Acute Abdomen: Clinical Context and Indications for Imaging

The acute abdomen is characterized by the sudden onset of severe abdominal pain, which requires emergency medical or surgical consultation. It can be caused by diseases of any of the abdominal organs or organ systems, and, as such, the acute abdomen represents a physical condition rather than a disease. However, extra-abdominal disease may also lead cause an acute abdomen. A rapid and accurate diagnosis is essential because various potentially life-threatening processes may be the underlying causes of the physical complaints. Because of the wide spectrum of diseases that may cause an acute abdomen, the use of imaging techniques, in particular, multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI), is often warranted because of their ability to suggest alternative diagnoses if the suspected clinical diagnosis is unconfirmed by ultrasonography (US). Depending on the clinical pattern and basic diagnosis, the treatment of such injuries requires a balance between the quick availability, the possible diagnostic benefit of additional and potential radiation exposures by imaging, possible time delay. These circumstances are particularly relevant for patients with life-threatening illnesses, when MDCT should be immediately be performed, and for pregnant woman when dedicated MRI can be a diagnostic option. Thus, early use of MDCT has been shown to reduce the number of serious diagnoses that are missed. Advanced diagnostics that may be used to guide and treat both trauma and non-trauma patients include such techniques as endoscopy or selective angiography, e.g., for the treatment of gastrointestinal or visceral organ hemorrhage. Parenchymateous organ or hollow organ visceral bleeding, including perforations, is representative of classical, life-threatening diagnoses secured by MDCT. However, advanced testing in patients that require surgery for abdominal emergencies will result in a delay in the necessary treatments. The present chapter defines the clinical context of patients presenting with an acute abdomen and provides information’s on clinical pattern and diagnostic strategies.