Diagnostic Accuracy of Clinical and Laboratory Characteristics in Suspected Nonsurgical Nosocomial Central Nervous System Infections

Background: The diagnosis of meningitis in non-surgical hospitalized patients is often difficult and diagnostic accuracy of clinical, laboratory, and radiological characteristics is unknown. Aim: To assess diagnostic accuracy for individual clinical characteristics of patients suspected of non-surgical nosocomial central nervous system (CNS) infections. Methods: In a prospective multi-centre cohort study in the Netherlands with adults suspected of CNS infections, consecutive patients who underwent a lumbar puncture for the suspicion of a non-surgical nosocomial CNS infection were included. All episodes were categorized into five final clinical diagnosis categories, as reference standard: CNS infection, CNS inflammatory disease, systemic infection, other neurological disease, or non-systemic, non-neurological disease. Findings: Between 2012 and 2022, 114 out of 1275 (9%) patients included in the cohort had suspected non-surgical nosocomial CNS infection: 16 (14%) had a confirmed diagnosis, including four (25%) with bacterial meningitis, nine (56%) with viral CNS infections, two (13%) fungal meningitis, and one (6%) parasitic meningitis. Diagnostic accuracy of individual clinical characteristics was generally low. Elevated CSF leucocyte count had the highest sensitivity (81%; 95% confidence interval (CI): 54–96) and negative predictive value (NPV) (96%; 95% CI: 90–99). When combining the presence of abnormalities in neurological or CSF examination, sensitivity for diagnosing a CNS infection was 100% (95% CI: 79–100) and NPV 100% (95% CI: 78–100). CSF examination changed clinical management in 47% of patients. Conclusion: Diagnostic accuracy for individual clinical characteristics was low, with elevated CSF leucocyte count having the highest sensitivity and NPV.