Chronic meningitis

This code represents a persistent inflammation of the meninges, the protective membranes surrounding the brain and spinal cord, lasting for at least four weeks. It indicates an ongoing, rather than acute, infectious or inflammatory process affecting the central nervous system coverings.

Assign this code when documentation clearly indicates meningitis that has been present for an extended duration, typically four weeks or more. This is appropriate for cases where the etiology (e.g., fungal, tuberculous, syphilitic, or other chronic infections) is not specified or is unknown, but the chronicity is established.

• Do not use this code for acute meningitis; refer to codes in the 320.xx or 321.xx series.
• If the underlying cause of the chronic meningitis is known, code the specific etiology first, followed by this code.
• Ensure documentation specifies the duration or characterization as "chronic" to support this diagnosis.