Abstract: Background：Clinical cases of children with inflammatory bowel disease complicated with acute pancreatitis are rarely reported in China. Objective：To summarize and analyze the clinical characteristics, treatment and prognosis of children with inflammatory bowel disease(IBD) with acute pancreatitis(AP) in a single center. Design：Case series report. Methods：The basic characteristics, clinical manifestations, physical examination, laboratory examination, imaging examination, treatment and follow-up information were retrospectively collected and analyzed from continuous cases of inflammatory bowel disease with acute pancreatitis hospitalized in the Department of Gastroenterology at Children's Hospital of Fudan University from January 2017 to June 2022. Main outcome measuresAP-related laboratory indicators and IBD endoscopic score. Results：A total of 406 children with inflammatory bowel disease from January 2017 to June 2022 were retrospectively analyzed, and 11 cases (2.7%) were complicated with acute pancreatitis. Among them, 9 were male and 2 were female. The median age of initial diagnosis of IBD and AP was 9.8(5.5, 13.1) and 10.2(5.7, 14.0) years old, respectively. The median duration of AP disease was 22(7, 56) days. Among the 11 children, IBD was confirmed before AP in 8 cases including 5 cases of Crohn's disease (CD) and 3 cases of ulcerative colitis (UC), and AP was confirmed before CD in 3 cases. Serum amylase was 238 (158,573) U·L-1 and blood lipase was 466 (360,1 376) U·L-1 at the diagnosis of IBD and AP, and both decreased after 3, 6 and 12 months with statistical significance. Imaging examination showed pancreatic lesions in 9/10 cases. The pediatric Crohn's disease activity index (PCDAI) and simplified endoscopic score for Crohn's disease (SES-CD) of 8 CD children were 36.3 (25.6, 49.4) and 17.5 (7.8, 22.2) at the diagnosis of CD and AP, and both decreased after 3 months with statistical significance. The pediatric ulcerative colitis disease activity index (PUCAI) score and Mayo endoscopic score (MES) of the 3 UC children were 40(25, 42.5) and 2(2, 2.5) at the onset of AP, and turned to 15(0, 30) and 2.5(2, 3) after 3 months of discharge. During 3 years of follow-up, there was no recurrence of AP in the 11 children. One UC child treated with 5 aminosalicylic acid and infliximab before onset of AP, who stopped taking the medication themselves after the onset of AP, had persistent hyperamylasemia, hyperlipemia, and pancreatic duct dilatation at 2 years of follow-up, and was progressed to chronic pancreatitis(CP) at 3 years of follow-up. Conclusions：Children with inflammatory bowel disease can be complicated with acute pancreatitis during the active stage, and acute pancreatitis may also be a rare extraintestinal manifestation of inflammatory bowel disease. During the diagnosis and treatment of inflammatory bowel disease, we should pay attention to the evaluation and follow-up of pancreatic function.

Key words: Inflammatory bowel disease, Crohn's disease, Ulcerative colitis, Acute pancreatitis, Children