S5022 Appendiceal Crohn’s Disease Mimicking Acute Appendicitis in a Patient on Infliximab: A Diagnostic and Surgical Challenge

Introduction: Acute appendicitis is the most common abdominal surgical emergency, typically resulting from luminal obstruction by fecaliths, lymphoid hyperplasia, or neoplasia. Although rare, Crohn’s disease can manifest in the appendix, mimicking or precipitating appendicitis. Appendiceal Crohn’s disease, with a reported incidence of 0.2% to 0.55%, often necessitates surgical management, especially when ileocecal involvement is present. Infliximab, a tumor necrosis factor-α inhibitor commonly used to manage Crohn’s disease, carries a known risk of serious infections, including gastrointestinal perforation and potentially appendicitis, although a direct causal link remains unconfirmed. Case Description/Methods: We present the case of a 28-year-old woman with fistulizing Crohn’s disease, recently initiated on infliximab, who was admitted with signs of sepsis and acute abdominal pain. Computed tomography revealed a fecalith within the appendix, peri-appendiceal inflammation, and extraluminal gas. Same-day exploratory laparotomy uncovered distal ileal perforation, thickened bowel segments, and feculent peritonitis. A right hemicolectomy was performed. Histology of the appendix confirmed acute serositis with transmural inflammation and ulceration, consistent with Crohn’s pathology. Postoperatively, the patient developed intra-abdominal abscesses requiring percutaneous drainage and experienced a duodenal ulcer bleed. She was managed with antibiotics and supportive therapy and discharged in stable condition. Discussion: This case underscores the diagnostic difficulty in distinguishing appendiceal Crohn’s disease from acute appendicitis, especially in patients on immunosuppressive therapy. It also highlights the importance of considering broader surgical intervention when ileocecal Crohn’s disease is suspected, as appendectomy alone may be insufficient. Further studies are warranted to elucidate the relationship between infliximab therapy and the risk of appendiceal complications.