The role of cross sectional imaging in the management of acute pyogenic inguinal abscess - extrapelvic versus intrapelvic origin

BACKGROUND: Abscesses involving the inguinal region as manifestations of complex soft-tissue infections are rare, and the infectious route is usually unclear. The purpose of this study was to ascertain the importance of imaging study and whether the clinical presentations differ between the extrapelvic and intrapelvic origin. METHODS: Patients who presented with inguinal abscess between January 2003 and December 2010 were evaluated retrospectively. All patients received broad-spectrum antibiotic therapy and debridement. Imaging studies, including computed tomography or magnetic resonance imaging, were performed in all patients to elucidate the origin and extent of infectious disease, and the results were reviewed. Clinical data, laboratory examination findings, and culture results were analyzed. RESULTS: Twenty-eight patients were enrolled in the study: 13 patients whose infections were of extrapelvic origin (Group 1) and 15 patients of intrapelvic origin (Group 2). Imaging studies yielded information that helped guiding the treatment. Gram-positive coccus infection was more frequent in Group 1 (p < 0.001), while mixed pathogen and anaerobic bacterial infection were more frequent in Group 2 (p = 0.002 and p = 0.006, respectively). Group 2 had a higher incidence of history of malignancy and chronic renal failure (p = 0.044 and p = 0.038, respectively). CONCLUSIONS: Computed tomography and magnetic resonance imaging are helpful in diagnosing cases of inguinal abscess and determining the extent of infection. In patients presenting with acute pyogenic inguinal abscess, a higher prevalence of chronic renal failure and history of malignancy were found in those with an intrapelvic, as compared with an extrapelvic, origin of infection.