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An 83-year-old man was brought to the ED by ambulance for progressive shortness of breath of one day duration. On arrival, he was in severe respiratory distress and was unable to provide a detailed medical history.

Vital signs: blood pressure: 150/80 mm Hg; pulse: 120 irregular beats/min; respirations: 36 breaths/min; pulse oximetry SO2 78% on room air.

On examination, there was poor air movement bilaterally. His abdomen was distended, tympanitic to percussion, and nontender. Bowel sounds were quiet, but present. The patient stated that he had been constipated for six days, but had a bowel movement the previous day.

On 100% oxygen by face mask, the pulse oximetry SO2 was 92%.

ABG: pH 7.20, Pco2 59 mm Hg, 79 mm Hg, Po2 79 mm Hg

The patient was intubated.

His chest and abdominal radiographs are shown in Figure 1.

  • What is this patient’s diagnosis?


Chest radiography often provides useful information about the cause of a patient’s respiratory failure, for example pulmonary edema or pneumonia. In this patient, although the lungs are clear, the chest radiograph does provide a clue to the cause of respiratory failure—a very shallow level of inspiration (Figure 1A). Although shallow inspiration is common in technically suboptimal, supine portable radiographs in critically ill patients, in this case, the shallow inspiration was due to massive abdominal distention—the cause of the patient’s respiratory failure.

The abdominal radiograph shows markedly distended, air-filled bowel (Figure 2). The first issue is whether this is distended small or large bowel. One bowel segment extends horizontally across the midabdomen (T). Small bowel tends to have a central location, although the transverse colon is also centrally located. The mucosal indentations of small bowel are numerous, closely spaced, and extend entirely across the bowel lumen, in contrast to large bowel haustra. However, markedly distended small bowel can have an appearance similar to large bowel (Figure 3). Nonetheless, it is unusual for small bowel to dilate to this extent (10 cm). In addition, although the mucosal indentations are long and thin, like in small bowel, they do not extend entirely across the bowel lumen, which is characteristic of haustra (Figure 2). This segment of bowel is therefore the transverse colon.

Figure 2

Patient 2—Abdominal radiograph

There is a markedly distended loop of bowel extending across the midabdomen (T) and air in the rectosigmoid colon (R). A thin soft tissue stripe extends diagonally across the abdomen (arrows).

Figure ...

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