Gastric emptying rate and small bowel transit time in patients with irritable bowel syndrome determined with 99mTc-labeled pellets and scintigraphy

Evaluation of gallbladder contractility and Doppler findings in patients with irritable bowel syndrome; a case-control study

BACKGROUND

Irritable Bowel Syndrome (IBS) is a common gastrointestinal disorder causing abdominal pain, altered bowel habits and bloating without structural issues. Gallbladder dysfunction may be linked to IBS due to disrupted cholecystokinin release. This study aims to assess gallbladder function and related hemodynamic parameters using Doppler ultrasound in IBS before and after meals.

METHOD

In this case-control study, we investigated gallbladder function differences between constipation-predominant IBS (C-IBS) patients and healthy volunteers. Participants underwent ultrasonography to measure gallbladder parameters before and after consuming a predefined meal. Gallbladder volume, wall thickness and resistance index (RI) of cystic and superior mesenteric arteries (SMA) were assessed. Student t-test and paired t-test were used to compare case and control groups and pre- and post-meal data, respectively.

RESULTS

A total of 34 people (18 C-IBS and 16 healthy control) were included. The mean (Standard deviation) of gallbladder fasting volume was measured 24.74 (8.85) and 29.73 (9.65) cubic millimeter for case and controls, respectively. Postprandial volume was 11.34 (5.66) and 16.9 (6.16) cubic millimeter for case and controls respectively. We observed a statistically significant difference in emptying fractions (EF) between groups (p value = 0.009). IBS patients had a smaller fasting SMA RI (p value = 0.016) but the fraction of change after meal was not significant (p value = 0.10). The cystic artery RI did not reach statistical significance between the fasting and post-meal values (p value = 0.067).

CONCLUSION

IBS patients have a higher emptying fraction and lower change in SMA RI compared to healthy controls. Further studies with larger sample size, inclusion of patients with different coexisting conditions and subtypes of IBS and combining colon transit study with gallbladder ejection fraction evaluation can be used to further provide more meaning to this study.

Postprandial effect of gastrointestinal hormones and gastric activity in patients with irritable bowel syndrome

Altered gut regulation, including motor and secretory mechanisms, is characteristic of irritable bowel syndrome (IBS). The severity of postprandial symptoms in IBS patients is associated with discomfort and pain; gas-related symptoms such as bloating and abdominal distension; and abnormal colonic motility. The aim of this study was to assess the postprandial response, i.e., gut peptide secretion and gastric myoelectric activity, in patients with constipation-predominant IBS. The study was conducted on 42 IBS patients (14 males, 28 females, mean age 45.1 ± 15.3 years) and 42 healthy participants (16 males, 26 females, mean age 41.1 ± 8.7 years). The study assessed plasma gut peptide levels (gastrin, CCK-Cholecystokinin, VIP-Vasoactive Intestinal Peptide, ghrelin, insulin) and gastric myoelectric activity obtained from electrogastrography (EGG) in the preprandial and postprandial period (meal-oral nutritional supplement 300 kcal/300 ml). Mean preprandial gastrin and insulin levels were significantly elevated in IBS patients compared to the control group (gastrin: 72.27 ± 26.89 vs. 12.27 ± 4.91 pg/ml; p < 0.00001 and insulin: 15.31 ± 12.92 vs. 8.04 ± 3.21 IU/ml; p = 0.0001), while VIP and ghrelin levels were decreased in IBS patients (VIP: 6.69 ± 4.68 vs. 27.26 ± 21.51 ng/ml; p = 0.0001 and ghrelin: 176.01 ± 88.47 vs. 250.24 ± 84.55 pg/ml; p < 0.0001). A nonsignificant change in the CCK level was observed. IBS patients showed significant changes in postprandial hormone levels compared to the preprandial state-specifically, there were increases in gastrin (p = 0.000), CCK (p < 0.0001), VIP (p < 0.0001), ghrelin (p = 0.000) and insulin (p < 0.0001). Patients with IBS showed reduced preprandial and postprandial normogastria (59.8 ± 22.0 vs. 66.3 ± 20.2%) compared to control values (83.19 ± 16.7%; p < 0.0001 vs. 86.1 ± 9.4%; p < 0.0001). In response to the meal, we did not observe an increase in the percentage of normogastria or the average percentage slow-wave coupling (APSWC) in IBS patients. The postprandial to preprandial power ratio (PR) indicates alterations in gastric contractions; in controls, PR = 2.7, whereas in IBS patients, PR = 1.7, which was significantly lower (p = 0.00009). This ratio reflects a decrease in gastric contractility. Disturbances in the postprandial concentration of gut peptides (gastrin, insulin and ghrelin) in plasma may contribute to abnormal gastric function and consequently intestinal motility, which are manifested in the intensification of clinical symptoms, such as visceral hypersensitivity or irregular bowel movements in IBS patients.

Asia-Pacific guidelines for managing functional dyspepsia overlapping with other gastrointestinal symptoms

Contemporary systems for the diagnosis and management gastrointestinal symptoms not attributable to organic diseases (Functional GI Disorders, FGID, now renamed Disorders of Gut-Brain Interaction, DGBI) seek to categorize patients into narrowly defined symptom-based sub-classes to enable targeted treatment of patient cohorts with similar underlying putative pathophysiology. However, an overlap of symptom categories frequently occurs and has a negative impact on treatment outcomes. There is a lack of guidance on their management. An Asian Pacific Association of Gastroenterology (APAGE) working group was set up to develop clinical practice guidelines for management of patients with functional dyspepsia (FD) who have an overlap with another functional gastrointestinal disorder: FD with gastroesophageal reflux (FD-GERD), epigastric pain syndrome with irritable bowel syndrome (EPS-IBS), postprandial distress syndrome with IBS (PDS-IBS), and FD-Constipation. We identified putative pathophysiology to provide a basis for treatment recommendations. A management algorithm is presented to guide primary and secondary care clinicians.

Recent advances in the diagnosis of irritable bowel syndrome

The symptom-based diagnosis of irritable bowel syndrome (IBS) has not been established in everyday clinical practice, and the diagnosis of this disorder remains one of exclusion. It has been demonstrated that the densities of duodenal chromogranin A, rectal peptide YY and somatostatin cells are good biomarkers for the diagnosis of sporadic IBS, and low-grade mucosal inflammation is a promising biomarker for the diagnosis of postinfectious IBS. Genetic markers are not useful as biomarkers for IBS since the potential risk genes have yet to be validated, and the intestinal microbiota cannot be used because of the lack of an association between a specific bacterial species and IBS. Furthermore, gastrointestinal dysmotility and visceral hypersensitivity tests produce results that are too nonconsistent and noncharacteristic to be used in the diagnosis of IBS. A combination of symptom-based assessment, exclusion of overlapping gastrointestinal diseases and positive biomarkers appears to be the best way to diagnose IBS.

Analysis of factors influencing gastric emptying of pellets in a fed state

OBJECTIVES

The aim of the present study is to evaluate the influence of factors such as biopharmaceutical properties and study protocol on the emptying of pellets from the human stomach in a fed state.

METHODS

A systematic literature search for data on human gastric emptying of pellets from a fed stomach state investigated by γ-scintigraphy was carried out. After selection of comparable data, a joint statistical analysis on the basis of multiple linear regression with 132 individual t50 values (time for 50% of the pellets to be emptied from the stomach) was performed. Parameters such as a second meal administration that can influence t50 values were also examined and included into the interpretation of the results.

RESULTS

The results showed that an increase in the caloric value of the meal in the interval between 1200 and 3600 kJ increased the mean t50 value. Pellets with a density of 2.8 g/cm(3) remained in the stomach longer than pellets of usual density with the same caloric value of the meal. Pellets incorporated in a tablet are emptied faster from the stomach than encapsulated pellets. A 45-min delay in the application of pellets after the start of the meal significantly diminished the mean t50 value, compared with application immediately after consuming the meal.

CONCLUSION

Thus, in the development of non-disintegrating pellets intended for fed-state application, all of these cited factors should be considered because of their potential influence on the gastric residence time.

Interaction between ingested nutrients and gut endocrine cells in patients with irritable bowel syndrome (review)

Several endocrine cell abnormalities have been reported in different segments of the gastrointestinal tract of patients with irritable bowel syndrome (IBS). These cells have specialized microvilli that project into the lumen; they function as sensors for the gut contents and respond to luminal stimuli (mostly ingested nutrients) by releasing hormones into the lamina propria, where they exert their effects via a paracrine/endocrine mode of action. Certain food items trigger the symptoms experienced by IBS patients, including those rich in fermentable oligo-, di- and monosaccharides, and polyols (FODMAPs). In this review, we present the argument that the effects of both FODMAPs and the proportional intake of proteins, fats and carbohydrates on IBS symptoms may be caused by an interaction with the gut endocrine cells. Since the gut hormones control and regulate gastrointestinal motility and sensation, this interaction may be responsible for abnormal gastrointestinal motility and the visceral hypersensitivity observed in these patients. There is no consistent evidence that IBS patients suffer from food allergy. The role of gluten intolerance in the development of IBS symptoms in these patients remains a matter of controversy. Individual guidance on food management, which includes restrictions in the intake of FODMAP-rich foods and testing diets with different proportions of proteins, fats and carbohydrates has been found to reduce the symptoms, improve the quality of life, and make the habitual diet of IBS patients more healthy.

Ultrasonographic assessment of liquid gastric emptying and antral motility according to the subtypes of irritable bowel syndrome in children

OBJECTIVES

Gastric motor abnormalities have been reported in adults with irritable bowel syndrome (IBS), commonly in constipation-predominant IBS (IBS-C); however, such studies are uncommon in children. Furthermore, differences of gastric motility have not been studied in children with different IBS subtypes.

METHODS

Seventy-six children (33 [43%] boys, age 4-14 years, mean 7.9 years, SD 3.0 years) fulfilling Rome III criteria for IBS and 20 healthy controls (8 [40%] boys, age 4-14 years, mean 8.4 years, SD 3.0 years) were recruited (diarrhea-predominant IBS=21, IBS-C=31, mixed IBS=19, and unsubtyped IBS=5). Liquid gastric emptying rate (GER) and antral motility were assessed using an ultrasound method.

RESULTS

Average GER (43.8% vs 66.2% in controls), amplitude of antral contractions (56.4% vs 89%), and antral motility index (5.1 vs 8.3) were lower and fasting antral area (1.6 vs 0.6) was higher in patients with IBS (P<0.0001). Frequency of antral contractions F (8.9 vs 9.3) did not show a significant difference. Patients exposed to stressful events had a significantly lower GER, compared to those not exposed to such events (P=0.03). Gastric motility parameters had no correlation with severity of symptoms. GER (42.6%, 46.3%, 39.6%), fasting antral area (1.4 cm², 1.8 cm², 1.8 cm²), amplitude of antral contractions (53%, 58.9%, 51.8%), frequency of antral contractions (8.7, 8.9, 9.2), and antral motility index (4.7, 5.3, 4.8) were not different among diarrhea-predominant IBS, IBS-C, and mixed IBS (P>0.05).

CONCLUSIONS

GER and antral motility parameters were significantly impaired in children with IBS compared with controls. GER and antral motility parameters were not different between IBS subtypes.

Asian motility studies in irritable bowel syndrome

Altered motility remains one of the important pathophysiologic factors in patients with irritable bowel syndrome (IBS) who commonly complain of abdominal pain and stool changes such as diarrhea and constipation. The prevalence of IBS has increased among Asian populations these days. Gastrointestinal (GI) physiology may vary between Asian and Western populations because of differences in diets, socio-cultural backgrounds, and genetic factors. The characteristics and differences of GI dysmotility in Asian IBS patients were reviewed. MEDLINE search work was performed including following terms, 'IBS,' 'motility,' 'transit time,' 'esophageal motility,' 'gastric motility,' 'small intestinal motility,' 'colonic motility,' 'anorectal function,' and 'gallbladder motility' and over 100 articles were categorized under 'esophagus,' 'stomach,' 'small intestine,' 'colon,' 'anorectum,' 'gallbladder,' 'transit,' 'motor pattern,' and 'effect of stressors.' Delayed gastric emptying, slow tansit in constipation predominant IBS patients, rapid transit in diarrhea predominant IBS patients, accelerated motility responses to various stressors such as meals, mental stress, or corticotrophin releasing hormones, and altered rectal compliance and altered rectal accomodation were reported in many Asian studies regarding IBS. Many conflicting results were found among these studies and there are still controversies to conclude these as unique features of Asian IBS patients. Multinational and multicenter studies are needed to be performed vigorously in order to elaborate characteristics as well as differences of altered motililty in Asian patients with IBS.

Peripheral factors in the pathophysiology of irritable bowel syndrome

The pathophysiology of IBS is complex and still incompletely known. Both central and peripheral factors are thought to contribute to the symptoms of IBS, including psychosocial factors, abnormal GI motility and secretion, and visceral hypersensitivity. In this review the involvement of peripheral factors in the pathophysiology in IBS is reviewed. Altered GI motility is commonly found in this patient group, even though a specific motor pattern has been hard to find. Colonic transit has been found to be of relevance for the bowel habit of the patient. Abnormal gas handling within the gut is also commonly seen, and seems to be one, but not the only factor responsive for bloating. There is also limited evidence supporting the presence of abnormal GI secretion in IBS, but its relevance for symptoms remains unclear. Visceral hypersensitivity is currently considered to be one of the most important pathophysiological factors in IBS. It can be modulated by several external and internal factors and recent studies support an association between colorectal sensitivity and the symptoms reported by the patients, especially pain.

Gastric myoelectrical and motor abnormalities in children and adolescents with functional recurrent abdominal pain

BACKGROUND AND AIMS

Recurrent abdominal pain is common among children and adolescents. The majority of the affected patients have no apparent cause for their symptoms. This study evaluated gastric myoelectrical activity and motility abnormalities in children and adolescents with functional recurrent abdominal pain.

METHODS

Forty-two children with functional recurrent abdominal pain [19 (45.2%) males, mean 8 years, SD 3 years, 19 functional abdominal pain, 9 irritable bowel syndrome, 9 functional dyspepsia, 1 abdominal migraine, 1 aerophagia and 3 non-specific abdominal pain according to Rome III criteria] and 20 healthy children [10 (50%) males, mean 9 years, SD 2.7 years] from the same geographical area underwent electrogastrography (EGG), and ultrasonographic assessment of gastric emptying rate and antral motility.

RESULTS

Average gastric emptying rate, amplitude of antral contractions and antral motility index were lower in patients (46.5%, 74.3% and 6.5 respectively) compared to controls (66.17%, 89% and 8.3 respectively) (P < 0.001). Gastric emptying rate had a negative correlation with scores obtained for severity of symptoms (r = -0.63, P < 0.0001). Postprandial dominant frequency instability co-efficient (post-DFIC) was higher in patients than in controls (27.83% vs 18.3%, P = 0.0087), and correlated with the symptom score (r = 0.26, P = 0.045).

CONCLUSIONS

Gastric emptying and antral motility were significantly impaired in patients, indicating a possible role for gastric motility disturbances in the pathogenesis of childhood functional recurrent abdominal pain. Further studies, including therapeutic trials, are needed to confirm this association and for recommendation of prokinetic drugs in its management.

The clinical overlap between functional dyspepsia and irritable bowel syndrome based on Rome III criteria

BACKGROUND

Epidemiological studies suggest considerable overlap between functional dyspepsia (FD) and irritable bowel syndrome (IBS). To date, no surveys have been performed to investigate the clinical overlap between these two disorders using Rome III criteria. Our aim was to investigate the prevalence and risk factors for the overlap of FD and IBS based on Rome III criteria in a large clinical sample.

METHODS

Consecutive patients at the general gastroenterology outpatient clinic were requested to complete a self-report questionnaire. FD and IBS were defined by Rome III criteria.

RESULTS

Questionnaires were returned by 3014 patients (52.8% female, 89% response rate). FD-IBS overlap was observed in 5.0% of the patients, while 15.2% and 10.9% of the patients were classified as FD alone and IBS alone, respectively. Compared with non-IBS patients, the odds ratio of having FD among IBS patients was 2.09 (95% CI: 1.68-2.59). Patients with FD-IBS overlap had higher severity scores for the postprandial fullness symptom (2.35 +/- 1.49 vs. 1.72 +/- 1.59, P < 0.001) and overall FD symptom (6.65 +/- 2.88 vs. 5.82 +/- 2.76, P = 0.002) than those with FD alone. The only independent risk factor for FD-IBS overlap vs. FD alone was the presence of postprandial fullness symptom (OR 2.67, 95% CI: 1.34-5.31).

CONCLUSION

Clinical overlap of FD and IBS according to Rome III criteria is very common. One risk factor for FD-IBS overlap is the presence of postprandial fullness symptom. This study provides clues for future pathophysiological studies of FD and IBS.

The clinical overlap between functional dyspepsia and irritable bowel syndrome based on Rome III criteria

Background

Epidemiological studies suggest considerable overlap between functional dyspepsia (FD) and irritable bowel syndrome (IBS). To date, no surveys have been performed to investigate the clinical overlap between these two disorders using Rome III criteria. Our aim was to investigate the prevalence and risk factors for the overlap of FD and IBS based on Rome III criteria in a large clinical sample.

Methods

Consecutive patients at the general gastroenterology outpatient clinic were requested to complete a self-report questionnaire. FD and IBS were defined by Rome III criteria.

Results

Questionnaires were returned by 3014 patients (52.8% female, 89% response rate). FD-IBS overlap was observed in 5.0% of the patients, while 15.2% and 10.9% of the patients were classified as FD alone and IBS alone, respectively. Compared with non-IBS patients, the odds ratio of having FD among IBS patients was 2.09 (95% CI: 1.68–2.59). Patients with FD-IBS overlap had higher severity scores for the postprandial fullness symptom (2.35 ± 1.49 vs. 1.72 ± 1.59, P < 0.001) and overall FD symptom (6.65 ± 2.88 vs. 5.82 ± 2.76, P = 0.002) than those with FD alone. The only independent risk factor for FD-IBS overlap vs. FD alone was the presence of postprandial fullness symptom (OR 2.67, 95% CI: 1.34–5.31).

Conclusion

Clinical overlap of FD and IBS according to Rome III criteria is very common. One risk factor for FD-IBS overlap is the presence of postprandial fullness symptom. This study provides clues for future pathophysiological studies of FD and IBS.

Functional findings in irritable bowel syndrome

The pathophysiology of IBS is complex and still incompletely known. Both central and peripheral factors, including psychosocial factors, abnormal GI motility and secretion, and visceral hypersensitivity, are thought to contribute to the symptoms of IBS. Several studies have demonstrated altered GI motor function in IBS patients and the pattern differs between IBS subgroups based on the predominant bowel pattern. Few studies have so far addressed GI secretion in IBS, but there are some evidence supporting altered secretion in the small intestine of IBS patients. Visceral hypersensitivity is currently considered to be perhaps the most important pathophysiological factor in IBS. Importantly, several external and internal factors can modulate visceral sensitivity, as well as GI motility, and enhanced responsiveness within the GI tract to for instance stress and nutrients has been demonstrated in IBS patients. Today IBS is viewed upon as a disorder of dysregulation of the so-called brain-gut axis, involving abnormal function in the enteric, autonomic and/or central nervous systems, with peripheral alterations probably dominating in some patients and disturbed central processing of signals from the periphery in others.

Functional dyspepsia and irritable bowel syndrome, are they different entities and does it matter

A high prevalence of overlap between functional dyspepsia and irritable bowel syndrome has been consistently and universally reported. Recent studies demonstrating shared common pathophysiological disturbances including delayed gastric emptying and visceral hypersensitivity involving more than one region, suggest that these patients have a generalised rather than regional, disorder of the gut. Furthermore, a study of the natural history of dyspepsia suggests that with time, a substantial proportion will evolve into IBS. The recognition of IBS in dyspeptic patients has potentially profound therapeutic importance. It could help to reduce the risk of unnecessary cholecystectomy in IBS patients. The ability to appreciate the extent of involvement could allow us to address the disturbances more comprehensively, and thereby achieve greater patient satisfaction with their treatment.

Meta-analysis: The treatment of irritable bowel syndrome

To evaluate therapies available for the treatment of irritable bowel syndrome, and provide consensus recommendations for their use, a total of 51 double-blind clinical trials using bulking agents, prokinetics, antispasmodics, alosetron, tegaserod and antidepressants were selected. The quality of studies was assessed using 5-point scale. Meta-analyses were performed on all studies, and on 'high-quality studies'. The efficacy of fibre in the global irritable bowel syndrome symptoms relief (OR: 1.9; 95% CI:1.5-2.4) was lost after exclusion of low-quality trials (OR: 1.4; 95% CI: 1.0-2.0, P = 0.06). When excluding the low-quality trials, an improvement of global irritable bowel syndrome symptoms with all antispasmodics (OR: 2.1; 95% CI:1.8-2.9) was maintained only for octylonium bromide, but on the basis of only two studies. Antidepressants were effective (OR: 2.6, 95% CI: 1.9-3.5), even after exclusion of low-quality studies (OR: 1.9, 95% CI: 1.3-2.7). Alosetron (OR: 2.2; 95% CI: 1.9-2.6) and tegaserod (OR: 1.4; 95% CI: 1.2-1.5) showed a significant effect in women. We recommend the use of tegaserod for women with irritable bowel syndrome with constipation and alosetron for women with severe irritable bowel syndrome with diarrhoea. Antidepressants can be beneficial for irritable bowel syndrome with diarrhoea patients with severe symptoms. Loperamide can be recommended in painless diarrhoea. Evidence is weak to recommend the use of bulking agents in the treatment of irritable bowel syndrome with constipation.

Dyspeptic symptoms and gastric emptying in the irritable bowel syndrome

OBJECTIVES

Irritable bowel syndrome (IBS) and dyspepsia often overlap. Delayed gastric emptying has been reported in IBS patients, although conflicting results exist. Whether overlapping dyspepsia correlates with gastric emptying abnormalities in IBS patients has not been clarified. This study aimed to evaluate gastric emptying of solids and its relationship with dyspeptic symptoms in IBS patients.

METHODS

A total of 146 IBS outpatients seen in a referral center were evaluated for dyspeptic symptoms using a validated questionnaire. Gastric emptying of solids was evaluated scintigraphically in all patients and in 50 healthy controls.

RESULTS

Overlapping dyspepsia was diagnosed in 96 (66%) IBS patients. On average, gastric emptying rates were lower in IBS patients (mean +/- SEM, 33% +/- 1%/h) compared with controls (40% +/- 2%/h; p < 0.01). Specifically, gastric emptying was delayed in IBS patients with overlapping dyspepsia (31% +/- 1%/h; p < 0.01), whereas IBS patients without dyspeptic complaints showed gastric emptying rates (37% +/- 2%/h) that were similar to those of healthy controls (40% +/- 2%/h). Relevant postprandial fullness (OR = 4.7, 95% CI = 1.8-12.5) and relevant nausea (OR = 3.3, 95% CI 1.2-9.3) were independently associated with delayed gastric emptying.

CONCLUSIONS

IBS patients without overlapping dyspepsia have normal gastric emptying of solids. A significant association exists in IBS patients between delayed gastric emptying and overlapping relevant postprandial fullness and nausea.

Patient subgroups in irritable bowel syndrome that can be defined by symptom evaluation and physical examination

Subgroups of patients with irritable bowel syndrome (IBS) are likely to respond differently to existing and evolving therapies. The following criteria for subgrouping may be considered: (1) Patients with different predominant bowel habits respond differently to treatment (antidepressants, 5HT3-antagonists, psychotherapy). (2) Postprandial exacerbation of pain or other gastrointestinal symptoms is seen in approximately half of patients with IBS and may identify patients who are more responsive to some classes of drugs (e.g., those targeted at motility). (3) Women appear to respond differently from men to 5HT3-antagonists, and there may be gender differences in gastrointestinal physiology. (4) There is more overlap in the diagnosis of functional dyspepsia and IBS than would be predicted by chance, and both are associated with hyperalgesia to intraluminal distention.

Is functional dyspepsia just a subset of the irritable bowel syndrome?

To determine whether functional dyspepsia and irritable bowel syndrome are different entities, epidemiological data, factor analysis studies, physiological data and associated psychological symptoms were reviewed. Between 30% and 60% of patients with either diagnosis also meet the criteria for the other diagnosis, a level greater than expected to occur by chance but not sufficient to infer an identity. Most factor analysis studies identify independent clusters of symptoms corresponding to functional dyspepsia and irritable bowel syndrome. Visceral hypersensitivity is seen throughout the gastrointestinal tract in both disorders, but the motility patterns seen in association with functional dyspepsia (principally antral hypomotility and delayed gastric emptying) differ from the motility patterns seen in irritable bowel syndrome. Psychological symptoms are similar in these two disorders but are not believed to be aetiological for either of them. Thus, based on a factor analysis of gastrointestinal symptoms and differences in intestinal motility, functional dyspepsia and irritable bowel syndrome appear to be different entities.

Rapid gastric emptying in patients with functional diarrhea

OBJECTIVE

To analyze our experience in patients with chronic diarrhea by using a noninvasive transit study that measures gastric emptying as well as small bowel and colonic transit.

MATERIAL AND METHODS

Results from 94 consecutive transit tests, for which diarrhea was the main indication, were reviewed and correlated with the final classification of patients as having an organic or nonorganic disorder.

RESULTS

Sixty patients were considered to have a nonorganic cause of diarrhea, of whom 15 had previously undergone cholecystectomy. The other 34 patients were considered to have diarrhea on the basis of an organic diagnosis. Gastric emptying was more often rapid in patients with a nonorganic cause (P < 0.05), but not if cholecystectomy had been performed previously. Small bowel transit was fast more often in patients with organic diarrhea than in those with no organic cause of the diarrhea (P < 0.05); colonic transits showed no significant differences among groups.

CONCLUSION

The findings implicate a motor abnormality of the upper gut, rapid gastric emptying, as a pathophysiologic mechanism of functional bowel disorders with diarrhea. The results imply that additional prospective observations should be worth-while.

Influence of antidepressants on whole gut and orocaecal transit times in health and irritable bowel syndrome

BACKGROUND

Antidepressants are used in the treatment of irritable bowel syndrome but it is unclear whether any symptomatic improvement is due solely to correction of an associated affective disorder, or whether these drugs have effects on bowel function which may be of therapeutic benefit. Intestinal transit is known to be abnormal in some irritable bowel syndrome patients.

METHODS

We have studied the effects of imipramine, a tricyclic antidepressant with mixed pharmacological properties, and paroxetine, a selective 5-hydroxytryptamine re-uptake inhibitor, on intestinal transit times.

RESULTS

Median (range) whole gut transit time was lower in 10 diarrhoea-predominant irritable bowel syndrome patients, 22.2 (3.6-51.6) h, compared to 28 control subjects 39.6 (7.2-68.4) h, (P < 0.05). Similarly, orocaecal transit time was shorter at 55 (30-90) min in diarrhoea-predominant irritable bowel syndrome patients compared to 75 (40-150) min in controls, (P < 0.05). Four days' administration of imipramine increasing to a daily dose of 100 mg prolonged both orocaecal and whole gut transit times in 12 control subjects and six diarrhoea-predominant irritable bowel syndrome patients. In contrast, 30 mg paroxetine daily for 4 days reduced orocaecal transit time in ten controls and eight irritable bowel syndrome patients, but had no effect on whole gut transit time.

CONCLUSION

Short-term administration of antidepressants alters intestinal transit, but the selective 5-hydroxytryptamine re-uptake inhibitor, paroxetine, has different effects to the tricyclic drug, imipramine. These effects on transit precede any effects on mood. Although there is a high prevalence of affective disorder in irritable bowel syndrome clinic patients, these drugs may have additional therapeutic actions on the gut. These actions might be taken into account when prescribing antidepressants in irritable bowel syndrome.

Gastric emptying and dyspeptic symptoms in the irritable bowel syndrome

Many patients with irritable bowel syndrome (IBS) have symptoms suggestive of disturbances in gastric emptying, but so far no abnormalities in gastric emptying have been demonstrated in these patients. We studied gastric emptying of a solid meal with a 99mTc-labeled pancake in 16 healthy volunteers (8 women and 8 men; age, 20-33 years; mean age, 25 years) and 16 predominantly constipated IBS patients (10 women and 6 men; age, 17-43 years; mean age, 25 years). The incidence and severity of the symptoms nausea, vomiting, early satiety, and pain in the upper abdomen were scored. The duration of the lag phase of gastric emptying of the solid meal did not differ between the groups (controls, 16.6 +/- 4.7 min; IBS patients, 22.2 +/- 14.7 min). In normal subjects lag phase duration and emptying rate were correlated (r = 0.49, p greater than 0.05); in the IBS patients they were not. Post-lag gastric emptying of the solid meal was slower (p less than 0.01) in the IBS patients (0.58 +/- 0.24%/min) than in the control subjects (0.85 +/- 0.24%/min). No correlations were found, however, between the emptying rate and the severity of the upper abdominal symptoms. This study is the first to demonstrate that gastric emptying is delayed in IBS patients. This abnormality, however, appears not to be the major determinant of the upper abdominal symptoms often present in these patients.

Free radicals and other reactive oxygen metabolites in inflammatory bowel disease: cause, consequence or epiphenomenon?

Oxygen-derived free radicals and other reactive oxygen metabolites have emerged as a common pathway of tissue injury in a wide variety of otherwise disparate disease processes. This has given rise to the hope that efforts directed towards the pharmacologic control of free radical-mediated tissue injury (Reilly, P.M., Schiller, H. J. and Bulkley, G. B. (1991) Pharmacologic approach to tissue injury mediated by free radicals and other reactive oxygen metabolites. Am. J. Surg. 161: 488-503) may have particular application to patients suffering from Crohn's disease and/or ulcerative colitis. However, because tissue injury by any mechanism, even direct mechanical trauma, can elicit an inflammatory response which entails the secondary generation of toxic oxidants by neutrophils and tissue macrophages, it is important that the evidence for this association be examined critically, so as to discriminate the possibility of an etiologic role for these toxic compounds from their presence as a reflection of injury caused primarily by other agents. Similarly, in considering the therapeutic potential of free radical ablation for the treatment of patients with IBD it is important to distinguish between interventions that might specifically block the fundamental injury mechanism from those which would act in a more nonspecific, anti-inflammatory role.

Clinical evidence supporting the radical scavenger mechanism of 5-aminosalicylic acid

5-Aminosalicylic acid, the therapeutically active metabolite of sulfasalazine, was exposed to oxygen-derived free radicals produced by the Fenton reaction in vitro, and several metabolites were detected and characterized by high performance liquid chromatography and ultraviolet spectrophotometry. The majority of these metabolites were present in methanolic extracts of feces samples from sulfasalazine-treated patients with inflammatory bowel disease but not in rheumatoid arthritis patients with normal bowel function. The presence of these metabolites, which have not been demonstrated in vivo before, provides evidence of an interaction between 5-aminosalicylic acid and oxygen-derived free radicals in sulfasalazine-treated patients with inflammatory bowel disease. Since the concentration of lipid peroxides, which is dependent on the release of oxygen-derived free radicals, was significantly increased in pretreatment rectal biopsies of the patients, and further was normalized concomitantly with a significant improvement in disease activity over the 5-wk treatment period, an important role of the radical scavenger mechanism of 5-aminosalicylic acid in sulfasalazine therapy of chronic inflammatory bowel disease is strongly suggested.

Obstruction of the large and small intestine

This article provides an overview of mechanical small and large bowel obstruction with emphasis on newer diagnostic and therapeutic surgical techniques. Small and large intestinal pseudo-obstruction is discussed with reference to its diagnosis and appropriate treatment.

Gastric emptying of large single unit dosage forms

The gastrointestinal transit of two single unit dosage forms has been followed in healthy subjects under different feeding conditions. Transit was affected by the size of the meal administered. When two tablets were given concurrently they often emptied from the stomach at or about the same time, but in a number of cases the two units were seen to empty at widely different times.