on them and then touching your mouth, nose, or eyes.
  • From the pregnant parent to the baby during pregnancy.
  • Through contaminated food or water.
  • By being bitten by an infected insect or animal.
  • Through sexual contact (usually vaginal, anal and oral sex) with someone who has the infection.

How do viruses cause disease?

Viruses are like hijackers. They invade living, normal cells. They then use those cells to multiply (make copies of themselves). This process is also called replication. The process can kill, damage, or change the infected cells. Sometimes this can make you sick. The symptoms can range from mild to very severe. Other times, your immune system may be able to fight it off and you may not have any symptoms.

Each different virus usually only infects one type of cell in your body. For example, hepatitis viruses affect the cells in the liver. HIV infects a certain type of immune system cell.

What are the treatments for viral infections?

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

Can viral infections be prevented?

Vaccines can help prevent you from getting many viral diseases. You may be able to prevent some viral infections by:

  • Proper hand washing.
  • Paying attention to food safety.
  • Cleaning surfaces that may be infected with germs.
  • Avoiding contact with wild animals.
  • Preventing insect bites by using insect repellent when you go outdoors. If you travel to an area that has a high risk of diseases from insect bites, also wear long pants, shirts, and socks.
  • Practicing safe sex (using a condom every time you have anal, vaginal, or oral sex).
  • Avoiding close contact with people who are sick.

[Learn More in MedlinePlus]

Code History

  • FY 2024 - No Change, effective from 10/1/2023 through 9/30/2024
  • FY 2023 - No Change, effective from 10/1/2022 through 9/30/2023
  • FY 2022 - No Change, effective from 10/1/2021 through 9/30/2022
  • FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016. This was the first year ICD-10-CM was implemented into the HIPAA code set.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.