EP296 - Ileo-appendiceal fistula in the setting of Crohn’s disease

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Purpose/Background: Crohn’s disease, an autoimmune condition that leads to transmural inflammation of the intestine, can result in fistulas from bowel to other structures. Appendicitis can also independently lead to transmural inflammation and fistulas from appendix other structures. Alternatively, Crohn’s disease can involve the appendix itself, leading again to transmural inflammation and fistulas. Here, we describe an uncommon case of ileo-appendiceal fistula in a patient with Crohn’s disease.

Methods/Interventions: A 22 year old female with Crohn’s disease (diagnosed at age 15) presented with postprandial epigastric and right flank pain. She had not been on medical therapy since she was diagnosed with pulmonary tuberculosis three years ago. She was treated with antibiotics, but was lost to follow-up afterwards and did not resume treatment for Crohn’s disease. On return to care, CT enterography demonstrated terminal ileitis with fistulization to the appendix (Figure 1a, 1b). She was referred to colorectal surgery and agreed to laparoscopic ileocecectomy. Laparoscopic ports were placed. The cecum, terminal ileum, appendix, and mesentery were inflamed with many adhesions. The ileo-appendiceal fistula was identified. Specimen was freed of adhesions and native attachments. Specimen was transected at the terminal ileum 20 cm from the ileocecal valve, and at the mid-ascending colon. Specimen was extracted with the ileo-appendiceal fistula. A side-to-side ileo-colic anastomosis was performed. While running the bowel, multiple segments of small bowel strictures were identified. Heineke-Miculicz strictureplasty was performed on one especially stenotic stricture. Incisions were closed. Patient recovered without complications. Patient was referred to her gastroenterologist to initiate biological therapy.

Results/Outcomes: Pathology revealed severely active chronic ileitis and a fistula between the terminal ileum and appendix. The ileum was noted to have transmural inflammation, perforation, hemorrhage, and granulomas with multinucleated giant cells, consistent with Crohn’s inflammation. The appendix had focal acute appendicitis, periappendicitis, hemorrhage, and focal necrosis.

Conclusion/Discussion: In this case, the patient had severe Crohn’s disease without medical management for years. Interestingly, only the terminal ileum had pathological signs of Crohn’s disease, while the appendix had focal inflammation at the fistula. This suggests that the fistula formed as most Crohn’s fistulas do, where an intestinal defect extends and epithelializes in a tubular fashion until it reaches another epithelialized target. In this case, the appendix served as an unlikely endpoint. As the appendix is a reservoir for commensal bacteria and is believed to influence Crohn’s disease, it is interesting to consider if and how this fistula involving the appendix modified disease course in the absence of immunomodulators.