title: Acute central nervous system infections in adults--a retrospective cohort study in the NHS North West region.
abstract: BACKGROUND
  Over the last 15 years, bacterial meningitis has received considerable attention, including national guidelines, whilst viral central nervous system (CNS) infections have been relatively neglected. A recent pilot study suggested that management of patients with suspected viral encephalitis was often suboptimal.
  
  
  OBJECTIVE
  To examine the relative incidence, clinical features and management of suspected acute CNS infections in adults across the NHS North West Region.
  
  
  METHODS
  A multicentre cross-sectional retrospective cohort study at 10 hospitals across the region over 3 months (from September to December 2007). Following a screen of all patients who had cerebrospinal fluid (CSF) analysis or received intravenous aciclovir and/or third-generation cephalosporin, those with clinical features suspicious of a CNS infection were included. Management was compared with the national meningitis and regional encephalitis guidelines.
  
  
  RESULTS
  Three hundred and eighty-five patients were screened; 217 patients had a suspected CNS infection and 44 (20%) had a CNS infection: 18 aseptic meningitis (one herpes simplex virus [HSV]-2), 13 purulent meningitis (four Streptococcus pneumoniae) and 13 encephalitis (three HSV-1). The median (range) time from admission to suspicion of CNS infection and to LP was longer for patients with encephalitis than meningitis [4 (0.3-312) vs. 0.3 (0.1-12) h, P<0.001, and 23 (4-360) vs. 12 (2-48) h, P=0.042, respectively]; and the median time to treatment was longer for aciclovir than cephalosporin [7 (0.5-312) vs. 3 (0.3-312) h, P=0.002].
  
  
  CONCLUSIONS
  Encephalitis was as common as purulent meningitis, and HSV as common as Streptococcus pneumoniae. However, the management of patients with encephalitis was worse than meningitis. National encephalitis guidelines are needed.
authors.affiliation: Brain Infections Group, Division of Neurological Science, University of Liverpool, Liverpool, UK.
authors.forename: B D
authors.initials: BD
authors.lastname: Michael
authors.forename: M
authors.initials: M
authors.lastname: Sidhu
authors.forename: D
authors.initials: D
authors.lastname: Stoeter
authors.forename: M
authors.initials: M
authors.lastname: Roberts
authors.forename: N J
authors.initials: NJ
authors.lastname: Beeching
authors.forename: A
authors.initials: A
authors.lastname: Bonington
authors.forename: I J
authors.initials: IJ
authors.lastname: Hart
authors.forename: R
authors.initials: R
authors.lastname: Kneen
authors.forename: A
authors.initials: A
authors.lastname: Miller
authors.forename: T
authors.initials: T
authors.lastname: Solomon
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D020806:Central Nervous System Bacterial Infections / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology; D020805:Central Nervous System Viral Diseases / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology; D004739:England / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D016896:Treatment Outcome; D055815:Young Adult