ICD-10 Diagnosis Code A86

Unspecified viral encephalitis

Diagnosis Code A86

ICD-10: A86
Short Description: Unspecified viral encephalitis
Long Description: Unspecified viral encephalitis
This is the 2017 version of the ICD-10-CM diagnosis code A86

Code Classification
  • Certain infectious and parasitic diseases
    • Viral and prion infections of the central nervous system (A80-A89)
      • Unspecified viral encephalitis (A86)

Information for Medical Professionals

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The ICD-10 and ICD-9 GEMs are used to facilitate linking between the diagnosis codes in ICD-9-CM and the new ICD-10-CM code set. The GEMs are the raw material from which providers, health information vendors and payers can derive specific applied mappings to meet their needs.

  • Acute necrotizing encephalitis
  • Acute viral encephalitis
  • Chronic echovirus meningoencephalitis
  • Chronic meningitis
  • Chronic viral encephalitis
  • Dementia associated with viral encephalitis
  • Echovirus disease
  • Echovirus meningitis
  • Enterovirus meningitis
  • Epidemic encephalitis
  • Infective ventriculitis, brain
  • Primary encephalitis
  • Primary viral encephalitis
  • Ventriculitis of the brain
  • Viral encephalitis
  • Viral meningoencephalitis
  • Viral ventriculitis, brain

Index of Diseases and Injuries
References found for the code A86 in the Index of Diseases and Injuries:

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
  • CSF analysis
  • Encephalitis
  • Japanese Encephalitis Vaccine: What You Need to Know (Centers for Disease Control and Prevention)
  • Subacute sclerosing panencephalitis

[Read More]

Viral Infections

Viruses are capsules with genetic material inside. They are very tiny, much smaller than bacteria. Viruses cause familiar infectious diseases such as the common cold, flu and warts. They also cause severe illnesses such as HIV/AIDS, smallpox and hemorrhagic fevers.

Viruses are like hijackers. They invade living, normal cells and use those cells to multiply and produce other viruses like themselves. This eventually kills the cells, which can make you sick.

Viral infections are hard to treat because viruses live inside your body's cells. They are "protected" from medicines, which usually move through your bloodstream. Antibiotics do not work for viral infections. There are a few antiviral medicines available. Vaccines can help prevent you from getting many viral diseases.

NIH: National Institute of Allergy and Infectious Diseases

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

[Read More]
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