Clinical Gastroenterology Vol.24 No.12(5)

Theme The Functional Gastrointestinal Disorders -- Clinical Practice Based on the Understanding of Its Basic Mechanisms
Title Clinical Assessment of Small Intestinal Function
Publish Date 2009/11
Author Yoshihisa Urita Department of General Medicine and Emergency Care, Toho University
Author Tadashi Maeda Department of General Medicine and Emergency Care, Toho University
Author Tsunetake Arai Department of General Medicine and Emergency Care, Toho University
Author Masaki Sanaka Department of General Medicine and Emergency Care, Toho University
Author Hitoshi Nakajima Department of General Medicine and Emergency Care, Toho University
Author Motonobu Sugimoto Department of General Medicine and Emergency Care, Toho University
[ Summary ] The major functions of the small intestine are to digest and absorb nutrients. Mixing and propulsive motor functions are important components of these functions. It is not easy to assess small intestinal function clinically because endoscopic methods can not be used to reach the small bowel. Small intestinal transit has been assessed by scintigraphy, breath tests, and radiopaque markers. In breathtests, measurements of oro-cecal transit time usually employ non-absorbable carbohydrates. A greater than 20 ppm increase in hydrogen in breath samples is indicative of the presence of a substrate in the cecum. Recently, capsule endoscopy has been used as a tool to measure gastrointestinal transit. Absorption of nutrients has been primarily assessed withnuturient-ch allenge tests suchas the DXylose test, the mannitol test, the Schilling test, or the UDCA test. Many kinds of 13C-substrate are used in breath tests for the assessment of gastric emptying oro-cecal transit time, liver function, fat malabsorption, and bacterial overgrowth. Breath tests enable physicians and patients to benefit from rapid, novel and non-invasive methods to monitor the progress of disease severity and to optimize individually tailored treatment therapies. However, they cannot discriminate between absorptive and metabolic functions. The simplicity of breath tests makes them very applicable to clinical settings. However, they must be compared to the existing gold standard tests.
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