Herpetic meningoencephalitis

This code represents an acute inflammatory condition affecting both the brain (encephalitis) and the meninges (meningitis) caused by a herpes simplex virus infection. It is a serious neurological complication that can lead to significant morbidity and mortality.

Use this code when documentation clearly indicates a diagnosis of meningoencephalitis specifically attributed to a herpes simplex virus. This typically involves positive viral studies (e.g., PCR from CSF) confirming HSV as the causative agent in a patient presenting with symptoms of both meningitis and encephalitis.

• Ensure the documentation explicitly states "herpetic" or "herpes simplex" as the etiology of the meningoencephalitis.
• Differentiate from other viral or bacterial causes of meningoencephalitis; if the etiology is unspecified or due to another organism, a different code is appropriate.
• Consider sequencing this code as the primary diagnosis when it is the main reason for the encounter and treatment.