Figure 1
Supine abdominal radiograph
Pneumoperitoneum ?
SectionAbdominal imaging
Case TypeAnatomy and Functional Imaging
AuthorsBirchall JD
Connected authors
63 years, male
Clinical History
The patient presented with increasing epigastric pain over a 48 hour period associated with angor anima and epigastric tenderness.
Imaging Findings
The patient presented with increasing epigastric pain over a 48 hour period associated with angor anima and epigastric tenderness. A supine abdominal radiograph (figure 1a) and an erect PA chest radiograph were performed (figure 2a).
Chest radiograph (figure 2b) demonstrated a large pneumoperitoneum (a), the supine abdominal radiograph (figure 2a) demonstrated free gas with a positive Riggler’s sign ( gas on both sides of the bowel wall [a]). Following intravenous IV fluid resuscitation and antibiotics he underwent a diagnostic laparotomy at which a perforated duodenal ulcer was found. A more subtle perforation is presented in figure 3 an 18 year old man who had a chest radiograph due to clinical concern of a right basal pneumonia. The chest radiograph revealed a small right subdiaphragmatic pneumoperitoneum , in view of this and ongoing pyrexia a laparotomy was performed at which a perforated appendix was found.
Chest radiograph (figure 2b) demonstrated a large pneumoperitoneum (a), the supine abdominal radiograph (figure 2a) demonstrated free gas with a positive Riggler’s sign ( gas on both sides of the bowel wall [a]). Following intravenous IV fluid resuscitation and antibiotics he underwent a diagnostic laparotomy at which a perforated duodenal ulcer was found. A more subtle perforation is presented in figure 3 an 18 year old man who had a chest radiograph due to clinical concern of a right basal pneumonia. The chest radiograph revealed a small right subdiaphragmatic pneumoperitoneum , in view of this and ongoing pyrexia a laparotomy was performed at which a perforated appendix was found.
Discussion
Investigations for a perforated viscus traditionally involve an erect PA chest radiograph with the patient having been erect for 10 minutes prior to the exposure. This technique can be very sensitive in the detection of small volumes of free gas being able to detect even 1 to 10 mls of free gas.
Unfortunately due to the various peritoneal reflections not all free gas rises to below the diaphragm or is perpendicular to the X-ray beam on the PA erect chest radiograph. Hence a solitary PA chest radiograph will detect free gas in 70-75% of cases where free gas can be demonstrated on an accompanying lateral chest radiograph. If the patient is to unwell for a PA chest radiograph a left lateral decubitus film (ie right side up) can often demonstrate free gas lateral to the liver.
Unfortunately lateral chest radiographs and left lateral decubitus radiographs can be difficult for the referring clinician to interpret. Hence in a patient in whom there is a high clinical suspicion of perforation and the initial PA chest radiograph does not exclude a visceral perforation and further imaging is considered, a CT abdomen would be appropriate as is most likely to demonstrate any potential pneumoperitoneum and to also reveal the site of perforation.
Differential diagnosis in the presence of pneumoperitoneum includes perforation of viscus due to peptic ulcer, diverticulitis, appendicitis, toxic megacolon, bowel infarction, malignant neoplasm or trauma. Occasionally perforation can follow medical intervention such as prior abdominal surgery, recent peritoneal dialysis exchange or following endoscopy.
Unfortunately due to the various peritoneal reflections not all free gas rises to below the diaphragm or is perpendicular to the X-ray beam on the PA erect chest radiograph. Hence a solitary PA chest radiograph will detect free gas in 70-75% of cases where free gas can be demonstrated on an accompanying lateral chest radiograph. If the patient is to unwell for a PA chest radiograph a left lateral decubitus film (ie right side up) can often demonstrate free gas lateral to the liver.
Unfortunately lateral chest radiographs and left lateral decubitus radiographs can be difficult for the referring clinician to interpret. Hence in a patient in whom there is a high clinical suspicion of perforation and the initial PA chest radiograph does not exclude a visceral perforation and further imaging is considered, a CT abdomen would be appropriate as is most likely to demonstrate any potential pneumoperitoneum and to also reveal the site of perforation.
Differential diagnosis in the presence of pneumoperitoneum includes perforation of viscus due to peptic ulcer, diverticulitis, appendicitis, toxic megacolon, bowel infarction, malignant neoplasm or trauma. Occasionally perforation can follow medical intervention such as prior abdominal surgery, recent peritoneal dialysis exchange or following endoscopy.
Differential Diagnosis List
Perforated duodenal ulcer
Final Diagnosis
Perforated duodenal ulcer
References
[1]
Woodring JH, Heiser MJ.
Detection of pneumoperitoneum on chest radiographs: comparison of upright lateral and posteroanterior projections.
AJR Am J Roentgenol. 1995 Jul;165(1):45-7. (PMID: 7785629)
[2]
Healy JC, Reznek RH.
The peritoneum, mesenteries and omenta: normal anatomy and pathological processes.
Eur Radiol. 1998;8(6):886-900. (PMID: 9683690)
[3]
DeMeo JH, Fulcher AS, Austin RF.
Anatomic CT demonstration of the peritoneal spaces, ligaments, and mesenteries: normal and pathologic processes.
Radiographics. 1995 Jul;15(4):755-70. (PMID: 7569127)
[4]
Stapakis JC, Thickman D.
Diagnosis of pneumoperitoneum: abdominal CT vs. upright chest film.
J Comput Assist Tomogr. 1992 Sep-Oct;16(5):713-6. (PMID: 1522261)
Case information
| URL: | https://www.eurorad.org/case/2845 |
| DOI: | 10.1594/EURORAD/CASE.2845 |
| ISSN: | 1563-4086 |
