title: The value of C-reactive protein in the management of shunt infections.
abstract: OBJECTIVE
  Shunt infections and their management remain a clinically important problem in patients with hydrocephalus. The authors evaluated, in comparison with traditional parameters, C-reactive protein (CRP) in blood/serum (S-CRP) and in cerebrospinal fluid (CSF; C-CRP) for its power to identify and treat patients with infected shunts.
  
  
  METHODS
  On 84 different occasions, CSF and blood samples from 59 children suspected of having shunt/CSF infections were obtained and evaluated. An infection was proven by a CSF culture in 35 of 84 evaluations. Values for S-CRP in infected individuals were higher than in noninfected ones (91.8 +/- 70.2 mg/L compared with 16.1 +/- 28.3 mg/L, p < 0.0001). The sensitivity of S-CRP testing was 97.1%, the specificity 73.5%, the negative predictive value 97.3%, and the receiver operating characteristic area 91.6%. The probability of shunt/CSF infection--provided that the S-CRP level was greater than 7 mg/L--rose from 41.7% (prevalence) to a posttest level of 72.3%. Specificity and posttest probability were 87.8 and 87.2%, respectively, if cases with other concurrent infections were excluded. The probability of missing a CSF/shunt infection at an S-CRP lower than 7 mg/L was 2.7%. All other diagnostic parameters did not yield useful test results. The rate of reinfection was elevated in patients in whom S-CRP levels were greater than 7 mg/L at the time of shunt reimplantation.
  
  
  CONCLUSIONS
  Analysis of these data suggests that the S-CRP level should be included in the first-line workup of patients with suspected shunt/CSF infection. It seems justified to avoid performing a shunt tap if S-CRP levels are less than 7 mg/L. A larger multicenter trial is necessary to confirm these promising diagnostic results and to deliver hard data concerning whether or not a normalized S-CRP level is a reliable indicator of successful antibiotic therapy and whether a shunt can be safely reimplanted.
authors.affiliation: Department of Pediatric Neurosurgery, Children's Hospital of Michigan, USA. mus@uniklinik-leipzig.de
authors.forename: Martin U
authors.initials: MU
authors.lastname: Schuhmann
authors.forename: Kimberly R
authors.initials: KR
authors.lastname: Ostrowski
authors.forename: Emily J
authors.initials: EJ
authors.lastname: Draper
authors.forename: Jau-Wen
authors.initials: JW
authors.lastname: Chu
authors.forename: Steven D
authors.initials: SD
authors.lastname: Ham
authors.forename: Sandeep
authors.initials: S
authors.lastname: Sood
authors.forename: James P
authors.initials: JP
authors.lastname: McAllister
mesh_terms: D000293:Adolescent; D000328:Adult; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D015415:Biomarkers / Q000097:blood* / Q000134:cerebrospinal fluid*; D002097:C-Reactive Protein / Q000032:analysis* / Q000134:cerebrospinal fluid*; D002557:Cerebrospinal Fluid Shunts / Q000009:adverse effects*; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D006849:Hydrocephalus / Q000628:therapy; D007239:Infections / Q000175:diagnosis*; D008297:Male; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012680:Sensitivity and Specificity
chemical_list: D000900:Anti-Bacterial Agents; D015415:Biomarkers; D002097:C-Reactive Protein