Arachnoiditis is a broad term denoting inflammation of the meninges and
subarachnoid space. A variety of etiologies exist, including infectious, inflammatory, and neoplastic processes. Infectious etiologies include bacterial, viral, fungal, and parasitic agents. Noninfectious inflammatory processes include surgery, intrathecal hemorrhage, and the administration of intrathecal agents such as myelographic contrast media, anesthetics, and steroids.