title: Clinical Guidelines for the Emergency Department Evaluation of Subarachnoid Hemorrhage.
abstract: BACKGROUND
  Subarachnoid hemorrhage (SAH) is frequently caused by the rupture of an intracranial aneurysmal vessel or arteriovenous malformation, leading to a cascade of events that can result in severe disability or death. When evaluating for this diagnosis, emergency physicians have classically performed a noncontrast computed tomography (NCCT) scan, followed by a lumbar puncture (LP). Recently, however, as CT technology has advanced, many studies have questioned the necessity of the LP in the SAH diagnostic algorithm and have instead advocated for noninvasive techniques, such as NCCT alone or NCCT with CT angiogram (CTA).
  
  
  OBJECTIVE
  The primary goal of this literature search was to determine the appropriate emergency department (ED) management of patients with suspected SAH.
  
  
  METHODS
  A MEDLINE literature search from October 2008 to June 2015 was performed using the keywords computed tomography AND subarachnoid hemorrhage AND lumbar puncture, while limiting the search to human studies written in the English language. General review articles and single case reports were omitted. Each of the selected articles then underwent a structured review.
  
  
  RESULTS
  Ninety-one articles were identified, with 31 papers being considered appropriate for analysis. These studies then underwent a rigorous review from which recommendations were developed.
  
  
  CONCLUSIONS
  The literature search supports that NCCT followed by CTA is a reasonable approach in the evaluation of ED patients with possible SAH.
authors.affiliation: Department of Emergency Medicine, University of Michigan Health System, Ann Arbor, Michigan.
authors.forename: William J
authors.initials: WJ
authors.lastname: Meurer
authors.affiliation: Department of Emergency Medicine, Morristown Medical Center, Morristown, New Jersey.
authors.forename: Brian
authors.initials: B
authors.lastname: Walsh
authors.affiliation: Department of Emergency Medicine, University of California San Diego School of Medicine, San Diego, California.
authors.forename: Gary M
authors.initials: GM
authors.lastname: Vilke
authors.affiliation: Department of Emergency Medicine, University of California San Diego School of Medicine, San Diego, California.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Coyne
mesh_terms: D002533:Cerebral Angiography; D003937:Diagnosis, Differential; D004636:Emergency Service, Hospital; D006801:Humans; D017410:Practice Guidelines as Topic; D013129:Spinal Puncture; D013345:Subarachnoid Hemorrhage / Q000175:diagnosis*; D014057:Tomography, X-Ray Computed
keywords: CTA; NCCT; angiogram; computed tomography; headache; lumbar puncture; subarachnoid hemorrhage