Evaluation of patients with the diagnosis of central nervous system infection, a single center experience of 19 (nineteen) years

Objective: Central nervous system (CNS) infections are clinical conditions associated with high morbidity and mortality, requiring prompt diagnosis and treatment. This study aimed to evaluate the demographic characteristics, risk factors, presenting symptoms, clinical findings, laboratory and microbiological features of adult patients diagnosed with CNS infections. Materials and Methods: The study included patients aged ≥18 years who were followed with a diagnosis of CNS infection between 2006 and 2025. Based on diagnostic criteria, cases were categorized into four main groups: acute bacterial meningitis (ABM), healthcare-associated meningitis (HCAM), brain abscess (BA), and chronic meningitis (CM). Demographic data, clinical presentation, radiological imaging, cerebrospinal fluid (CSF) analysis, microbiological results, treatment regimens, and outcomes were retrospectively reviewed. Comparative statistical analyses were performed across diagnostic groups, and factors associated with mortality were identified. Results: A total of 393 adults diagnosed with central nervous system infections were included (230 males, 163 females; mean age 52.4±18.5 years). Of these, 184 had acute bacterial meningitis (ABM), 131 had healthcare-associated meningitis (HCAM), 31 had brain abscess (BA), and 47 had chronic meningitis (CM). Diabetes mellitus was more frequent in ABM (OR=2.00) and BA (OR=3.13). Human immunodeficiency virus infection was strongly associated with CM (OR=21.55). The most common risk factors were neurosurgical procedures (n=118) and shunt presence (n=56). Ear infections were associated with ABM (OR=2.61) and BA (OR=7.99), dental infections with ABM (OR=4.13) and BA (OR=4.10), and sinusitis with ABM (OR=1.99) and BA (OR=4.18). The most frequent presenting symptoms were headache (n=324) and fever (n=317); altered consciousness was prominent in ABM, focal neurological deficits in BA, and weight loss/night sweats in CM. CSF protein and leukocyte levels were highest in ABM; culture positivity was significantly higher in patients without prior antibiotic use (OR=4.76). The most common pathogens were S. pneumoniae (n=46) in ABM, coagulase-negative staphylococci (n=40) and Acinetobacter spp. (n=18) in HCAM, anaerobes (n=5) in BA, and Cryptococcus spp. (n=4) and M. tuberculosis(n=4) in CM. Guideline-concordant empirical therapy was initiated in 340 patients. ICU admission was required in 131 patients. Overall, 52 patients (13.2%) died and 13 (3.3%) developed permanent neurological sequelae. Mortality was highest in the HCAM group (n=39, 29.8%). Conclusion: This study highlights the importance of careful evaluation of presenting symptoms, physical findings, and risk factors in CNS infections. As causative microorganisms and antimicrobial resistance profiles evolve over time, empirical treatment strategies should be guided by national and institutional surveillance data. The findings contribute to improving clinical approaches to CNS infections and strengthening epidemiological data in our country.