Powassan virus disease

This code represents a tick-borne viral encephalitis caused by the Powassan virus. It is a rare but serious neurological infection that can lead to long-term neurological complications or death.

Use this code for confirmed cases of Powassan virus disease, typically presenting with fever, headache, vomiting, weakness, confusion, seizures, or other neurological symptoms following a tick bite. Documentation should include laboratory confirmation of Powassan virus infection (e.g., PCR, serology) and clinical signs consistent with encephalitis or meningoencephalitis.

• Ensure documentation specifies "Powassan virus" to differentiate from other tick-borne encephalitides.
• Code any associated neurological manifestations (e.g., G04.90 for encephalitis, unspecified) as secondary diagnoses if not fully encompassed by the primary diagnosis.
• Do not confuse with other arboviral encephalitides; verify the specific viral agent.