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5. Radiology Case 1
Keywords
Upright abdominal radiographRight hemidiaphragmPneumoperitoneumAir/microperforationsComputerized tomographyPathologyIndication for the Exam
Radiologic Findings
Upright abdominal radiograph demonstrating free air under the right hemidiaphragm.
Diagnosis
Learning Points
Priming Questions
- 1.
Which radiographic features help to identify pneumoperitoneum?
- 2.
What are some common causes of pneumoperitoneum?
- 3.
In the neonatal population, what might one consider when a patient presents with pneumoperitoneum?
Introduction/Background
Free air/gas within the peritoneum, also known as pneumoperitoneum, can be a sign of a critical pathology, postoperative complication, trauma, or can arise from iatrogenic causes [1, 2]. Prompt and accurate diagnosis is life-saving in this population to reduce enteric contamination. Surgical intervention is often indicated.
Pathophysiology/Mechanism
Pneumoperitoneum occurs when the wall of a hollow viscus organ is disrupted [1]. The differential diagnosis is broad, and hence, combining clinical history with the location of free air is important in determining etiology.
Making the Diagnosis
Upright chest and abdominal radiographs and left lateral decubitus radiographs are sensitive imaging modalities to diagnose pneumoperitoneum [3].
On an upright chest radiograph, the presence of subdiaphragmatic gas indicates free intraperitoneal air as seen on the above radiograph. On supine chest imaging, free air located midline underneath the central diaphragmatic tendon can also suggest free intraperitoneal air; however, it is less sensitive (free air moves up with gravity) [1–3].
Radiographs are not as sensitive for small foci of free air/microperforations; hence, in these situations, computerized tomography should be utilized [1].