Herpesviral encephalitis

This code signifies inflammation of the brain caused specifically by the herpes simplex virus (HSV). It represents a severe neurological infection that can lead to significant morbidity and mortality if not promptly diagnosed and treated.

Use this code when documentation confirms encephalitis due to herpes simplex virus. This typically involves positive HSV PCR from cerebrospinal fluid (CSF) or characteristic clinical presentation with imaging findings consistent with viral encephalitis.

• Carefully review documentation to ensure the causative agent is explicitly identified as herpes simplex virus.
• Distinguish from other forms of viral encephalitis; if the specific herpesvirus type is not HSV, a different code from B10.0- may be more appropriate.
• Pay close attention to the "Excludes1" notes to avoid incorrect co-coding with herpesvirus 6, 7, or other non-simplex herpesviral encephalitides.