Lesley A. Houghton

Guidelines on the irritable bowel syndrome: mechanisms and practical management

Background: IBS affects 5–11% of the population of most countries. Prevalence peaks in the third and fourth decades, with a female predominance. Aim: To provide a guide for the assessment and management of adult patients with irritable bowel syndrome. Methods: Members of the Clinical Services Committee of The British Society of Gastroenterology were allocated particular areas to produce review documents. Literature searching included systematic searches using electronic databases such as Pubmed, EMBASE, MEDLINE, Web of Science, and Cochrane databases and extensive personal reference databases. Results: Patients can usefully be classified by predominant bowel habit. Few investigations are needed except when diarrhoea is a prominent feature. Alarm features may warrant further investigation. Adverse psychological features and somatisation are often present. Ascertaining the patients’ concerns and explaining symptoms in simple terms improves outcome. IBS is a heterogeneous condition with a range of treatments, each of which benefits a small proportion of patients. Treatment of associated anxiety and depression often improves bowel and other symptoms. Randomised placebo controlled trials show benefit as follows: cognitive behavioural therapy and psychodynamic interpersonal therapy improve coping; hypnotherapy benefits global symptoms in otherwise refractory patients; antispasmodics and tricyclic antidepressants improve pain; ispaghula improves pain and bowel habit; 5-HT3 antagonists improve global symptoms, diarrhoea, and pain but may rarely cause unexplained colitis; 5-HT4 agonists improve global symptoms, constipation, and bloating; selective serotonin reuptake inhibitors improve global symptoms. Conclusions: Better ways of identifying which patients will respond to specific treatments are urgently needed.

Clinical trial: the effects of a fermented milk product containing Bifidobacterium lactis DN‐173 010 on abdominal distension and gastrointestinal transit in irritable bowel syndrome with constipation

Background  A sensation of abdominal swelling (bloating) and actual increase in girth (distension) are troublesome features of irritable bowel syndrome (IBS), which is more common in patients with constipation, especially those with delayed transit.

The menstrual cycle affects rectal sensitivity in patients with irritable bowel syndrome but not healthy volunteers

Background: We have previously shown that the menstrual cycle has no effect on rectal sensitivity of normal healthy women, despite them having looser stools at the time of menses. Patients with irritable bowel syndrome (IBS) often report significant exacerbation of their IBS symptoms with menses, raising the possibility that IBS patients may respond differently to the menstrual cycle. Aim and methods: Rectal responses to balloon distension during days 1–4 (menses), 8–10 (follicular phase), 18–20 (luteal phase), and 24–28 (premenstrual phase) of the menstrual cycle were assessed in 29 female IBS patients (aged 21–44 years), diagnosed by the Rome I criteria. During the course of the study patients completed symptom diaries to assess abdominal pain and bloating (visual analogue scale), and frequency and consistency of bowel habits. In addition, levels of anxiety and depression were assessed using the hospital anxiety and depression questionnaire. Results: Menses was associated with a worsening of abdominal pain and bloating compared with most other phases of the menstrual cycle (p<0.05). Bowel habits also became more frequent (p<0.05) and patients tended to have a lower general well being. Rectal sensitivity increased at menses compared with all other phases of the cycle (p<0.05). There was no associated change in rectal compliance, wall tension, or motility index. Neither was there any difference in resting anal pressure or the distension volumes required to relax the internal anal sphincter during the menstrual cycle. Conclusion: These data (1) confirm that IBS symptomatology is exacerbated at menses and (2) show for the first time that in contrast with healthy women, rectal sensitivity changes with the menstrual cycle. These cyclical changes in sensitivity suggest that women with IBS respond differently to fluctuations in their sex hormonal environment or its consequences compared with healthy females.

Hypnotherapy in irritable bowel syndrome: A large-scale audit of a clinical service with examination of factors influencing responsiveness

Hypnotherapy in irritable bowel syndrome: a large-scale audit of a clinical service with examination of factors influencing responsiveness

Increased platelet depleted plasma 5-hydroxytryptamine concentration following meal ingestion in symptomatic female subjects with diarrhoea predominant irritable bowel syndrome.

Background: Meal ingestion is often associated with exacerbation of gastrointestinal symptoms in subjects with irritable bowel syndrome (IBS). Furthermore, recent preliminary data suggest that 5-hydroxytryptamine (5-HT) concentration in platelet poor plasma is elevated following meal ingestion in some subjects with diarrhoea predominant IBS (d-IBS) compared with healthy subjects, although it is not known whether this is related to postprandial symptomatology. Aim: To expand on previous data by evaluating a larger number of subjects but also to assess plasma 5-hydroxyindole acetic acid (5-HIAA) concentrations, 5-HT turnover, platelet 5-HT stores, and any relationship to symptomatology. Methods: We assessed platelet depleted plasma 5-HT and 5-HIAA concentrations for two hours (60 minute intervals) under fasting conditions, and then for a further four hours (30 minute intervals) after a standard carbohydrate meal (457 kcal), together with fasting platelet 5-HT concentrations in 39 female subjects with d-IBS (aged 19–52 years; mean age 33) and 20 healthy female volunteers (aged 20–46 years, mean age 28). IBS symptomatology, in particular abdominal pain and bloating, and urgency to defecate were assessed throughout the study Results: When related to fasting levels, there was no statistically significant difference in postprandial plasma 5-HT concentrations between d-IBS and healthy subjects. However, when fasting levels were not taken into consideration, d-IBS subjects exhibited higher postprandial plasma 5-HT concentrations compared with healthy subjects (p=0.040). Furthermore, d-IBS subjects who exhibited postprandial symptomatology had higher levels of postprandial plasma 5-HT, whether assessed with respect to fasting baseline levels (p=0.069) or not (p=0.047), compared with d-IBS subjects who did not report postprandial symptomatology. This appeared to be associated with a concomitant increase in plasma 5-HIAA (p=0.161) but reduction in turnover (p=0.058). Lastly, d-IBS subjects had higher platelet concentrations of 5-HT than healthy subjects (p=0.009). Conclusions: These data suggest that postprandial symptomatology may be associated with increased platelet depleted plasma 5-HT concentrations in female subjects with d-IBS. In addition, the presence of increased platelet stores of 5-HT may act as a useful marker for the diagnosis and management of d-IBS.

Effect of a second‐generation α2δ ligand (pregabalin) on visceral sensation in hypersensitive patients with irritable bowel syndrome

Background: Visceral hypersensitivity is an important pathophysiological factor in irritable bowel syndrome (IBS). Pre-clinical studies suggest that the α2δ ligand pregabalin reduces both visceral allodynia and hyperalgesia, but is inactive on basal sensitivity. Aim: To assess the effect of pregabalin on the perception of rectal distension in hypersensitive IBS patients. Methods: Twenty-six patients with Rome-II-defined IBS (aged 18–46 years, 7 male) were included in a randomized, double-blind, placebo-controlled, parallel-group study in which they received either 3 weeks oral pregabalin (titrated: 50 mg tid days 1–3, 100 mg tid days 4–7, 150 mg tid days 8–11; fixed 200 mg tid days 12–21 ±4) or placebo control. Rectal sensitivity was assessed using a barostat technique, in which sensory thresholds were determined using the ascending method of limits, followed by tracking both before and after treatment. Only patients with a pain threshold of ⩽28 mmHg were included in the study. Results: Pregabalin significantly increased the sensory thresholds from baseline for first sensation (p = 0.045), desire to defecate (p = 0.008) and pain (p = 0.048) compared with placebo control. In addition, pregabalin significantly increased rectal compliance (p<0.0001), although this appeared to be unrelated to the changes in sensitivity. Despite the occurrence of mild dizziness and somnolence, pregabalin was generally well tolerated. Conclusions: Pregabalin increased distension sensory thresholds to normal levels in IBS patients with rectal hypersensitivity. A concomitant increase in rectal compliance appeared to be unrelated to the reduction in sensitivity. These data suggest that α2δ ligands are worthy of further investigation in the treatment of visceral pain disorders, including IBS.

Gut-focused hypnotherapy normalizes disordered rectal sensitivity in patients with irritable bowel syndrome

Background : We have previously shown that hypnotherapy alters rectal sensitivity in some patients with irritable bowel syndrome. However, this previous study used incremental volume distension of a latex balloon, which might be susceptible to subject response bias and might compromise the assessment of compliance. In addition, the study group was symptomatically rather than physiologically defined.

Acoustic Cough?Reflux Associations in Chronic Cough: Potential Triggers and Mechanisms

BACKGROUND & AIMS Central sensitization is thought to play a role in chronic cough and might explain the temporal association between cough and gastroesophageal reflux (GOR) in patients in whom non-GOR causes have been excluded. Using our novel simultaneous acoustic cough recording and impedance/pH monitoring technique, we aimed to explore this further by assessing such temporal associations and their relationship to the acidity, duration, and proximal extent of reflux and the presence of erosive disease and cough reflex sensitivity in unselected patients (ie, including non-GOR causes) with chronic cough. METHODS Twenty-four hour ambulatory acoustic cough monitoring with simultaneous impedance/pH recording was carried out in 71 unselected patients with chronic cough, aged 51-64 years (47 female). In addition, all patients underwent cough reflex sensitivity testing to citric acid, and 66 patients underwent gastroscopy. Temporal associations between cough and reflux were expressed using the symptom association probability. RESULTS Seventy percent of patients exhibited temporal associations, with 48% having a positive symptom association probability (SAP(R-C)) for cough preceded by reflux (mainly distal), 56% a positive symptom association probability (SAP(C-R (2 min))) for reflux preceded by cough, and 32% both. Moreover, SAP(R-C) positive patients had a more sensitive cough reflex (P = .03) but similar esophageal reflux exposure and erosive disease, together with similar prevalence of extraesophageal causes of cough compared with SAP(R-C) negative patients. Reflux immediately following cough was rare. CONCLUSIONS Cough temporally associates with reflux irrespective of proposed diagnoses, may be self-perpetuating in some patients, and is likely to be driven by central processes.

Physiological effects of emotion: assessment via hypnosis

Assessment of the physiological effects of physical and emotional stress has been hampered by a lack of suitable laboratory techniques. Since hypnosis can be used safely to induce specific emotional states of considerable intensity, we studied the effect on distal colonic motility of three hypnotically induced emotions (excitement, anger, and happiness) in 18 patients aged 20-48 years with irritable bowel syndrome. Colonic motility index was reduced by hypnosis on its own (mean change 19.1; 95% CI 0.8, 37.3; p less than 0.05) and this change was accompanied by decreases in both pulse (12; 8, 15) and respiration (6; 4, 8) rates (p less than 0.001 for both). Anger and excitement increased the colonic motility index (50.8; 29.4, 72.2; and 30.4; 8.9, 51.9, respectively; p less than 0.01 for both), pulse rate (26; 22, 30; and 28; 24, 32; p less than 0.001 for both), and respiration rate (14; 12, 16; and 12; 10, 14; p less than 0.001 for both). Happiness further reduced colonic motility although not significantly from that observed during hypnosis alone. Changes in motility were mainly due to alterations in rate than in amplitude of contractions. Our results indicate that hypnosis may help in the investigation of the effects of emotion on physiological functions; this approach could be useful outside the gastrointestinal system. Our observation that hypnosis strikingly reduces fasting colonic motility may partly explain the beneficial effects of this form of therapy in functional bowel disorders.

Alosetron, a 5-HT3 receptor antagonist, delays colonic transit in patients with irritable bowel syndrome and healthy volunteers

Alosetron is a potent and selective 5‐HT3 receptor antagonist, which has been shown to be beneficial in the treatment of female patients with non‐constipated irritable bowel syndrome.