Diagnosis and treatment of intra-abdominal abscesses

Despite recent advances in the diagnosis and management of intra-abdominal abscesses, these infections still cause substantial morbidity and mortality. Low pH, large bacterial inocula, poor perfusion, the presence of hemoglobin, and large amounts of fibrin (which impedes antibiotic penetration) make the abscess a cloistered environment that is penetrated poorly by many antimicrobial therapies. Therefore, management of these infections requires prompt recognition, early localization, and effective drainage, as well as appropriate antimicrobial use. Although various imaging techniques, such as ultrasonography, gallium scans, and indium-labeled white-blood-cell scans, can be used for the diagnosis and localization of intra-abdominal abscesses, computer-assisted tomography is the most useful study. Once the diagnosis is made and the abscess is localized, treatment should begin promptly. Percutaneous or open surgical drainage should be used. Broad-spectrum antibiotics should be given until culture and sensitivity data are obtained. Once these data are obtained, a therapy with appropriate coverage that is likely to work in the abscess environment should be chosen. Percutaneous drainage is inappropriate for abscesses in the posterior subphrenic space or in the porta hepatis, for those among loops of small bowel, for suspected echinococcal cysts, and for abscesses containing necrotic or neoplastic tissues. Finally, surgeons need to be cognizant of risk factors, such as advanced age, obesity, complex abscesses, and high Acute Physiology and Chronic Health Evaluation (APACHE) II or APACHE III scores, which correlate with poor outcomes for these patients.