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

BackgroundAlthough 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 ReportA 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.