Comprehensive update on select immune-mediated gastroenterocolitis syndromes: implications for diagnosis and management.

There is a heterogeneous group of noninfectious gastroenterocolitis syndromes that are characterized by immune dysregulation. Recent advances in pathologic analysis have allowed for better characterization of many of these disorders. Some entities demonstrate characteristic disease distribution, epidemiologic features, natural history, and response to specific therapy. For instance, celiac disease occurs in genetically susceptible individuals who are sensitive to gluten, eosinophilic esophagitis is an immune response to ingested allergens, and microscopic colitis predominantly occurs in older patients with chronic diarrhea and is induced or exacerbated by drugs. Eosinophilic gastroenteritis has a variety of clinical and imaging manifestations. Crohn disease and ulcerative colitis are multifactorial immune-mediated chronic inflammatory disorders and have become increasingly prevalent in recent years. Multidetector computed tomography and magnetic resonance imaging provide valuable information that may be used to diagnose these conditions, guide treatment, and assess changes after treatment, and the role of imaging in evaluating response to therapy continues to evolve and expand. © RSNA, 2010.