title: Usefulness of interleukin 6 levels in the cerebrospinal fluid for the diagnosis of bacterial meningitis.
abstract: OBJECTIVE
  Interleukin 6 (IL-6) is a proinflammatory cytokine produced during infections. We hypothesized that IL-6 levels in the cerebrospinal fluid (CSF) would be elevated in bacterial meningitis and useful for diagnosing and predicting neurologic outcomes.
  
  
  METHODS
  For the differentiation of bacterial meningitis, serum and CSF samples were obtained from patients with an altered level of consciousness. Patients were classified into 3 groups: bacterial meningitis, nonbacterial central nervous system disease, and other site sepsis.
  
  
  RESULTS
  Of the 70 patients included in this study, there were 13 in the bacterial meningitis group, 21 in the nonbacterial central nervous system disease group, and 36 in the other site sepsis group. The CSF IL-6 level was significantly higher in the bacterial meningitis group than in the other 2 groups (P<.0001). Of the 5 CSF parameters assessed, CSF IL-6 level exhibited the largest area under the receiver operating characteristic curve (0.962), with a cut-off value of 644 pg/mL (sensitivity, 92.3%; specificity, 89.5%). To examine a potential association between a high CSF level and neurologic outcome, CSF IL-6 levels were divided into 4 quartiles, and each level was compared with the frequency of a good neurologic outcome. The frequency of a good neurologic outcome was significantly lower in the highest CSF IL-6 quartile than in the other 3 quartiles (odds ratio, 0.18; 95% confidence interval, 0.05-0.69; P=.013).
  
  
  CONCLUSIONS
  Measurement of the CSF IL-6 level is useful for diagnosing bacterial meningitis.
authors.affiliation: Chiba University Graduate School of Medicine, Department of Emergency and Critical Care Medicine, Chiba, Japan.
authors.forename: Waka
authors.initials: W
authors.lastname: Takahashi
authors.affiliation: Chiba University Graduate School of Medicine, Department of Emergency and Critical Care Medicine, Chiba, Japan. Electronic address: taka.nakada@nifty.com.
authors.forename: Taka-aki
authors.initials: TA
authors.lastname: Nakada
authors.affiliation: Chiba University Graduate School of Medicine, Department of Emergency and Critical Care Medicine, Chiba, Japan.
authors.forename: Ryuzo
authors.initials: R
authors.lastname: Abe
authors.affiliation: Chiba University Graduate School of Medicine, Department of Emergency and Critical Care Medicine, Chiba, Japan.
authors.forename: Kumiko
authors.initials: K
authors.lastname: Tanaka
authors.affiliation: Chiba University Graduate School of Medicine, Department of Emergency and Critical Care Medicine, Chiba, Japan.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Matsumura
authors.affiliation: Chiba University Graduate School of Medicine, Department of Emergency and Critical Care Medicine, Chiba, Japan.
authors.forename: Shigeto
authors.initials: S
authors.lastname: Oda
mesh_terms: D000328:Adult; D000368:Aged; D002493:Central Nervous System Diseases / Q000097:blood / Q000134:cerebrospinal fluid / Q000175:diagnosis; D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000097:blood / Q000134:cerebrospinal fluid*; D008297:Male; D016920:Meningitis, Bacterial / Q000097:blood / Q000134:cerebrospinal fluid / Q000175:diagnosis* / Q000382:microbiology; D008875:Middle Aged; D011379:Prognosis; D012372:ROC Curve; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D018805:Sepsis / Q000097:blood / Q000134:cerebrospinal fluid / Q000175:diagnosis
chemical_list: D015850:Interleukin-6
keywords: Bacterial meningitis; Cerebrospinal fluid; Diagnosis; Interleukin 6; Neurologic outcome