title: Risk score for identifying adults with CSF pleocytosis and negative CSF Gram stain at low risk for an urgent treatable cause.
abstract: BACKGROUND
  We aimed to derive and validate a risk score that identifies adults with cerebrospinal fluid (CSF) pleocytosis and a negative CSF Gram stain at low risk for an urgent treatable cause.
  
  
  METHODS
  Patients with CSF pleocytosis and a negative CSF Gram stain were stratified into a prospective derivation (n = 193) and a retrospective validation (n = 567) cohort. Clinically related baseline characteristics were grouped into three composite variables, each independently associated with a set of predefined urgent treatable causes. We subsequently derived a risk score classifying patients into low (0 composite variables present) or high (≥ 1 composite variables present) risk for an urgent treatable cause. The sensitivity of the risk score was determined in the validation cohort and in a prospective case series of 214 adults with CSF-culture proven bacterial meningitis, CSF pleocytosis and a negative Gram stain.
  
  
  RESULTS
  A total of 41 of 193 patients (21%) in the derivation cohort and 71 of 567 (13%) in the validation cohort had an urgent treatable cause. Sensitivity of the dichotomized risk score to detect an urgent treatable cause was 100.0% (95% CI 93.9-100.0%) in the validation cohort and 100.0% (95% CI 97.8-100.0%) in bacterial meningitis patients.
  
  
  CONCLUSIONS
  The risk score can be used to identify adults with CSF pleocytosis and a negative CSF Gram stain at low risk for an urgent treatable cause.
authors.affiliation: Department of Internal Medicine, University of Texas Health Science Center in Houston, Houston, Texas 77030, USA. Rodrigo.Hasbun@uth.tmc.edu
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Hasbun
authors.forename: Merijn
authors.initials: M
authors.lastname: Bijlsma
authors.forename: Matthijs C
authors.initials: MC
authors.lastname: Brouwer
authors.forename: Nabil
authors.initials: N
authors.lastname: Khoury
authors.forename: Christiane M
authors.initials: CM
authors.lastname: Hadi
authors.forename: Arie
authors.initials: A
authors.lastname: van der Ende
authors.forename: Susan H
authors.initials: SH
authors.lastname: Wootton
authors.forename: Lucrecia
authors.initials: L
authors.lastname: Salazar
authors.forename: Md Monir
authors.initials: MM
authors.lastname: Hossain
authors.forename: Mark
authors.initials: M
authors.lastname: Beilke
authors.forename: Diederik
authors.initials: D
authors.lastname: van de Beek
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000553:Ambulatory Care / Q000379:methods*; D003955:Diagnostic Tests, Routine / Q000379:methods*; D005260:Female; D006090:Gram-Negative Bacteria / Q000302:isolation & purification; D016905:Gram-Negative Bacterial Infections / Q000175:diagnosis* / Q000188:drug therapy*; D006801:Humans; D007964:Leukocytosis / Q000175:diagnosis* / Q000188:drug therapy*; D008297:Male; D012680:Sensitivity and Specificity; D055815:Young Adult