Clinical characteristics of pneumoperitoneum with pneumatosis intestinalis detected using computed tomography: A descriptive study

Pneumoperitoneum has always been considered a surgical emergency as it represents a perforation of the gastrointestinal tract. Although several cases of pneumoperitoneum with pneumatosis intestinalis (PI) have been reported, the characteristics of such cases remain unclear. The current study aimed to clarify the clinical characteristics of pneumoperitoneum cases with PI detected using computed tomography (CT). This descriptive study was conducted at a single center. In a total of 18,513 abdominal CT scans obtained between January 2010 and February 2017, extraluminal free air was detected in 254 examinations of 182 cases. The medical records and CT images of these 182 patients were retrospectively analyzed. Pneumoperitoneum with PI was detected through 23 examinations in 21 cases, and the average age of the patients was 80.1 years. The frequency was 0.12% in all abdominal CT examinations, but 24.7% in the 85 cases with extraluminal free air, excluding iatrogenic air. PI was classified as benign in 20 cases and as life-threatening in 1 case. The majority of cases with benign PI showed good general and local findings and little leukocytosis, while the case with life-threatening PI showed severe conditions. No evidence of bowel wall discontinuity, segmental bowel-wall thickening, perivisceral fat stranding, and abscesses were observed. Ascites were detected less frequently in the cases with PI than in the other pneumoperitoneum cases (P < .01). Pneumoperitoneum and PI occasionally recurred, and PI and/or extraluminal free air generally disappeared quickly. Pneumoperitoneum with PI is a relatively common condition in older patients, and the majority of cases are caused by benign PI. The characteristics of pneumoperitoneum cases with benign PI include well-maintained physical conditions, normal laboratory data, absence of CT findings indicative of peritonitis, and infrequent ascites. In pneumoperitoneum cases with PI, predicting whether the PI is benign or life-threatening is clinically very important, whereas the presence of extraluminal free air is considered to be insignificant.