2025 ICD-10-CM code A81.9
Atypical virus infection of the central nervous system, unspecified.
Medical necessity for the diagnostic workup and treatment of atypical viral CNS infections is established by the presence of signs and symptoms suggestive of CNS involvement. The need for specific treatments, such as antiviral medications (if applicable) or supportive care, should be documented based on the patient's clinical condition and the severity of the infection.
Diagnosis and management of atypical viral infections of the CNS often involves neurological examination, laboratory testing (blood and cerebrospinal fluid), imaging studies (MRI, EEG), and symptomatic treatment (e.g., corticosteroids). Patient education on preventive measures, such as vaccinations, may also be provided.
In simple words: This code refers to an infection of the brain and spinal cord caused by a virus that is not clearly identified.These infections can be long-lasting and cause a range of problems with thinking, behavior, and physical abilities.
Atypical virus infections of the central nervous system (CNS) are subacute or chronic infectious diseases involving the brain and spinal cord caused by viruses. This code is used when the provider does not specify the type of atypical virus infection of the CNS.
Example 1: A patient presents with progressive cognitive decline, personality changes, and seizures. After extensive testing, including MRI and CSF analysis, a diagnosis of an unspecified atypical viral infection of the CNS is made., A patient with a history of HIV infection develops neurological symptoms, including vision loss and dementia.Testing reveals evidence of CNS involvement by a virus, but the specific virus is not identified. A81.9 is used to code the diagnosis., A patient experiences fever, headache, and muscle spasms. Lumbar puncture reveals signs of CNS infection, but no specific viral agent is isolated. In the absence of further specification, A81.9 is used.
Documentation should include details of the patient's clinical presentation (neurological symptoms, disease progression), laboratory results (CSF analysis, antibody tests), imaging findings (MRI, EEG), and any other diagnostic tests performed to exclude other conditions. The rationale for diagnosing an unspecified atypical viral infection should be clearly documented.
- Specialties:Neurology, Infectious Disease
- Place of Service:Inpatient Hospital, Outpatient Hospital, Office