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Adv Biomed Res 2023,  12:177

A case of pneumoperitoneum after colonoscopy without frank perforation

1 Isfahan Gastroenterology and Hepatology Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
2 Department of Clinical Pharmacy and Pharmacy Practice, School of Pharmacy and Pharmaceutical Sciences, Isfahan, Iran
3 Department of Internal Medicine, Al-Zahra Hospital, Isfahan University of Medical Sciences, Isfahan, Iran

Date of Submission07-Nov-2022
Date of Acceptance01-Jan-2023
Date of Web Publication20-Jul-2023

Correspondence Address:
Dr. Amir Aria
Department of Internal Medicine, Al-Zahra Hospital, Isfahan University of Medical Sciences, Isfahan
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/abr.abr_376_22

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Benign pneumoperitoneum can happen after colonoscopy, which shows itself as free air in the abdomen without symptoms or pneumoperitoneum without peritonitis. In this case, we reported a rare case of an elderly man who had acute abdominal stiffness after colonoscopy and observation of free air under the diaphragm that no perforation was observed in the intestine during laparoscopy and only one tiny intestinal tumor was randomly reported. There is no consensus on the treatment of pneumoperitoneum after colonoscopy. Patients with peritonitis benefit from laparoscopy but patients with micro perforation and asymptomatic patients benefit from intravenous antibiotic treatment and bowel rest.

Keywords: Colonoscopy, intestine, laparoscopy, peritonitis, pneumoperitoneum

How to cite this article:
Soheilipour M, Momenzadeh M, Aria A, Saghar F, Tabesh E. A case of pneumoperitoneum after colonoscopy without frank perforation. Adv Biomed Res 2023;12:177

How to cite this URL:
Soheilipour M, Momenzadeh M, Aria A, Saghar F, Tabesh E. A case of pneumoperitoneum after colonoscopy without frank perforation. Adv Biomed Res [serial online] 2023 [cited 2023 Sep 26];12:177. Available from:

  Introduction Top

A colonoscopy is a risk-free procedure with a low rate of complications.[1] Colonoscopy is commonly used for colorectal disease screening, diagnostic, and therapeutic reasons, as well as follow-up.[1] It allows for early diagnosis and removal of polyps or colorectal cancer in its early stages. The most frequent complications linked with colonoscopy are bleeding and perforation or vasovagal issues, mesenteric injury, splenic injury, pneumothorax, pneumo-peritoneum, and intestinal volvulus.[1] One of the most significant consequences of colonoscopy is colonoscopic perforation (CP). The incidence of CPs during diagnostic colonoscopy is reported to be between 0.1 and 0.8%, and between 0.15 and 3% during therapeutic colonoscopy.[1]

Approximately 45 to 60% of CPs are detected by the endoscopist during colonoscopy. Although a significant number of CPs are not identified immediately, they can be identified based on clinical signs and symptoms after endoscopy.[2] The interval between diagnosis and therapy is one of the most significant aspects of CP management. There are a variety of CP treatments available, including conservative, endoscopic, and surgical options.[2]

Recent studies are acquiring evidence for laparoscopic and endoluminal repair using clips for perforation closure. Early diagnosis of perforation symptoms, as well as early and appropriate treatment, may help reduce the risk of (severe) consequences and death from iatrogenic colon perforations.[3],[4],[5]

Perforation and bleeding are the most serious consequences. Perforation is an uncommon complication that requires more investigation owing to its high morbidity and death rate.[6]

Benign pneumoperitoneum seen by endoscopy is defined as asymptomatic free air in the abdomen or as a pneumoperitoneum without peritonitis. BP after diagnostic and therapeutic colonoscopy occurs only between 0 and 3%. Symptomatic free air requires surgery but there is controversy in the management of asymptomatic pneumoperitoneum. If micro perforation is the cause of the condition, the conventional therapy is intravenous antibiotics and intestinal rest. The transmural airflow that does not affect the intestinal wall, in contrast, may not need any intervention. Therefore, many cases of pneumoperitoneum after colonoscopy require emergency surgery, and in some cases of iatrogenic perforation, conservative methods are used.[6] Until large-scale studies on definition, incidence, and treatment are performed, all cases of pneumoperitoneum after colonoscopy should be treated as perforation.[6]

In this report, we present a rare case of an elderly patient who acquired free peritoneal air and acute abdominal stiffness after undergoing a colonoscopic procedure. Following a laparotomy that failed to identify the perforation location, a tiny intestinal tumor was discovered incidentally.

  Case Report Top

A 76-year-old male patient was admitted to the hospital for investigation of newly diagnosed iron deficiency anemia.

At the time of admission, the patient's hemoglobin was 5.6 g/dL and as a consequence, 2 unit pack cells were injected.

Then, colonoscopy was conducted and we used room air for inflating the colon during the colonoscopy procedure.

A sessile polyp measuring about 8 by 8 mm was seen in the sigmoid colon and was resected by a cold snare polypectomy [Figure 1].
Figure 1: Cold snare polypectomy

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Histologically, it was a tubular adenoma with low-grade dysplasia. Post colonoscopy, the patient developed severe diffuse abdominal pain. On physical exam, acute abdomen with involuntary guarding and diffuse tenderness on light palpation was observed. A standing X-ray showed air under the diaphragm bilaterally [Figure 2].
Figure 2: Standing X-ray showed air under the diaphragm bilaterally

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Laboratory findings are given in [Table 1]:
Table 1: Laboratory data at admission

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During the patient's hospitalization, the progression of the hemoglobin content was as follows:

Hb (g/dL) =5.6 - 8.7 - 9 - 9.1 - 8.5 - 10.6 - 9.4

The gastroenterologist that had performed the procedure indicated that the colonoscopic procedure was not complex and was performed safely. Urgent laparotomy was performed during which the colon was carefully examined without identifying a site of frank perforation. Then, the small bowel was inspected for possible perforation, and a small lesion of 2.5 cm located 200 cm distally to the ligament of Treitz was detected. The lesion was then totally resected and end-to-end anastomosis was done. The specimen was sent to the pathology department and the final report was a low-risk gastrointestinal stromal tumor (GIST) tumor of the small bowel, spindle cell type (histologic grade G1, pathologic stage classification PT2). On day 3 postoperation, the patient was started on an oral diet and discharged from the hospital 1 week later. Two weeks after surgery, a CT scan of the abdomen and pelvis was performed to detect the presence of metastasis.

  Discussion Top

A colonoscopy is a low-risk procedure that has a significant influence on the diagnosis and treatment of colon and rectum illnesses. Colon perforation as a consequence of colonoscopic procedures is also uncommon. However, it may have catastrophic consequences, including high death and morbidity rates.[6],[7]

Previous studies have found that old age, female gender, low BMI, low albumin content, hospitalization in an intensive care unit, hospitalization conditions, various comorbidities, diverticulosis, intestinal obstruction, previous abdominal surgery, and Crohn's disease are all risk factors for colonoscopy perforation. The sigmoid colon and/or rectosigmoid colon are the most common sites for perforations that need surgical intervention.[6]

Colon perforations caused by diagnostic techniques normally occur immediately or within 24 h, but they do not manifest as rapidly in the case of therapeutic colonoscopies owing to the reduced size of the perforation. As a result of the delay in surgery, peritoneal infection may be more common in therapeutic CPs.[1]

Even though colon perforation is uncommon during colonoscopy, it is still the most serious consequence. Furthermore, there is currently no agreement on how to treat perforation. Mechanical perforation by the tip of an endoscope or loop, barotrauma due to excessive bloating, which usually involves the cecum, and therapeutic approaches such as electrocoagulation for polypectomy and laser or plasma argon coagulation are the three most common mechanisms of colon perforation. Mechanical perforations are often bigger and have a higher risk of morbidity and death. As a result, a more forceful strategy is required.[4] Perforations that develop during therapy are often minor and are seldom observed during the procedure. Peritoneal contamination may be less prevalent due to the tiny size of the perforations. The general condition of the patient is more regular, and in this group conservative approach is usual.[8],[9] Conservative, endoscopic, and surgical treatment methods are available (open or laparoscopic approach). Each therapy should be tailored to the patient's specific clinical needs. During a colonoscopy, if perforation is suspected, the patient should be closely monitored. The pillars of minimizing morbidity and mortality are early diagnosis and treatment.[10] Therefore in our case, the patient had involuntary guarding and a standing X-ray showed air under the diaphragm bilaterally; thus, an urgent laparotomy was performed. In a group of patients whose overall condition is stable and who do not exhibit signs of peritoneal irritation, a conservative strategy should be explored. Stopping oral nutrition, intravenous antibiotics, and hydration, as well as monitoring for 3 to 6 h, is the widely acknowledged cautious strategy.[10] Because our patient had diffuse tenderness on light palpation, our plan was surgery. Pneumoperitoneum is not a surgical indication by itself. Pneumoperitoneum may be treated conservatively in patients who are well-selected, clinically stable, and show no symptoms of peritoneal stimulation. The patient's clinical appearance will improve in 24 to 48 h if conservative therapy is effective. If there is no clinical improvement, complex intra-abdominal infections should be evaluated and treated more aggressively.[11] Considering that our patient had symptoms of peritoneal stimulation, he underwent immediate surgical intervention. Conservative therapy of colonoscopy-induced perforations is effective in 33 to 73% of patients in different trials.[11] According to recent surveys, the share of conservative approaches is growing.[12] Shorter hospital stays, earlier return to regular life, and lower morbidity are all advantages of conservative care in eligible patients.[3],[13] The absence of pneumoperitoneum and retropneumoperitoneum does not rule out a perforation diagnosis: 14% of the patients in Garbay et al.'s series[13] and 20% in the series of Hureau et al.[14] had normal plain abdominal radiographs. The use of contrast media enema has been suggested in those with clinical suspicion of perforation without radiological signs on plain abdominal radiographs. The sigmoid colon was the most prevalent site of perforation in this and previous studies because of its physical characteristics and because it is the most common location of polypectomy.[14],[15]

Pneumoperitoneum is often associated with perforation of the abdominal viscera, which necessitates emergency surgery in 85 to 95% of patients. Pneumoperitoneum situations that do not exhibit perforation and are caused by a different source do not need emergency surgery.[7] Asymptomatic free intra-abdominal air or pneumoperitoneum without peritonitis is described as a distinctive radiolucency visible on chest radiographs under the diaphragm or abdominal radiographs in the upper dependent area.[16],[17] The patient in our case report had acute abdomen with involuntary guarding but he did not have leukocytosis, thus the patient was diagnosed with BP without peritonitis.

BP has been well characterized in a range of clinical settings, including after subcutaneous endoscopic gastrostomy, laparotomy, or intestinal pneumatosis, in addition to colonoscopy. Colonoscopic BP is reported to be more likely following polypectomy or difficult investigations, as well as excessively blown air through the colon. Rare studies have prospectively investigated BP after colonoscopy.[18] Most likely, colonoscopic BP in our case report happened after excessively blown air through the colon. The bulk of research looking at colonoscopy problems was retrospective. As a result, all occurrences of pneumoperitoneum have been discovered in symptomatic patients who have had radiographs taken because of stomach discomfort.[18] Prospective investigations by Pearl et al.[18] conducted prospective studies, benign pneumoperitoneum could not be detected after colonoscopy. Therefore, our knowledge of BP is limited to a small number of case reports. According to these publications, BP following diagnostic and therapeutic colonoscopy is uncommon, with a frequency of 0 to 3%.[18] Pneumoperitoneum discovered following a colonoscopy may provide a management challenge. Some people feel that all individuals with a perforated colon should undergo surgery right away following their colonoscopy.[6] Early laparotomy is expected to have a lower risk of morbidity and death.[19] Thus in our study, because a standing X-ray showed air under the diaphragm bilaterally and there was a possibility of colon perforation, the patient underwent laparotomy immediately. However, management of intra-abdominal free air is various: overt perforations necessitate laparotomy. Non-surgical instances of pneumoperitoneum or micro-perforation should be evaluated when abdominal discomfort and distention are minor and there is no evidence of peritoneal signs, fever, or leukocytosis. These should be treated with intravenous antibiotics and intestinal rest.[6] Transmural passage of air may not require treatment.[18] Although inflation of the colon with CO2 compared with air, significantly reduces abdominal pain, bloating, and flatulence scores during at least 3h after colonoscopy in patients, achieving comparable intraprocedural outcomes.[20] It is possible we performed a colonoscopy with air for the patient, the patient had symptoms of abdominal pain and bloating.

Our patient had an acute abdomen with involuntary guarding, widespread discomfort to mild touch, and standing X-rays showing air under the diaphragm on both sides. Therefore, we conducted a laparotomy although no perforation was observed. As a result, we infer that the free air within the abdomen is due to transmural air passage or micro-perforation rather than perforation.

  Conclusion Top

There is no consensus on the best therapy for pneumoperitoneum following colonoscopy, whether conservative or surgical. All occurrences of pneumoperitoneum following colonoscopy should be handled as perforation rather than a harmless air transmural passage until a large-scale investigation specifies the incidence and treatment options. Patients with peritonitis benefit from laparotomy, whereas those with symptoms associated with micro-perforation or those who have no symptoms may benefit from conservative treatment, for example, intravenous antibiotics and intestinal rest. Conservative therapy should only be used on a small number of patients.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that his name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Lim DR, Kuk JK, Kim T, Shin EJ. The analysis of outcomes of surgical management for colonoscopic perforations: A 16-years experiences at a single institution. Asian J Surg 2020;43:577-84.  Back to cited text no. 1
de'Angelis N, Di Saverio S, Chiara O, Sartelli M, Martínez-Pérez A, Patrizi F, et al. 2017 WSES guidelines for the management of iatrogenic colonoscopy perforation. World J Emerg Surg 2018;13:1-20.  Back to cited text no. 2
Anderson ML, Pasha TM, Leighton JA. Endoscopic perforation of the colon: Lessons from a 10-year study. Am J Gastroenterol 2000;95:3418-22.  Back to cited text no. 3
Iqbal CW, Cullinane DC, Schiller HJ, Sawyer MD, Zietlow SP, Farley DR. Surgical management and outcomes of 165 colonoscopic perforations from a single institution. Arch Surg 2008;143:701-7.  Back to cited text no. 4
Lüning TH, Keemers-Gels ME, Barendregt WB, Tan AC, Rosman C. Colonoscopic perforations: A review of 30,366 patients. Surg Endosc 2007;21:994-7.  Back to cited text no. 5
Ustek S, Boran M, Kismet K. Benign pneumoperitoneum after colonoscopy. Case Rep Med 2010;2010:631036.  Back to cited text no. 6
Seitz ST, Rückel A, Siebenlist G, Besendörfer M, Schellerer VS. Case report: Tension pneumoperitoneum after diagnostic colonoscopy in an 11 y/o boy with Crohns disease. Int J Surg Case Rep 2020;75:413-7.  Back to cited text no. 7
Castellvi J, Pi F, Sueiras A, Vallet J, Bollo J, Tomas A, et al. Colonoscopic perforation: Useful parameters for early diagnosis and conservative treatment. Int J Colorectal Dis 2011;26:1183-90.  Back to cited text no. 8
Yeh JH, Chen JC, Hsu CC, Wang WL, Lin CW. Massive pneumoperitoneum with abdominal pain and fever mimicking delayed perforation following endoscopic resection: A case report. Adv Dig Med 2021;8:121-4.  Back to cited text no. 9
Yee J, Kumar NN, Godara S, Casamina JA, Hom R, Galdino G, et al. Extracolonic abnormalities discovered incidentally at CT colonography in a male population. Radiology 2005;236:519-26.  Back to cited text no. 10
Lohsiriwat V. Colonoscopic perforation: Incidence, risk factors, management and outcome. World J Gastroenterol 2010;16:425-30.  Back to cited text no. 11
Iqbal CW, Chun YS, Farley DR. Colonoscopic perforations: A retrospective review. J Gastrointest Surg 2005;9:1229-36.  Back to cited text no. 12
Garbay JR, Suc B, Rotman N, Fourtanier G, Escat J. Multicentre study of surgical complications of colonoscopy. Br J Surg 1996;83:42-4.  Back to cited text no. 13
Hureau J, Avtan L, Germain M, Blanc D, Chaussade G. Perforation colique au cours de la coloscopie. Chirurgie 1992;118:703-15.  Back to cited text no. 14
Orsoni P, Berdah S, Verrier C, Caamano A, Sastre B, Boutboul R, et al. Colonic perforation due to colonoscopy: A retrospective study of 48 cases. Endoscopy 1997;29:160-4.  Back to cited text no. 15
Schlinkert RT, Rasmussen TE. Laparoscopic repair of colonoscopic perforations of the colon. J Laparoendosc Surg 1994;4:51-4.  Back to cited text no. 16
Mularski RA, Sippel JM, Osborne ML. Pneumoperitoneum: A review of nonsurgical causes. Crit Care Med 2000;28:2638-44.  Back to cited text no. 17
Pearl JP, McNally MP, Elster EA, DeNobile JW. Benign pneumoperitoneum after colonoscopy: A prospective pilot study. Mil Med 2006;171:648-9.  Back to cited text no. 18
Ghazi A, Grossman M. Complications of colonoscopy and polypectomy. Surg Clin North Am 1982;62:889-96.  Back to cited text no. 19
Falt P, Šmajstrla V, Fojtík P, Hill M, Urban O. Carbon dioxide insufflation during colonoscopy in inflammatory bowel disease patients: A double-blind, randomized, single-center trial. Eur J Gastroenterol Hepatol 2017;29:355-9.  Back to cited text no. 20


  [Figure 1], [Figure 2]

  [Table 1]


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