Appendicitis is a rare complication of diagnostic colonoscopy and therapeutic endoscopic procedures, including endoscopic mucosal resection (EMR). The incidence of appendicitis after EMR involving the caecum proximal to the appendix is reported to be 0.5%–1.2%.¹ The incidence of appendicitis after colonoscopy is reported to be about 0.038%.²

A 36-year-old female patient had a cecal polyp detected at the appendix orifice during a previous colonoscopy. She was hospitalized for an endoscopic polypectomy. Abdominal ultrasonography showed a normal appendix, about 4 mm in diameter, containing air and showing no signs of surrounding infiltration. She underwent polypectomy while lying on the left side. Gastroenterologists inserted the scope through the anus into the cecum to the appendix orifice, approaching a polyp at about 10 mm (Fig. 1). The appendix orifice is easily found near the ileocecal valve through endoscopy. However, a colon polyp in this specific location presents a challenge because it is quite mobile, situated next to the appendiceal orifice, moving in and out through the appendix hole. The endoscopist encountered some difficulty and needed several attempts to immobilize the polyp to perform the procedure. A submucosal injection with adrenaline solution diluted 1/10,000 and methylene blue raised the lesion, after which a snare was used for polypectomy without complications. Eventually, en bloc resection of the lesion was performed via EMR. Histopathology confirmed the final result, showing a tubular adenoma with low-grade dysplasia. She was given prophylactic medication (625 mg of Medoclav, 2 tablets per day and 325 mg of Taphenplus, 3 tablets per day) for 5 days. Three days later, the patient presented with severe abdominal pain and persistent dull pain in the right iliac fossa. Abdominal ultrasonography suggested appendicitis, with the appendix about 8 mm in diameter, fluid-filled, and surrounded by fatty infiltrates. Computed tomography was indicated to further evaluate other conditions and rule out post-polypectomy complications such as microscopic perforation, but she did not consent to undergo this procedure. After an interdisciplinary consultation, the doctors offered options, including medical treatment with antibiotics and anti-inflammatories, or surgical treatment. Based on the patient’s pain level and the standard evidence of acute appendicitis on ultrasonography, the doctors recommended the second option—that is, surgical treatment. The patient then underwent a laparoscopic appendectomy and continued to take antibiotics and anti-inflammatory drugs for 4 days. She was discharged after 3 days in a stable condition. One week later, the patient returned for a follow-up examination and reported no abdominal pain or other unusual signs. However, the patient declined an endoscopic examination and only underwent abdominal ultrasonography.

Figure 1. A polyp (arrowhead) at the appendiceal orifice (arrow) in white-light imaging (A) and narrow-band imaging (B), showing a few small hemorrhagic spots on the surface.

Informed consent was obtained from the patient.

In our case, a patient experienced no complications after receiving an initial colonoscopy during which a polyp was diagnosed near the orifice of the appendix. Acute appendicitis occurred after a second colonoscopy to perform EMR of the polyp at the orifice of the appendix. The main mechanism causing this complication is believed to be inflammation and edema, which result in obstruction of the orifice of the appendix. In addition, it may be caused by fecaliths, lymphoid hyperplasia, foreign bodies, parasites, or overinflated air during endoscopy.^3,4 However, appendicitis after a colonoscopy or EMR-based diagnosis remains a subject of research and discussion, either as an incidental finding or an actual complication of this procedure.^4,5

It is important to emphasize here that in cases where a polyp is detected near the orifice of the appendix, the optimal option is EMR to avoid malignant transformation of the polyp. Before an endoscopic polypectomy procedure, the patient should be counseled that the appendix may need to be removed by laparoscopic surgery later if there are signs of appendicitis. Physicians must have a multidisciplinary discussion in advance to prepare for treatment options if appendicitis occurs. If appendicitis develops, a laparoscopic appendectomy should be performed to avoid serious complications from it. The experience drawn from this case is that an adequate dose of anti-inflammatory drugs should be given to avoid excessive edema of the appendix orifice. Non-steroidal anti-inflammatory drugs (NSAIDs) have the ability to reduce pain and inflammation during and after endoscopic colon polypectomy, but have not been thoroughly studied in the literature in this context. However, it is necessary to avoid using NSAIDs that are associated with blood clotting disorders to avoid bleeding during the procedure.⁶ In addition, if the polyp is smaller than 1 cm and is benign, cold snare polypectomy may also be useful.^7,8

None.

The data that support the findings of this study are available from the corresponding author upon reasonable request.

No potential conflict of interest relevant to this article was reported.