Pneumoretroperitoneum
Updates to Article Attributes
Pneumoretroperitoneum is by definition presence of gas within the retroperitoneal space.
Pathology
Pneumoretroperitoneum is always abnormal and has a relatively small differential:
-
perforated retroperitoneal hollow viscus
-
duodenum
- peptic ulcer disease
- blunt or penetrating abdominal trauma
- endoscopy +/- biopsy (rare) 3
- ERCP: especially when a sphincterotomy is performed; incidence 0.5-2% 3
-
ascending/descending colon
- colorectal carcinoma (CRC)
- diverticulitis
- endoscopy +/- biopsy
- ischaemic colitis
-
rectum
- surgery, e.g. transanal excision of rectal carcinoma 2
- foreign body insertion
- endoscopy
- trauma
- rarely an intraperitoneal hollow viscus can perforate into the intramesenteric space and then track air to the retroperitoneal spaces
-
duodenum
-
residual air from retroperitoneal surgery
- urological/adrenal 4
- spinal (anterolateral approach) 5
If localised, and especially in the presence of an air-fluid level, a retroperitoneal abscess should be suspected.
Radiographic features
Pneumoretroperitoneum is best appreciated by CT, however can also be detected by plain abdominal radiograph and even by transabdominal ultrasound (see veiled right kidney sign) 6,7. Generally, air is most commonly seen surrounding the kidneys in the right and left upper quadrants of the abdomen 6. There may also be a loss of the normal psoas muscle shadow 6.
Differential diagnosis
On plain radiography the differential is that of gas in other spaces which also projects over the abdomen. It thus includes:
CT has little difficulty in distinguishing these.
See also
- +<li><a title="Pseudopneumoretroperitoneum" href="/articles/pseudopneumoretroperitoneum">pseudopneumoretroperitoneum</a></li>
-</ul><p>CT has little difficulty in distinguishing these.</p><h4>See also</h4><ul><li><a href="/articles/abnormal-intraabdominal-gas">abnormal intraabdominal gas</a></li></ul>- +</ul><p>CT has little difficulty in distinguishing these.</p><h4>See also</h4><ul><li><a href="/articles/abnormal-intraabdominal-gas">abnormal intra-abdominal gas</a></li></ul>