Pyogenic liver abscesses caused by Klebsiella pneumoniae:: US appearance and aspiration findings

Purpose: To retrospectively compare the ultrasonographic ( US) appearance and amount of pus obtained at initial aspiration for liver abscesses caused by Klebsiella pneumoniae with those for liver abscesses caused by other bacterial pathogens. Materials and Methods: This study had medical ethics committee approval; informed consent was not required. Asian patients with pyogenic liver abscesses in a 5-year period were included. Abscess clinical, laboratory, and microbiologic characteristics and treatment and outcome were analyzed. US images were classified according to the size of the largest liver abscess, the echogenic pattern of the lesion, the presence of any echogenic debris within the lesion, increased through transmission in the posterior aspect of the lesion, and the lesion margin. Clinical and US characteristics of patients with K pneumoniae monomicrobial liver abscesses and those with non-K pneumoniae monomicrobial or polymicrobial liver abscesses were compared. The chi(2) or Fisher exact test was used for categorical variables; the Student t test was used for continuous variables. Results: There were 120 patients with pyogenic liver abscesses. Median patient age was 69 years ( range, 13-94 years). Fifty-nine patients were male, and 61 were female. Fifty patients with K pneumoniae monomicrobial and 33 patients with non-K pneumoniae monomicrobial or polymicrobial liver abscesses underwent US. K pneumoniae monomicrobial liver abscesses were associated with diabetes mellitus ( P < .001), higher blood glucose levels at admission ( P < .05), predominantly solid US appearances ( P < .001), irregular or indistinct lesion margins ( P < .05), less than 2 mL of pus aspirated ( P < .001), and longer duration of antibiotic treatment ( P < .05). Conclusion: A predominantly solid appearance at US is associated with K pneumoniae monomicrobial liver abscess. K pneumoniae liver abscess is associated with a much smaller quantity of pus at initial aspiration.