Functional Gut Disorders and Inflammatory Bowel Disease: Comorbidity and Clinical Challenges

10 INTRODUCTION F unctional gastrointestinal disorders (FGD) are a group of syndromes defined as variable combinations of chronic or recurrent gastrointestinal symptoms not explained by structural or biochemical abnormalities. They are classified according to the international Rome criteria for which the 3rd edition has recently been published (1). The most common and best studied among this broad range of disorders are functional dyspepsia (FD), affecting mainly the upper gut, and irritable bowel syndrome (IBS) affecting the intestine. IBS represents the most frequent reason for consultation with a gastroenterologist in the Unites States (2), its overall prevalence ranging from 3% to 25% (3). The pathophysiology of IBS most likely results from a combination of psychosocial factors, altered gastrointestinal motility and increased sensitivity (4,5). The etiological factors are obscure, but an altered function of the gut neuromuscular apparatus due to previous or ongoing inflammatory events seems likely (6). Inflammatory bowel disease (IBD) comprises Crohn’s disease (CD) and ulcerative colitis (UC) and is thought to arise from inappropriate and ongoing activation of the gastrointestinal mucosal immune system driven by the presence of normal flora in genetically predisposed subjects (7). The main clinical features are fever, abdominal pain, diarrhea, rectal bleeding, weight loss and malnutrition. Therapeutic efforts are mainly anti-inflammatory or immunomodulatory and aimed at inducing remission. Functional Gut Disorders and Inflammatory Bowel Disease: Comorbidity and Clinical Challenges INFLAMMATORY BOWEL DISEASE: A PRACTICAL APPROACH, SERIES #45