Effect of painless rectal distension on gastrointestinal transit of solid meal

Assessing impaired gastric accommodation in children with functional constipation using the water load test

BACKGROUND

This study aimed to evaluate gastric accommodation in pediatric patients with functional constipation using the water load test.

METHOD

This was a cross-sectional case-control study. Herein, the water load test results of children aged >4 years with functional constipation referred to a Pediatric Gastroenterology Outpatient Clinic (functional constipation group) were compared with those of a control group (without functional constipation or chronic abdominal pain) recruited from two public schools. Clinical manifestations outlined in the Rome IV criteria were used to diagnose functional constipation. Water load tests were performed after 3 h of fasting. For the test, the participants were asked to drink as much water as possible in 3 min.

KEY RESULTS

A total of 36 patients and 77 students were included in the functional constipation and control groups, respectively. There was no significant difference in age between the groups (8.6 ± 2.3 years and 8.8 ± 1.8 years in the functional constipation and control groups, respectively). The water load test showed intake volumes of 390 ± 245 mL and 528 ± 219 mL in the functional constipation and control groups, respectively (p = 0.001). The maximum volume in the water load test correlated with the 24 h daily intake of energy (rS = +0.42, p = 0.012), protein (rS = +0.48, p = 0.004), and water (rS = +0.39, p = 0.020) only in the group with functional constipation.

CONCLUSIONS & INFERENCES

According to the water load test, gastric accommodation was impaired in children with severe functional constipation. The impairment of gastric accommodation in children with severe functional constipation is related to food intake.

Ten controversies in gastroparesis and a look to the future

BACKGROUND

Gastroparesis is a complex, challenging gastrointestinal disorder presenting with upper gastrointestinal symptoms, especially nausea and vomiting, with significant impact on patients' quality of life. After ruling out mechanical obstruction, it is essential to identify delay in gastric emptying for definitive diagnosis. The most common causes are idiopathic (no identified etiology), diabetes mellitus, and postsurgical status. Management of gastroparesis focuses on dietary modifications and treatment directed to symptom relief. Unfortunately, approximately one-third of patients are refractory to pharmacological therapy, and the effectiveness of the few nonpharmacological options has been questioned.

PURPOSE

Extensive review of the literature identifies several uncertainties or controversies regarding the differential diagnosis based on the spectrum of symptoms, the lack of availability of reliable diagnostic test, and questions regarding effective therapeutic options. In this review, we discuss ten controversies regarding gastroparesis: clinical presentation, diagnosis, overlap syndromes, pathophysiology, etiology, as well as pharmacological and nonpharmacological therapeutic options. In addition, we briefly review studies exploring pathological, inflammatory, and molecular disturbances affecting the intrinsic neuromuscular elements that may be involved in the pathophysiology of gastroparesis and may constitute possible therapeutic targets in the future. Finally, we tabulate future research opportunities to resolve these controversies in the management of patients with gastroparesis.

Neural signalling of gut mechanosensation in ingestive and digestive processes

Eating and drinking generate sequential mechanosensory signals along the digestive tract. These signals are communicated to the brain for the timely initiation and regulation of diverse ingestive and digestive processes - ranging from appetite control and tactile perception to gut motility, digestive fluid secretion and defecation - that are vital for the proper intake, breakdown and absorption of nutrients and water. Gut mechanosensation has been investigated for over a century as a common pillar of energy, fluid and gastrointestinal homeostasis, and recent discoveries of specific mechanoreceptors, contributing ion channels and the well-defined circuits underlying gut mechanosensation signalling and function have further expanded our understanding of ingestive and digestive processes at the molecular and cellular levels. In this Review, we discuss our current understanding of the generation of mechanosensory signals from the digestive periphery, the neural afferent pathways that relay these signals to the brain and the neural circuit mechanisms that control ingestive and digestive processes, focusing on the four major digestive tract parts: the oral and pharyngeal cavities, oesophagus, stomach and intestines. We also discuss the clinical implications of gut mechanosensation in ingestive and digestive disorders.

Duodenal and proximal jejunal motility inhibition associated with bisacodyl-induced colonic high-amplitude propagating contractions

Bisacodyl is a stimulant laxative often used in manometric studies of pediatric constipation to determine if it can initiate propulsive high-amplitude propagating contractions (HAPCs). Whereas the effects of bisacodyl infusion on colonic motility are well described, the effects of the drug on other regions of the gut after colonic infusion are not known. The aim of the present study was to characterize the effects of bisacodyl on both colonic and small bowel motility. Twenty-seven children (9.3 ± 1.2 yr) undergoing simultaneous high-resolution antroduodenal and colonic manometry were included. Small bowel and colonic motor patterns were assessed before and after colonic infusion of bisacodyl. Patients were divided into two groups: responders and nonresponders based on the presence of high-amplitude propagating contractions (HAPCs) after bisacodyl infusion. Nineteen patients were responders. A total of 188 postbisacodyl HAPCs was identified with a mean count of 10.4 ± 5.5 (range, 3-22), at a frequency of 0.6 ± 0.2/min and mean amplitude of 119.8 ± 23.6 mmHg. No motor patterns were induced in the small bowel. However, in the 19 responders the onset of HAPCs was associated with a significant decrease in small bowel contractile activity. In the nonresponders, there was no detectable change in small bowel motility after bisacodyl infusion. Bisacodyl-induced HAPCs are associated with a significant reduction in small bowel motility probably mediated by extrinsic sympathetic reflex pathways. This inhibition is potentially related to rectal distension, caused by the HAPC anal propulsion of colonic content.NEW & NOTEWORTHY The present study has shown, for the first time, that the presence of high-amplitude propagating contractions induced by bisacodyl is associated with a significant reduction in small bowel motility. These findings support of possible existence of a reflex pathway that causes inhibition of small bowel motility in response to rectal distension.

Severe gastroparesis is associated with an increased incidence of slow-transit constipation as measured by wireless motility capsule

BACKGROUND

Dysmotility in one region of the gastrointestinal tract has been found to predispose patients to developing motility disorders in other gastrointestinal segments. However, few studies have evaluated the relationship between gastroparesis and constipation.

METHODS

Retrospective review of 224 patients who completed 4-hour, solid-phase gastric emptying scintigraphy (GES), and wireless motility capsule (WMC) testing to evaluate for gastroparesis and slow-transit constipation, respectively. When available, anorectal manometry data were reviewed to evaluate for dyssynergic defecation. Patients were divided into two groups based on the results of the GES: 101 patients with normal gastric emptying and 123 patients with gastroparesis (stratified by severity). Differences in constipation rates were compared between the groups.

KEY RESULTS

Slow-transit constipation was more common in the gastroparesis group, but statistical significance was not reached (42.3% vs 34.7%, p = 0.304). Univariate logistical regression analysis found no association between slow-transit constipation and gastroparesis (OR 1.38, 95% CI 0.80-2.38, p = 0.245) nor dyssynergic defecation and gastroparesis (OR 0.88, 95% CI 0.29-2.70, p = 0.822). However, when stratifying gastroparesis based on severity, slow-transit constipation was found to be associated with severe gastroparesis (OR 2.45, 95% CI 1.20-5.00, p = 0.014). This association was strengthened with the exclusion of patients with diabetes mellitus (OR 3.5, 95% CI 1.39-8.83, p = 0.008) - a potential confounder.

CONCLUSIONS & INFERENCES

Patients with severe gastroparesis (>35% gastric retention at the 4-hour mark on solid-phase GES) have an increased likelihood of having underlying slow-transit constipation. Dyssynergic defecation does not appear to be associated with gastroparesis (of any severity).

Gastrointestinal Dysfunction in Parkinson's Disease

Parkinson’s disease (PD) is the second most common neurodegenerative disease. Patients show deposits of pathological, aggregated α-synuclein not only in the brain but throughout almost the entire length of the digestive tract. This gives rise to non-motor symptoms particularly within the gastrointestinal tract and patients experience a wide range of frequent and burdensome symptoms such as dysphagia, bloating, and constipation. Recent evidence suggests that progressive accumulation of gastrointestinal pathology is underway several years before a clinical diagnosis of PD. Notably, constipation has been shown to increase the risk of developing PD and in contrast, truncal vagotomy seems to decrease the risk of PD. Animal models have demonstrated gut-to-brain spreading of pathological α-synuclein and it is currently being intensely studied whether PD begins in the gut of some patients. Gastrointestinal symptoms in PD have been investigated by the use of several different questionnaires. However, there is limited correspondence between subjective gastrointestinal symptoms and objective dysfunction along the gastrointestinal tract, and often the magnitude of dysfunction is underestimated by the use of questionnaires. Therefore, objective measures are important tools to clarify the degree of dysfunction in future studies of PD. Here, we summarize the types and prevalence of subjective gastrointestinal symptoms and objective dysfunction in PD. The potential importance of the gastrointestinal tract in the etiopathogenesis of PD is briefly discussed.

Insight into the Colonic Disposition of Sulindac in Humans

NSAIDs such as celecoxib and sulindac play a critical role in the treatment of colorectal cancer, yet it is not understood how sufficiently high concentrations are reached in colonic tissue. We previously demonstrated that an incomplete small intestinal absorption of celecoxib enables gut driven drug accumulation in caecal tissue, which is most likely needed for inducing remission. However, a multistage dissolution experiment suggested a more extensive absorption of sulindac relative to celecoxib, though still incomplete. To study whether caecal accumulation of sulindac is solely plasma driven or also gut driven, we performed an exploratory clinical study in healthy volunteers. After intake of a tablet of sulindac (200 mg; Arthrocine), two colonoscopies (1.0-2.5 h, and 6.0-7.5 h after drug intake) were performed to assess concentrations of sulindac and metabolites in plasma, caecal tissue and caecal contents. We observed that sulindac, even without the use of a colon-targeted delivery strategy, can arrive at the colonic lumen due to incomplete absorption and biliary excretion, and that the microbiota can catalyse the production of sulindac sulfide, which then accumulates in a high and local manner in the colonic tissue. These data can be relevant for drug development in the treatment of colorectal adenomas and cancer.

Gastroparesis: New insights into an old disease

Gastroparesis (Gp) is a chronic disease characterized by a delayed gastric emptying in the absence of mechanical obstruction. Although this condition has been reported in the literature since the mid-1900s, only recently has there been renewed clinical and scientific interest in this disease, which has a potentially great impact on the quality of life. The aim of this review is to explore the pathophysiological, diagnostic and therapeutical aspects of Gp according to the most recent evidence. A comprehensive online search for Gp was carried out using MEDLINE and EMBASE. Gp is the result of neuromuscular abnormalities of the gastric motor function. There is evidence that patients with idiopathic and diabetic Gp may display a reduction in nitrergic inhibitory neurons and in interstitial cells of Cajal and/or telocytes. As regards diagnostic approach, 99-Technetium scintigraphy is currently considered to be the gold standard for Gp. Its limits are a lack of standardization and a mild risk of radiation exposure. The C13 breath testing is a valid and safe alternative method. ¹³C acid octanoic and the ¹³C Spirulina platensis recently approved by the Food and Drug Administration are the most commonly used diagnostic kits. The wireless motility capsule is a promising technique, but its use is limited by costs and scarce availability in many countries. Finally, therapeutic strategies are related to the clinical severity of Gp. In mild and moderate Gp, dietary modification and prokinetic agents are generally sufficient. Metoclopramide is the only drug approved by the Food and Drug Administration for Gp. However, other older and new prokinetics and antiemetics can be considered. As a second-line therapy, tricyclic antidepressants and cannabinoids have been proposed. In severe cases the normal nutritional approach can be compromised and artificial nutrition may be needed. In drug-unresponsive Gp patients some alternative strategies (endoscopic, electric stimulation or surgery) are available.

Insight into the colonic disposition of celecoxib in humans

Although the effect of NSAIDs such as celecoxib on the progression of colorectal polyps has been established, it is currently unknown how sufficiently high concentrations of celecoxib are reached in colonic tissue. Indeed, the lipophilic and poorly soluble celecoxib is orally dosed as an immediate release capsule without any colon-targeting delivery strategy. In the present study, we aimed to distinguish between plasma and gut driven caecal tissue accumulation of celecoxib in healthy volunteers. After developing a protocol to reliably collect colonic biopsies and contents, the disposition of celecoxib was assessed in plasma, caecal tissue and caecal contents collected after intake of a celecoxib capsule (200 mg; Celebrex®) with 240 mL of tap water. During a first colonoscopy (1.0-2.5 h after drug intake), plasma concentrations of celecoxib and its carboxy metabolite were increasing, while caecal tissue concentrations were relatively low. As no celecoxib was present in caecal contents, tissue accumulation was clearly plasma driven. During a second colonoscopy (6.0-7.5 h after drug intake), tissue concentrations of the drug and its metabolite were substantially higher despite decreasing plasma concentrations. As a high amount of celecoxib was found in the caecal contents, the increased tissue accumulation most likely resulted from direct uptake of celecoxib from the gut. These data demonstrate that incomplete small intestinal absorption of the poorly soluble drug celecoxib enables gut driven drug accumulation in caecal tissue, which is, most likely, critical for the role of this NSAID in the prevention of colorectal cancer.

Evaluation of Patients with Suspected Gastroparesis

There is substantial overlap between the symptoms of gastroparesis and a variety of alternative disorders. These conditions include rumination syndrome, drug-induced gastric emptying delay, cannabinoid hyperemesis syndrome, and eating disorders, which can be identified based on the history alone. The remaining patients require a diagnostic approach of physical examination, laboratory tests, evaluation with esophagogastroduodenoscopy or contrast radiography, and a test to measure gastric emptying. Symptomatic patients who have normal nutritional status and gastric emptying that is either normal or mildly delayed should be diagnosed with functional dyspepsia, whereas patients with moderate or severe gastric emptying delay are diagnosed with gastroparesis.

Objective Colonic Dysfunction is Far more Prevalent than Subjective Constipation in Parkinson's Disease: A Colon Transit and Volume Study

BACKGROUND

Gastrointestinal function has received increased interest in the context of Parkinson's disease (PD). Constipation is among the most frequent non-motor symptoms, but our understanding of the underlying pathology is limited. Subjective constipation correlates poorly with objective markers.

OBJECTIVE

The aims were to evaluate colonic transit time and volume in PD and to correlate these measures with subjective symptoms and gastric emptying.

METHODS

Thirty-two PD patients and 26 controls were included. Colonic transit time, computed tomography-based volume estimation, and gastric emptying were performed as objective markers of gastrointestinal function. Subjective gastrointestinal symptoms were evaluated by three different questionnaires.

RESULTS

Seventy-nine percent of PD patients displayed prolonged colonic transit time (p < 0.0001) and 66% of patients had significantly increased colonic volume (p = 0.0002). Particularly the transverse and rectosigmoid segments were affected. There was no difference in gastric emptying time between groups. The prevalence of subjective constipation in PD patients was significantly lower and ranged from 3% to 38% depending on the type of questionnaire.

CONCLUSIONS

Significantly delayed colonic transit time and increased volume were frequent findings in PD patients, and objective dysfunction was considerably more prevalent than subjective constipation symptoms. Also, the prevalence of subjective constipation varied widely depending upon which questionnaire was employed. These findings highlight the need for more research on how to define constipation in PD and also the need for improved understanding of the relationship between subjective symptoms and objective dysfunction.

Constipation in parkinson's disease: Subjective symptoms, objective markers, and new perspectives

Constipation is among the first nonmotor symptoms to develop in the prodromal phase of PD. Pathological alpha-synuclein deposition is present throughout the gastrointestinal tract up to 20 years preceding diagnosis. Nevertheless, constipation in the context of PD remains ill defined and poorly understood. In this review, we summarize current knowledge of subjective symptoms and objective measures of constipation in PD. More than 10 different definitions of constipation have been used in the PD literature, making generalizations difficult. When pooling results from the most homogeneous studies in PD, a median constipation prevalence of 40% to 50% emerges, but with large variation across individual studies. Also, constipation prevalence tends to increase with disease progression. A similar prevalence is observed among patients with idiopathic rapid eye movement sleep behavior disorder. Interestingly, we detected a correlation between constipation prevalence in PD patients and healthy control groups in individual studies, raising concerns about how various constipation questionnaires are implemented across study populations. More than 80% of PD patients exhibit prolonged colonic transit time, and the same is probably true for de novo PD patients. Thus, the prevalence of objective colonic dysfunction exceeds the prevalence of subjective constipation. Colonic transit time measures are simple, widely available, and hold promise as a useful biomarker in manifest PD. More research is needed to elucidate the role of gastrointestinal dysfunction in disease progression of PD. Moreover, colonic transit measures may have utility as a more accurate risk factor for predicting PD in the prodromal phase. © 2016 International Parkinson and Movement Disorder Society.

Regional gastrointestinal transit times in severe ulcerative colitis

BACKGROUND

Gastrointestinal (GI) dysmotility may present secondary to inflammatory bowel disease. The main aim of this study was to investigate GI motility in ulcerative colitis (UC) patients during severe disease activity.

METHODS

Twenty patients with severe UC were studied with a novel telemetric capsule system (3D-Transit) designed for minimally invasive, ambulatory assessment of total and regional GI transit times. Ten patients were available for follow-up during remission. Data were compared to those of 20 healthy subjects (HS).

KEY RESULTS

Total GI transit time was significantly longer in patients with severe UC (median 44.5 h [range 9.9-102.7 h]) than in HS (median 27.6 h [range 9.6-56.4 h]) (p = 0.032). Additionally, during severe UC, transit time was prolonged through the proximal colon (p = 0.003) and there were strong trends toward longer than normal small intestinal transit time (HS: median 4.9 h [range 3.4-8.3 h] vs severe UC patients: median 5.9 h [range 3.9-11.9 h]; p = 0.053) and colorectal transit times (HS: median 18.2 h [range 1.5-43.7] vs severe UC patients: median 34.9 h [range 0.4-90.9 h]; p = 0.056). Our data further indicate that total GI and colorectal transit times may be prolonged in UC during early remission.

CONCLUSIONS & INFERENCES

Total GI transit times are significantly prolonged during severe UC.

Sonographic evaluation of gallbladder motility in children with chronic functional constipation

Background/Aims

Studies in adults suggest that constipation may not be a purely colonic pathology and may be a component of a generalized gastrointestinal (GI) motor disorder in which proximal GI motility can be impaired. Pediatric data are scarce, and the natural history of the disorder remains undefined. We aimed to evaluate gallbladder motility in a subset of Asian children with chronic functional constipation.

Methods

Abdominal ultrasound was performed on 105 children, including 55 patients (aged 3 to 13 years) with chronic functional constipation who met the inclusion criteria and 50 age- and gender-matched controls. The gallbladder contractility index was calculated based on the preprandial and postprandial gallbladder areas. Preprandial and postprandial values for gallbladder volume and wall thickness were evaluated.

Results

The mean value of the contractility index for the patients (15.77±24.68) was significantly lower than the mean value for the controls (43.66±11.58) (p=0.001). The mean postprandial gallbladder volumes and areas were larger in children with gallbladder hypomotility (p<0.05). The mean duration of constipation (4.8 months) was significantly higher (p=0.004) in the children with gall-bladder hypomotility.

Conclusions

Gallbladder motility is significantly impaired in children with chronic functional constipation. This study contributes to the understanding of the underlying pathophysiology, which will enable advancement in and improved management of children with chronic constipation and associated gallbladder hypomotility.

Daily laxative therapy reduces organ dysfunction in mechanically ventilated patients: a phase II randomized controlled trial

INTRODUCTION

Constipation is a common problem in intensive care units. We assessed the efficacy and safety of laxative therapy aiming to promote daily defecation in reducing organ dysfunction in mechanically ventilated patients.

METHODS

We conducted a prospective, randomized, controlled, nonblinded phase II clinical trial at two general intensive care units. Patients expected to remain ventilated for over 3 days were randomly assigned to daily defecation or control groups. The intervention group received lactulose and enemas to produce 1-2 defecations per day. In the control group, absence of defecation was tolerated up to 5 days. Primary outcome was the change in Sequential Organ Failure Assessment (SOFA) score between the date of enrollment and intensive care unit discharge, death or day 14.

RESULTS

We included 88 patients. Patients in the treatment group had a higher number of defecations per day (1.3 ± 0.42 versus 0.7 ± 0.56, p < 0.0001) and lower percentage of days without defecation (33.1 ± 15.7% versus 62.3 ± 24.5%, p < 0.0001). Patients in the intervention group had a greater reduction in SOFA score (-4.0 (-6.0 to 0) versus -1.0 (-4.0 to 1.0), p = 0.036) with no difference in mortality rates or in survival time. Adverse events were more frequent in the treatment group (4.5 (3.0-8.0) versus 3.0 (1.0-5.7), p = 0.016), including more days with diarrhea (2.0 (1.0-4.0) versus 1.0 (0-2.0) days, p < 0.0001). Serious adverse events were rare and did not significantly differ between groups.

CONCLUSIONS

Laxative therapy improved daily defecation in ventilated patients and was associated with a greater reduction in SOFA score.

TRIAL REGISTRATION

Clinical Trials.gov NCT01607060, registered 24 May 2012.

Prokinetic effects of mirtazapine on gastrointestinal transit

Mirtazapine is a noradrenergic and specific serotonergic antidepressant. The aim of this study was to investigate the effects of mirtazapine on gastrointestinal motility in dogs, including solid gastric emptying, antral and small intestinal contractions, and small intestinal and colonic transit. Six dogs were implanted with two cannulas located at the duodenum and the ascending colon; another six dogs were implanted with gastric cannula 6 cm proximal to the pylorus. Mirtazapine 45 mg was administered orally 90 min before the study. We found that 1) Mirtazapine accelerated gastric emptying during the entire 3 h in normal dogs (P < 0.04) and accelerated delayed gastric emptying induced by rectal distention (P < 0.04). 2) Mirtazapine restored impaired gastric tone and accommodation induced by rectal distention (P < 0.05). 3) No significant changes were noted in small intestinal contractions or transit with mirtazapine (P > 0.1). 4) Mirtazapine accelerated colonic transit at 2 and 4 h but not 6 h. The geometric center was increased from 1.9 ± 0.6 to 3.0 ± 0.5 and 3.9 ± 0.5 to 4.7 ± 0.1 at 2 and 4 h respectively (P = 0.04 vs. corresponding control). In conclusion, mirtazapine improves gastric emptying in healthy dogs and normalizes rectal distention-induced delay in gastric emptying and accelerates colon but not small intestinal transit in healthy dogs. Clinical studies are warranted to assess the effects of mirtazapine on gastrointestinal motility and sensory functions in patients with functional gastrointestinal diseases.

Prevalence of colonic motor or evacuation disorders in patients presenting with chronic nausea and vomiting evaluated by a single gastroenterologist in a tertiary referral practice

BACKGROUND

Nausea and vomiting are thought to result from upper gastrointestinal dysfunctions. Our clinical observations led to the hypothesis that colonic motor dysfunction is associated with nausea and vomiting.

METHODS

We reviewed electronic medical records (EMR) of 149 patients presenting with complaints of nausea and/or vomiting in a tertiary gastroenterology practice to investigate the association with disorders of colonic motor or evacuation disorders. We extracted demographics, gastric emptying (GE in 149) and colonic transit (CT in 138) of solids, ascending colon emptying half-time (AC t1/2 ), rectal evacuation by anorectal manometry (ARM) in 91 and balloon expulsion test (BE) in 55 patients. We estimated the proportions with delayed GE or CT, based on the 5th percentile of GE (in 319) and CT in 220 healthy volunteers using same method.

KEY RESULTS

Among 11 patients with nausea and/or vomiting with only GE measured, five had delayed and six normal GE. Among the 149 patients, 77 (52%) patients had evacuation disorders, confirmed by objective tests in 68 patients, and clinical examination in nine patients. In the 138 patients with both GE and CT measured, 106 (76%) had both normal GE and CT, 11 (8%) only delayed GE, 16 (11%) normal GE with delayed CT, and five (3%) delayed GE and CT. Among 21 patients (15%) with delayed CT, nine had slow AC t1/2 and 12 evacuation disorder.

CONCLUSIONS & INFERENCES

In patients with chronic nausea and/or vomiting in gastroenterology practice, evaluation of colonic motility and rectal evacuation should be considered, since about half the patients have abnormal functions that conceivably contribute to the presenting nausea and/or vomiting.

Gastric emptying of water in children with severe functional fecal retention

The objective of this study was to evaluate gastric emptying (GE) in pediatric patients with functional constipation. GE delay has been reported in adults with functional constipation. Gastric emptying studies were performed in 22 children with chronic constipation, fecal retention and fecal incontinence, while presenting fecal retention and after resuming regular bowel movements. Patients (18 boys, median age: 10 years; range: 7.2 to 12.7 years) were evaluated in a tertiary pediatric gastroenterology clinic. Gastric half-emptying time of water (reference range: 12 ± 3 min) was measured using a radionuclide technique immediately after first patient evaluation, when they presented fecal impaction (GE₁), and when they achieved regular bowel movements (GE₂), 12 ± 5 weeks after GE₁. At study admission, 21 patients had reported dyspeptic symptoms, which were completely relieved after resuming regular bowel movements. Medians (and interquartile ranges) for GE₁ and GE₂ were not significantly different [27.0 (16) and 27.5 (21) min, respectively (P = 0.10)]. Delayed GE seems to be a common feature among children with chronic constipation and fecal retention. Resuming satisfactory bowel function and improvement in dyspeptic symptoms did not result in normalization of GE data.

Exploring anorectal manometry as a method to study the effect of locally administered ropivacaine in patients with ulcerative colitis

The symptoms of distal ulcerative colitis have been related to changes in rectal sensitivity and capacity due to inflammation, altered gastrointestinal motility, and sensory perception. With the use of anorectal manometry, the function was measured in seven patients with active distal proctitis during local treatment with ropivacaine. Seven healthy subjects were studied in the same way for comparison with normal conditions. The anal resting pressure and squeezing pressure were similar in all groups. Significantly lower rectal distention volumes were required for rectal sensation, critical volume, and to induce rectal contractility in patients with active disease compared to controls. Rectal compliance was significantly reduced in patients with active and quiescent disease. The increased rectal sensitivity and contractility in patients with active colitis appear to be related to active mucosal inflammation and ulceration. The frequency and urgency of defecation and the fecal incontinence may be due to a hypersensitive, hyperactive, and poorly compliant rectum. The findings in our study indicate that the inflammatory damage to the rectal wall with poor compliance is unaffected by local anaesthetics such as ropivacaine. The symptomatic relief and reduction in clinical symptoms following treatment are not reflected in the anorectal manometric findings.

Functional abdominal bloating with distention

Ten to 25% of healthy persons experience bloating. It is particularly common in persons with the irritable bowel syndrome and constipation. While the cause of bloating remains unknown old explanations such as a excessive intestinal gas, exaggerated lumbar lordosis and psychiatric problems have been disproved. New suggestions include recent weight gain, weak or inappropriately relaxed abdominal muscles, an inappropriately contracted diaphragm and retained fluid in loops of distal small bowel. No treatment is of unequivocal benefit but a low FODMAPs diet, probiotics and the non-absorbable antibiotic rifaximin offer some hope. Treatment by weight loss, abdominal exercise, prokinetics and girdles need more study.

Effects and possible mechanisms of acupuncture at ST36 on upper and lower abdominal symptoms induced by rectal distension in healthy volunteers

Background acupuncture (AP) has been shown to have a therapeutic potential for gastrointestinal motility disorders. The aims of this study were to investigate the effects and possible mechanisms of acupuncture on postprandial upper and lower abdominal symptoms induced by rectal distension (RD). Twenty healthy volunteers were involved in a two-session study (AP and sham-AP, AP and no-AP, or sham-AP and no-AP). In 12 of the volunteers, RD was performed for 60 min in the postprandial state, and AP at ST36 or sham-AP was performed during the second 30-min period of RD. Gastric slow waves and heart rate variability (HRV) were recorded using the electrogastrogram and electrocardiogram, respectively. Upper and lower abdominal symptoms were scored during RD with AP and sham-AP. In five of the subjects, an additional experiment with two sessions (with AP and no-AP) was performed. In the remaining eight volunteers, the same experiment was performed with sham-AP and no-AP was performed. The results were, first, RD at an average volume of 171 ml induced upper and lower abdominal symptoms (P < 0.01). AP, but not sham-AP or no-AP, reduced both upper and lower abdominal symptoms (P < 0.05). Second, RD decreased the percentage of normal gastric slow waves (P < 0.05). AP improved gastric slow waves compared with sham-AP or no-AP (P < 0.05). Third, in the larger, but not smaller, sample size experiment, the vagal activity during the RD plus AP period was significantly higher than that during the RD alone period in the same session and the corresponding period with sham-AP or no-AP in other sessions (P < 0.05). Neither sham-AP nor no-AP showed any effects on vagal activity (P > 0.05). Finally, in the experiment with eight volunteers, neither sham-AP nor no-AP showed any effects on RD-induced impairment in gastric slow waves, abdominal symptoms, or vagal activity (P > 0.05). The conclusions are RD induces upper or lower abdominal symptoms and impairs gastric slow waves in healthy volunteers. AP at ST36 is able to improve upper and lower abdominal symptoms and impaired gastric slow waves induced by RD, possibly mediated via the vagal pathway.

Electroacupuncture improves rectal distension-induced delay in solid gastric emptying in dogs

The aim of this study was to investigate the effects and mechanisms of electroacupuncture (EA) on rectal distension (RD)-induced delay in solid gastric emptying in dogs. Gastric emptying of solids was assessed in 12 dogs chronically implanted with a duodenal cannula by collecting samples at different time points from the cannula and measuring the dried weights of the samples. Bethanechol and atropine were used to qualitatively validate the method. In separate experiments, gastric emptying of solids was measured in a number of sessions: control, RD, RD + sham-EA, RD + EA of 6 mA, RD + EA of 3 mA, and RD + EA + naloxone. The method of gastric emptying by collecting and drying gastric chyme from the duodenal cannula was found to be accurate and reliable. Using the method, we found gastric emptying to be accelerated with bethanechol (70.01 ± 8.10% vs. 82.61 ± 4.15%, P = 0.04, vs. control) and delayed with atropine (4.31 ± 1.57%, P < 0.001, vs. control). RD substantially and significantly delayed gastric emptying. EA, but not sham-EA, attenuated delayed gastric emptying induced by RD (sham-EA: 48.79 ± 9.47% vs. EA: 74.28 ± 5.96%, P < 0.01). The effect was more potent with EA of 6 mA than EA of 3 mA and blocked by naloxone. EA is able to attenuate RD-induced delay in gastric emptying of solids, and this ameliorating effect may be mediated via the opioid pathway. EA may have a therapeutic potential for treating delayed gastric emptying attributed to lower gut distension.

Management and prevention of fecal impaction

Fecal impactions occur in both sexes at any age but are particularly concentrated in children, in the institutionalized or impaired elderly, and in patients with certain psychiatric disorders or medical conditions that predispose to obstipation. The clinical consequences may be disabling and occasionally life threatening. Clinical manifestations include fecal incontinence, abdominal distention and pain, anorexia, weight loss, intestinal obstruction, and stercoral ulceration with bleeding or colonic perforation. Diagnosis begins with recognition of possible fecal impaction and confirmation by digital examination or abdominal radiography. Management consists of disimpaction, colon evacuation, and a maintenance bowel program to prevent recurrent impactions.

Clinical presentation and patterns of slow transit constipation do not predict coexistent upper gut dysmotility

BACKGROUND

Slow transit constipation (STC) is associated with upper gastrointestinal tract motor abnormalities in a subset of patients. This could influence the clinical approach, particularly in those rare cases where surgical management is considered.

AIMS

To identify factors that predict proximal gut dysmotility in patients with STC.

METHODS

Esophageal and small bowel motor function were evaluated in 77 patients with STC. Severity and pattern of colonic transit delay, prevalence of a co-existent rectal evacuatory disorder, and type (if present), and duration, and onset of constipation symptoms were compared.

RESULTS

Of the 77 patients studied, 43% exhibited altered motor function in the esophagus and/or small bowel. Frequency of defecation was lower in these patients than in those without upper gastrointestinal dysmotility (0.5 +/- 0.1 vs. 1.3 +/- 0.3 bowel movements/per week, respectively; P = 0.04). Severity and patterns of colonic transit delay and the mechanism associated with the onset of constipation symptoms or with their duration were similar in subjects with or without upper gastrointestinal tract dysmotility. Small bowel but not esophageal motor dysfunction was more frequently associated with a co-existent rectal evacuatory disorder (P = 0.01).

CONCLUSION

Upper gastrointestinal tract dysmotility in patients with STC is frequent, but prediction on the basis of clinical history and characteristics of colonic transit is problematic.

Validity of segmental transit studies used in routine clinical practice, to characterize defaecatory disorder in patients with functional constipation

OBJECTIVE

Segmental colonic transit can be determined by performing regional counts of radio-opaque markers on an abdominal radiograph. It has been claimed that the pattern of markers can be used to characterize the type of constipation, with a concentration of markers seen in the rectosigmoid region in patients with defaecatory disorders. The aim of our study was to examine this hypothesis in a cohort of patients with functional constipation.

METHOD

Consecutive patients presenting to a specialist constipation clinic and satisfying inclusion criteria were studied. All patients had the following assessments: radio-opaque marker study performed according to a standard protocol; proforma-based symptom assessment using Likert scoring; and radioisotope defaecating proctogram. Transit study data included total transit time, rectosigmoid transit time and geometric mean of markers. Symptom scores were recorded for straining, incomplete evacuation and digitation, together with a cumulative symptom score. Evidence of outlet obstruction from the proctogram included four previously described parameters.

RESULTS

A total of 108 patients with functional constipation according to the Rome criteria with a median age of 41 years were studied. Neither rectosigmoid transit time nor the geometric centre of markers could differentiate patients with a functional defaecatory disorder (FDD). There was no correlation between the pattern of marker distribution and any of the parameters denoting outlet obstruction.

CONCLUSION

Our data do not support the hypothesis that assessment of segmental transit, using standard methods applicable to routine clinical practice can determine the type of constipation. In particular, patients exhibiting evidence of FDD are no more likely to have recto-sigmoid retention of markers than those without.

Electroacupuncture improves impaired gastric motility and slow waves induced by rectal distension in dogs

Rectal distension (RD) is known to induce upper gastrointestinal (GI) symptoms. The aim of this study was to investigate the effects and underlying mechanisms of RD on gastric slow waves (GSW) and motor activity and furthermore to investigate the effects and mechanisms of electroacupuncture (EA) on GSW and motor activity. Eight female hound dogs chronically implanted with gastric serosal electrodes and a gastric fistula were studied in six separate sessions. Antral motility, GSW, heart rate variability, and rectal pressure were evaluated for the above purposes. 1) RD at a volume of 120 ml suppressed antral motility significantly. Guanethidine blocked the inhibitory effect of RD. EA at ST36 was able to restore the suppressed antral contractions induced by RD (16.6+/-1.7 vs. 8.0+/-1.4, P<0.001). Naloxone partially blocked the effect of EA on antral contractions. 2) RD reduced the percentage of normal GSW from 98.8+/-0.8% at baseline to 76.1+/-8.6% (P<0.05) that was increased to 91.8+/-3.0% with EA. The effects of EA on the GSW were nullified by the presence of naloxone. 3) EA did not show any significant effect on rectal pressure, suggesting that the ameliorating effects of EA on RD-induced impaired gastric motility were not due to a decrease in rectal pressure. 4) EA increased the vagal activity suppressed by RD. In conclusion, RD inhibits postprandial gastric motility and impairs GSW in dogs, and the inhibitory effects are mediated via the adrenergic pathways. EA at ST36 is able to restore the RD-induced impaired GSW and motor activities, possibly by enhancing vagal activity, and is partially mediated via the opioid pathway. EA may have therapeutic potential for functional gastrointestinal disorders.

Dyspeptic symptoms in children: the result of a constipation-induced cologastric brake?

BACKGROUND & AIMS

Patients with constipation frequently complain of dyspeptic symptoms that may be explained by reflex inhibition of upper-gastrointestinal motor activity by colonic stimuli. We sought to evaluate the following: (1) the prevalence of functional constipation (FC) and gastric emptying characteristics in children with functional dyspepsia (FD), and (2) the efficacy of osmotic laxatives on constipation, dyspeptic symptoms, and gastric motility.

METHODS

We recruited 42 children (males/females, 22/20; mean age, 80.5 mo) affected by FD (Rome II criteria). All subjects underwent ultrasonographic measurement of the total gastric emptying time (TGEt) at baseline (T0) and after 3 months (T3). Children's bowel habits and the dyspeptic symptomatic score were evaluated at entry and after 1 (T1), 2 (T2), and 3(T3) months. Constipated patients were treated with osmotic laxatives for 3 months. Dyspeptic children without constipation represented the comparison group.

RESULTS

FC was present in 28 of 42 (66.6%) patients. Constipated dyspeptic children had significantly more prolonged TGEt than subjects without constipation (median value [interquartile range], 180 (50) vs 150 (28) min, respectively; P = .004). Patients on osmotic laxatives had a significant decrease in TGEt at 3 months (P < .001). The median dyspeptic symptomatic score as well as the number and consistency of evacuations per week significantly improved at T1 in comparison with T0 and even more at T2 and T3 (P < .001, for each).

CONCLUSIONS

In our study group, the majority of children with FD were affected by FC associated with delayed gastric emptying. Normalization of bowel habit may improve gastric emptying as well as dyspeptic symptoms.

Gallbladder motility in children with chronic constipation

OBJECTIVE

The aim of this study was to evaluate gallbladder motility in constipated children.

PATIENTS AND METHODS

A cross-sectional study was conducted on pediatric patients with refractory constipation examined in a pediatric gastroenterology unit of a teaching hospital between January 2005 and August 2006. All of the patients seen during the period were included (age range, 2-16 years). The control group, matched for sex and age, was selected among patients seen at the same basic health units where patients were seen before being referred to pediatric gastroenterologists. A gallbladder contractility index was calculated based on fasting and postprandial gallbladder areas, using an ultrasonographic method. Ultrasonography studies were performed prospectively and blindly by the same physician. Measurements obtained in patients were compared with those obtained in controls.

RESULTS

A total of 132 constipated children and the same number of healthy controls were included in the study. Median and mean fasting gallbladder areas were similar in patients and controls. Postprandial gallbladder areas were larger in the patient group, mean +/- SD = 594.8 +/- 206.4 mm, median, 562.5 mm, than in the control group, mean +/- SD = 541.1 +/- 156.1 mm, median, 530.5 mm; P = .031. Logistic regression showed that the risk of a contractility index <25% was 5.2 times greater in patients (odds ratio [OR] 5.2; 95% confidence interval [CI] 2.5-10.81) than in controls. Age was found to be a protective factor (OR 0.79; 95% CI 0.71-0.88).

CONCLUSIONS

Gallbladder motility disorder was identified in a group of children with severe constipation. This finding may contribute to the understanding of functional constipation in children.

In patients with slow transit constipation, the pattern of colonic transit delay does not differentiate between those with and without impaired rectal evacuation

BACKGROUND

Severe constipation may be subclassified on the basis of speed of colonic transit and efficacy of rectal evacuation. It is hypothesized that rectal evacuatory disorder (RED) may be associated with a secondary transit delay.

OBJECTIVES

To determine whether scintigraphy can discriminate between slow transit constipation (STC) with or without coexistent RED on the basis of progression of isotope throughout the colon and by analyses of specific regions of interest.

METHODS

One hundred ninety-six patients with STC (radio-opaque marker study) were subclassified according to results of proctography into those with a RED (STC-RED N = 30) or normal (STC-ONLY N = 41) evacuation. Patients subsequently underwent colonic scintigraphy. Distribution of generalized or left-sided patterns of colonic transit was assessed. Severities of transit delay and regional transit at specific time points were also evaluated.

RESULTS

Time-activity curves and severity of global transit delay were similar between groups as were the incidences of generalized and left-sided patterns of delay. Percentage of radioisotope retention in the right colon at 18 h was higher for the STC-ONLY group (P < 0.05), but this was poorly discriminative. No differences were observed for the percentage of radioisotope retained in the left colon at later scans.

CONCLUSIONS

Global and regional assessment of colonic transit by scintigraphy failed to discriminate between patients with STC with or without coexistent RED. Thus, RED is not associated with a specific pattern of transit delay and scintigraphy alone cannot predict the presence or absence of RED, knowledge of which is important for management.

TRPV1 receptor signaling mediates afferent nerve sensitization during colitis-induced motility disorders in rats

Rats with experimental colitis suffer from impaired gastric emptying (GE). We previously showed that this phenomenon involves afferent neurons within the pelvic nerve. In this study, we aimed to identify the mediators involved in this afferent hyperactivation. Colitis was induced by trinitrobenzene sulfate (TNBS) instillation. We determined GE, distal front, and geometric center (GC) of intestinal transit 30 min after intragastric administration of a semiliquid Evans blue solution. We evaluated the effects of the transient receptor potential vanilloid type 1 (TRPV1) antagonists capsazepine (5-10 mg/kg) and N-(4-tertiarybutylphenyl)-4-(3-cholorphyridin-2-yl)tetrahydropyrazine-1(2H)carboxamide (BCTC; 1-10 mg/kg) and the calcitonin gene-related peptide (CGRP) receptor antagonist CGRP-(8-37) (150 microg/kg). To determine TRPV1 receptor antagonist sensitivity, we examined their effect on capsaicin-induced relaxations of isolated gastric fundus muscle strips. Immunocytochemical staining of TRPV1 and RT-PCR analysis of TRPV1 mRNA were performed in dorsal root ganglion (DRG) L6-S1. TNBS-induced colitis reduced GE but had no effect on intestinal motility. Capsazepine reduced GE in controls but had no effect in rats with colitis. At doses that had no effects in controls, BCTC and CGRP-(8-37) significantly improved colitis-induced gastroparesis. Capsazepine inhibited capsaicin-induced relaxations by 35% whereas BCTC completely abolished them. TNBS-induced colitis increased TRPV1-like immunoreactivity and TRPV1 mRNA content in pelvic afferent neuronal cell bodies in DRG L6-S1. In conclusion, distal colitis in rats impairs GE via sensitized pelvic afferent neurons. We provided pharmacological, immunocytochemical, and molecular biological evidence that this sensitization is mediated by TRPV1 receptors and involves CGRP release.

Constipation

Chronic constipation is a common disorder manifested by a variety of symptoms. Assessments of colonic transit and anorectal functions are used to categorize constipated patients into three groups, i.e., normal transit or irritable bowel syndrome, pelvic floor dysfunction (i.e., functional defaecatory disorders) and slow transit constipation. 'Slow transit' constipation is a clinical syndrome attributed to ineffective colonic propulsion and/or increased resistance to propagation of colonic contents. Defaecatory disorders are caused by insufficient relaxation of the pelvic floor muscles or a failure to generate adequate propulsive forces during defaecation. Colonic transit is often delayed in patients with functional defaecatory disorders. Normal and slow transit constipation are generally managed with medications; surgery is necessary for a minority of patients with slow transit constipation. Functional defaecatory disorders are primarily treated with pelvic floor retraining using biofeedback therapy.

Rectal distension inhibits postprandial small intestinal motor activity partially via the adrenergic pathway in dogs

OBJECTIVE

Rectal distension is known to induce numerous upper gastrointestinal symptoms. The aim of this study was to investigate the effects and mechanisms of rectal distension on small intestinal myoelectrical and motor activities in 8 dogs using a pair of intestinal electrodes and an intestinal fistula.

MATERIAL AND METHODS

Experiment 1 entailed a 30-min baseline recording and a 30-min recording during rectal balloon distension at various volumes (60, 80, 100 and 120 ml) randomly. Experiment 2 comprised three sessions, each including a 30-min baseline recording, a 20-min recording after intravenous infusion of saline, phentolamine (3 mg/kg) or propranolol (3 mg/kg), respectively, and another 30-min recording during rectal balloon distending.

RESULTS

1) Rectal distension resulted in reduced intestinal motility in a dose-dependent manner (r=0.68, p<0.001). 2) The reduction in intestinal motility was significantly diminished when infusions of phentolamine (2.7+/-1.0 versus 8.4+/-1.5, p<0.01) or propranolol (3.7+/-1.4 versus 8.4+/-1.5, p<0.05) were given, suggesting partial involvement of the alpha- and beta-adrenergic pathways. 3) Rectal distension did not affect the percentage of normal 17-22 cycles/min intestinal slow waves (97.5+/-2.5 versus 93.0+/-5.3, p>0.05), or their dominant frequency (17.2+/-1.2 counts per minute (cpm) versus 17.7+/-1.0 cpm, p>0.05), or dominant power (-4.8+/-2.5 versus -8.2+/-2.9 dB, p>0.05).

CONCLUSIONS

Rectal distension inhibits postprandial small intestinal motor activity in a distension volume-dependent manner in dogs, and this inhibitory effect is at least partially mediated via the alpha and beta adrenergic pathways and does not involve any alterations in intestinal slow waves.

Proximal colon distension induces Fos expression in the brain and inhibits gastric emptying through capsaicin-sensitive pathways in conscious rats

We assessed brain nuclei activated during noxious mechanical distension of the proximal colon in conscious rats, using Fos as a marker of neuronal activation, and functional reflex changes in gastric emptying associated to colon distension. The role of capsaicin-sensitive afferents in Fos and gastric responses to distension was also investigated. Compared with sham distension, isovolumetric phasic distension of the proximal colon (10 ml, 30 s on/off for 10 min) increased significantly Fos expression 1 h after distension in selective brain areas, most prominently, the paraventricular and supraoptic nuclei of the hypothalamus (13-fold and 80-fold, respectively), the locus coeruleus-Barrington's nucleus complex (2-fold), area postrema (7-fold) and the nucleus tractus solitarius (4-fold). Increased Fos expression was also observed in the cingulate cortex, posterior paraventricular nucleus of the thalamus, periaqueductal gray and ventrolateral medulla. Distension of the proximal colon significantly inhibited gastric emptying by 82% and 34%, as measured 30 and 60 min after the distension respectively, compared with control. Pretreatment with systemic capsaicin prevented both the brain increase in Fos expression and the inhibition of gastric emptying induced by the colon distension. These results show that visceral pain arising from the proximal colon activates a complex neuronal network that includes specific brain nuclei involved in the integration of autonomic, neuroendocrine and behavioral responses to pain and an inhibitory motor reflex in other gut areas (delayed gastric emptying). Capsaicin-sensitive afferent pathways are involved in mediating brain neuronal activation and functional changes associated with noxious visceral stimulation.

Epidemiologic aspects of complete rectal prolapse

BACKGROUND AND AIMS

This study was undertaken to find out the incidence of rectal prolapse.

MATERIAL AND METHODS

Ninety-nine patients operated on for rectal prolapse at Jyväskylä Central Hospital were studied. Patients operated between 1988 and 1998 were studied retrospectively from hospital records using chart review and thirty-five patients operated on between 1999 and 2002 were studied prospectively using our proctologic database.

RESULTS

The annual incidence of diagnosed complete rectal prolapse in the district of Central Finland was mean 2.5 (range, 0.79-6.08) per 100 000 population. There were ten men (10 percent) and 89 women (90 percent). Median age of the patients was 69 (range, 21-91) years. Forty-eight percent of the patients had concomitant cardiovascular disease and 15 percent psychiatric illness. Anal incontinence affecting quality of life was seen in 64 percent and constipation in 72 percent of patients. Constipation tended to be more attributed to difficult evacuation (72 percent) than to impaired bowel action (18 percent).

CONCLUSION

The annual incidence of rectal prolapse is 2.5 per 100 000 population. Rectal prolapse is associated with anal incontinence and constipation in majority of patients.

Upper and lower gastrointestinal motor and sensory dysfunction after human spinal cord injury

This chapter describes the results of investigations of the upper and lower gastrointestinal tract in subjects with complete and incomplete spinal cord injury. In one study, gastric emptying was investigated and found delayed. The delay was tentatively attributed to a colo-gastric inhibitory reflex triggered by inappropriate colonic emptying. In another study, anorectal motor and sensory functions were measured. Decreased tone of the internal anal sphincter, exaggerated recto-anal reflexes following rectal distension and spontaneous high-amplitude rectal contractions at low distension volumes were among the findings of the study. Some of the subjects, classified as having a complete injury according to usual clinical criteria (American Spinal Injury Association, ASIA), reported sensation of distension of the rectum. This raises the issue of the need for better methods for the clinical assessment of sensory transmission in the spinal cord. Promising results obtained with functional magnetic resonance imaging of the brain during rectal stimulation in a small group of paraplegics, with complete injuries by ASIA criteria, showed evidence of activation of several brain regions.

Rectal distension modulates canine gastric tone and accommodation

Rectal distension affects upper GI myoelectrical activity and motility. The aim of this experiment was to investigate the effect of rectal distension on gastric tone, accommodation, and the underlying mechanism. Seven healthy dogs were surgically prepared and studied. Gastric tone and accommodation were assessed with a barostat. In Experiment 1, the effect of rectal distension on gastric tone and accommodation was evaluated; in Experiment 2, rectal distensions with various volumes were randomly applied and its effects on gastric tone were evaluated; and in Experiment 3, the role of the cholinergic pathway in distension-induced gastric relaxation was assessed. The results showed the following. (1) Rectal distension exerted an inhibitory effect on gastric tone, and this response was distension volume-dependent. (2) Postprandial gastric volume was similar in the control (468.6 +/- 24.7 ml) and the distension study (463.2 +/- 17.5 ml). However, rectal distension increased the preprandial gastric volume, and subsequently decreased the extent of gastric accommodation (139.3 +/- 34.7 ml), which was significantly lower than that of the control (383.2 +/- 26.3 ml; P < 0.001). (3) An intravenous bolus of atropine increased the astric volume from the baseline of 89.4 +/- 12.6 ml to 161.5 +/- 9.8 ml (P < 0.01), and subsequent rectal distension further increased this volume, but the overall change was comparable between the control (297.6 +/- 18.7 ml) and the atropine study (312.1 +/- 21.9 ml; P > 0.05). In conclusion, rectal distension inhibits gastric tone in a volume-dependent manner and impairs gastric accommodation. Atropine dose not block the effect of rectal distension on proximal gastric tone, suggesting that the observed effect may not be mediated by cholinergic pathway.

Impaired proximal colonic motor response to rectal mechanical and chemical stimulation in obstructed defecation

PURPOSE

Both motor and sensory dysfunction have been implicated in the pathogenesis of obstructed defecation. We have found that despite preservation of a defecatory urge, patients with obstructed defecation have lost the normal predefecatory augmentation in frequency and amplitude of colonic propagating pressure waves. This observation might be explainable by either altered rectal sensory thresholds or by dysfunction in the colonic motor apparatus. By measuring rectal sensory thresholds and proximal colonic motor responses to rectal mechanical and chemical stimuli, we tested the hypotheses that central perception of rectal stimuli is enhanced and that the proximal colonic motor response to rectal stimulation is attenuated.

METHODS

In seven patients with obstructed defecation and ten healthy volunteers we measured proximal colonic motor responses and sensory thresholds in response to both rectal balloon distention and rectal instillation of chenodeoxycholic acid.

RESULTS

In controls, but not in patients, rectal mechanical distention significantly reduced and chemical stimulation significantly increased the frequency of proximal colonic propagating sequences (P = 0.01). There was no significant difference in rectal sensory thresholds between patients and controls. Prior instillation of chenodeoxycholic acid significantly reduced (P < 0.03) maximum tolerated balloon volume and defecatory urge volume to comparable degree in both patients and controls.

CONCLUSIONS

In obstructed defecation, 1) the normal rectocolonic pathways mediating stimulation-induced proximal colonic propagating pressure waves are nonfunctioning, and. 2) central perception of these rectal stimuli is normal.

Attenuation of the colorectal tonic reflex in female patients with irritable bowel syndrome

Alterations in normal intestinointestinal reflexes may be important contributors to the pathophysiology of irritable bowel syndrome (IBS). Our aims were to compare the rectal tonic responses to colonic distension in female IBS patients with predominant constipation (IBS-C) and with predominant diarrhea (IBS-D) to those in healthy females, both fasting and postprandially. Using a dual barostat assembly, 2-min colonic phasic distensions were performed during fasting and postprandially. Rectal tone was recorded before, during, and after the phasic distension. Colonic compliance and colonic sensitivity in response to the distension were also evaluated fasting and postprandially. Eight IBS-C patients, 8 IBS-D patients, and 8 age- and sex-matched healthy subjects (group N) participated. The fasting increments in rectal tone in response to colonic distension in both IBS-C (rectal balloon volume change -4.6 +/- 6.1 ml) and IBS-D (-7.9 +/- 4.9 ml) were significantly reduced compared with group N (-34 +/- 9.7 ml, P = 0.01). Similar findings were observed postprandially (P = 0.02). When adjusted for the colonic compliance of individual subjects, the degree of attenuation in the rectal tonic response in IBS compared with group N was maintained (fasting P = 0.007; postprandial P = 0.03). When adjusted for colonic sensitivity there was a trend for the attenuation in the rectal tonic response in IBS patients compared with group N to be maintained (fasting P = 0.07, postprandial P = 0.08). IBS patients display a definite attenuation of the normal increase in rectal tone in response to colonic distension (colorectal reflex), fasting and postprandially. Alterations in colonic compliance and sensitivity in IBS are not likely to contribute to such attenuation.

Breath hydrogen test after a bean meal demonstrates delayed oro-cecal transit time in children with chronic constipation

OBJECTIVE

To evaluate oro-cecal transit time in children with chronic constipation.

METHODS

34 patients with chronic functional constipation age 3 to 13 years and 15 controls without constipation. Oro-cecal transit time was evaluated using the hydrogen breath test after ingestion of lactulose and after a standard meal of cooked beans. Total and segmental colonic transit times were measured with radiopaque markers.

RESULTS

Of 34 patients with chronic constipation 61.8% had increased total colonic transit time (>62 hours). Oro-cecal transit time measured with lactulose as substrate was similar (p=0.727) in constipated patients with increased colonic transit time (63.8+/-16.3 minutes), in constipated patients with normal colonic transit time (66.9+/-22.9 minutes), and in controls (65.3+/-15.5 minutes). Using a test meal of beans, the hydrogen breath test showed that oro-cecal transit time of constipated patients with increased total colon transit time was higher (252.4+/-23.2 minutes) than oro-cecal transit time of constipated patients with normal colonic transit time (227.7+/-39.6 minutes) or controls (205.3+/-23.3 minutes) (p<.05).

CONCLUSION

Hydrogen excretion in breath after a bean test meal showed delayed oro-cecal transit time in children with chronic constipation with abnormal total colonic transit time.

Biofeedback benefits only patients with outlet dysfunction, not patients with isolated slow transit constipation

BACKGROUND & AIMS

Biofeedback is reported to be as effective for slow transit constipation as for pelvic floor dyssynergia and no more effective than education. We aimed to test the hypothesis that biofeedback benefits only patients with pelvic floor dyssynergia, describe the physiologic mechanism of treatment, and identify predictors of success.

METHODS

Fifty-two patients (49 women; average age, 35 years), all with delayed whole gut transit, included 34 with pelvic floor dyssynergia, 12 with slow transit only, and 6 who met only 1 of 2 criteria for pelvic floor dyssynergia. All received 5 weekly biofeedback sessions directed at increasing rectal pressure and relaxing pelvic floor muscles during straining plus practice defecating a balloon. Patients were retested by questionnaire; symptom diary; balloon defecation; transit study at 1, 6, 12, and 24 months; and anorectal manometry at 1 and 6 months.

RESULTS

At 6 months, greater improvements were seen in pelvic floor dyssynergia compared with slow transit only; 71% versus 8% reported satisfaction ( P = .001), and 76% versus 8% reported >/=3 bowel movements per week ( P < .001). Improvements were maintained at 24 months of follow-up. Biofeedback eliminated dyssynergia in 91% and enabled 85% to defecate the balloon. Satisfaction was correlated with improved ability to defecate the balloon (rho = .73; P < .001), reductions in dyssynergia (rho = .69; P < .001), and increased rectal pressure during straining (rho = .36; P < .01). Success was predicted by pelvic floor dyssynergia, milder constipation, and less frequent abdominal pain at baseline.

CONCLUSIONS

Biofeedback is an effective treatment for pelvic floor dyssynergia but not slow transit constipation.

Effect of sex steroids on colonic distension-induced delay of gastric emptying in rats

BACKGROUND AND AIM

The objective of the present study was to examine the effect of gonadal hormones on gastric motor response to non-noxious and noxious stimuli of colonic distension.

METHODS

Male Wistar albino rats were used. Under ketamine anesthesia some rats underwent castration (n = 24), while the rest of the rats were sham-operated (n = 67) and divided into different groups (n = 7-8 per group). On the 15th day of surgery, liquid gastric emptying studies were commenced.

RESULTS

Non-noxious (P < 0.05) or noxious (P < 0.01) colonic distension inhibited gastric emptying rate. Estradiol pretreatment (20 micro g/kg per day, for 5 days, s.c.) inhibited gastric motility, while estradiol pretreatment or castration of the rats prior to noxious distension prevented the delay in gastric emptying. In contrast, blockade of testosterone receptors had no effect on the delay in gastric emptying induced by either modes of distension.

CONCLUSIONS

The results suggest that sex steroids have a modulatory role on the feedback control of gastric motility induced by noxious colonic distension.

Recurrent vomiting and persistent gastroesophageal reflux caused by unrecognized constipation

Over a 2-year period, 34 children were referred to the division of pediatric gastroenterology at the University of Virginia with chronic upper gastrointestinal symptoms whose symptoms rapidly and completely resolved when their unrecognized constipation was treated. The average age at presentation was 8.24 (SD 0.78) years and average duration of upper intestinal symptoms was 15.6 (SD 3.5) months. Twenty-six of 34 had experienced recurrent vomiting, 6 complained of chronic nausea, 17 had chronic symptoms of gastroesophageal reflux, and 20 complained of chronic or recurrent abdominal pain, most often in the epigastric region. Smaller numbers had experienced early satiety, choking, gagging, dysphagia, or intermittent diarrhea. Given the prevalence of constipation in childhood, it seems likely that many children who experience chronic upper intestinal symptoms may be suffering from chronic unrecognized constipation as the cause of their upper intestinal symptoms.

Influence of continuous isobaric rectal distension on gastric emptying and small bowel transit in young healthy women

Patients with slow transit constipation frequently have delayed gastric emptying. In animals rectal distensions inhibit gastrointestinal motility. In healthy volunteers isovolumetric rectal distensions delay upper gut transit. The purpose of this study was to determine the effect of continuous isobaric rectal distension on gastric emptying and oro-cecal transit in young females. Using validated 13C octanoic and lactose-[13C] ureide breath tests gastric half-emptying time and oro-cecal transit time for a meal were measured in 12 volunteers. The tests were repeated in randomized order: during isobaric balloon distension and during sham distension. Isobaric rectal distension was applied using a polyethylene bag connected to a barostat. Intraballoon pressure was kept just below the threshold for the urge sensation. Mean gastric half-emptying time during rectal distension (92.3 +/-5.1 min) was significantly higher than during sham distension (78.8 +/- 4 min; P = 0.015). Mean oro-cecal transit time during rectal distension (391.3 +/-29.1 min) and sham distension (328.8 +/- 38.4 min) were not significantly different. In conclusion, these findings indicate that isobaric rectal distension inhibits gastric emptying, but not small bowel transit in young healthy women. Studies in patients with constipation are indicated.