Retroperitoneal colon perforation after endoscopic polypectomy successfully treated by conservative treatment

A 55-year-old woman with past history of hypertension visited our hospital for health examination. A 1.5-cm polyp at ascending colon (Figure 1A) and a 0.8-cm rectal polyp (Figure 1C) were noted on colonoscopy under conscious sedation. Polypectomy was performed and clips were used to close the wound (Figure 1B and 1D). She complained of right shoulder pain and could not raise her right arm after recovery of consciousness. The symptoms improved a few minutes later. Unfortunately, she developed abdominal fullness, chest tightness, shortness of breath, and dysphagia later. She was sent to our emergency department. On physical examination, the abdomen was soft without peritoneal sign on palpation. Subcutaneous air was palpable around the neck. The chest X-ray is shown in Figure 2. Computed tomography of chest and abdomen using lung window showed pneumomediastinum (Figure 3), pneumopericardium, pneumoretroperitoneum (Figure 4), and subcutaneous emphysema. Retroperitoneal colonic perforation after the colonic polypectomy was diagnosed. Surgeon was consulted immediately. As there were no signs of diffuse peritonitis or abdominal sepsis, she was treated with conservative treatment including bowel rest and empiric antibiotics. The pathologic report of the ascending colon polyp showed adenomatous polyp with adenocarcinoma in situ. The symptoms improved and she was discharged on the seventh hospital day. Colon perforation is the most serious complication of colonoscopy. Delayed diagnosis can lead to sepsis or even mortality. Its incidence is increasing, parallel with the advance of therapeutic endoscopy. In clinical practice, colon perforation usually presents with acute abdominal pain with peritoneal sign. The chest X-ray can reveal the presence of subdiaphragmatic free air. Extraluminal air that is too small to be detected by conventional radiography can be demonstrated by computed tomography.1 Retroperitoneal perforation is a relatively rare occurrence and can induce pneumoretroperitoneum, pneumopericardium, pneumomediastinum, and/or subcutaneous emphysema. Clinical symptoms include abdominal pain, back pain, chest pain, shoulder pain, dyspnea, or dysphagia. As abdominal discomfort is not uncommon after colonoscopy and there is no obvious peritoneal sign on palpation of abdomen, the diagnosis may easily be missed or delayed. Some patients can be managed nonsurgically if the symptoms improve over 24 hours. Treatment includes bowel rest, intravenous fluid, and broad-spectrum antibiotics. Endoscopic clipping or band ligation has been reported to close the perforation successfully, especially if the lesion is less than 10 mm.2 However, if diffuse peritonitis or abdominal sepsis develops, urgent surgical intervention is indicated.3 Answer: (4)