Chapter 17 - Normal Lower Gastrointestinal Mucosa

Summary

Inflammatory bowel disease (IBD) typically involves the large bowel, small bowel (ileum / jejunum), or both. Involvement of the upper GI tract is less common, although its frequency is uncertain because common causes of inflammation such as gastro-oesophageal reflux and Helicobacter pylori infection also require exclusion. In the setting of known IBD, upper GI inflammation generally favours Crohn’s disease over ulcerative colitis (UC), while granulomas strongly suggest involvement by IBD and indicate Crohn’s disease rather than UC. New upper GI inflammation may raise the possibility of IBD, while unexplained new upper GI granulomas require exclusion of Crohn’s disease. Unfortunately, few histological patterns apart from granulomas are specific or discriminant. Lymphocytic oesophagitis is a poorly defined entity associated with IBD and/or Crohn’s disease in some studies. Focally enhanced gastritis (FEG), though initially regarded as typical of Crohn’s disease, probably has limited value apart from perhaps predicting IBD in children. Rarely, UC patients develop a duodenitis resembling the colorectal changes histologically. UC may also be associated, infrequently, with characteristic patterns of gastritis. Compared with adults, children with IBD are more likely to have upper GI involvement, to develop GI granulomas, and to undergo investigation for upper GI disease. Overall, upper GI granulomas assist with the diagnosis and classification of IBD but few other upper GI features are discriminatory between IBD and other causes or between UC and Crohn’s disease.