Central nervous system infections in the elderly.

Review of records of patients aged 65 years and older admitted to The Mount Sinai Hospital, New York, NY, during the period from 1970 through 1985 revealed 57 episodes of central nervous system infections, including 50 meningitides, 5 brain abscesses, 1 subdural empyema, and 1 epidural abscess. Predisposing conditions were present in 17 patients with meningitis, and concurrent infections occurred in 19 patients. Streptococcus pneumoniae accounted for 43% of all isolates; 25% were gram-negative organisms. Of the patients in this sample, fever was present in 100%, meningismus was present in 58%, and change in mental status was present in 86%. Sixty-five percent of patients with meningitis survived; increased mortality was associated with altered mental status, inappropriate initial antibiotic therapy, and hypoglycorrhachia. Delay in diagnosis, underlying disease, and bacteremia did not significantly alter outcome. All patients with focal infections presented with localizing signs and all survived.