Pneumoperitoneum after percutaneous endoscopic gastrostomy: worrisome or not?

Clinical History

Elderly man with history of postradiation distal colonic stricture following rectal resection and radiotherapy, worsening Parkinson’s disease symptoms underwent percutaneous endoscopic gastrostomy (PEG) positioning using the pull technique to relieve dysphagia, without immediate post-procedural complications. Twenty-four hours later, he complained of abdominal pain and distension.

Imaging Findings

Prior to PEG positioning, colonic overdistension secondary to known postradiation stenosis (Fig. 1) was noted.
The day after the procedure, massive pneumoperitoneum and associated posterior pneumomediastinum were detected radiographically (Fig. 2a-c) and by CT (Fig. 2d-g). Furthermore, CT confirmed correct positioning of the PEG bumper in the stomach. Without fever and clinical signs of peritonism, the patient started enteral nutrition and was discharged.
Three weeks later the patient suffered from diarrhoea, profound asthenia, abdominal pain without clinical peritoneal irritation. Rectal tube drained two litres of enteral nutrition-like fluid. Laboratory revealed severe hypokalaemia, increased C-reactive protein. Repeated radiographs (Fig. 3a-c) and CT (Fig. 3d-f) showed reduced pneumoperitoneum, abundant endoluminal fluid in the large bowel, the PEG bumper located within haustra in the distal transverse colon.
After endoscopic confirmation of absent internal bumper in the stomach, laparotomic surgery (including gastrostomy, hemicolectomy and colonostomy) was needed to remove the PEG device which had migrated through a gastro-colonic fistula.

Discussion

Percutaneous endoscopic gastrostomy (PEG) is currently established as the preferred method to provide medium- and long-term nutrition support and prevent lung aspiration in patients unable to take oral feeding, with a high procedural success rate and limited morbidity. Due to the steady increase in referrals for PEG positioning, clinicians and radiologists are increasingly faced with suspected post-procedural complications [1].
In almost half of patients variable degrees of pneumoperitoneum (PNP) are observed shortly after PEG positioning, particularly when post-procedural radiographs are routinely acquired, and result from air insufflated during endoscopy that enters the peritoneal cavity through the puncture site in the gastric wall. Lack of PNP is highly consistent (negative predictive value 100%) with technical success and complication-free procedure. However, the clinical significance of PNP is debated. In the vast majority (85%) of cases PNP is a self-limiting occurrence which typically resolves within days. As demonstrated by the first part of this case (Figure 1), even massive pneumoperitoneum usually does not represent a true complication, and does not warrant further investigation nor surgical treatment provided that (a) the correct device positioning is verified by means of CT, and (b) signs and symptoms of peritoneal inflammation or systemic infection are absent [2-5].
Conversely, as seen in the second part of this case (Figure 2) persistent pneumoperitoneum may occasionally herald severe complications such as PEG dislocation. Sporadically reported in literature, device migration from the stomach to the transverse colon may result from colonic perforation during tube placement, or occur secondarily from excessive tension leading to dislodgement and gastro-colic fistulization. This exceedingly rare complication typically occurs days to weeks after PEG insertion, may be facilitated by interposition of the colon between the stomach and the anterior abdominal wall, and causes sudden diarrhoea and cramping [6-8].
In conclusion, differentiation of benign PNP from underlying bowel injury often represents a diagnostic dilemma because symptoms and signs of peritoneal irritation are unreliable in patients with impaired mental status, on long-term sedation and ventilatory support, and laboratory changes suggesting sepsis are common in intensive care patients. With or without water-soluble contrast medium administration through the external access, CT is highly helpful and reliable to check the correct PEG device positioning, and to investigate possible complications requiring reintervention [9].

Differential Diagnosis List

Final Diagnosis

Percutaneous endoscopic gastrostomy (PEG) device dislocation to the colon

URL:	https://www.eurorad.org/case/11713
DOI:	10.1594/EURORAD/CASE.11713
ISSN:	1563-4086