Accuracy of cerebrospinal fluid ferritin for purulent meningitis

Objective To evaluate the use of cerebrospinal fluid (CSF) ferritin levels in the diagnosis of purulent meningitis (PM). Method We studied 81 children between 28 days and 12 years of age who presented with clinical suspicion of meningitis to the emergency department. CSF ferritin levels were measured and compared between diagnostic groups (PM, aseptic meningitis (AM) and no meningitis). Results The median age was 24 (IQR 8–69) months. There were 32 patients with AM (39%), 23 with PM (28%) and 26 with no meningitis (32%). Median CSF ferritin was 4.2 ng/mL (IQR 3.0–6.5), 52.9 ng/mL (IQR 30.7–103 ng/mL) and 2.4 ng/mL (IQR 2–4), respectively. CSF ferritin was higher in children with PM compared with AM (p<0.001) or no meningitis (p<0.001). There was no difference between AM and no meningitis. Conclusion CSF ferritin may be a useful biomarker to discriminate PM in children with clinical symptoms of this disease.