W1323 Small Intestinal Bacterial Overgrowth in Irritable Bowel Syndrome: Association with Colon Motility, Bowel Symptoms, and Psychological Distress

AGA Abstracts

were collected. RESULTS: Of a total of 850 subjects, 9.5% (n=78, 52F) met the criteria for IBS. Intrauterine exposure to famine did not increase the risk of developing IBS (7.7% versus 8.7%, NS). However, after birth, age at exposure to famine significantly influenced the prevalence of IBS (odds ratio 2.36, 95% confidence interval 1.16-4.84, p=0.019, logistic regression, corrected for gender). Of all adults exposed to famine between 1 and 1.5 years of age 15.3% met the criteria for IBS compared to 8.4% of those not exposed to famine in early life (p=0.029). The prevalence of IBS was not significantly different in subjects exposed to famine in the first half year of life (8.1%) and in those between 0.5 and 1 year of age (12.5%) compared to the group not exposed to famine in early life. Baseline cortisol concentrations (exposed: 4.5 ± 0.2 nmol/l, not exposed: 4.5 ± 0.2 nmol/l, NS) and the peak cortisol response during the stress test (exposed: 3.0 ± 0.3 nmol/l, not exposed: 2.6 ± 0.2 nmol/l, NS), were comparable between the groups. Age at exposure to famine did not significantly influence the basal cortisol or the peak cortisol response levels. CONCLUSIONS: Although famine in early life is not associated with an altered stress-response, this study shows that famine in early life is a risk factor to develop IBS in adulthood. To what extent this increased risk of developing IBS is attributable to famine alone or is (also) associated with the stressful environment of famine and war remains unclear.

for the development of IBS symptoms. It is unlikely that psychological distress could mediate the association between SIBO and bowel symptoms. Methane production is associated with constipation bowel pattern. [Supported by RO1 DK31369, R24 DK067674, & MO1 RR00046] W1324 The Development of IBS, Abdominal Pain and Constipation Following Elective Hysterectomy Ami D. Sperber, Carolyn B. Morris, Lev Greemberg, Shrikant I. Bangdiwala, David Goldstein, Eyal Sheiner, Yefim Rusabrov, Yuming J. Hu, Miriam Katz, Douglas A. Drossman Background. There have been reports of women with no prior bowel complaints developing constipation, straining, bloating, and a feeling of incomplete evacuation following hysterectomy. Also, epidemiological studies correlate hysterectomy with IBS. However, previously published studies were either retrospective (based on patient recall) or prospective, but uncontrolled. Thus, it is not clear whether there is a significant change in bowel habit or whether IBS develops following hysterectomy. Previously, we showed that abdominal pain developed significantly more in women who underwent elective gynecological surgery than controls. The aim of this aspect of our prospective, controlled study was to assess whether constipation or other changes in bowel habit develop after elective hysterectomy. Methods. 132 women, without IBS, undergoing elective gynecologic surgery were compared to 123 matched non-surgery controls seen in a gynecology clinic. We evaluated abdominal pain and bowel habits at enrollment (prior to surgery) and 3 and 12 months after surgery. Results. A sub-set of 58 women underwent elective hysterectomy and were compared to the 123 controls. No hysterectomy patients or non-surgery controls developed IBS. Significantly more hysterectomy patients without baseline pain (N=48) developed abdominal pain at 3 or 12 months than non-surgery controls (16.7% vs. 3.6%, P=0.008). In contrast, there was no noteworthy change between the hysterectomy and control groups between baseline and either follow-up point in functional constipation (P=1.0), frequency of stools (P=0.92), stool consistency (P=0.42), straining (P=0.43), feeling of obstruction (P=0.6) or need to manually evacuate stool (P=1.0). Conclusions. The results of this prospective, controlled study show there was no significant change in bowel habit or stool characteristics in women undergoing hysterectomy for non-pain indications even though a significant number of them developed abdominal pain. Possibly, hysterectomy may lead to surgical injury of pelvic nerves that generates pain stimuli, but does not affect the enteric nervous system, thereby not affecting intestinal motility. IBS does not develop since based on Rome criteria the pain that develops is not associated with change in bowel habit. This prospective study challenges existing data regarding the effect of hysterectomy on bowel habit. Its strength, compared to previous studies, stems from its design as a prospective trial of hysterectomy patients compared to appropriate non-surgery controls. Research in larger groups of hysterectomy patients is warranted to assess bowel change specifically among patients who develop pain.

W1322 Do Patients with Chronic Intractable Constipation and Rectal Hyposensitivity Also Have Evidence of Rectal Motor Dysfunction? Natalia Zarate, Subash P. Vasudevan, Peter J. Lunniss, Mark Scott BACKGROUND: integrity of rectal sensory and motor function is crucial to normal defaecation. Impaired rectal sensation to volumetric distension (rectal hyposensitivity: RH) is frequently found in constipated patients; however, it is unclear whether alteration in the sensory domain is associated with a disturbance of motor function. Prolonged manometric studies of the distal colon have revealed periodic rectal motor activity (rectal motor complexes [RMCs]), which may be considered a marker of enteric neuromotor function. Disturbance of RMC activity may thus reflect an intrinsic motor neuropathy AIMS: to evaluate rectosigmoid motor activity, using prolonged ambulatory manometry, in patients with chronic constipation and rectal hyposensitivity. METHODS: 7 patients (6F) with functional constipation (Rome II) and RH (sensory thresholds to volumetric balloon distension elevated beyond the normal range), and 12 healthy volunteers (5F) underwent 24 hour ambulatory manometry, using a 6 channel solid-state catheter. Each recording was divided into diurnal and nocturnal periods, and recording sites at +25 cm, +15 cm, and +10 cm above the mid anal canal, representing the sigmoid colon, rectosigmoid, and mid-rectum, respectively, were chosen for analysis. Automated analysis of various parameters of overall phasic contractile activity and RMC activity was performed and results compared between groups. RESULTS: for grouped data, parameters of diurnal and nocturnal phasic activity were similar between patients and controls: contraction frequency (43±5 /h vs 38±3 [day: P=0.4], and 30±5 vs 26±3 [night: P=0.6], summed over the 3 chosen channels); mean contraction amplitude (22±4 mmHg vs 23±1 [day: P=0.4], and 25±3 vs 22±1 [night: P=0.3]); area under the curve (6738323 ± 85022 vs 599006 ± 95883 [day: P=0.8], and 250578 ± 36897 vs 286341 ± 49838 [night: P=0.9]). Most parameters of RMC activity (contractions frequency, duration, average amplitude and AUC) were also similar between patients and controls both during the day and at night. However, during the nocturnal period, the time occupied by RMC activity was significantly shorter for patients (9.5 ± 2 min/hour) compared to controls (15 ± 1.6 min/hour: P<0.02). For individuals, 3 showed average RMC complexes duration outside the normal range (longer). Conclusions: although parameters of overall phasic activity and RMC expression were generally similar between patient and control groups, some individuals with RH demonstrated evidence of altered RMC activity, which may reflect a combined sensory and motor disorder. Such studies may help to further characterise pathophysiological subgroups in chronic constipation.

W1325 Postprandial Rectosigmoid Tone Modification: A New Diagnostic Test for Irritable Bowel Syndrome? Michele Di Stefano, Paola Tana, Samanta Mazzocchi, Gino Roberto Corazza Backgrounds and Aims: We previously showed (1) that in IBS an alteration of postprandial modification of rectosigmoid tone is evident. In our experience, the prevalence of this alteration was very high and, on clinical grounds, an hypothetical application in a diagnostic test might be suggested. Therefore, the aim of this study was the assessment of postprandial rectosigmoid tone modification in a large cohort of IBS patients and in a group of patients with gastrointestinal organic disorders. Patients and Methods: 106 patients (70 female, meanage: 38±5 yrs) came to our secondary care setting for a modification of the stool habit. All patients underwent a barostat test as previously described (1) to evaluate the postprandial recto-sigmoid tone after a 200 Kcal liquid meal and Rome II criteria evaluation. According to our previous results, a reduction of postprandial rectosigmoid tone lower than 28% was considered abnormal. Final diagnosis were: IBS C=49; IBS D=37; organic diseases=20 (colonic diverticulosis, chronic pancreatitis, colorectal cancer, Crohn's disease, ulcerative colitis). Results: Postprandial recto-sigmoid tone showed an abnormal modification in 81/86 IBS patients (94%). All patients with organic diseases had a postprandial volume reduction higher than 28%. All IBS patients fulfilled Rome II criteria, but also 4 patients with organic disease. Conclusions: The evaluation of postprandial rectosigmoid tone modification in a large cohort of IBS patients confirms our previous results and could be considered as a useful tool to discriminate between organic and IBS patients. 1. Di Stefano et al. Gut 2006;55:1409-14

W1323 Small Intestinal Bacterial Overgrowth in Irritable Bowel Syndrome: Association with Colon Motility, Bowel Symptoms, and Psychological Distress Madhusudan Grover, Motoyori Kanazawa, Denesh K. Chitkara, Lisa M. Gangarosa, Olafur S. Palsson, Douglas A. Drossman, Marsha J. Turner, William E. Whitehead Background: Small intestinal bacterial overgrowth (SIBO) has been implicated in the pathogenesis of irritable bowel syndrome (IBS), but the significance of SIBO in IBS is unclear. Aims: To determine the prevalence of SIBO and its association with colonic motility, bowel symptoms and psychological distress in IBS patients. Methods: 158 IBS patients, diagnosed by Rome II criteria and confirmed by physician diagnosis, and 34 healthy controls were tested for SIBO using a Quintron hydrogen and methane analyzer for 2 hours following ingestion of 50 g sucrose. Balloon distensions in the descending colon were performed using a G&J Electronic barostat to assess pain and urge thresholds by the ascending method of limits. Colonic phasic motility was determined with the motility index (MI, average area under the curve of phasic contractions). Subjects completed questionnaires on psychological distress (Brief Symptom Inventory-18, Recent Physical Symptom Questionnaire, and Catastrophizing Scale), IBS Symptom Severity scale (IBS-SS), IBS Quality of Life (IBS-QOL) and self reported bowel symptoms. Results: 52/158 (32.9%) of IBS had abnormal breath tests compared with 6/34 (17.9%) of controls (χ2=0.079). Patients with SIBO (SIBO+) and Non-SIBO (SIBO-) did not differ in the prevalence of IBS-subtypes, IBS-SS, IBS-QOL or psychological distress. SIBO- showed a trend towards lower pain thresholds compared to SIBO+ (25.9 vs. 30.1, p=0.055). Compared to controls, both SIBO+ and SIBO- had a greater post-distension increase in MI (625.6 and 642.9 vs. 313.3, p<0.05) but the MI was not different between these two groups. Predominant methane producers (PMP) had higher urge thresholds (28.4 vs. 18.3, p<0.05) and higher baseline MI (461 vs. 301.45, p<0.05) than SIBO- IBS, and they were more likely to report hard or lumpy stools at least 25% of the time when compared to predominant hydrogen producers (PHP) (90% vs. 52%, p<0.05) and SIBO- IBS (90% vs. 53%, p< 0.05). The IBS-SS scale did not significantly correlate with peak hydrogen in the PHP group (rho=-0.06) or peak methane production in the PMP group (rho=-0.11). Conclusions: SIBO is unlikely to contribute significantly to the pathogenesis or morbidity of IBS. Visceral hypersensitivity and SIBO appear to be independent mechanisms

AGA Abstracts

W1326 Prevalence of Breath Methane Excretion Is Not Correlated to Clinical Presentation in IBS. the Role of Different Patterns of Breath Methane Excretion Michele Di Stefano, Paola Tana, Samanta Mazzocchi, Gino Roberto Corazza Background and Aims: Colonic production of methane is an effective pathway for hydrogen consumption. In small samples of IBS patients, it was previously shown that intestinal methane production correlates with clinical presentation and slows colonic transit time. However these data have not yet been confirmed and its pathophysiological role is still unknown. The aim of the study was to verify the role of methane on both clinical presentation and motility in a large cohort of IBS patients. Patients and Methods: A group of 100 IBS (Rome II) patients (26 males, mean age 41±12 yrs) underwent the lactulose breath test to evaluate breath excretion of intestinal gases. Ten grams of lactulose in 250 ml of water were given orally after fasting breath sampling, and breath samples were then collected every 15 minutes for 4 hours for hydrogen and methane detection. Cumulative gas production was evaluated by the area under the time-concentration curve calculation (AUC). Fourty-six

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