Zoster encephalitis

This code represents an inflammation of the brain caused by the varicella-zoster virus (VZV), which is the same virus that causes chickenpox and shingles. It is a serious neurological complication of herpes zoster, characterized by symptoms such as altered mental status, seizures, and focal neurological deficits.

Assign this code when documentation explicitly states zoster encephalitis or varicella-zoster virus encephalitis. This typically occurs in patients with a history of shingles or chickenpox who subsequently develop neurological symptoms and have laboratory confirmation of VZV in the cerebrospinal fluid (CSF) or brain tissue.

• Differentiate from other viral encephalitides; ensure the documentation specifies zoster as the causative agent.
• Do not confuse with postherpetic neuralgia (G53.0) or other neurological complications of zoster that do not involve brain inflammation.
• Code any associated manifestations, such as rash or cranial nerve palsies, as secondary diagnoses.