ICD-10 Code A69.21 – Meningitis due to Lyme disease (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code A69.21 – Meningitis due to Lyme disease
What it is
A69.21 identifies meningitis caused by Lyme disease, an infection from Borrelia burgdorferi. Use it when documentation links the meningitis directly to Lyme disease.
Clinical signs
Clinical features vary; refer to documentation. Commonly, you may see headache, neck stiffness, fever, or other neurologic findings consistent with meningeal inflammation.
When to use this code
Use A69.21 when the provider documents Lyme disease with meningitis, neuroborreliosis, or meningeal involvement attributed to Lyme infection. Code it from confirmed clinical documentation, not suspicion alone. If the record only says Lyme disease without meningitis, choose the more specific documented diagnosis.
Do not use for
Do not use this code for uncomplicated Lyme disease, isolated neurologic symptoms, or meningitis from another cause. Check documentation if the etiology is unclear.
Coding tip
Look for explicit provider linkage between Lyme disease and meningitis before assigning A69.21.