A 78-year-old man is brought to the emergency department after he was found obtunded and moaning in bed at his nursing care facility. For 2 days prior, he refused to eat most of his food. Medical history is significant for early Alzheimer disease, hypertension, hyperlipidemia, bilateral knee replacement, and right hemicolectomy for stage I colon cancer. The patient has a 50-pack-year smoking history but no longer smokes or drinks alcohol. Temperature is 38.7 C (101.7 F), blood pressure is 102/54 mm Hg, pulse is 114/min, and respirations are 22/min. The patient is holding his abdomen and groaning. He opens his eyes to a loud voice but does not follow commands. The abdomen is distended, tympanitic to percussion, and rigid to palpation. Stool guaiac test is negative. The patient cannot tolerate sitting upright. Lateral decubitus x-ray of the abdomen is shown below.
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Which of the following is the best next step in management of this patient?
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This patient with abdominal pain, fever, and peritonitis (eg, abdominal rigidity) has subdiaphragmatic free air on lateral decubitus x-ray, indicating perforated viscus. Given his history of hemicolectomy, the most likely cause of perforation is postoperative adhesions leading to bowel obstruction (eg, anorexia, x-ray findings of dilated small-bowel loops with air-fluid levels) complicated by increased intraluminal pressure.
Clinical suspicion of gastrointestinal perforation can be confirmed by demonstration of intraperitoneal free air (ie, pneumoperitoneum) on imaging. Plain radiographs often confirm the diagnosis (sensitivity ~50%-70%). Upright radiographs of the chest and abdomen are usually performed, but supine and lateral decubitus x-rays can be obtained for patients, such as this one, who cannot tolerate being upright. Free air on x-ray and clinical signs of peritonitis should prompt emergent surgical exploration to prevent deterioration and possible death.
In patients in whom perforation is suspected and plain radiographs are negative (unlike this patient), CT scan of the abdomen with IV contrast can help detect smaller amounts of free air or free fluid. In this patient with peritonitis and an x-ray confirming perforation, operative intervention should be immediately initiated (if operating availability is delayed, it would be reasonable to perform a CT scan to try to visualize the site of perforation) (Choice C).
(Choices A and F) Barium enema and upper gastrointestinal series use contrast to outline the lumen of the gastrointestinal tract for diagnosis of functional or structural abnormalities (eg, obstructing mass). However, barium contrast is contraindicated if perforation is suspected because it incites a severe inflammatory response if leaked into the peritoneal cavity. In addition, emergent surgical exploration should not be delayed for further imaging because of the patient's peritonitis and radiographic confirmation of perforation.
(Choice B) This patient has risk factors (eg, hyperlipidemia, 50-pack-year smoking history) for chronic mesenteric ischemia (which can be evaluated by contrast angiography), but this type of ischemia typically causes recurrent episodes of postprandial pain, which are not seen in this patient. Pneumoperitoneum is not expected except in severe cases with bowel necrosis, in which case surgical intervention is the correct next step.
(Choice D) Nasogastric tube placement may be helpful for decompressing the patient's small-bowel obstruction. However, operative intervention, rather than observation with serial abdominal examinations, is indicated due to this patient's peritonitis and radiographic evidence of perforation.
Educational objective:
Small-bowel obstruction can be complicated by bowel perforation. Free air on x-ray and clinical signs of peritonitis should prompt emergent surgical exploration.