title: IgG-index predicts neurological morbidity in patients with infectious central nervous system diseases.
abstract: BACKGROUND
  Prognosis assessment of patients with infectious and neoplastic disorders of the central nervous system (CNS) may still pose a challenge. In this retrospective cross-sectional study the prognostic value of basic cerebrospinal fluid (CSF) parameters in patients with bacterial meningitis, viral meningoencephalitis and leptomeningeal metastases were evaluated.
  
  
  METHODS
  White blood cell count, CSF/serum glucose ratio, protein, CSF/serum albumin quotient and Immunoglobulin indices for IgG, IgA and IgM were analyzed in 90 patients with bacterial meningitis, 117 patients with viral meningoencephalitis and 36 patients with leptomeningeal metastases in a total of 480 CSF samples.
  
  
  RESULTS
  In the initial spinal tap, the IgG-index was the only independent predictor for unfavorable outcome (GOS < 5) in patients with infectious CNS diseases but not in patients with leptomeningeal metastases. The sensitivity and specificity of an IgG-index of 0.75 and higher for predicting unfavorable outcome was 40.9% and 80.8% in bacterial meningitis and 40% and 94.8% in viral meningoencephalitis, respectively. No significant associations between CSF parameters and outcome could be observed in follow-up CSF samples.
  
  
  CONCLUSIONS
  The present study suggests that in infectious CNS diseases an elevated IgG-Index might be an additional marker for the early identification of patients at risk for neurological morbidity.
authors.affiliation: Department of Neurology, Innsbruck Medical University, Austria. peter.lackner@i-med.ac.at
authors.forename: Peter
authors.initials: P
authors.lastname: Lackner
authors.forename: Elif
authors.initials: E
authors.lastname: Guengoer
authors.forename: Ronny
authors.initials: R
authors.lastname: Beer
authors.forename: Gregor
authors.initials: G
authors.lastname: Broessner
authors.forename: Raimund
authors.initials: R
authors.lastname: Helbok
authors.forename: Florian
authors.initials: F
authors.lastname: Deisenhammer
authors.forename: Erich
authors.initials: E
authors.lastname: Schmutzhard
authors.forename: Bettina
authors.initials: B
authors.lastname: Pfausler
mesh_terms: D000328:Adult; D000368:Aged; D002555:Cerebrospinal Fluid / Q000737:chemistry / Q000166:cytology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000134:cerebrospinal fluid*; D008297:Male; D008577:Meningeal Neoplasms / Q000175:diagnosis* / Q000276:immunology / Q000556:secondary*; D016920:Meningitis, Bacterial / Q000175:diagnosis* / Q000276:immunology / Q000382:microbiology; D008590:Meningoencephalitis / Q000175:diagnosis* / Q000276:immunology / Q000821:virology; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D016896:Treatment Outcome
chemical_list: D007074:Immunoglobulin G