# Meal-induced recto-sigmoid tone modification: a low-caloric meal accurately separates



## Kathleen M. (Nov 16, 1999)

Gut. 2006 Jan 24; [Epub ahead of print]Meal-induced recto-sigmoid tone modification: a low-caloric meal accurately separates functional and organic gastrointestinal disease patients.Di Stefano M, Miceli E, Missanelli A, Mazzocchi S, Corazza G.I Department of Medicine, University of Pavia, IRCCS S.Matteo Hospital, Italy.BACKGROUND AND AIMS: Diagnosis of irritable bowel syndrome is based on arbitrary criteria due to the lack of an accurate diagnostic test. The aim of this study was to evaluate whether recto-sigmoid tone modification after a meal represents an accurate diagnostic approach. METHODS: In a secondary care setting, 32 constipation-predominant and 24 diarrhoea-predominant IBS patients, 10 functional diarrhoea and 10 functional constipation patients, 29 organic gastrointestinal disease patients and 10 healthy volunteers underwent a rectal barostat test in order to measure fasting and post- prandial recto-sigmoid tone. Recto-sigmoid response was assessed following three meals containing different amounts of calories, 200 Kcal, 400 Kcal and 1000 Kcal. RESULTS: After 200 Kcal, healthy volunteers and patients with organic diseases showed a reduction of recto-sigmoid volume of at least 28% of fasting volume, indicating a meal-induced increase of muscle tone. On the contrary, patients with diarrhoea-predominant IBS showed a dilation of the recto-sigmoid colon, indicative of reduced tone and patients with constipation-predominant IBS showed a mild volume reduction or no modification. Functional diarrhoea and constipation patients showed recto-sigmoid tone modification resembling that of the corresponding IBS subtype. A 400 Kcal meal normalized recto-sigmoid tone in more than half the constipation- predominant IBS patients but none of the diarrhoea- predominant IBS patients. On the contrary, a 1000 Kcal meal normalized tone response in all IBS patients. Sensitivity of the test was 100%, specificity 93%, positive predictive value 96% and negative predictive value 100%. CONCLUSION: A post-prandial reduction of recto- sigmoid tone of at least 28% of fasting value after a low- caloric meal accurately separates organic and functional gastrointestinal disease patients. This parameter may, therefore, be used in the positive diagnosis of IBS.


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