A 51-year-old man presented to the ED with progressive abdominal
pain of one day's duration. He had not eaten all day and had vomited
twice. There was no associated diarrhea or melena.
He had a history of alcoholic hepatitis, COPD, and surgical repair
of a colonic-bladder fistula 10 years earlier. He had mild constipation
and abdominal discomfort for the past few months.
On examination, the patient was in moderate distress due to abdominal
pain. Vital signs: blood pressure 130/70 mm Hg; pulse 118
beats/min; respirations 24 breaths/min; temperature
100.8º F (rectal).
His abdomen was distended but soft, with mild diffuse tenderness
and no rebound tenderness. His stool was negative for occult blood.
He was anicteric.
The initial chest and abdominal radiographs were interpreted
as negative (Figure 1A–C). Upon his return from the radiology
suite, he vomited dark bilious material that tested positive for
blood. A nasogastric tube was inserted. Because of concern that
he might have a perforated peptic ulcer, 300 mL of air was insufflated
via a nasogastric tube and the upright abdominal radiograph was repeated
(Figure 1D). The air noted under the left hemidiaphragm was interpreted
as being in the patient’s distended stomach.
A. Erect AP chest radiograph. B. Supine abdomen. C. Upright abdomen. D. Upright abdomen repeated after insufflation of 300 mL air
via a nasogastric tube
Two hours later, an abdominal CT was performed that revealed
the correct diagnosis.
The diagnosis was evident on the initial radiographs (Figure
Detection of free intraperitoneal air (pneumoperitoneum)
is one of the principal uses of radiography in patients with abdominal
pain. Pneumoperitoneum is nearly always due to perforation of the
gastrointestinal tract, and virtually all patients require surgery.
In 80–90% of cases, free intraperitoneal air is
due to a perforated peptic ulcer. An upright chest radiograph
is the preferred imaging test because it readily detects free air
under the diaphragm.
Radiography to detect free intraperitoneal air in indicated in
patients suspected of having a perforated peptic ulcar. The patient
typically presents with an abrupt onset of severe abdominal pain. The
abdomen is diffusely tender with rigidity and rebound tenderness.
In many patients, there is no history of prior peptic ulcer disease.
In most cases, the clinical and radiographic findings are obvious,
and radiography serves to confirm the diagnosis. Diagnostic difficulty
arises when the clinical presentation is muted, particularly ...