Distension In Irritable Bowel Syndrome Research Articles

Abdominal distension in health and irritable bowel syndrome: The effect of bladder filling.

Abdominal distension is a common feature of irritable bowel syndrome (IBS), which is difficult to treat and can have the appearance of late pregnancy. It results from an abnormality of the normal accommodation reflex which keeps abdominal girth constant despite changes in gastrointestinal volume resulting from food ingestion or gas accumulation. We speculated that bladder filling might also trigger this abnormal reflex in IBS and this study tested this hypothesis. Eight females with IBS (aged 21-43, mean 34) were compared with seven female controls (aged 19-56, mean 31) at the same time in the menstrual cycle. Abdominal girth in response to maximum tolerated bladder filling following ingestion of 1500mls of water was measured using abdominal inductance plethysmography. Symptoms, girth change after bladder emptying, and urine volumes were also recorded. Baseline girth of patients and controls was 84.8 and 79.9cm respectively. After reaching maximum tolerated bladder filling, girth increased by a mean of 6.4 (Standard deviation (SD) 2.1) cm in patients compared with 3.5 (1.1) in controls (P=0.006), with patients having symptoms of bladder hypersensitivity. After voiding urine, girth reduced by 5.3 (3.1) and 1.9 (1.2) in patients vs controls (P=0.018), despite passing similar mean urine volumes, 789 (364)mls vs 671(286) (P=0.50). Bladder filling contributes to abdominal distension in IBS and is unrelated to urine volume suggesting that bladder stretch or hypersensitivity might trigger this response. Frequent bladder emptying may help control this intrusive problem which is very challenging to manage.

Quantitative Meta-analysis Identifies Brain Regions Activated During Rectal Distension in Irritable Bowel Syndrome

The responsiveness of the central nervous system is altered in patients with irritable bowel syndrome (IBS). However, because of variations in experimental paradigms, analytic techniques, and reporting practices, little consensus exists on brain responses to visceral stimulation. We aimed to identify brain regions consistently activated by supraliminal rectal stimulation in IBS patients and healthy subjects (controls) by performing a quantitative meta-analysis of published studies. Significant foci from within-group statistical parametric maps were extracted from published neuroimaging studies that employed rectal distension. Voxel-based activation likelihood estimation was applied, pooling the results and comparing them across groups. Across studies, there was consistent activation in regions associated with visceral afferent processing (ie, thalamus, insula, anterior midcingulate) among IBS patients and controls, but considerable differences in the extent and specific location of foci. IBS patients differed from controls in that there were more consistent activations in regions associated with emotional arousal (pregenual anterior cingulate cortex, amygdala) and activation of a midbrain cluster, a region playing a role in endogenous pain modulation. Controls showed more consistent activation of the medial and lateral prefrontal cortex. Patients with IBS have greater engagement of regions associated with emotional arousal and endogenous pain modulation, but similar activation of regions involved in processing of visceral afferent information. Controls have greater engagement of cognitive modulatory regions. These results support a role for central nervous system dysregulation in IBS. These findings provide specific targets for guiding development of future neuroimaging protocols to more clearly define altered brain-gut interactions in IBS.

Bloating and Distension in Irritable Bowel Syndrome: The Role of Gastrointestinal Transit

Bloating and Distension in Irritable Bowel Syndrome: The Role of Gastrointestinal Transit

Citalopram Provides Little or No Benefit in Nondepressed Patients With Irritable Bowel Syndrome

Data on the benefit of selective serotonin reuptake inhibitors (SSRIs) in irritable bowel syndrome (IBS) are conflicting. The longitudinal relationship between clinical symptoms and sensitivity to barostat-mediated rectal distension in IBS remains unclear. We assessed the benefit of citalopram and explored the relationships between symptoms, quality of life (QOL), and rectal sensitivity to barostat distension in non-depressed IBS patients. Patients from primary, secondary, and tertiary care settings were randomly assigned to receive citalopram (20 mg/day for 4 weeks, then 40 mg/day for 4 weeks) or placebo in a study with double-masking and concealed allocation. Symptoms were assessed weekly, and IBS-QOL and rectal sensation by barostat were assessed at the beginning and end of the study. Patients receiving citalopram did not achieve a higher rate of adequate relief of IBS symptoms than patients receiving placebo (12/27 [44%] vs 15/27 [56%]; P = .59), regardless of IBS subtype. The odds ratio for weekly response with citalopram vs placebo was 0.80 (95% confidence interval, 0.61-1.04). Improvements in specific symptom and IBS-QOL scores were not superior for citalopram. Changes in IBS-QOL score and pressure eliciting pain showed a modest correlation (r = 0.33; 95% confidence interval, 0.03-0.57), but changes in symptoms and IBS-QOL scores or rectal sensitivity were not correlated substantially. Citalopram was not superior to placebo in treating non-depressed IBS patients. Changes in symptoms were not substantially correlated with changes in rectal sensation assessed by barostat. Any benefit of citalopram in non-depressed IBS patients is likely to be modest at best.

Bloating and Distension in Irritable Bowel Syndrome: The Role of Gastrointestinal Transit

Patients with irritable bowel syndrome and constipation (IBS-C) show more abdominal distension than do those with diarrhea. Because constipation is often associated with delayed gastrointestinal transit, this study aimed at establishing whether patients with delayed transit show more distension and bloating than do those with normal transit. Abdominal girth was recorded for 24 h using abdominal inductance plethysmography (AIP) in 30 IBS-C (Rome II criteria) patients (aged 18-68 years; 27 women) and in 30 healthy volunteers (21-58 years of age; 26 women). Within 2 weeks of this recording, orocecal and colonic transits were assessed. Orocecal transit was determined from the increase in breath hydrogen after a standard meal, and colonic transit from the number of radio-opaque markers identified on a plain abdominal X-ray. Bloating severity was assessed hourly during AIP recording using a 0-5 scale. IBS-C patients showed more bloating and distension than did healthy volunteers (P<0.001). They also had prolonged colonic (P<0.001) and orocecal (P=0.05) transits than did healthy volunteers, such that 47 and 17%, respectively, had colonic and orocecal transit times greater than the normal reference range. Those with delayed colonic (P=0.025) and orocecal (P=0.13) transits had greater distension but not bloating (P=0.63 and P=0.48, respectively) compared with those with normal transit. Moreover, distension directly correlated with orocecal (r=0.40; P=0.03) and colonic (r=0.51; P=0.004) transit times and inversely with stool consistency (r=-0.43; P=0.07). IBS-C patients with delayed transit show greater abdominal distension than do those with normal transit. Therefore, drugs that accelerate transit may be expected to alleviate this troublesome problem.

Vagal dysfunction in irritable bowel syndrome assessed by rectal distension and baroreceptor sensitivity

Autonomic nervous system dysfunction has been implicated in the pathophysiology of irritable bowel syndrome (IBS). This study characterized the autonomic response to rectal distension in IBS using baroreceptor sensitivity (BRS), a measure of autonomic function. Rectal bag pressure, discomfort, pain, ECG, blood pressure and BRS were continuously measured before, during and after rectal distension in 98 healthy volunteers (34 +/- 12 years old, 52 females) and 39 IBS patients (39 +/- 11 years old, 35 females). In comparison with the healthy volunteers, IBS patients experienced significantly more discomfort (69 +/- 2.2% vs 56 +/- 3.6%; P < 0.05), but not pain (9 +/- 1.4% vs 6 +/- 2.4%; ns) with rectal distension despite similar distension pressures (51 +/- 1.4 vs 54 +/- 2.4 mmHg; ns) and volumes (394 +/- 10.9 vs 398 +/- 21.5 mL; ns). With rectal distension, heart rate increased in both healthy volunteers (66 +/- 1 to 71 +/- 1 bpm; P < 0.05) and IBS patients (66 +/- 2 to 74 +/- 3 bpm; P < 0.05). Systolic blood pressure also increased in both healthy volunteers (121 +/- 2 to 143 +/- 2 mmHg; P < 0.05) and patients (126 +/- 3 to 153 +/- 4 mmHg (P < 0.05) as did diastolic blood pressure, 66 +/- 2 to 80 +/- 2 mmHg (P < 0.05), compared with 68 +/- 3 to 84 +/- 3 mmHg (P < 0.05) in IBS patients. The systolic blood pressure increase observed in IBS patients was greater than that seen in healthy volunteers and remained elevated in the post distension period (139 +/- 3 mmHg vs 129 +/- 2 mmHg; P < 0.05). IBS patients had lower BRS (7.85 +/- 0.4 ms mmHg(-1)) compared with healthy volunteers (9.4 +/- 0.3; P < 0.05) at rest and throughout rectal distension. Greater systolic blood pressure response to rectal distension and associated diminished BRS suggests a compromise of the autonomic nervous system in IBS patients.

Abdominal distension in irritable bowel syndrome (IBS): Is there a relationship to visceral sensitivity?

Abdominal distension in irritable bowel syndrome (IBS): Is there a relationship to visceral sensitivity?

Alterations in cerebral potentials evoked by rectal distension in irritable bowel syndrome.

Central nervous system correlates of the visceral hyperalgesia documented in patients with irritable bowel syndrome are limited. Reproducible cerebral evoked potentials can be recorded in response to rhythmic balloon distension of the rectum in healthy adults. Irritable bowel syndrome patients and healthy subjects were studied to compare the characteristics of mechanically-evoked rectal cerebral potentials obtained during fasting and after the ingestion of a standard meal. Twenty-two pairs of age-matched healthy female subjects and female irritable bowel syndrome patients were studied. Cerebral evoked potentials were recorded in response to rhythmic rectal distension (two distension series each of 100 repetitions at 0.8 hertz); cerebral evoked potential recordings were repeated after a 1000 kcal (46% fat) liquid meal. Trait and state anxiety questionnaires were also completed. Compared to healthy subjects, irritable bowel syndrome patients demonstrated higher prevalence of cerebral evoked potential early peaks (latency < 100 ms) postprandially, and uniformly shorter cerebral evoked potential latencies both before and after feeding. These findings provide further objective evidence for defective visceral afferent transmission in irritable bowel syndrome patients.

Alterations in cerebral potentials evoked by rectal distension in irritable bowel syndrome

OBJECTIVE: Central nervous system correlates of the visceral hyperalgesia documented in patients with irritable bowel syndrome are limited. Reproducible cerebral evoked potentials can be recorded in response to rhythmic balloon distension of the rectum in healthy adults. Irritable bowel syndrome patients and healthy subjects were studied to compare the characteristics of mechanically-evoked rectal cerebral potentials obtained during fasting and after the ingestion of a standard meal. METHODS: Twenty-two pairs of age-matched healthy female subjects and female irritable bowel syndrome patients were studied. Cerebral evoked potentials were recorded in response to rhythmic rectal distension (two distension series each of 100 repetitions at 0.8 hertz); cerebral evoked potential recordings were repeated after a 1000 kcal (46% fat) liquid meal. Trait and state anxiety questionnaires were also completed. RESULTS: Compared to healthy subjects, irritable bowel syndrome patients demonstrated higher prevalence of cerebral evoked potential early peaks (latency < 100 ms) postprandially, and uniformly shorter cerebral evoked potential latencies both before and after feeding. CONCLUSION: These findings provide further objective evidence for defective visceral afferent transmission in irritable bowel syndrome patients.

Ambulatory abdominal inductance plethysmography: towards objective assessment of abdominal distension in irritable bowel syndrome

BACKGROUNDAbdominal distension is one of the cardinal features of irritable bowel syndrome (IBS) with patients often ranking it as more intrusive than their pain or bowel dysfunction. If this symptom...

Ambulatory abdominal inductance plethysmography (AIP): Towards objective assessment of abdominal distension in irritable bowel syndrome

Ambulatory abdominal inductance plethysmography (AIP): Towards objective assessment of abdominal distension in irritable bowel syndrome

Bloating and distension in irritable bowel syndrome: Are they the same?

Bloating and distension in irritable bowel syndrome: Are they the same?