Risk of meningitis with cerebrospinal fluid rhinorrhea.
The annual risk of meningitis in unrepaired fistulas is widely quoted to be approximately 10% per annum. Our aim was to review our experience with cerebrospinal fluid (CSF) leaks and to calculate the overall risk and the annual incidence of meningitis, and to correlate our findings with the causation and the effect of operative intervention in a subgroup of patients who had a history of meningitis. We prospectively collected data on all patients referred with a CSF leak to our tertiary referral center over a 12-year period between 1994 and 2006. We had a follow-up rate of 91%. One hundred eleven patients had a proven leak on endoscopy, beta-2 transferrin, imaging, and/or fluorescein lumbar puncture. The accumulated duration of an active CSF leak in the cohort was 190 years. The total number of episodes of meningitis was 57 in 21 patients, giving an overall risk of developing meningitis of 19%, with an overall incidence of 0.3 episodes per year. There was a progressive reduction in the incidence of meningitis with time, and most episodes occurred within the first year following the onset of the CSF leak. However, the risk persisted as long as the CSF leak was active. The overall risk of meningitis in patients with persistent CSF rhinorrhea was 19%. The annual incidence of meningitis was 0.3 episodes per year, with most episodes occurring within the first year following the onset of the leak. Endoscopic closure is the treatment of choice in most CSF leaks; if successful, it reduces the risk of meningitis.