Abstract

Arachnoiditis consists of thickening, scarring, and inflammation of the arachnoid membrane. These abnormalities may be self-limited or may lead to compression of the nerve roots and spinal cord. In addition to pain, patients with arachnoiditis may experience numbness, weakness, loss of reflexes, and bowel and bladder symptoms. The exact cause of arachnoiditis is unknown, but it may be related to herniated disk, infection, tumor, myelography, spinal surgery, or intrathecal administration of drugs. Anecdotal reports of arachnoiditis after epidural and subarachnoid administration of methylprednisolone have surfaced as have reports of arachnoiditis after repeat high volume epidural blood patches to treat post-dural puncture headache. Patients suffering from arachnoiditis complain of pain, numbness, tingling, and paresthesias in the distribution of the affected nerve root or roots. Weakness and lack of coordination in the affected extremity may be noted; muscle spasms, back pain, and pain referred to the buttocks are common. Decreased sensation, weakness, and reflex changes are demonstrated on physical examination. Occasionally, patients with arachnoiditis experience compression of the lumbar spinal cord, nerve roots, and cauda equina, with resulting lumbar myelopathy or cauda equina syndrome. These patients experience varying degrees of lower extremity weakness and bowel and bladder symptoms.