Clinical Communications: Adult
Pneumomediastinum, Pneumothorax, and Subcutaneous Emphysema Caused by Colonoscopic Perforation: A Report of Two Cases

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Abstract

Background

Although colonoscopy is generally a safe procedure, lethal complications can occur. Colonoscopic perforation is one of the most serious complications, and it can present with various clinical symptoms and signs. Aggravating abdominal pain and free air on simple radiography are representative clinical manifestations of colonoscopic perforation. However, unusual symptoms and signs, such as dyspnea and subcutaneous emphysema, which are less likely to be related with complicating colonoscopy, may obscure correct clinical diagnosis. We present two cases of pneumomediastinum, pneumothorax, and subcutaneous emphysema caused by colonoscopic perforation.

Case Report

A 75-year-old woman and a 65-year-old man presented with dyspnea, and facial swelling and abdominal pain, respectively. In the first case, symptoms occurred during polypectomy, whereas they occurred after polypectomy in the second case. Chest radiograph and computed tomography scans revealed pneumomediastinum, pneumothorax, and subcutaneous emphysema in the neck. During both operations, an ascending colonic subserosa filled with air bubbles was observed, and laparoscopic right hemicolectomy was performed in the first case. In the second case, after mobilization of the right colon, retroperitoneal colonic perforation was identified and primary repair was performed. The postoperative course was uneventful.

Why Should an Emergency Physician be Aware of This?

These cases show the unusual clinical manifestations of colonoscopic perforation, which depend on the mechanism of perforation. Awareness of these less typical manifestations is crucial for prompt diagnosis and management for an emergency physician.

Introduction

As the volume of colonoscopies has increased over the years for colorectal cancer screening, the frequency of therapeutic procedures has also increased (1). Although colonoscopy is a generally safe procedure, related complications may be inevitable. Colonoscopic perforation is one of the most serious complications, because it can lead to leakage of bowel content into the peritoneal cavity and eventually sepsis. Therefore, early diagnosis and prompt management play a critical role in morbidity and mortality risk (2). However, unusual clinical manifestations can interfere with accurate diagnosis and ultimately delay treatment. Pneumomediastinum, pneumothorax, and subcutaneous emphysema are extremely rare presentations after colonoscopic perforation 3, 4. We present two cases of pneumomediastinum, pneumothorax, and subcutaneous emphysema caused by retroperitoneal colonic perforation by colonoscopic polypectomy.

A 75-year-old woman presented to the emergency department with abdominal pain, dyspnea, and facial swelling. One month earlier, screening colonoscopy had been performed at a local clinic, and she was then referred to the department of gastroenterology for treatment of a lateral spreading tumor (LST) of the ascending colon following polypectomy for two small polyps. She had no specific medical history except for well-controlled diabetes mellitus diagnosed 5 y earlier. During colonoscopy, an LST of about 3 cm was identified (Figure 1) and endoscopic submucosal dissection was performed (Figure 2). However, at the end of the procedure, the patient complained of dyspnea and abdominal pain, with concurrently developing neck and facial swelling. Even though a precise perforation site was not identified, the procedure was terminated because of the possibility of perforation. Initial vital signs at the emergency department were as follows: body temperature 37.5°C; blood pressure 130/89 mm Hg; heart rate 92 beats/min; and respiratory rate 21 breaths/min, with SpO2 of 100% on 2 L/min of oxygen by facial mask. On physical examination, the abdomen was distended, tympanic, and tender over the whole abdomen, without definite signs of peritoneal irritation. The patient had an acutely ill appearance with neck and facial swelling. A clear crepitus was palpated on the neck and anterior chest wall, indicating subcutaneous emphysema. Laboratory test results were within normal limits, except for a white blood cell count of 12,000/μL. Chest radiograph revealed pneumothorax, pneumomediastinum, pneumoperitoneum, and soft tissue emphysematous changes in the neck (Figure 3). The patient underwent emergency laparoscopic surgery because the LST was not completely removed and the abdominal pain was aggravated over 2 h. During laparoscopic surgery, although the perforation site was not identifiable, a subserosal layer of the ascending colon filled with air bubbles was observed (Figure 4). Right hemicolectomy was performed and the resected specimen revealed a 2-mm perforation on the side of the retroperitoneal attachment. Follow-up chest radiography on the third postoperative day showed interval improvement of both the pneumothorax and pneumoperitoneum, with residual pneumomediastinum and subcutaneous emphysema (Figure 5). The postoperative course was uneventful, and the patient was discharged on postoperative day 9.

A 65-year-old man presented to the emergency department with the chief complaint of abdominal pain and distension. The patient had undergone a colonoscopy for diarrhea at a local clinic 7 h earlier. During the colonoscopy, four small polyps, ranging from 2–4 mm, on the ascending colon, hepatic flexure, and sigmoid colon were identified and removed by endoscopic mucosal resection using a snare, which was performed without immediate complication. However, about 1 h after the colonoscopy, the patient complained of acute abdominal pain that was aggravated over time. He had no specific medical history. Initial vital signs at the emergency department were within normal limits, with diffuse subcutaneous crepitus over the neck, chest, and upper abdomen. Abdominal examination revealed a distended and tympanic abdomen. Although the whole abdomen was found to be tender, peritoneal signs were not apparent. Laboratory test results were within normal limits, except for a white blood cell count of 14,500/μL. Chest radiography revealed pneumomediastinum and severe subcutaneous emphysema extending from the abdomen to the neck (Figure 6). A computed tomography (CT) scan of the abdomen revealed pneumoretroperitoneum of the right abdomen, pneumoperitoneum, and subcutaneous emphysema without detection of a colonic wall (Figure 7). A CT scan of the chest revealed pneumomediastinum, pneumothorax, and subcutaneous emphysema (Figure 8). Although the patient did not complain of dyspnea, the abdominal pain was worsening. Under the presumptive diagnosis of retroperitoneal colonic perforation by polypectomy, emergency laparotomy was performed. After exploration of the abdomen, peritoneal soiling was minimal and the perforation site was not discovered, but after mobilization of the right colon extending from the cecum to the hepatic flexure, a 0.5-cm measured perforation was identified on the retroperitoneal side of the distal ascending colon. Even though there was some inflammatory change at the perforation site, primary repair was feasible after trimming the edge of the perforation site. Follow-up chest radiograph on postoperative day 7 showed resolved pneumomediastinum with residual subcutaneous abdominal emphysema (Figure 9). The postoperative course was uneventful, and the patient was discharged on postoperative day 8.

Section snippets

Discussion

Colonoscopy has become a standard tool for colorectal cancer screening, and clinicians have gained increased experience performing colonoscopies; therefore, the incidence of colonoscopic perforation shows a decreasing trend (5). However, certain complications associated with the procedure may be inevitable. Colonoscopic perforation is one of the most serious complications of colonoscopy, and its incidence was shown to be <0.1% in a previous large, population-based study (6).

Many factors, such

Why Should an Emergency Physician Be Aware of This?

History-taking, physical examination, and simple radiography are critical clues toward diagnosis in the emergency department. While pneumomediastinum, pneumothorax, and subcutaneous emphysema are typically easily diagnosed using basic evaluation tools, unusual clinical manifestations may obscure correct diagnosis of underlying causes if the clinician lacks sufficient experience or knowledge. Therefore, awareness of the potentially unusual clinical manifestations of retroperitoneal perforation,

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