Massive bleeding and perforation due to post-colectomy pan-enteritis with a significant response to biologic in a patient with ulcerative colitis: a case report.

Background: Post-colectomy pan-enteritis in ulcerative colitis (UC) is very rare, but it is often severe and fatal. We present a case of massive bleeding and perforation due to post-colectomy pan-enteritis, which showed a significant response to biologics in a UC patient.

Case presentation: A 30-year-old woman with a 5-month history of pancolitis UC underwent subtotal colectomy with ileostomy and mucosal fistula for refractory UC. She was diagnosed with small bowel obstruction on postoperative day (POD) 8 and bowel bleeding was observed on POD18. Reoperation was performed for bowel obstruction and bleeding on POD20. Intraoperatively, adhesive small bowel obstruction in the ileum and multiple erosions and ulcers with perforation were observed throughout the small bowel. We diagnosed post-colectomy pan-enteritis, and jejunostomy, lavage, adhesiolysis, and a simple closure of the perforated ileum were performed. High-dose steroid therapy for pan-enteritis was administered immediately after reoperation, and infliximab was administered because of worsening bleeding on day 3 after reoperation. Bleeding decreased one day after biologic administration and bleeding completely disappeared on day 10 after biologic administration. Specimens obtained from the terminal ileum at colectomy showed a normal ileum without inflammation and villus atrophy, while specimens from the perforated ileum showed congestion, villous atrophy, epithelial erosion, and mononuclear cell infiltration. No cryptitis, crypt distortion, or basal plasmacytosis (common characteristics in UC) were observed in either specimen.

Conclusion: An early diagnosis and intervention are important for post-colectomy pan-enteritis, and infliximab may be effective. Post-colectomy pan-enteritis with a multiple ulcer phenotype has different histological characteristics from UC and may have a different pathogenesis.