ICD-10 Code A42.81 – Actinomycotic Meningitis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code A42.81 – Actinomycotic meningitis
What it is
A42.81 identifies meningitis caused by Actinomyces infection. Use it when documentation states actinomycotic involvement of the meninges, not just a general Actinomyces infection.
Clinical signs
Clinical features vary; refer to documentation. Typical meningitis findings may include headache, neck stiffness, fever, altered mental status, or neurologic deficits, but the chart should support CNS infection.
When to use this code
Use A42.81 when the provider documents actinomycotic meningitis, actinomycotic meningitis due to Actinomyces, or a confirmed CNS infection tied to this organism. It may also apply when the diagnosis is listed as the principal or a secondary condition. Check documentation for site and specificity.
Do not use for
Do not use this code for meningitis from other bacteria, viruses, fungi, or parasites. It is also incorrect for nonspecific Actinomyces infection without meningeal involvement.
Coding tip
Verify that the record links Actinomyces to the meningitis diagnosis before assigning A42.81.