Clinical manifestations and prognostic factor of iliopsoas abscess.

Introduction: Iliopsoas abscess (IPA) is a collection of pus in the iliopsoas compartment, which is considered rare in Japan. However, the number of patients with IPA has recently increased among the elderly or compromised hosts.

Subjects And Methods: This retrospective study aims to examine the clinical pictures, pathological findings, and the prognostic factor of IPA. We analyzed all patients with IPA who were admitted to our hospital from April 2006 to July 2011. Patients' characteristics, treatment, clinical outcome, radiological findings, bacteria isolated, and comorbidities were evaluated. The comorbidities were evaluated by the Charlson comorbidity index (CCI). We compared the survival and non-survival groups to assess the prognostic factors of IPA.

Results: A total of 33 patients were enrolled in this study, which included 14 males and 19 females. The mean age of the patients was 71.5 years (range 32-92 years). The most common underlying disease was spinal disease (16 of 33, 48.5%). Twenty-nine patients (87.9%) were cured and four patients (12.1%) died. While 12 patients (36.4%) were initially treated conservatively with antibiotics alone, percutaneous drainage was performed initially in 19 patients (57.6%). Two patients (6%) directly underwent exploratory surgery and open drainage. In terms of patients' characteristics, there were no significant differences in either group. The score of CCI in non-survivors was higher than that in survivors (1.38 vs. 5.5, P < 0.001).

Conclusions: The epidemiology of IPA is quite different from what it used to be. CCI appears to be useful in evaluating the patients' prognosis with IPA.