Postinfection Irritable Bowel Syndrome

Following acute gastroenteritis (AGE) due to bacteria, viruses, or protozoa, a subset of patients develop new onset Rome criteria positive irritable bowel syndrome (IBS), called postinfection IBS (PI-IBS). The pooled prevalence of PI-IBS following AGE was 11.5%. PI-IBS is the best natural model that suggests that a subset of patients with IBS may have an organic basis. Several factors are associated with a greater risk of development of PI-IBS following AGE including female sex, younger age, smoking, severity of AGE, abdominal pain, bleeding per rectum, treatment with antibiotics, anxiety, depression, somatization, neuroticism, recent adverse life events, hypochondriasis, extroversion, negative illness beliefs, history of stress, sleep disturbance, and family history of functional gastrointestinal disorders (FGIDs), currently called disorder of gut-brain interaction. Most patients with PI-IBS present with either diarrhea-predominant IBS or the mixed subtype of IBS, and overlap with other FGIDs, such as functional dyspepsia is common. The drugs used to treat non-constipation IBS may also be useful in PI-IBS treatment. Since randomized controlled trials on the efficacy of drugs to treat PI-IBS are rare, more studies are needed on this issue.     

Postinfectious Irritable Bowel Syndrome

Opinion statement  

Gastroparesis and Small Bowel Dysmotility in Irritable Bowel Syndrome

Alterations in both gastric emptying (GE) andsmall bowel motility have been reported in irritablebowel syndrome (IBS); the relationship, however, betweenthese different measures of upper gut motor function in IBS has not been assessed. The aims of thisstudy were therefore: (1) to compare the prevalence andcharacteristics of altered small bowel motility in IBSpatients with and without delayed GE; and (2) to assess the interrelationships betweenfasting and postprandial small bowel motility in IBS,accounting for delayed GE. Forty-four IBS patients and25 healthy controls underwent 24 hr ambulant recording of interdigestive and digestive small bowelmotility. On a separate occasion the IBS patients had GEof both solids and liquids measured by a dual-isotopescintigraphic technique. Thirty-nine percent of IBS patients had delayed GE. Patients withnormal GE had no interdigestive small bowelabnormalities. However, in patients with delayed GEfasting phase II burst frequency was higher than incontrols [median 0.21/hr (IQR 0.15–0.34) vs 0.06/hr(0–0,16), P = 0.004]. Postprandially, abnormalphase III-like activity was higher indiarrhea-predominant IBS patients (0–0.08/hr vs0/hr, P = 0.01), than in patients with normal GE or controls. Furthermore, IBSpatients with delayed GE did not have the normalcorrelation between fasting and postprandial motorparameters (percentage occurrence of clusteredcontractions, postprandial pattern duration vs preceding MMC cyclelength). In conclusion, small bowel motor dysfunctionoccurs more frequently in IBS patients with concomitantgastroparesis than in patients with normal GE. These findings provide further evidence that aneuropathic process may contribute to the pathogenesisof IBS in a subgroup of IBS patients.     

Bronchial Hyperresponsiveness in Irritable Bowel Syndrome

Extraintestinal symptoms are often found in patients with irritable bowel syndrome (IBS). Recent studies suggest that IBS is associated with bronchial hyperresponsiveness. But it is still arguable that the bronchial hyperresponsiveness is associated with IBS patients. The purpose of this study is to investigate the possible relationship between IBS and bronchial hyperresponsiveness. Forty-two patients with IBS and 42 control subjects were included in this study. All patients underwent pulmonary function, methacholine challenge, and skin prick tests. There was no statistical difference between the two groups with respect to percentage of all pulmonary function test parameters, including FEV₁%, FCV%, FVC/FEV₁, and FEF_{25 − 75}%. Only two persons in the alternating-type IBS patient group and one person in the control group tested positive in the methacholine provocation test. But all PC₂₀ values were above 16 mg/ml. These results do not demonstrate a relationship between bronchial hyperresponsiveness and IBS. However, a relationship might exist in a subpopulation of IBS patients.     

膳食纤维与肠易激综合征

肠易激综合征(IBS)为常见功能性肠病,临床表现多样,严重影响患者生活质量,消耗大量医疗资源。饮食调整是IBS的重要治疗手段之一。膳食纤维一般指食物中不被人体小肠内源性酶水解的碳水化合物聚合物,具有增加粪便容积的作用。很多研究探讨了增加膳食纤维摄入对IBS的影响,但尚无明确结论。多数研究认为不溶性纤维对IBS症状无益,而可溶性纤维则有一定作用。分别研究不溶性和可溶性纤维对不同IBS亚型作用的设计良好的大样本随机对照试验有待开展。