Bacterial meningitis in the elderly.

To assess the implications of meningitis in a more mature population, we reviewed the records of patients with meningitis: 71 aged 50 years and older and 138 patients aged 15 to 49 years. Among the older population, 54 (76%) had bacterial, nine (13%) had granulomatous, and eight (11%) had aseptic meningitis. Among the cases of bacterial meningitis in the older age group, Streptococcus pneumoniae accounted for 24% (13/54) and enteric bacilli accounted for 17% (9/54). Serious complications occurred in 38 elderly patients (70%) with bacterial meningitis, and mortality occurred in 24 (44%). In the younger age group with bacterial meningitis, the complication rate and mortality were 41% (13/32) and 13% (4/32), respectively. Meningitis in the elderly is likely to be bacterial and to cause greater morbidity and mortality.