title: Retrospective review of clinical presentations, microbiology, and outcomes of patients with psoas abscess.
abstract: OBJECTIVE
  The clinical features of patients with psoas abscess in a local setting, including the microbiology, incidence and aetiologies, have not been well described. This study aimed to review such clinical features and patient outcomes.
  
  
  METHODS
  Retrospective case series.
  
  
  METHODS
  Regional hospital, Hong Kong.
  
  
  METHODS
  Adults (aged ≥18 years) with psoas abscess admitted to Tuen Mun Hospital from 1 January 2006 to 31 December 2010 were included. The clinical presentations, aetiologies, microbiology, treatments, hospital stays, intensive care unit admissions, and outcomes of these patients were reviewed.
  
  
  RESULTS
  The series entailed 42 patients, five of whom developed their psoas abscess after admission and seven were intravenous drug abusers. The most common presenting symptom in community-onset cases was back, hip, or thigh pain (43% [16/37]). Fever was present at presentation in 41% (15/37) of these patients, four of whom presented with fever only. The diagnosis was made by computed tomography in 95% (40/42) of these cases. In all, 23 abscesses were considered secondary; the most common aetiology being infective spondylitis or spondylodiscitis. The commonest causative organism for a primary psoas abscess was methicillin-sensitive Staphylococcus aureus, while for secondary abscesses they were more commonly from the gastro-intestinal and genitourinary tracts. Overall in-hospital mortality rate was 14% (6/42). Secondary psoas abscess patients had longer hospital stays (mean, 62 vs 34 days; P=0.007).
  
  
  CONCLUSIONS
  Psoas abscess is an uncommon condition. Most patients presented with only non-specific symptoms leading to difficulty in making an early diagnosis. In more than half of these patients, the psoas abscesses were secondary, the aetiology of which differed from reported overseas experience.
authors.affiliation: Department of Anaesthesia and Intensive Care, Tuen Mun Hospital, Tuen Mun, New Territories, Hong Kong.
authors.forename: O F
authors.initials: OF
authors.lastname: Wong
authors.forename: P L
authors.initials: PL
authors.lastname: Ho
authors.forename: S K
authors.initials: SK
authors.lastname: Lam
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005334:Fever / Q000453:epidemiology / Q000209:etiology*; D006723:Hong Kong; D017052:Hospital Mortality; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D015994:Incidence; D007362:Intensive Care Units / Q000706:statistics & numerical data; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000453:epidemiology / Q000209:etiology; D016659:Psoas Abscess / Q000382:microbiology / Q000473:pathology* / Q000628:therapy; D012189:Retrospective Studies; D013203:Staphylococcal Infections / Q000473:pathology* / Q000628:therapy; D013211:Staphylococcus aureus / Q000302:isolation & purification*; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
keywords: Discitis; Muscles; Psoas abscess; Sepsis; Spondylitis