swazamight
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10.25.05 (2 years ago)
#11
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It seems, X-ray, barium and CT may be correct.
This is from Oxford textbook of Surgery :
"Plain film radiographs of the abdomen can be helpful in diagnosing small bowel obstruction. Three films are usually obtained. An upright chest radiograph is best for ruling out free air under the diaphragm. Free air characteristically accumulates over the liver or just below the diaphragm. A chest film also allows for evaluation of diaphragmatic hernias and other intrathoracic Pathology
. An abdominal plain film is usually performed in the upright position. Signs of small bowel obstruction include bowel dilatation proximal to the site of obstruction, air–fluid levels, paucity of large bowel gas, bowel wall thickening, a fixed loop, and ground glass appearance signifying intraluminal fluid. In early small intestinal obstruction, however, there may still be gas in the large bowel due to incomplete evacuation of contents distal to the point of obstruction. Air–fluid levels may suggest small bowel obstruction in a patient with a consistent history, though this finding can be present in any illness which decreases bowel motility resulting in ileus. Plain films can also appear normal in the setting of small bowel obstruction. They have been shown to be diagnostic in 50 to 60 per cent of cases, which leaves 40 to 50 per cent either equivocal or normal. This lack of sensitivity and specificity has led to the use of other radiographic modalities in diagnosing obstruction.
Upper gastrointestinal studies with small bowel follow through are often utilized in diagnosing small bowel obstruction. Barium or gastrograffin are administered with timed plain films to evaluate intraluminal transit. This study can show the point of obstruction, the degree of narrowing in the case of a partial small bowel obstruction, and associated mucosal abnormalities. It involves an initial bolus of enteral contrast with subsequent filming to document transit through the small bowel to the colon. When contrast does not reach the colon after several hours, a complete obstruction must be postulated. In patients with stomas, a retrograde contrast study through the stoma can delineate parastomal herniation causing complete obstruction. Enteroclysis has also been advocated in diagnosing small bowel obstruction. This involves placement of a long nasoenteric tube followed by contrast and air administration. It has been shown to be accurate in approximately 85 per cent of cases, and like upper gastrointestinal studies with small bowel follow through, allows one to gauge the severity of obstruction. Complete as opposed to partial obstruction is often discernible, especially with delayed films, as is the level of obstruction. Enteroclysis, however, is uncomfortable for the patient, difficult to perform in an emergency setting, evaluates only the intestinal lumen, and requires skilled interpretation at the time the study is being performed.
Computed tomography (CT) is playing a growing role in the diagnosis of intestinal obstruction (Fig. 1). Initial studies indicated a greater than 90 per cent accuracy in defining both the site and nature of obstruction. Proximal obstructions are more easily diagnosed by CT with an accuracy approaching 95 per cent. Distal obstructions have a lower sensitivity and specificity ranging from 60 to 75 per cent. High-grade obstructions are also more accurately diagnosed by CT scan than low-grade obstructions. Signs of obstruction by CT scan include proximal dilatation with transition point and closed-loop obstruction with a 'beak' sign. Small bowel strangulation can be shown as circumferential thickening of the bowel wall, increased small bowel attenuation, pneumatosis, and 'target sign' secondary to thickening. CT scans are easily obtainable in an emergency setting, require less technical expertise than enteroclysis, are non-invasive and quick, and provide imaging of the entire abdomen. Contrast administration is helpful, though fluid-filled loops of small bowel often act as their own contrast medium. Rectal contrast is useful in ruling out large bowel obstruction as the etiology of small bowel obstructive symptoms. Current recommendations include utilizing CT scan in cases where plain films are non-diagnostic, there is a disparity between clinical and radiographic findings, there is postoperative small bowel obstruction, and cases where neoplasms are suspected."
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