Irritable bowel syndrome: a little understood organic bowel disease?

Irritable bowel syndrome affects 10% of adults with an unexplained female predominance. Although only a few people see their family doctor, the disease causes reduced quality of life and represents a multi-billion pound health-care problem. The disorder clusters in families, which is possibly because of intra-familial learning and a genetic predisposition. Visceral hypersensitivity is a key feature in most patients. Results of imaging studies of regional cerebral blood flow during rectal distension suggest underlying disturbances of central processing of afferent signals, though this is not unique to the disorder, since it is seen in other chronic pain syndromes. Environmental factors that are strongly implicated in at least some patients include gastrointestinal infection and inflammation and chronic stress. Diagnosis is based on positive symptoms and absence of any alarm indicators. Treatment remains unsatisfactory and hinges on an excellent doctor-patient relationship, with drugs for symptom exacerbations. Cognitive behavioural treatment, psychotherapy, and hypnosis could provide long-lasting benefit in some patients. Tricyclic antidepressants in low doses seem to be the most effective class of drugs for the disorder on the basis of limited data.     

Irritable bowel syndrome and inflammatory bowel disease: infectious gastroenteritis-related disorders?

Infectious gastroenteritis may be one of the important factors in the development of irritable bowel syndrome (IBS), with affected individuals often categorized as having post-infectious IBS (PI-IBS), and is linked to the onset of symptoms in approximately 10–20% of patients diagnosed with IBS. Intestinal mucosal infiltration of T cells and mast cells, and enterochromaffin cell hyperplasia are significant immunological and pathological findings that reveal the pathogenesis of PI-IBS, and results of laboratory studies using animal models of PI-IBS clearly support clinical evidence. Recently, infectious gastroenteritis has also been suggested to be associated with the development of inflammatory bowel disease (IBD), and various studies have suggested that individuals with IBS or IBS-like symptoms may be susceptible to initiation of IBD. However, it is still unclear whether infectious gastroenteritis is directly or indirectly (through PI-IBS) linked to the initiation of IBD. Additional studies are necessary to understand the clinical overlap among infectious gastroenteritis, IBS, and IBD.     

Irritable bowel syndrome – Diarrhoea

IBS is a functional gastrointestinal disorder which has been subtyped according to bowel habits. This review presents recommendations for IBS-D which makes up about 1/3 of all patients and which is defined as IBS with loose or watery stools with ≥25% of bowel movements. Because IBS is a complex biopsychosocial illness, treatment cannot and should not be directed only to altered bowel habits. Evidence will be presented for dietary manipulations, probiotics and pharmacotherapies including tricyclic agents, antibiotics, serotonin antagonists and anti-diarrhoeal agents in the management of patients with IBS-D.     

Irritable bowel syndrome or endometriosis, or both?

Both irritable bowel syndrome and endometriosis are common conditions, although symptomatic gastrointestinal endometriosis is extremely rare. We report the case of a patient initially thought to have irritable bowel syndrome, in whom the diagnosis of endometriosis only became clear following a laparotomy for small bowel obstruction. This case highlights the need to question the diagnosis in patients with irritable bowel syndrome when there is any uncertainty, and also to appreciate that other pathology can arise, even when the diagnosis is secure.     

Irritable bowel syndrome: is the search for lactose intolerance justified?

OBJECTIVES: To determine if confirmation of hypolactasia offers any benefit to the dietary treatment of patients with irritable bowel syndrome (IBS). METHODS: One hundred and twenty-two consecutive IBS patients (37 male, 85 female) were given lactose hydrogen breath tests (LHBT). Those with positive LHBT followed a low lactose diet for 3 weeks. Those improving on the diet were given double-blind, placebo-controlled challenges (DBPCC) with 5 g, 10 g and 15 g of lactose and a placebo, to confirm lactose intolerance. Those who did not respond to the low lactose diet followed either an exclusion or low fibre diet. Symptoms scores were kept prior to the LHBT, 8 h post-LHBT and daily whilst following any dietary change. Patients with negative LHBT returned to clinic and subsequent dietary interventions were recorded. RESULTS: LHBT was positive in 33/122 (27%) IBS patients. Syrr otom scores prior to LHBT were not significantly different between the two groups, but after LHBT the symptoms in the positive group were significantly worse. Twenty-three patients followed a low-lactose diet of which only nine (39%) improved. Six who did not improve followed an exclusion diet, three improved and all were intolerant of milk. Three tried a low fibre diet with two improving. DBPCC were inconclusive. In the negative LHBT group 35 agreed to try a diet and 24 improved (69%). Eight were intolerant of cow's milk. CONCLUSIONS: Use of a low lactose diet was disappointing in IBS patients with lactose malabsorption. Food intolerance was demonstrated in IBS patients with positive or negative LHBT and milk was identified as a problem in both groups. DBPCC were inconclusive. There appears to be little advantage in trying to separate patients who malabsorb lactose from others with IBS.     

Irritable bowel syndrome and bronchial hyperresponsiveness: is there a link?

BACKGROUND/AIM: Many studies have demonstrated a high prevalence of bronchial hyperresponsiveness in patients with irritable bowel syndrome (IBS). The aim of this 24-month prospective study was to evaluate the prevalence of IBS in asthmatic patients. METHODS: We analyzed 623 asthmatic patients that were evaluated for body mass index, sex, and age before undergoing both a methacholine challenge test (MCHt) and skin prick tests. RESULTS: We found that 276 asthmatic patients (44.3%) were positive on the MCHt, while 347 (55.7%) were negative. We also found that 27 (9.7%) of the 276 patients with a positive MCHt and 44 (12.7%) of the 347 patients with a negative MCHt were affected by IBS. Therefore, there was no statistically significant difference between positive MCHt tests and IBS. The PC(20) (mean provocation concentration of methacholine producing a 20% reduction in forced expiratory volume in 1 s < or =16 mg/ml) in all patients tested was 8.64 +/- 2.58 mg/ml, being 8.75 +/- 2.52 and 8.55 +/- 2.32 mg/ml for males and females, respectively. CONCLUSIONS: These results do not demonstrate a relationship between MCHt and IBS. However, a relationship might still exist in a subpopulation of patients whose symptoms worsen by stress.     

Is irritable bowel syndrome an organic disorder?

Irritable bowel syndrome(IBS)is a common gastrointestinal disorder that is generally considered to be functional because there appears to be no associated anatomical defect.Stress and psychological factors are thought to play an important role in IBS.The gut neuroendocrine system(NES),which regulates all functions of the gastrointestinal tract,consists of endocrine cells that are scattered among the epithelial cells of the mucosa,and the enteric nervous system.Although it is capable of operating independently from the centra nervous system(CNS),the gut NES is connected to and modulated by the CNS.This review presents evidence for the presence of an anatomical defect in IBS patients,namely in the gastrointestinal endocrine cells.These cells have specialized microvilli that project into the lumen and function as sensors for the luminal content and respond to luminal stimuli by releasing hormones into the lamina propria,which starts a chain reaction that progresses throughout the entire NES.The changes in the gastrointestinal endocrine cells observed in IBS patients are highly consistent with the other abnormalities reported in IBS patients,such as visceral hypersensitivity,dysmotility,and abnormal secretion.     

Is irritable bowel syndrome an inflammatory disorder?

Histopathologic data demonstrate low-grade mucosal inflammation in a subset of patients with irritable bowel syndrome (IBS). This inflammatory infiltrate is mainly represented by increased numbers of T lymphocytes and mast cells lying in the lamina propria. The close apposition of immunocytes to gut nerves supplying the mucosa provides a basis for neuroimmune cross-talk, which may explain gut sensorimotor dysfunction and related symptoms in patients with IBS. A previous gastroenteritis (due to Campylobacter jejuni, Salmonella, Shigella, Escherichia coli, and, likely, viruses) is now an established etiologic factor for IBS (hence, postinfectious IBS). Other putative causes, such as undiagnosed food allergies, genetic abnormalities, stress, or bile acid malabsorption, may also promote and maintain a low-grade mucosal inflammation in IBS. The identification of mucosal inflammation in IBS has pathophysiologic implications and paves the way for novel therapeutic options.     

Irritable bowel syndrome: gender, infection, lifestyle or what else?

Irritable bowel syndrome (IBS) is characterised by abdominal pain and an erratic bowel habit, which depending on the definition used affects 5-10% of the population. As a typical complex disease, it is likely that the condition will develop when a genetically susceptible individual is exposed to an appropriate environment stimulus. This bio-psycho-social model assumes that there is no one cause of IBS, but rather that it is the product of complex interactions between host and environment. Host factors include gender, age and psychological characteristics, while environmental factors include psychosocial stressors, gastrointestinal infections, antibiotics and food.     

Irritable bowel syndrome: Bacteria and inflammation—Clinical relevance now

Opinion statement Irritable bowel syndrome (IBS) is a ubiquitous but heterogeneous syndrome characterized by abdominal pain and erratic bowel habits that affects 5% to 10% of the population. Although current definitions specify that there are no structural or biochemical abnormalities to account for the symptoms, there is growing evidence that in at least a subset of IBS patients, there is low-grade inflammation characterized by increased T lymphocytes and mast cells. Whether this is cause or effect is uncertain, as there is also clear evidence of bidirectional communication between the immune and nervous systems, and at least some of the mucosal changes could be secondary to psychological stress. A small percentage (6%–17%) of patients develop IBS symptoms for the first time after an acute episode of infective gastroenteritis (postinfective IBS), which appears to be directly responsible for low-grade immune activation. However, even in this group, preexisting psychological factors are as important as mucosal ones. Specific anti-inflammatory treatments have not been systematically evaluated, but there is no evidence of benefit currently.     

Irritable bowel syndrome and the Rome III criteria: for better or for worse?

The paper by Sperber et al. in this issue is an early evaluation of the Rome III criteria against the Rome II criteria for irritable bowel syndrome that throws up several important observations. A three to four-fold increase was observed in irritable bowel syndrome prevalence with the Rome III criteria. Individuals with the Rome II criteria had more doctor visits, perception of stress and a negative global feeling. There could be a shift of individuals between irritable bowel syndrome and other functional bowel disorder diagnostic groups such as functional constipation and functional bloating. In this review, it is suggested that rigid application of the symptom frequency and duration requirements of the older Rome criteria could have introduced a selection bias for patients with greater psychological disturbance, and that this could have impacted negatively on our perception and management of irritable bowel syndrome. The findings of Sperber et al. suggest that the new Rome III criteria may enable us to pay more attention to the average irritable bowel syndrome patient we see in our clinics as opposed to the chronically severe patient. It is proposed that improved management of our average patient may translate into better outcomes in terms of reduction in specialist referral, unnecessary surgery and potentially harmful alternative treatments.     

Irritable bowel syndrome and chronic pelvic pain： A singular or two different clinical syndrome？

Irritable bowel syndrome （IBS） and chronic pelvic pain （CPP） are both somatoform disorders with a high prevalence within the population in general. The objective was to compare both entities, to find the differences and the similarities related to epidemiology and psychosocial aspects like stressful life events, physical and sexual abuse, illness behaviour and comorbidity. The technical literature was reviewed systematically from 1971 to 2006 and compared. According to literature, IBS and CPP seem to be one rather than two different entities with the same Iocalisation of pain. Both syndromes also are similar concerning prevalence, the coexistence of mental and somatoform disorders, the common history of sexual and physical abuse in the past and their health care utilization. It could be shown that there were many similarities between IBS and CPP. Nevertheless both are traded as different clinical pictures as far. Therefore it seems to be reasonable and necessary to generate a common diagnosis algorithm and to bring gynaecologists and gastroenterologists into dialogue.     

Irritable bowel syndrome and gastroesophageal reflux disease in primary care: is there a link?

Population-based studies have shown that gastroesophageal reflux disease (GERD) and irritable bowel syndrome (IBS) coexist more commonly than expected by chance. We aimed to investigate the relationship between GERD and IBS in primary care. The General Practice Research Database was used to identify patients with a first diagnosis of GERD (n = 6,421) or IBS (n = 2,932). Patients were followed up for 12 months after diagnosis to investigate the incidence of IBS among GERD patients and GERD among IBS patients. The relative risk (RR) of developing IBS was 3.5 (95% CI: 2.3–5.4) in the GERD cohort compared with the comparison cohort. The RR of developing GERD was 2.8 (95% CI: 1.7–4.9) in the IBS cohort compared with the comparison cohort. A first diagnosis of either IBS or GERD significantly increases the risk of a subsequent diagnosis of the other condition.