Clinical Characteristics and Therapeutic Outcomes of Postneurosurgical Bacterial Meningitis in Elderly Patients over 65: A Hospital-based Study.

Purpose: To investigate the clinical characteristics, laboratory features and prognostic factors of elderly patients with postneurosurgical bacterial meningitis.

Methods: Five hundred and forty patients with adult bacterial meningitis (ABM) were collected from 1986-2015, of whom 167 were ≥ 65 years. Of these 167 elderly patients, 82 had postneurosurgical infections and 85 had spontaneous infections. Clinical, laboratory and therapeutic data of these two groups were compared.

Results: The 82 elderly ABM patients with postneurosurgical infections included 48 men and 34 women with a median age of 71 years (range: 65-84 years). In addition to the postneurosurgical condition, the other most common underlying conditions included diabetes mellitus (29.3%) and hydrocephalus (29.3%). The major clinical presentations were fever (80.5%), altered consciousness (50.0%), hydrocephalus (43.9%), seizure (24.4%) and septic shock (15.9%). Of the implicated pathogens, staphylococcal species (spp.) were the most common (31.7%), followed by Acinetobacter spp. (12.2%), Enterobacter spp. (7.3%), Pseudomonas spp. (7.3%), Enterococcus faecalis (7.3%) and Escherichia coli (6.1%). The implicated staphylococcal spp. had a high rate of non-susceptibility to methicillin (84.6%), and the implicated Acinetobacter spp. and Enterobacter spp. had non-susceptible rates to ceftazidime of 60% and 50%, respectively. The mortality rate was 28.1%, and septic shock was the most significant prognostic factor. Compared with the clinical characteristics of the other 85 elderly patients with spontaneous ABM, there were significant differences in underlying condition, clinical and laboratory features and therapeutic outcomes.

Conclusions: Elderly patients accounted for 30.9% of all cases of ABM, of whom 49.1% had postneurosurgical ABM. The clinical characteristics of the elderly patients with postneurosurgical ABM were non-specific, and cerebrospinal fluid studies were needed to confirm the diagnosis. The mortality rate of this group of patients was high, and septic shock was an important prognostic factor. The clinical and laboratory features and therapeutic outcomes were different between the elderly patients with postneurosurgical and spontaneous ABM.