2006 ICD-9-CM Volume 1 Diagnosis Codes Home > Diseases Of The Nervous System And Sense Organs 320-389 > Inflammatory Diseases Of The Central Nervous System 320-327 > 2006 ICD-9-CM Diagnosis 322 Meningitis of unspecified cause View the most recent version of ICD-9-CM 322 Inflammation of the coverings of the brain and/or spinal cord, which consist of the PIA MATER; ARACHNOID; and DURA MATER. Infections (viral, bacterial, and fungal) are the most common causes of this condition, but subarachnoid hemorrhage (HEMORRHAGES, SUBARACHNOID), chemical irritation (chemical MENINGITIS), granulomatous conditions, neoplastic conditions (e.g., carcinomatous meningitis), and other inflammatory conditions may produce this syndrome. 322 is a non-specific code that cannot be used to specify a diagnosis 322 Includes arachnoiditis with no organism specified as cause leptomeningitis with no organism specified as cause meningitis with no organism specified as cause pachymeningitis with no organism specified as cause