Surg Today (2003) 33:305–308

Pneumoretroperitoneum, Pneumomediastinum, Pneumopericardium,and Subcutaneous Emphysema Complicating Sigmoidoscopy:Report of a Case

Hirofumi Ota1, Shoichi Fujita

1, Takashi Nakamura1, Shinji Tanaka

1, Toshiharu Tono2, Yuji Murata

2,Noriaki Tanaka

2, and Shiro Okajima1

Departments of 1 Surgery and 2 Medicine, Tanaka-Kitanoda Hospital, 707 Kitanoda Sakai, Osaka 599-8123, Japan

caused pneumoperitoneum, pneumopericardium, pneu-momediastinum, and subcutaneous emphysema. Wediscuss the associated pathophysiology of this unusualcomplication.

Case Report

An 80-year-old woman presented to our hospital witha 3-day history of abdominal pain and blood-stainedstools. On digital rectal examination, a movable tumorwith an ulcer was palpated. A colonoscopy was per-formed, which revealed a type II tumor, 4 cm in diam-eter, in the rectum, 2 cm distal to the anal verge (Fig. 1),and a biopsy was taken. The colonoscopy was com-pleted in the area of the sigmoid colon. About 2h afterthe sigmoidoscopy, mild facial edema and subcutaneousemphysema developed around her neck. However, thepatient did not complain of any abdominal discomfortor pain and her abdomen was flat and soft at the time. Achest X-ray showed pneumopericardium, pneumomedi-astinum, and subcutaneous emphysema (Fig. 2). Anabdominal X-ray demonstrated a retroperitoneal airshadow along the lateral borders of the psoas musclesand fine shadows delineating the sigmoid colon andits mesentery (Fig. 3). On the second day, laboratoryanalysis showed leukocytosis (22000/mm3), elevatedC-reactive protein (15.5 mg/dl), blood urea nitrogen(39 mg/dl), and creatinine (3.4mg/dl), but no other ab-normal values were found. Over the next 2 days, thenotable physical examination findings included a feverof about 38.0°C, subcutaneous emphysema over thecervical area, impairment of speech, and a feeling ofabdominal fullness. It was thought that the rectal wallat the site of the tumor might have been perforated bymanipulation of the fiberscope or during biopsy. Hence,an exploratory laparotomy was performed 2 days afterthe sigmoidoscopy. The laparotomy showed that boththe intraluminal and subserosal spaces of the sigmoid

AbstractAn 80-year-old woman presented to our outpatient cen-ter with abdominal pain and blood-stained stools. Sheunderwent a colonoscopy, which showed a 4-cm type IItumor in the rectum. About 2h after the colonoscopy,mild facial edema and subcutaneous emphysema devel-oped around her neck. A chest X-ray showed pneumo-pericardium, pneumomediastinum, and subcutaneousemphysema, and an abdominal X-ray demonstrated ret-roperitoneal air. An exploratory laparotomy was per-formed on the second day after the colonoscopy, whichshowed air in the subserosal space of the sigmoid colon.The air seemed to have leaked from a 2-cm inflameddiverticulum in the sigmoid colon. The mesosigmoidwas also expanded by air. We discuss the anatomicalmechanism of the various clinical presentations ofextraluminal air following colonoscopy.

Key words Colonoscopy · Diverticulum ·Pneumoretroperitoneum · Pneumopericardium ·Pneumomediastinum

Introduction

Colonoscopy is used widely in the diagnosis andtreatment of colorectal diseases, and although consid-ered a relatively safe procedure, complications such asperforation, hemorrhage, and coagulation syndromesdo occur. We report a case of air insufflation forcolonoscopy creating an air leak into the retroperito-neal space through an inflamed diverticulum, which

Reprint requests to: H. OtaReceived: September 7, 2001 / Accepted: May 7, 2002

306 H. Ota et al.: Diverticular Subserosal Perforation

colon were filled with air (Fig. 4). Furthermore, a 2-cminflamed diverticulum in the middle of the sigmoid co-lon had penetrated through the abdominal wall, and themesentery of the sigmoid colon was diffusely expanded

by air. There was minimal gas in the perirectal spaceand the ulcerated floor of the rectal cancer had notperforated. Because we strongly suspected that the airleakage originated from a fragile part of the inflamedlarge diverticula in the sigmoid colon, this area of thesigmoid colon was resected. A sigmoid colostomy was

Fig. 1. Endoscopy showed a type II tumor in the rectum

Fig. 2. Chest X-ray on admission showed pneumopericardium(arrows) and cervical and axillary subcutaneous emphysema(arrowheads), but no subdiaphragmatic free air

Fig. 3. Abdominal X-ray showed the shadow of the wholesigmoid colon (arrows) and a retroperitoneal air shadow(arrowheads) along the lateral borders of the psoas muscles

Fig. 4. Intraoperative photograph. The sigmoid colon wasexpanded by diffuse subserosal gas

307H. Ota et al.: Diverticular Subserosal Perforation

created, but the rectal tumor was not resected at thistime because the patient’s condition was considered toounstable to proceed with this operation. Instead, wedecided that it would be more appropriate to resect thetumor at a later date with minimally invasive surgery.Postoperatively, congestive heart failure developed, aswell as bleeding from the mesenteric artery below thecolostomy, despite which the patient recovered almostcompletely within 6 weeks. Due to her poor cardiac andrenal function, we decided to resect the rectal tumortransanally under lumbar anesthesia. The resected spe-cimen is shown in Fig. 5. Histopathological examinationof the resected tumor showed well-differentiated ad-enocarcinoma. The patient had an uneventful clinicalcourse and was discharged 10 weeks after her initialoperation.

Discussion

Perforation is a rare complication of both diagnosticand therapeutic colonoscopy, but it is associated withhigh morbidity and mortality.1 The findings of a studydone by Bakker et al.2 in the 20 years preceding 1985indicated that the incidence of perforation differed withthe type of colonoscopy, the mean incidence of perfora-tion in therapeutic colonoscopy being twice as high asthat in diagnostic clonoscopy (0.44% vs 0.16%).

Our patient suffered some very uncommon com-plications of colonoscopy, namely, retroperitonealemphysema, pneumomediastinum, and subcutaneousemphysema caused by air leakage through an inflameddiverticulum. Although several cases of extraluminal airaccumulation during colonoscopy have been reported,our case was unique. Rupture of a diverticulum canoccur upon air insufflation, particularly if the tip of thecolonoscope is accidentally impacted in a diverticularopening.3,4 In our patient, the subserosal space ofthe mesentery was dissected by air escaping throughthe perforated diverticulum. Once the air reached theretroperitoneum, it may have then traveled to the medi-astinum and subcutaneous tissues. More interestingly,the air spread under the peritoneum of the mesentery,but not into the peritoneal cavity. This suggests thatsubserosal perforation5 occurred without subsequent airleak into the peritoneal cavity due to the severe adhe-sion between the diverticulum and the peritoneum ofthe lateral abdominal wall.

Recent reports suggest some mechanisms of the per-foration. Brayko et al.6 investigated 11 segments ofdiverticulum-lined sigmoid colon insufflated with air viaa colonoscope from human cadaver specimens. Serosaltears occurred at a mean pressure of 202 � 15mmHg,and mucosal rupture occurred at a mean pressure of 226� 14mmHg. There were no diverticular blowouts intheir study. They concluded that most colonic perfora-tions in the sigmoid area occur as a result of instrumenttrauma, rather than air insufflation causing diverticularblowout. Although excessive air insufflation can resultin serosal laceration and mucosal rupture in the normalcolon, diverticular blowout is probably limited tothe setting of acute diverticulitis. Our patient’s diver-ticulitis was so severe that air could escape throughan inflamed diverticulum even without direct damageby the colonoscope. Perforation during colonoscopycan also occur as a result of electrocautery injury,mechanical manipulation, a transmural burn caused byexcessive air current during insufflation, or inadvertentcauterization of the mucosa. Several cases of surgicalemphysema secondary to colonic perforation duringcolonoscopy have been described,9 including cases ofpneumothorax.5

Our patient experienced difficulty with speaking dueto the subcutaneous emphysema around her neck.Webb10 reported a case of a sudden neck and facialswelling with airway obstruction and hypoxia. However,our patient did not experience respiratory difficulty anddid not require endotracheal intubation. The anatomi-cal route by which extraperitoneal gas results in pneu-momediastinum and pneumothoraces was described byMaunder et al.11 in a review of subcutaneous and medi-astinal emphysema. The soft tissue compartment of theneck, thorax, and abdomen contains four regions de-

Fig. 5. The resected specimen contained a large diverticulumthat had penetrated into the adjacent peritoneum

308 H. Ota et al.: Diverticular Subserosal Perforation

fined as the subcutaneous tissue, prevertebral tissue,visceral space, and previsceral space. The visceral spaceinvests the trachea and esophagus and continues withthese structures into the mediastinum and bronchovas-cular sheaths. It follows the esophagus through the dia-phragmatic hiatus into the retroperitoneal soft tissuespace. Thus, there is continuity along the neck, chest,and abdomen. Air arising from an abnormality in anyone of these regions could reach another area by travel-ing along the fascial planes, as in our patient.

Interestingly, the symptoms of peritonitis were notobvious following colon perforation in our patient. Wesuspect that the rapid onset of symptoms after perfora-tion by the colonoscopy depends on whether it is intra-peritoneal or extraperitoneal. Whereas intraperitonealperforation may predominantly show signs of peri-tonitis, retroperitoneal perforations may be silent. Al-though abdominal pain is usually the most prominentsymptom after perforation of the colon, the clinicalmanifestations may vary depending on the site of ec-topic bowel gas. In our patient, subcutaneous emphy-sema over the neck was the initial manifestation in theabsence of any prominent abdominal symptoms. There-fore, physicians must be aware of the potential forseemingly unrelated complaints that may indicate acomplication of colonoscopy.

In summary, our patient who underwent colonoscopyfor investigation of a rectal tumor also had a largeinflamed diverticulum in the sigmoid colon, whichultimately penetrated the adjacent peritoneum. The airleakage that occurred was not anticipated because nolarge and inflamed diverticula in the sigmoid colonhad ever been previously diagnosed. Thus, physiciansshould be aware of the clinical manifestations of an air

leakage in the colon, so that such an event can be imme-diately recognized and appropriate treatment initiatedwithout delay. We strongly believe that surgicalendoscopists should be familiar with the anatomy andthe mechanism of the development of extraluminal airby colonoscopy.

References

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