Cerebrospinal Fluid (CSF) Ferritin for Differentiation of Aseptic and Bacterial Meningitis in Adults

Problem statement: Bacterial meningitis is one of the most important causes of mortality and morbidity. Rapid diagnosis of bacterial cause is very important and critical, because early antibiotic therapy prevents complications; different tests have been developed for rapid diagnosis of bacterial meningitis. One of them is CSF ferritin, which is evaluated in this study. Approach: During cross sectional study from 2008-2009 for 2 years, CSF was collects from 61 adults suspected to have meningitis. These patients admitted to Emam Reza and Sina hospitals of Tabriz. CSF was analyzed for ferritin, glucose, protein, cell count, culture and gram stains. Clinical data's were collected for all patients. Collected data's were analyzed by SPSS software. Results: From 61 specimens, 19 cases had bacterial, 19 cases had aseptic meningitis and 23 cases had no criteria for diagnosis of meningitis. CSF ferritin in bacterial meningitis was 231.63 ± 61.26 ng dL⁻¹ that was significantly higher, than that of aseptic meningitis group. Cut off value for ferritin was estimated 155ng dL⁻¹ with sensitivity of 94% and specificity of 21.7% in this study. Symptoms such as levels of consciousness, fever and seizure were not considered as a criteria for diagnosis of bacterial meningitis (p>0.05). But symptoms such as headache, nausa, vomiting and neck stefness were significantly higher in bacterial and aseptic groups than no meningitis group (p<0.05). Conclusion: In this study CSF ferritin in bacterial meningitis group was significantly higher than aseptic meningitis group. But due to low specificity of CSF ferritin for differentiation of bacterial from aseptic meningitis, we don't recommend performance of this test in early phase of meningitis course.