The term “acute abdomen” refers to the sudden onset of severe abdominal pain requiring emergency medical or surgical management. It is one of the most common reasons for presentation at the emergency department.
The potential causes are numerous. A review of 10,682 patients presenting with acute abdomen found that 28% had appendicitis, 9.7% cholecystitis, 4.1% small bowel obstruction, 4% a gynecologic disorder, 2.9% pancreatitis, 2.9% renal colic, 2.5% peptic ulcer disease, 1.5% cancer, 1.5% diverticular disease, and 9% had a selection of less common conditions.1 One third of patients did not receive a positive diagnosis.
Subsequent patient management depends on the diagnosis. A rapid and accurate diagnosis is essential if the patient is to be referred promptly to the appropriate clinical team and to minimize morbidity and mortality. Physical examination and laboratory investigations are often nonspecific. Clinical findings may be equivocal or misleading in up to 50% of patients with blunt abdominal trauma.2,3 Imaging, consequently, plays a vital role.
Plain-film radiography, ultrasound, and CT are all used frequently in the acute situation. A sound knowledge of the advantages and potential pitfalls associated with the choice of investigation, the applied technique, and image interpretation is crucial.
INVESTIGATIVE OPTIONS
The role of the abdominal radiograph is limited. The images are rarely diagnostic and are easily misinterpreted (Figure 1). One study evaluating 871 patients with abdominal pain reported that plain-film x-rays were interpreted as nonspecific in 588 cases (68%), normal in 200 (23%), and abnormal in 83 (10%). Abdominal radiography had 0% sensitivity for appendicitis, pyelonephritis, pancreatitis, and diverticulitis.4
Radiography is, despite this, often the preliminary imaging investigation in the emergency department. It is essential that radiologists and emergency clinicians maintain their interpretive skills while this practice continues. Important clinical findings, such as pneumoperitoneum, pneumobilia, portal venous gas, small and large bowel obstruction, and intramural gas, should not be missed.
