title: Ruptured aneurysmal subarachnoid hemorrhage in the emergency department: Clinical outcome of patients having a lumbar puncture for red blood cell count, visual and spectrophotometric xanthochromia after a negative computed tomography.
abstract: OBJECTIVE
  Over the last decade, computed tomography scanners have gained resolution and have become the standard of care in the investigation of neurologically intact patients suffering from acute headache. The added value of the combined assessment of red blood cells count, visual and spectrophotometric xanthochromia, to detect ruptured aneurysmal subarachnoid hemorrhage (ASAH) following a negative head computed tomography (NHCT) was studied.
  
  
  METHODS
  The population consisted of all patients who had cerebrospinal fluid tested for spectrophotometric xanthochromia between 2003 and 2009 identified through the clinical-laboratory database and who met all the inclusion criteria: >14 years old, had an initial Glasgow Coma Score of 15, a non-traumatic acute headache with a suspected subarachnoid hemorrhage recorded in the initial ED differential diagnosis and an initial negative head CT scan.
  
  
  RESULTS
  A total of 706 patients were included. LP identified 5 ASAH (prevalence: 0.7%). In these patients, LP parameters were as follows: high red blood cell count (from 1310 to 63,000×10(6)/L), positive visual xanthochromia in 4 out of 5 ASAH, and positive spectrophotometric xanthochromia in 5 out of 5 ASAH. All ASAH patients were neurologically intact after intervention. No deaths or missed ASAH were reported. Angiographies were performed on 127 patients (19.5%) of which 47 (34.1%) had positive xanthochromia (visual or spectrophotometric).
  
  
  CONCLUSIONS
  Considering the low prevalence of ASAH following an NHCT, intense resources were utilized to identify all 5 ASAH. Lumbar puncture analyses combining red blood cell count, visual and spectrophotometric xanthochromia identified all ASAH, allowing intervention and a positive clinical outcome. Our data support 1) that LP identifies the presence of a ruptured ASAH after an NHCT and 2)` that a guide to define a subpopulation of patients who would benefit from a lumbar puncture after an NHCT would be desirable.
authors.affiliation: Axe Santé des populations et pratiques optimales en santé, Centre de recherche du CHU de Québec, Hôpital de l'Enfant-Jésus, Quebec, Canada; CHU de Québec, Emergency departement.
authors.forename: Anne
authors.initials: A
authors.lastname: Gangloff
authors.affiliation: Université Laval, Quebec, Canada; CHU de Québec, Emergency departement.
authors.forename: Linda
authors.initials: L
authors.lastname: Nadeau
authors.affiliation: Ottawa Hospital Research Institute, Ottawa, Canada; University of Ottawa Department of Emergency Medicine, Ottawa, Canada.
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Perry
authors.affiliation: CHU de Québec, Emergency departement.
authors.forename: Pierre
authors.initials: P
authors.lastname: Baril
authors.affiliation: Axe Santé des populations et pratiques optimales en santé, Centre de recherche du CHU de Québec, Hôpital de l'Enfant-Jésus, Quebec, Canada; Université Laval, Quebec, Canada; CHU de Québec, Emergency departement. Electronic address: marcelemond1@me.com.
authors.forename: Marcel
authors.initials: M
authors.lastname: Émond
mesh_terms: D000328:Adult; D017542:Aneurysm, Ruptured / Q000097:blood / Q000175:diagnosis*; D015331:Cohort Studies; D003937:Diagnosis, Differential; D004636:Emergency Service, Hospital / Q000592:standards; D004906:Erythrocyte Count / Q000592:standards; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013053:Spectrophotometry / Q000592:standards; D013129:Spinal Puncture / Q000592:standards; D013345:Subarachnoid Hemorrhage / Q000097:blood / Q000175:diagnosis*; D014057:Tomography, X-Ray Computed / Q000592:standards; D016896:Treatment Outcome
keywords: Aneurysmal subarachnoid haemorrhage; Cerebrospinal fluid; Negative head computed tomography; Spectrophotometric xanthochromia; Visual xanthochromia