Characterization of chemical meningitis after neurological surgery

We reviewed the records of 70 consecutive adult patients with meningitis after a neurosurgical procedure, to determine the characteristics that might help to distinguish a sterile postoperative chemical meningitis from bacterial infection. The spinal fluid profiles in bacterial and chemical meningitis are similar. The exceptions are that a spinal fluid white blood cell count >7500/muL (7500 x 10(6)/L) and a glucose level of <10 mg/dL were not found in any case of chemical meningitis. The clinical setting and clinical manifestations were distinct enough that no antibiotic was administered after lumbar puncture to 30 (43%) of the 70 patients with postoperative meningitis. Chemical meningitis was infrequent after surgery involving the spine and sinuses. Patients with chemical meningitis did not have purulent wound drainage or significant wound erythema or tenderness, coma, new focal neurological findings, or onset of a new seizure disorder. They rarely had temperatures >39.4 degreesC or cerebrospinal fluid rhinorrhea or otorrhea.