TYPICAL RADIOGRAPHIC SIGNS OF DIFFERENT TYPES OF ACUTE ABDOMEN

Abstract

In the context of acute abdomen, an emergency condition requiring rapid diagnosis, abdominal radiography is a fundamental tool for identifying the cause of the condition. In cases of obstructive acute abdomen, which occurs due to mechanical obstruction of the small or large intestine, the most common radiographic signs include gaseous distension, where the intestinal loops appear dilated and filled with gas and fluids. Air-fluid levels, which are visible interfaces between gas and fluid at different heights in the intestinal loops, indicating obstruction, may also be observed. A classic example is the presence of multiple air-fluid levels on an abdominal radiograph, in addition to the absence of gas in the distal portion of the intestine, such as the rectum, suggesting that there is an obstruction above that point. Another illustrative sign is the "coffee bean sign" in the sigmoid colon, characterized by a dilated loop with a rounded and excavated appearance, typical of sigmoid volvulus. For acute perforated abdomen, resulting from the perforation of a hollow viscus, such as a peptic ulcer, the classic sign is pneumoperitoneum, which appears on radiography as a radiolucent area under the diaphragm, indicating free air in the peritoneal cavity. In cases of esophageal perforation, air may be observed in the mediastinum or pericardial spaces, in addition to air under the diaphragm. An example is the radiograph of a patient with a perforated ulcer, where free air under the right diaphragm is easily detectable, confirming the presence of pneumoperitoneum. In acute inflammatory or infectious abdomen, such as appendicitis or diverticulitis, radiographic signs may be less specific, but some examples help in identification. In diverticulitis, an increase in volume can be observed in a region of the colon, possibly with the presence of a soft tissue mass, in addition to the obliteration of the fat lines around the inflamed organ. In cases of abscess, a soft tissue mass may be seen, sometimes with signs of periabdominal infiltration. In an appendicitis X-ray, there may be distension of intestinal loops near the cecum, as well as signs of localized ileus, with distension of specific segments of the intestine. Finally, acute vascular abdomen, resulting from ischemia or hemorrhage, presents more nonspecific signs on X-ray. An example is adynamic ileus, which manifests as diffuse gaseous distension without air-fluid levels, indicating a dysfunction in intestinal motility. Another important sign is pneumatosis intestinalis, which consists of the presence of gas in the intestinal wall, suggesting ischemia or necrosis. This condition is visualized as radiolucent areas within the intestinal wall, frequently associated with severe vascular compromise. It is important to emphasize that abdominal radiography is a valuable diagnostic tool, but it should always be interpreted in conjunction with a detailed clinical history, physical examination, and other complementary tests, such as computed tomography, to confirm the diagnosis and plan appropriate treatment.