[Details of meningitis in the elderly]

Elderly patients being more at risk for infections than younger people, this study was aimed at defining the epidemiological and clinical features of meningitis in this population, with the objective of improving diagnosis and management.

Over a period of 10 years, all cases admitted to an infectious diseases unit for acute meningitis were reviewed. Patients infected by human immunodeficiency virus (HIV), fungi meningitis, and who were younger than 15 years of age were excluded from the study. According to age, two groups were constituted (group A: < 65 years and group B: > or = 65 years) and compared.

One hundred fifty-two patients were included in the study: 110 (72.4%) in group A (29 with bacterial and 81 with viral meningitis) and 42 (26.7%) in group B (32 with bacterial and ten with viral meningitis); the mean age was, respectively, 32.7 +/- 12.9 years (range: 15-61 years) and 75.9 +/- 7.6 years (range: 65-94 years). Diagnosis was less frequently evoked in the elderly (n = 11; 26%) than in younger patients (n = 78; 71%) (P < 0.001). Streptococcus pneumoniae, Listeria monocytogenes, and herpes simplex virus were the three most common causal agents in group B. Confusion was the most common symptom among the elderly (88 vs. 17%; P < 0.001). The mortality rate was more important in group B than in group A (11.9 vs. 2.7%; P = 0.04).

Diagnosis of acute meningitis is difficult and must be evoked in the presence of any new neurologic sign. Cranial computerized tomography should not delay lumbar puncture, except in the presence of focal neurologic symptoms. Antimicrobial therapy takes into account the bacterial epidemiology.