title: Usefulness of blood and cerebrospinal fluid laboratory testing to predict bacterial meningitis in the emergency department.
abstract: BACKGROUND
  The classic clinical presentation of bacterial meningitis (BM) is observed in less than half of the cases in adults, and symptoms are less specific in children, the elderly or immunocompromised, and other chronic patients. The usual signs and symptoms do not provide optimal sensitivity and specificity for distinguishing possible BM from viral meningitis (VM), which may lead to a delay in the appropriate antimicrobial therapy. Society therefore stands to benefit from the development of effective, objective, and rapid tools able to predict and identify patients with BM. These tools include laboratory tests for blood and cerebrospinal fluid (CSF). The aim of this review is to summarise recently published scientific evidence in order to clarify existing controversies and compare the usefulness and diagnostic ability of the different parameters used to predict BM.
  
  
  METHODS
  Systematic search of the main bibliographic databases and platforms to identify articles published between January 2000 and January 2016. We selected 59 articles that meet the objectives of this review.
  
  
  CONCLUSIONS
  CSF lactate, proportion of polymorphonuclear leukocytes, and CSF glucose, as well as serum procalcitonin (PCT), are the independent factors most predictive of bacterial aetiology. The model that combines serum PCT and CSF lactate achieves the highest predictive power for BM, with a sensitivity and specificity exceeding 99%. We should consider BM when CSF lactate >33 md/dL and/or PCT>0.25ng/mL.
authors.affiliation: Servicio de Urgencias, Complejo Hospitalario de Toledo, Toledo, España. Electronic address: agustinj@sescam.jccm.es.
authors.forename: A
authors.initials: A
authors.lastname: Julián-Jiménez
authors.affiliation: Servicio de Neurología, Complejo Hospitalario de Toledo, Toledo, España.
authors.forename: M I
authors.initials: MI
authors.lastname: Morales-Casado
mesh_terms: D015415:Biomarkers / Q000097:blood / Q000134:cerebrospinal fluid; D001774:Blood Chemical Analysis; D003937:Diagnosis, Differential; D004636:Emergency Service, Hospital; D006801:Humans; D016920:Meningitis, Bacterial / Q000097:blood* / Q000134:cerebrospinal fluid* / Q000175:diagnosis; D008587:Meningitis, Viral / Q000097:blood / Q000134:cerebrospinal fluid / Q000175:diagnosis
chemical_list: D015415:Biomarkers
keywords: Acute meningitis; Bacterial meningitis; Biomarcadores; Biomarkers; Emergency department; Lactate; Lactato; Meningitis aguda; Meningitis bacteriana; Procalcitonin; Procalcitonina; Servicio de urgencias