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Pneumoperitoneum modification.jpg
Frontal chest X-ray. The air bubble below the right hemidiaphragm (on the left of the image) is a pneumoperitoneum.
Classification and external resources
Specialty gastroenterology
ICD-10 K66.8
ICD-9-CM 568.89, 770.2
DiseasesDB 31511
eMedicine radio/562
MeSH D011027
Another pneumoperitoneum on chest X-ray.
Pneumoperitoneum seen on X-ray with the patient lying on his left side.

Pneumoperitoneum is pneumatosis (abnormal presence of air or other gas) in the peritoneal cavity, a potential space within the abdominal cavity. When present, it can often be seen on radiography, but small amounts are often missed, and CT scan is nowadays regarded as a criterion standard in the assessment of a pneumoperitoneum.[1] CT can visualize quantities as small as 5 cm³ of air or gas. The most common cause is a perforated abdominal viscus, generally a perforated peptic ulcer, although any part of the bowel may perforate from a benign ulcer, tumor or abdominal trauma. A perforated appendix seldom causes a pneumoperitoneum.

In the mid-twentieth century, an "artificial" pneumoperitoneum was sometimes intentionally administered as a treatment for a hiatal hernia. This was achieved by insufflating the abdomen with carbon dioxide. The practice is currently used by surgical teams in order to perform laparoscopic surgery.


Differential diagnosis[edit]

Subphrenic abscess, bowel interposed between diaphragm and liver (Chilaiditi syndrome), and linear atelectasis at the base of the lungs can simulate free air under the diaphragm on a chest X-ray.


Pneumoperitoneum can be described as peritoneal emphysema,[4] just as pneumomediastinum can be called mediastinal emphysema, but pneumoperitoneum is the usual name.

See also[edit]


  1. ^ Ali Nawaz Khan. " Pneumoperitoneum". 
  2. ^ Necrotizing Enterocolitis Bugs, Drugs and Things That Go Bump in the Night
  3. ^ Sexual Activity as Cause for Non-Surgical Pneumoperitoneum
  4. ^ Marian, K; et al. (2015), "Spontaneous pneumoperitoneum in a patient after ventilation therapy", Pol Przegl Chir 86 (12): 601–603, doi:10.1515/pjs-2015-0008, PMID 25803061.