Recent research suggests a link between colonoscopy and appendicitis

Scientists have proffered that patients who have undergone a colonoscopy may develop appendicitis a week after the procedure. The study, which was published in JAMA Surgery, offers a new perspective on appendicitis and whether certain people are predisposed to it.

• Researchers gained approval and a waiver of informed consent from the University of North Dakota and the Fargo Veteran Affairs Medical Center for the study. This allowed them to look at screening codes from the U.S. Department of Veterans Affairs.
• In particular, they looked at data for colonoscopy cases between January 2009 and June 2014. Incomplete colonoscopy and sigmoidoscopy codes were excluded from the study.
• The team identified a total of 392,485 cases. They looked at the year after the procedures were undertaken, looking at codes for appendectomy and appendicitis.
• For the findings, they calculated the incidence rate ratio (IRR) for appendicitis a week after a colonoscopy and for the following weeks at a confidence interval of 95 percent.
• Researchers found out that cases of appendicitis or an appendectomy were coded more frequently a week following a colonoscopy. The results were the same even if the cases were broken down to reflect their respective age groups.
• On the first week, they found that 26 cases were coded for appendicitis, while 10 were coded for an appendectomy. The incidence rate was higher compared to other procedures such as bronchoscopy, knee replacement surgery, cataract surgery, or knee arthroscopy.
• Moreover, 12 patients were coded to have appendicitis and had an appendectomy a week following a colonoscopy. Over the following weeks, 79 patients were identified to have appendicitis.

While the correlation between a colonoscopy and the increased risk of appendicitis is still unclear, the study offers some speculation. In particular, these include asking whether the changes in bacteria within the colon before a colonoscopy can increase the likelihood of inflammation, or whether the increased air pressure caused by it can affect colonic mucosa and cause predisposition to appendicitis.

Journal Reference:

Basson MD, Persinger D, Newman WP. ASSOCIATION OF COLONOSCOPY WITH RISK OF APPENDICITIS. JAMA Surgery. 2018;153(1):90. DOI: 10.1001/jamasurg.2017.3790