Pneumoperitoneum after Colonoscopic Polipectomy. A Therapeutic Dilemma

Óscar Cano-Valderrama, Carlos Ferrigni, Iris Sánchez-Egido, Susana Martín-Garre, María Jesús Pérez-Contín, Manuel Giner

Óscar Cano-Valderrama, Carlos Ferrigni, Iris Sánchez-Egido, Susana Martín-Garre, María Jesús Pérez-Contín, Manuel Giner, Department of Surgery, Hospital Clínico San Carlos, Complutense University of Madrid, 28040-Madrid, Spain. dp085@ucm.es

Correspondence to: Manuel Giner, Professor, Department of Surgery, School of Medicine, Complutense University of Madrid, 28040-Madrid, Spain.
Telephone: +034-913941217
Received: November 12, 2012
Revised: November 26, 2012
Accepted: November 29, 2012
Published online: March 21, 2013


Backgound Pneumoperitoneum may occur following colonoscopy that may be accompanied by perforation of the colon. Most of these cases are managed by emergency surgery. However, this attitude may result in an unnecessary surgery. Cases report Two demonstrative cases of post-colonoscopy pneumoperitoneum are reported. In both cases the pneumoperitoneum appeared a few hours after uncomplicated colonoscopy plus polipectomy without clinical or laboratory evidence of peritonitis. In the first case, since perforation was suspected, a laparotomy was performed that turned out to be an unnecessary procedure. Moreover, pneumoperitoneum recurred and was satisfactorily treated by paracentesis. In our second case, conservative management under close observation was chosen and the patient made an uncomplicated recovery. Conclusion Our experience, which coincides with others’, suggests that in absence of peritoneal irritation, a conservative management should be chosen. However, if the patient deteriorates with conservative management, one should proceed to surgery.

Key words: Colonoscopy; Polipectomy; Complications; Pneumoperitoneum; Perforation

© 2013 The Authors. Published by ACT Publishing Group Ltd.

Cano-Valderrama Ó, Ferrigni C, Sánchez-Egido I, Martín-Garre S, Pérez-Contín MJ, Giner M. Pneumoperitoneum after Colonoscopic Polipectomy. A Therapeutic Dilemma. Journal of Gastroenterology and Hepatology Research 2013; 2(2): 423-425 Available from: URL: http://www.ghrnet.org/index./joghr/


Pneumoperitoneum, defined as the presence of air within the abdominal cavity, indicates hollow viscus perforation in up to 90% of cases and most of these cases are managed by emergency surgery. The remaining 10% of cases are known as non-surgical or benign pneumoperitoneum (NSP), defined by the presence of air in the peritoneal space that is detectable by roentgenogram and either is managed successfully by observation and supportive care alone or results in a nondiagnostic laparotomy[1]. The leading cause of NSP is open or laparoscopic surgery followed by mechanical ventilation, cardiopulmonary resuscitation and pneumothorax.

Less frequently pneumoperitoneum may occur following colonoscopy with or without polipectomy, that may be accompanied or not by perforation of the colon. The estimated incidence of benign pneumoperitoneun after diagnostic and therapeutic colonoscopy is between 0% and 3%[2]. When post-colonoscopy pneumoperitoneum appears, perforation is often suspected and laparotomy indicated on an emergency basis. However, some reports have proved that this attitude may result in an unnecessary surgery[3-6]. We report two cases of pneumoperitoneum post colonoscopic polipectomy showing the possibilities and utility of a conservative management.


A 54-year-old man was readmitted in hospital, because of abdominal pain, 12 hours after an uncomplicated colonoscopy that included a snare excision of a 7 mm sigmoid polyp (Figure 1). Exams showed tachycardia (100 bpm), mild leukocytosis (12 000/µL), abdominal distension and mild tenderness without fever or signs of peritonitis. Abdominal radiography as well as computed tomography revealed a large pneumoperitoneum with no other significant findings (Figures 2 and 3). Colon perforation was suspected and laparotomy indicated. Surgery was guided by intraoperative colonoscopy. The insufflated colon was submerged in normal saline solution and inspected for bubbles. No cause of pneumoperitoneum or other abnormalities were found at surgery.

Five days after operation, the patient complained of abdominal distension and dyspnea. Toraco-abdominal computed tomography revealed a greater pneumoperitoneum with a small amount of free fluid (Figure 4). Sonography-guided paracentesis was performed with immediate symptomatic improvement. Post-paracentesis abdominal radiographs showed complete resolution and the patient was satisfactorily discharged 14 days after admission.


A 72-year-old woman was readmitted the day after a screening colonoscopy that included excision, by biopsy forceps, of a 3 mm sigmoid polyp. The patient’s only complaint was abdominal pain. Physical exam revealed mild tenderness in the right abdomen. Blood tests were normal. Plain abdominal radiography and computed tomography showed a large pneumoperitoneum without intraperitoneal fluid (Figure 5). Without clinical or laboratory evidence of peritonitis, a conservative management under close observation was chosen. Although the pneumoperitoneum persisted during the patient’s hospital stay, she recovered from symptoms and was discharged after six days of clinical and radiological observation.


In case of pneumoperitoneum, the route of introduction of air into the abdominal cavity can be abdominal, thoracic, gynecologic, or idiopathic. In a search of the medical literature from 1970 to 1999 using the key words pneumoperitoneum and benign, nonsurgical, spontaneous, iatrogenic, barotrauma, pneumatosis, diaphragmatic defects, free air, mechanical ventilation, gynecologic, and pelvic, 482 articles were identified and all case reports and reviews of NSP were reviewed[1]. Most cases of NSP occurred as a procedural complication or as a complication of medical intervention. The most common abdominal etiology of NSP was retained postoperative air (prevalence 25% to 60%). NSP occurred frequently after peritoneal dialysis catheter placement (prevalence 10% to 34%) and after gastrointestinal endoscopic procedures (prevalence 0.3% to 25%, varying by procedure). The most common thoracic causes included mechanical ventilation, cardiopulmonary resuscitation, and pneumothorax. One hundred ninety-six case reports of NSP were recorded, of which 45 involved surgical exploration without evidence of perforated viscus.

Pneumoperitoneum after colonoscopy with polipectomy is commonly attributed to microperforation. Perforation was not evident in our first case by means of the used technique (presence of air bubbles coming from the submerged colon). Moreover, there is evidence that NSP is possible after colonoscopic polipectomy without perforation[6].

Many patients complain of bowel distension and abdominal pain after air insufflation of the intestinal tract during colonoscopy; the method used by us in both cases. Recently, carbon dioxide (CO2) instead of air has been used. A meta-analysis focused to evaluate the efficiency, safety, and comfort of colonoscopy with CO2 versus air, demonstrated that CO2 insufflation produced less abdominal discomfort during and following the procedure, without any additional adverse reactions, warranting its routine clinical use[7]. On the other hand, in a recent comparative study to evaluate the effects of CO2 insufflation on pneumoperitoneum and bowel distension after percutaneous endoscopic gastrostomy, a lower incidence of pneumoperitoneum and less distension of the small bowel were shown in the CO2 group in comparison to the air counterpart[8].

The treatment of benign pneumoperitoneum can be conservative or surgical. Perhaps the most important maneuver for differentiating between the two possibilities is by performing a through history and physical examination. This in conjunction with a diagnostic peritoneal lavage, contrast studies, or endoscopic evaluation can help prevent a patient from having needless surgery[9]. Pneumoperitoneum can be seen by three different ways: i) air can enter abdominal cavity transmurally from colon without any perforation.These cases may be treated with only follow-up, ii) a microperforation in colon wall without signs of peritonitis and leucocytosis may be also treated with antibiotics in selected cases, and iii) a true perforation can occur during colonoscopy with intraabdominal air. Overt perforation or signs of peritonitis with fever and other inflammatory signs indicates surgery. Since there were no signs of frank peritonitis, surgery could have been avoided in both of our patients.

Colon perforation which complicates less than 0.5% of colonoscopies[10], too often promotes laparotomy. After colonoscopy, perforation of the colon requires surgical intervention more frequently than bleeding[11]. There are three mechanisms responsible for colonoscopic perforation: mechanical perforation directly from the colonoscope or another instrument, barotrauma from excessive air insufflation, and, finally, perforations that occur during therapeutic procedures. If a perforation does occur, patient’s signs and symptoms are related to the size and site of the perforation, adequacy of the bowel preparation, amount of peritoneal soilage, underlying colonic pathology, and, finally, overall clinical condition of the patient.

In a recent study a total of 17 357 consecutive endoscopic procedures of the colon (13 699 colonoscopies and 3 658 flexible sigmoidoscopies), performed over a 9-year period, were reviewed[12]. Fifteen patients (0.09%) had colonic perforation, 14 from colonoscopy and 1 from sigmoidoscopy. Perforations were caused by direct trauma from either the shaft or the tip of the endoscope (n=12, 80%) and endoscopic polypectomy (n=3, 20%). All patients with post-colonoscopy perforation underwent surgical management: primary repair (27%) or bowel resection (73%). The mortality rate was 13% and postoperative complication rate was 53%.

Classically, treating all post-colonoscopy pneumoperitoneums by laparotomy has been advocated[13,14]. Our experience, which coincides with others’[3-5], suggests that in absence of peritoneal irritation, a conservative management should be chosen, though paracentesis may occasionally be required to evacuate a large pneumoperitoneum[3]. After colonoscopy, pneumoperitoneum appears occasionally without colon perforation[6]. On the other hand, a localized perforation may be demonstrated with lack of pneumoperitoneun. Even with small perforations, conservative approaches with intravenous antibiotics and bowel rest could be attempted, after considering whether there is coexisting peritonitis, the timing of diagnosis and the patient’s clinical condition. However, if the patient deteriorates with conservative management, one should proceed to surgery.


The authors express their gratitude to Mr. James P. Nowlan for his help in translating the manuscript.


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Peer reviewer: Yosuke Tsuji, Department of Gastroenterology, NTT Medical Center Tokyo, 5-9-22, Shinagawa-ku, Tokyo, 141-8625, Japan; Everson L.A. Artifon, ua guimaraes passos 260 apto 111, University of Sao Paulo(USP)-Sao Paulo, Brazil.


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