Chemical meningitis following cerebellopontine angle tumor surgery

OBJECTIVE: Postoperative chemical meningitis mimics bacterial meningitis, complicating the diagnosis until results of cerebrospinal fluid (CSF) cultures can be obtained. We analyzed clinical and laboratory data from a series of 1146 patients to identify findings that could exclude bacterial meningitis. SUBJECTS AND METHODS: We reviewed the charts of patients who developed meningitis after cerebellopontine angle surgery. Lumbar puncture data from asymptomatic postoperative patients were our control. STUDY DESIGN: Clinical symptoms, CSF profiles, and serum white blood cell (WBC) counts were compared between patients with chemical meningitis, bacterial meningitis, and asymptomatic patients. RESULTS: The incidence of meningitis in our series of 1146 patients was 4.54 percent: 0.87 percent was culture-proven bacterial meningitis. The patients with bacterial meningitis had significantly higher CSF and serum WBC counts, and lower CSF glucose. The major difference between asymptomatic patients and those with chemical meningitis was the significantly lower ratio of CSF WBCs to red blood cells (RBCs) in asymptomatic patients. CONCLUSION: Patients with mild CSF leukocytosis and normal CSF glucose without high serum WBC counts or focal neurological deficits may be treated for chemical meningitis. (c) 2008 American Academy of Otolaryngology-Head and Neck Surgery Foundation. All rights reserved.