Crohn’s disease (CD) and ulcerative colitis (UC), collectively known as inflammatory bowel disease (IBD), are idiopathic, lifelong, destructive chronic inflammatory conditions of the gastrointestinal tract which typically manifest during late childhood and adolescence.1 The burden of these chronic relapsing diseases and their devastating effects imposed on affected children and teenagers may be considerable. IBD is divided into CD and UC based on clinical characteristics, although 5% to 24 % of patients do not clearly fit into either category and are termed inflammatory bowel disease–unspecified (IBD-U).2 Chronic inflammation in CD can involve any part of the gastrointestinal tract and is characterized by discontinuous inflammation with intervening areas of normal mucosa (skip lesions) and transmural inflammation, which can result in fistulae, perforations, and strictures. Finding of noncaseating granulomas histologically in the mucosal biopsies are hallmark of CD. Intestinal involvement of UC is limited to the colon and typically begins distally in the rectum and extends proximally. Inflammation in UC is superficial.
The etiopathogenesis of IBD has been linked to a combination of genetic and environmental factors, but the exact cause remains elusive.3 Current thinking suggests patients with a genetically determined predisposition develop an immune-mediated response to an environmental trigger or intestinal microbial dysbiosis, which leads to chronic dysregulated inflammation.4 The early discovery of several genes, including CARD15 and the OCTN cation transporter associated with CD lends support to this hypothesis.5-7 Subsequent advances in the genetics of IBD have implicated many genes representing several aspects of intestinal homeostasis including maintenance of the epithelial barrier, immune surveillance, neutrophil dysfunction, defects in innate immunity, and intracellular processes (e.g. autophagy, oxidative stress, carbohydrate metabolism).8 This highlights the fact that IBD represents a heterogeneous group of diseases beyond the clinical phenotypes of CD versus UC.
Population-based studies suggest that IBD is unevenly distributed throughout the world, with the highest disease rates occurring in Western countries.9 Epidemiologic surveys have also suggested that IBD incidence rates have changed over the second half of the twentieth century, gradually increasing for both UC and CD.10-12 Recently an epidemiological study was completed which evaluated all children in Wisconsin with a new diagnosis of IBD over an 8-year period.13 The incidence of IBD was 9.5 per 100,000 in children under 18 years of age. The incidence of IBD was noted to be equal among all ethnic groups. Children from sparsely as well as densely populated counties were also equally affected. Over a 4-year period of follow-up, 17% of children with CD and 13% of those with UC required surgery. This epidemiologic data highlights the importance for pediatric hospitalists to be knowledgeable in the care of children with IBD.
Patients with IBD can present with a diverse constellation of signs and symptoms. The clinical presentation of CD varies with the anatomic location(s) of involvement.1,14 In UC the clinical ...