Ambulatory 24-Hour Jejunal Motility in Diarrhea-Predominant Irritable Bowel Syndrome

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Abstract
Background: Whether small-bowel motility is abnormal in the irritable bowel syndrome (IBS) is a controversy at present. The aim of our study was to compare ambulatory long-term jejunal motility in 35 IBS patients with predominant diarrhea to normal values obtained in 50 healthy controls. Methods: Twenty-four-hour motility was recorded in the proximal jejunum with a portable datalogger and tubemounted miniature pressure sensors. Fasting motility in the waking (W) and sleeping (S) state and the motor response to a standardized evening meal of 600 kcal underwent visual and computer-aided analysis. Results: Fasting motility in patients showed migrating motor complex (MMC) cycles of normal length and composition. Uninterrupted runs of discrete clustered contractions during phase II (W) occurred in 57% of patients and 52% of controls but had a significantly longer duration in patients (33 ± 5 versus 19 ± 7 min; p < 0.005). During phase II (W) IBS patients had an increase in aborally propagated contractions (41 ± 2% versus 35 ± 2%; p < 0.01) and higher contraction amplitudes (26.3 ± 0.8 versus 23.0 ± 0.5 mm Hg; p < 0.01). Similar differences were obtained during postprandial motility (47 ± 3% versus 39 ± 3%; p < 0.01, and 25.9 ± 0.9 versus 23.8 ± 0.05 mm Hg; p < 0.02). In three patients (8.6%) disturbed aboral migration of phase III and irregular burst activity, manometric features of chronic idiopathic intestinal pseudo-obstruction, were identified. Whereas 57% of patients had an entirely normal 24-h manometry, 43% had at least one finding not present in any healthy control. Conclusion: Small-intestinal motility is frequently but not universally abnormal in diarrhea-predominant IBS. The abnormal manometric findings are heterogeneous and range from subtle quantitative changes to severe qualitative abnormalities resembling chronic idiopathic intestinal pseudo-obstruction in a small subset of patients.