Human herpesvirus 6 encephalitis

This code signifies an inflammatory condition of the brain caused specifically by Human Herpesvirus 6 (HHV-6) infection. It represents a serious neurological complication resulting from HHV-6, which can manifest with various central nervous system symptoms.

Use this code when diagnostic testing, such as PCR from cerebrospinal fluid (CSF) or brain biopsy, confirms HHV-6 as the causative agent of encephalitis. Documentation should clearly state the presence of encephalitis and laboratory confirmation of HHV-6 infection.

• Ensure documentation specifies HHV-6 as the etiology; do not use for encephalitis of unspecified viral origin.
• Consider sequencing this code as the primary diagnosis if the encephalitis is the reason for the encounter.
• Distinguish from other viral encephalitides (e.g., herpes simplex encephalitis) which have different ICD-10-CM codes.