2025 ICD-10-CM code A83.8
Other mosquito-borne viral encephalitis
The medical necessity for using A83.8 is established by the confirmed diagnosis of mosquito-borne viral encephalitis when the specific virus is not identified as one of the types with specific ICD-10-CM codes. Documentation must support the diagnosis of encephalitis and indicate that it is caused by a mosquito-borne virus other than those specifically listed elsewhere in the ICD-10-CM.
A patient with viral encephalitis may experience a range of symptoms from none at all to fever, headache, lethargy, stiff neck and back, nausea, and vomiting. Severe cases can involve brain swelling, confusion, partial paralysis, loss of consciousness, memory loss, seizures, and coma. Diagnosis is based on patient history, physical and neurological examination, and imaging studies (CT, EEG, MRI). A spinal tap confirming the virus in cerebrospinal fluid is definitive. Treatment includes corticosteroids to reduce inflammation, rest, fluids, pain relievers, and sedatives. Severe cases require hospitalization. Preventative measures include mosquito repellents and eliminating breeding grounds.
- Certain infectious and parasitic diseases (A00-B99)
- Viral and prion infections of the central nervous system (A80-A89)
In simple words: This code indicates a type of brain inflammation caused by a virus transmitted through a mosquito bite, other than the more common types like West Nile, St. Louis, or western equine encephalitis.
Mosquito-borne viral encephalitis refers to inflammation and/or swelling of the brain due to a mosquito bite. The mosquito acquires the viral infection when it bites infected birds or animals. The most common mosquito-borne viruses are West Nile virus (WNV), St. Louis encephalitis (SLE), and western equine encephalomyelitis (WEE). This code identifies a type of mosquito-borne viral encephalitis not specifically named in any other code in this category.
Example 1: A patient presents with fever, headache, and altered mental status after a recent camping trip. Imaging and cerebrospinal fluid analysis confirm mosquito-borne viral encephalitis, but the specific virus is not identified as West Nile, St. Louis, or western equine encephalitis. A83.8 is used., A child develops seizures and becomes unresponsive after several days of flu-like symptoms. Testing reveals encephalitis caused by a mosquito-borne virus not otherwise specified, as other common arboviruses are ruled out. A83.8 is the appropriate code., An individual with a compromised immune system experiences severe neurological symptoms following mosquito bites. Diagnostic tests confirm viral encephalitis, and the specific virus is identified as a rare mosquito-borne virus not classified elsewhere. Code A83.8 is used to capture this diagnosis.
Documentation should include details of the patient's symptoms, history of mosquito exposure, physical and neurological examination findings, results of imaging studies (CT, MRI, EEG), and laboratory confirmation of the viral encephalitis.If a specific virus is identified, it should be documented. It's crucial to note that this code is used when the specific virus is not identified as one of the commonly coded arboviruses.
- Specialties:Infectious Disease, Neurology, Pediatrics
- Place of Service:Inpatient Hospital, Outpatient Hospital, Office