ICD-10 Code A42.82 – Actinomycotic encephalitis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code A42.82 – Actinomycotic encephalitis
What it is
Actinomycotic encephalitis is a rare brain infection caused by Actinomyces species. Use this code when documentation identifies encephalitis due to actinomycosis.
Clinical signs
Clinical features vary; refer to documentation. Reported findings may include neurologic deficits, headache, fever, confusion, or seizures when the infection involves brain tissue.
When to use this code
Use A42.82 when the provider documents actinomycotic infection of the brain or encephalitis due to Actinomyces. It may also apply when imaging, biopsy, or other workup supports the diagnosis in the record. If the note only says actinomycosis without CNS involvement, check documentation.
Do not use for
Do not use this code for generic actinomycosis, meningitis, or other neurologic infections unless encephalitis is specifically documented. Check documentation if the site of infection is unclear.
Coding tip
Confirm that the record links Actinomyces to encephalitis before assigning A42.82.