[Diagnosis of intra-abdominal infections: clinical findings and imaging]

Abdominal sepsis carries a high morbidity and mortality. Intra-abdominal infectious complications are one of the most common infectious etiologies seen in critically ill patients. Approximately 30% of patients admitted to an ICU with intra-abdominal infection succumb to their illness, and when peritonitis arises as a complication of a previous surgical procedure, or recurs during ICU admission, mortality rates exceed 50%. Thus early detection and treatment is essential to minimize patient complications. Critically ill patients are often clinically non valuable due to distracting injuries, respiratory failure, obtundation, or other pathology. Even when patients can be examined, the clinical exam is frequently unreliable and/or misleading. The diagnostic approach to identify abdominal problems will differ depending upon the hemo-dynamic stability of the patient. Patients who have low systolic blood pressures, who are pressor-dependent, may be too unstable to undergo studies that require trips away from the ICU or emergency department. Intra-abdominal pathology may be detected by ultrasound or diagnostic peritoneal lavage (DPL). When critically ill patients are stable enough to undergo some diagnostic evaluation of their abdomen the approach is somewhat simpler. Overall, computerized tomography (CT) is the imaging modality of choice for most intra-abdominal processes. For diagnosis of intra-abdominal conditions using CT scanning it is optimal if patients receive both oral and intravenous contrast. An exception to the use of CT scanning is evaluation of suspected biliary pathology, which is best imaged by ultrasound. It will identify cholecystitis with or without calculus and may show changes in the gallbladder or common bile duct associated with biliary obstruction.