Pediatric Inflammatory Bowel Disease: from diagnosis to transition

Abstract

The inflammatory bowel diseases (IBD) are chronic relapsing inflammatory disorders of the gastrointestinal tract, comprising Crohn’s disease (CD), ulcerative colitis (UC), and IBD-unclassified (IBD-U). CD is characterized by a transmural and often granulomatous inflammation that can involve any part of the gastrointestinal tract in a discontinuous manner, while UC is defined as a chronic inflammatory condition causing continuous mucosal inflammation of the colon, without granulomas on biopsy, affecting the rectum and a variable extent of the colon in continuity. The term IBD-U is used for patients presenting with IBD restricted to the colon without the specific features of either CD or UC.2 Early-onset IBD represents a distinct disease entity with differences in disease type, disease location, disease behavior, gender preponderance, and genetically attributable risk compared with late-onset IBD. As in adults, treatment of early-onset IBD is aimed at inducing and maintaining remission, but special considerations are needed regarding optimal growth, pubertal development, and the transition period to adult care. A better understanding of the differences between early-onset and late-onset IBD will eventually lead to a better understanding of the pathogenesis of the disease. One of the limitations of studying pediatric IBD is however that a relatively small number of patients is available for study at one institution, which requires ongoing collaborations between many institutions. This thesis will present six (inter)national multicenter studies, a single-center pilot study and a review, which all focus on the unique clinical aspects of pediatric IBD, thereby complementing the relatively small body of literature on the diagnosis and treatment of children with IBD