title: Inflammation as a predictor for delayed cerebral ischemia after aneurysmal subarachnoid haemorrhage.
abstract: BACKGROUND
  The mechanism of development of delayed cerebral ischemia (DCI) after aneurysmal subarachnoid hemorrhage (SAH) is poorly understood. Inflammatory processes are implicated in the development of ischemic stroke and may also predispose to the development of DCI following SAH. The objective of this study was to test whether concentrations of circulating inflammatory markers (C-reactive protein (CRP), interleukin-6 (IL-6) and interleukin 1 receptor antagonist (IL-1Ra)) were predictive for DCI following SAH. Secondary analyses considered white cell count (WCC) and erythrocyte sedimentation rate (ESR).
  
  
  METHODS
  This was a single-center case-control study nested within a prospective cohort. Plasma inflammatory markers were measured in patients up to 15 days after SAH (initial, peak, average, final and rate of change to final). Cases were defined as those developing DCI. Inflammatory markers were compared between cases and randomly selected matched controls.
  
  
  RESULTS
  Among the 179 participants there were 46 cases of DCI (26%). In primary analyses the rate of change of IL-6 was associated with DCI (OR 2.3 (95% CI 1.1 to 5.0); p=0.03). The final value and rate of change of WCC were associated with DCI (OR 1.2 (95% CI 1.0 to 1.3) and OR 1.3 (95% CI 1.0 to 1.6), respectively). High values of ESR were associated with DCI (OR 2.4 (95% CI 1.3 to 4.6) initial; OR 2.3 (95% CI 1.3 to 4.2) average; OR 2.1 (95% CI 1.1 to 3.9) peak; and OR 2.0 (95% CI 1.2 to 3.3) final value).
  
  
  CONCLUSIONS
  Leucocytosis and change in IL-6 prior to DCI reflect impending cerebral ischemia. The time-independent association of ESR with DCI after SAH may identify this as a risk factor. These data suggest that systemic inflammatory mechanisms may increase the susceptibility to the development of DCI after SAH.
authors.affiliation: Brain Injury Research Group, University of Manchester, Greater Manchester, UK.
authors.forename: Catherine J
authors.initials: CJ
authors.lastname: McMahon
authors.forename: Stephen
authors.initials: S
authors.lastname: Hopkins
authors.forename: Andy
authors.initials: A
authors.lastname: Vail
authors.forename: Andrew T
authors.initials: AT
authors.lastname: King
authors.forename: Debi
authors.initials: D
authors.lastname: Smith
authors.forename: Karen J
authors.initials: KJ
authors.lastname: Illingworth
authors.forename: Simon
authors.initials: S
authors.lastname: Clark
authors.forename: Nancy J
authors.initials: NJ
authors.lastname: Rothwell
authors.forename: Pippa J
authors.initials: PJ
authors.lastname: Tyrrell
mesh_terms: D000328:Adult; D000368:Aged; D001799:Blood Sedimentation; D002545:Brain Ischemia / Q000209:etiology* / Q000473:pathology; D002097:C-Reactive Protein / Q000032:analysis; D016022:Case-Control Studies; D002533:Cerebral Angiography; D015331:Cohort Studies; D003627:Data Interpretation, Statistical; D005260:Female; D006801:Humans; D007249:Inflammation / Q000473:pathology*; D018836:Inflammation Mediators; D053590:Interleukin 1 Receptor Antagonist Protein / Q000097:blood; D015850:Interleukin-6 / Q000097:blood; D007958:Leukocyte Count; D007964:Leukocytosis / Q000097:blood / Q000209:etiology; D008297:Male; D008875:Middle Aged; D018579:Patient Selection; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D013345:Subarachnoid Hemorrhage / Q000150:complications* / Q000473:pathology*; D055815:Young Adult
chemical_list: D018836:Inflammation Mediators; D053590:Interleukin 1 Receptor Antagonist Protein; D015850:Interleukin-6; D002097:C-Reactive Protein