Expression of inflammatory mediators in meningitis

Background: Infectious diseases cause a systemic inflammatory reaction. In some cases of meningitis it is difficult to determine whether the disease is of bacterial, viral or non-infectious origin. In order to distinguish between bacterial and viral diseases the levels of various inflammatory markers are used to determine the severity of the disease and the clinical prognosis. Objective: The purpose of this study was to determine whether the levels of different markers can be used to distinguish between bacterial or viral meningitis or non-infectious neurological disease. Methods: Patients with bacterial meningitis (n=8), viral meningitis (n=17), non-infectious neurological diseases (n=17) and healthy subjects (n=15) were studied. The levels of soluble CD14 (sCD14), interleukin-6 (IL-6), interleukin-1b (IL-1b) and soluble adhesion molecule-1 (sICAM-1) were determined in the blood of all participants and in spinal fluid only in patients who had clinical indication to perform lumbar puncture. Results: All the patients showed significant differences in the levels of blood and CSF markers measured compared to healthy subjects. In the blood, although some differences were significant, there was overlapping between all values of the measured markers in patient blood samples excluding IL-6, for which levels were significantly different between the bacterial and viral meningitis. Interestingly, the levels of all markers showed significant differences among all groups of patients. Conclusions: Among the blood markers examined, IL-6 can be used to distinguish between bacterial and viral diseases. However, the levels of cytokines examined in CSF, can serve to distinguish between bacterial and viral meningitis and non-infectious diseases.