Meningitis in elderly patients.

Meningitis is uncommon in elderly patients in emergency department (ED). The characteristics of bacterial meningitis (BM) and nonbacterial meningitis (NBM) occurring in older patients are compared. A prospective multicenter study was conducted in the EDs of three teaching hospitals. Consecutive adult patients (n=159) with a confirmed meningitis [cerebrospinal fluid (CSF) leukocyte count greater than 5 mm] were included in this study. Eighteen consecutive patients (11%) aged more than or equal to 60 years (median age of 67 years) presenting with confirmed meningitis were included. In the older group, the prevalence of BM was higher than in the younger group (50% vs. 11%, P<0.05). At admission in the ED, older patients experienced less typical symptoms of meningitis than the younger. Conversely, elderly patients presented more frequent signs of encephalitis. In older adults, CSF white blood cells count, CSF protein, and CSF/blood glucose ratio were different between NBM and BM. The causative species of BM were Streptococcus species other than pneumoniae in two episodes, and Streptococcus pneumoniae in two patients; the causative species of NBM were enterovirus in one episode, herpes simplex virus 1 in four (compared with the younger group, P<0.05), and varicella zoster virus in one. The prevalence of BM was higher in the older group than in the younger. Older patients experienced less typical symptoms of meningitis and more frequently signs of encephalitis, with a high prevalence of herpes simplex virus 1 meningitis.