title: Diagnosis of pyogenic liver abscess by abdominal ultrasonography in the emergency department.
abstract: BACKGROUND
  Delayed diagnosis of pyogenic liver abscess remains a challenging problem in the emergency department because of the associated high morbidity and mortality.
  
  
  OBJECTIVE
  To evaluate the sensitivity of ultrasono-graphy in the diagnosis of pyogenic liver abscess in patients presenting to the emergency department and the factors that may influence this sensitivity.
  
  
  METHODS
  A retrospective study was conducted in patients diagnosed with pyogenic liver abscess in the emergency department (ED) of a tertiary care teaching hospital for a period of 5 years. Between May 2001 and April 2006, 268 patients diagnosed with pyogenic liver abscess were evaluated by ultrasonography and/or CT scanning. The age, sex, clinical presentation, location and number of abscesses and the underlying disease of these two groups were compared.
  
  
  RESULTS
  Of the 268 patients admitted via the ED who were discharged or died with a diagnosis of pyogenic liver abscess, there was a predominance of men (M/F 173/95) and the mean age was 57.6 years (range 17-90). 38 had false negative findings on ultrasonography (sensitivity 85.8%) and required abdominal CT scanning for definitive diagnosis. In the other 230 cases, ultrasonography alone was sufficient for diagnosis. Location of the abscess in segments 4 and 5 of the liver raised the sensitivity of ultrasound for diagnosis, while location in segment 8 was most associated with delayed diagnosis by ultrasonography. Right costal angle knocking pain was significant for pyogenic liver abscess even if ultrasound was negative.
  
  
  CONCLUSIONS
  The size and location of the liver abscess and the underlying comorbid diseases may affect the diagnostic sensitivity of ultrasound for pyogenic liver abscess in clinical practice. A high index of suspicion should be maintained in patients with diabetes mellitus, previous biliary tract intervention or gastrointestinal malignancy. Follow-up CT scanning is recommended if right flank knocking pain is present, even if ultrasonography is non-revealing. A diagnostic protocol for liver abscess may be feasible in the future.
authors.affiliation: Emergency Department, Shin Kong Wu Ho-Su Memorial Hospital, Taiwan.
authors.forename: A C-M
authors.initials: AC
authors.lastname: Lin
authors.forename: D Y
authors.initials: DY
authors.lastname: Yeh
authors.forename: Y-H
authors.initials: YH
authors.lastname: Hsu
authors.forename: C-C
authors.initials: CC
authors.lastname: Wu
authors.forename: H
authors.initials: H
authors.lastname: Chang
authors.forename: T-N
authors.initials: TN
authors.lastname: Jang
authors.forename: C-H
authors.initials: CH
authors.lastname: Huang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D042241:Early Diagnosis; D004636:Emergency Service, Hospital; D004812:Epidemiologic Methods; D005188:False Negative Reactions; D005260:Female; D006801:Humans; D046290:Liver Abscess, Pyogenic / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D012737:Sex Factors; D013624:Taiwan; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography; D055815:Young Adult