Gastric mechanosensory and lower esophageal sphincter function in rumination syndrome

Gastric accommodation: Physiology, diagnostic modalities, clinical relevance, and therapies

BACKGROUND

Gastric accommodation is an essential gastric motor function which occurs following ingestion of a meal. Impaired gastric fundic accommodation (IFA) is associated with dyspeptic symptoms. Gastric accommodation is mediated by the vagal pathway with several important physiologic factors such as duodenal nutrient feedback playing a significant role. IFA has been described as a pathophysiologic factor in several gastrointestinal disorders including functional dyspepsia, diabetic gastropathy, post-Nissen fundoplication, postsurgical gastrectomy, and rumination syndrome. Modalities for gastric accommodation assessment include gastric barostat, intragastric meal distribution via scintigraphy, drinking tests (eg, water load), SPECT, MRI, 2D and 3D ultrasound, and intragastric high-resolution manometry. Several treatment options including sumatriptan, buspirone, tandospirone, ondansetron, and acotiamide may improve symptoms by increasing post-meal gastric volume.

PURPOSE

Our aim is to provide an overview of the physiology, diagnostic modalities, and therapies for IFA. A literature search was conducted on PubMed, Google Scholar, and other sources to identify relevant studies available until December 2020. Gastric accommodation is an important gastric motor function which if impaired, is associated with several upper gastrointestinal disorders. There are an increasing number of gastric accommodation testing modalities; however, each has facets which warrant consideration. Evidence regarding potentially effective therapies for IFA is growing.

Prevalence, symptoms and risk factor profile of rumination syndrome and functional dyspepsia: a population-based study

BACKGROUND

Rumination syndrome is a functional gastroduodenal disorder characterised by effortless regurgitation of recently ingested food. Emerging evidence reports duodenal eosinophilic inflammation in a subset, suggesting a shared pathophysiology with functional dyspepsia (FD).

AIM

To assess the clinical features of rumination syndrome and FD in a community-based study.

METHODS

We mailed a survey assessing gastrointestinal symptoms, diet and psychological symptoms to 9835 residents of Olmsted County, MN, USA in 2017-2018; diagnostic codes were obtained from linked clinical records. The two disorders were assessed as mutually exclusive in 'pure' forms with a separate overlap group, all compared to a control group not meeting criteria for either. Prevalence of associations, and univariate and independent associations with predictors were assessed by logistic regression.

RESULTS

Prevalence of rumination syndrome and FD were 5.8% and 7.1%, respectively; the overlap was 3.83-times more likely than expected by chance. Independent predictors for rumination (odds ratio (OR), 95% confidence interval (CI)) were female gender (1.79, 1.21-2.63), smoking (1.89, 1.28-2.78), gluten-free diet (1.58, 1.14-2.19), allergic rhinitis (1.45, 1.01-2.08) and depression (1.10, 1.05-1.16). FD was independently associated with female gender, depression, non-coeliac wheat sensitivity, migraine, irritable bowel syndrome and somatic symptoms. A similar reported efficacy (≥54%) of low fat or dairy-free diets was found with both disorders (P = 0.53 and P = 1.00, respectively). The strongest independent associations with overlapping FD and rumination syndrome were a history of rheumatoid arthritis (3.93, 1.28-12.06) and asthma (3.02, 1.44-6.34).

CONCLUSION

Rumination syndrome overlaps with FD with a shared risk factor profile, suggesting a common pathophysiology.

Rumination Syndrome in Children and Adolescents: A Mini Review

Introduction: Rumination syndrome involves recurrent regurgitation of food and is believed to be underdiagnosed with patients experiencing long delays in diagnosis. It can be associated with significant social consequences, high rates of school absenteeism, and medical complications such as weight loss. The primary aims of the current review are to assess the literature regarding prevalence, pathophysiology, and treatment outcomes with a focus on neurotypical children and adolescents. Results: Population studies in children/adolescents, 5 years of age or older, range from 0 to 5.1%. There are fewer studies in clinical settings, but the prevalence appears to be higher in patients with other gastrointestinal symptoms, particularly chronic vomiting. While physiologic changes that occur during a rumination episode are well-described, the underlying cause is less well-defined. In general, rumination appears to have similarities to other functional gastrointestinal disorders including dysmotility, possibly inflammation, and an interaction with psychologic function. While diaphragmatic breathing is considered the mainstay of treatment, pediatric data demonstrating efficacy is lacking, especially as an isolated treatment. Conclusion: Pediatric rumination syndrome remains greatly understudied, particularly regarding treatment. There is a need to better define prevalence in both the primary care and subspecialty clinical settings, especially in patients presenting with vomiting or apparent gastroesophageal reflux. There is a need to determine whether treatment of co-morbid conditions results in improvement of rumination. Diaphragmatic breathing needs to be studied and compared to other competing responses.

Prevalence of behavioral disorders in patients with vonoprazan-refractory reflux symptoms

BACKGROUND

Behavioral disorders, such as supragastric belching (SGB) and rumination syndrome (RS), which may be treated by cognitive behavioral therapy, are common in patients with reflux symptoms refractory to proton pump inhibitors (PPI). Vonoprazan (VPZ) has been used as a new type of acid inhibitor in Japan since 2015. We herein investigated the prevalence of behavioral disorders in patients with VPZ-refractory reflux symptoms and attempted to identify predictive factors.

METHODS

We retrospectively analyzed esophagogastroduodenograms, high-resolution manometry, and 24-h multiluminal impedance pH-metry (MIIpH) in patients with VPZ-refractory reflux symptoms (heartburn or regurgitation) receiving 20 mg VPZ who underwent these tests at our hospital between January 2015 and April 2020. Patients were divided as follows: non-erosive reflux disease with pathological esophageal acid exposure (NERD), functional heartburn (FH), reflux hypersensitivity (RH), excessive (> 13 per day) SGB, and possible RS based on MIIpH parameters.

RESULTS

Among 49 patients, 6 (12.2%) had SGB, 4 (8.2%) possible RS, 29 (59.2%) FH, 9 (18.4%) RH, and 1 (2%) NERD. Possible RS patients had more postprandial non-acid reflux events than FH patients (p < 0.05). The multivariate logistic regression analysis did not identify any predictive factors with statistical significance.

CONCLUSION

More than 20% patients with VPZ-refractory reflux symptoms had behavioral disorders. The use of HRM and MIIpH may be clinically relevant for a better diagnosis and more specific treatment.

Rumination syndrome: Assessment of vagal tone during and after meals and during diaphragmatic breathing

BACKGROUND

Pathophysiology of rumination syndrome (RS) is not well understood. Treatment with diaphragmatic breathing improves rumination syndrome. The aim of the study was to characterize vagal tone in patients with rumination syndrome during and after meals and during diaphragmatic breathing.

METHODS

We prospectively recruited 10 healthy volunteers (HV) and 10 patients with RS. Subjects underwent measurement of vagal tone using heart rate variability. Vagal tone was measured during baseline, test meal and intervention (diaphragmatic (DiaB), slow deep (SlowDB), and normal breathing). Vagal tone was assessed using mean values of root mean square of successive differences (RMSSD), and area under curves (AUC) were calculated for each period. We compared baseline RMSSD, the AUC and meal-induced discomfort scores between HV and RS. Furthermore, we assessed the effect of respiratory exercises on symptom scores, and number of rumination episodes.

KEY RESULTS

There was no significant difference in baseline vagal tone between HV and RS. During the postprandial period, there was a trend to higher vagal tone in RS, but not significantly (P > .2 for all). RS had the higher total symptom scores than HV (P < .011). In RS, only DiaB decreased the number of rumination episodes during the intervention period (P = .028), while both DiaB and SlowDB increased vagal tone (P < .05 for both). The symptom scores with the 3 breathing exercises showed very similar trends.

CONCLUSIONS AND INFERENCES

Patients with RS do not have decreased vagal tone related to meals. DiaB reduced number of rumination events by a mechanism not related to changes in vagal tone.

Psychological profiles of irritable bowel syndrome patients with different phenotypes

BACKGROUND/AIMS

Abnormal psychological profiles are frequently found in patients with functional gastrointestinal disorders (FGIDs). The present study aimed to evaluate the psychological profiles of FGID patients with irritable bowel syndrome (IBS), and IBS phenotypes.

METHODS

In 608 FGID patients, including 235 with IBS, have filled a Rome III questionnaire and the French version of the Minnesota Multiphasic Personality Inventory 2. Data analysis was performed using univariate analysis and multivariate logistic regression.

RESULTS

This study shows that IBS patients have abnormal psychological profiles with more significant symptom exaggeration and decreased test defensiveness than non-IBS patients. They have a significantly higher score for all clinical scales. Logistic regression analysis showed in IBS patients a decrease of body mass index (P= 0.002), and test defensiveness score K (P= 0.001) and an increase of Hypochondriasis (P< 0.001) and Masculinity-Femininity scale (P= 0.018). By comparison with non-IBS patients, IBS-constipation, IBS-diarrhea, and mixed IBS patients have increased Hypochondriasis value and Depression score, mixed IBS patients have higher Psychasthenia score and higher Hypomania score. No item was significantly different in the IBS-unspecified group.

CONCLUSIONS

This study shows that IBS patients have different psychological profiles than other FGID patients and that psychological characteristics are associated with IBS phenotypes except for patients with unsubtyped IBS.

Chronic vomiting in children: A prospective study reveals rumination syndrome is an important etiology that is underdiagnosed and untreated

BACKGROUND

The diagnosis of rumination syndrome is frequently overlooked, and under-recognized; children are subjected to unnecessary testing and inappropriate treatment for a condition which can be diagnosed clinically and managed easily. In the first ever systematic exploration of this condition from India, we present a prospective study on children with chronic vomiting in which rumination emerged as the predominant cause.

METHODS

This was a prospective study in which all consecutive children (5-18 years) presenting with chronic or recurrent vomiting of at least 2-month duration were enrolled. Clinical history was assessed by a physician-administered questionnaire. All subjects underwent standard testing followed by additional investigations as required. The ROME III criteria were used.

RESULTS

Fifty children (28 boys, age 12.2 + 3 years) were enrolled. Diagnosis was rumination syndrome 30, cyclical vomiting 8, functional vomiting 6, intestinal tuberculosis 4, intestinal malrotation 1, and superior mesenteric artery syndrome 1. Children with rumination syndrome had a relapsing and remitting (12, 40%) or a chronically symptomatic course (18, 60%). These children received incorrect diagnoses (26, 87%) or no diagnosis (3, 10%) and extensive investigation before referral. Before referral, children with rumination syndrome were treated with a median of four drugs (range 1 to 9); two underwent surgery (appendectomy) for their symptoms while one child was subjected to electroconvulsive therapy. Overall, resolution after treatment was seen in 26 (87%) with a relapse in 8 (27%) children.

CONCLUSION

The diagnosis of rumination syndrome is delayed and these children are often inappropriately treated. Therapy in the form of diaphragmatic breathing has a good success rate.

Rumination Syndrome: Recognition and Treatment

PURPOSE OF REVIEW

The purpose of this paper is to discuss current diagnostic and treatments of rumination. Rumination is often underdiagnosed or misdiagnosed in adults, especially when symptoms suggest regurgitation rather than vomiting accompanied by re-chewing and re-swallowing and should be included in the differential diagnosis. It is primarily diagnosed clinically by ROME-IV or DSM-5.

RECENT FINDINGS

That rumination can be re-affirmed by characteristic patterns on objective testing such as high-resolution esophageal manometry and 24-h pH impedance testing. However, although gastroduodenal manometry and EMG are helpful, these tests are slowly losing interest given their technical nature of data gathering, time consumption, cost burden, and patient discomfort.

SUMMARY

Rumination is primarily diagnosed clinically by ROME-IV or DSM-5 in addition to high-resolution esophageal manometry and 24-h pH impedance. Management is challenging and usually a combination of behavioral, pharmacological, and rarely surgical treatment. Recent data demonstrate that the combination of behavioral techniques such as diaphragmatic breathing exercises and/or with baclofen has promising results. Further research is necessary to further define objective criteria for diagnosis and other therapeutic modalities for treatment.

Treatment options for rumination syndrome: A systematic review

BACKGROUND

Rumination syndrome (RS) is characterized by recurrent effortless postprandial regurgitation of recently ingested food from the stomach to the oral cavity and has been associated with quality of life impairment and malnutrition. There is a general lack of consensus on the most appropriate treatment options for RS.

AIM

To summarize the literature on treatment options for RS.

METHODS

We conducted a systematic review according to PRISMA guidelines. We searched Medline (1946 to February 2019), EMBASE (1947 to February 2019), PsycINFO (1806 to February 2019) and Cochrane central register of controlled trials for articles discussing treatment options for adult patients (> 18 years) with RS. All relevant articles were accessed in full text. We extracted data on study designs, patient profiles, duration of symptoms, follow up periods, date, diagnostic criteria, interventions and outcomes. Risk of bias assessment was carried out independently by 3 reviewers via Cochrane Risk of Bias tool and Newcastle Ottawa Scale for randomized controlled trials and Cohort studies respectively.

RESULTS

Twelve articles were identified. A total of 254 patients were included in the analysis, with a mean age of 36.1 (range 18-89). 185 patients (72.8%) were females. 5 studies looked into behavioral therapies, primarily diaphragmatic breathing (DB) 2 studies looked at baclofen, 1 fundoplication and 1 supportive lifestyle changes. 3 studies looked at a combination of therapies involving pharmacological, behavioral and psychotherapies.

CONCLUSION

Although evidence for treatment options is still limited, the strongest evidence point towards the use of DB and Baclofen, and both should be considered depending on their availabilities.

Rumination Disorder: An Unexplained Case of Recurrent Vomiting

Rumination disorder or rumination syndrome is an infrequent clinical presentation reported in infants and young children as well as adults worldwide. Studies calculating prevalence and etiological considerations are very few, and the scientific literature mostly consists of anecdotal case reports and series. Awareness of this clinical entity is obscured by presentations mimicking upper gastrointestinal disorders, mostly recurrent vomiting. The repetitive, voluntary, habitual nature of this disorder is vulnerable to be missed out if not looked for specifically in the history. Here lies the importance of increasing the awareness about diagnosis of this disorder and the need to operationalize treatment guidelines for this disorder which has long-term physical, psychological, and economic consequences if not treated early in its course.

Pediatric rumination subtypes: A study using high-resolution esophageal manometry with impedance

BACKGROUND

The differential diagnosis of intractable reflux in children includes rumination syndrome, but confirming the diagnosis using antroduodenal manometry is invasive, is costly, and requires anesthesia. High-resolution esophageal manometry with impedance (HRM-MII) overcomes these limitations, and the goal of this study is to validate the use of HRM-MII as a diagnostic tool for rumination and to describe the subtypes of pediatric rumination.

METHODS

We reviewed the HRM-MII tracings of 21 children presenting with symptoms of intractable reflux in whom rumination was being considered. Patients underwent a standard and post-prandial HRM-MII. Peak intraluminal esophageal pressures, baseline gastric and thoracic pressures, and the timing of the R wave relative to LES relaxations and bolus flow were recorded. Chi-square analyses were used for comparison of proportions and means were compared using t-tests or non-parametric equivalent.

KEY RESULTS

Forty-one (55.5%) primary and 33 (44.5%) secondary rumination episodes were seen. Three types of primary rumination were identified: i) LES relaxation without retrograde flow preceding the R wave (51% of episodes); ii) LES relaxation after the R wave (20% of episodes); and iii) R waves with no LES relaxation (29% of episodes). Eleven patients had rumination episodes with a peak gastric pressure <30 mm Hg. A total of 44 (60%) rumination episodes occurred during the standard HRM-MII, and 30 (40%) occurred during or after the meal.

CONCLUSIONS & INFERENCES

HRM-MII can accurately diagnose rumination in children. We identify three types of primary rumination which may provide insight into therapeutic response.

Subtotal Gastrectomy as "Last Resort" Consideration in the Management of Refractory Rumination Syndrome

Rumination syndrome is a behavioral disorder resulting in effortless regurgitation of undigested food within minutes of meal intake that is subsequently either re-swallowed or ejected. It is commonly misdiagnosed, patients often undergo extensive testing and multiple therapies, many of which are directed at suspected gastroparesis. A 25-year-old Caucasian female initially presented to our care 1 year ago with a 4-year history of nausea and vomiting occurring in the immediate postprandial period, specifically within 15 minutes from oral intake. She had an extensive history of multiple diagnostic, therapeutic and surgical procedures over the previous 4 years which included cholecystectomy, botulin toxin injection into the pyloric sphincter, pyloroplasty, placement of a gastric stimulator and jejunal feeding tube with no sustained results. On a previous admission we determined the functional status of the stomach by obtaining full thickness gastric biopsies during a diagnostic laparoscopy. This revealed an adequate population number of cells of Cajal and myenteric neurons as well as normal stomach muscle. After 1 year of attempting “breathing relaxation techniques”, while being nutritionally maintained by nocturnal jejunostomy feedings, the patient presented again to our care with refractory nausea and vomiting and unable to work or function. Her weight was 90 lbs. She underwent a subtotal gastrectomy (80%) with Roux-en-Y reconstruction and continuation of jejunostomy feeding. The refractory nausea and vomiting significantly improved over the 4 weeks after discharge and breathing exercises were continued. On subsequent follow-up visits over a 6-month course, the refractory nausea and vomiting had resolved by more than 85% with and improvement in her BMI and quality of life.The recommended treatment of rumination syndrome is focused on breathing exercises and relaxation techniques to “distract” while eating. We believe our case is the first reported where a subtotal gastrectomy has been used to help overcome refractory rumination along with the usual therapy. This surgery is a “last resort” consideration to improve quality of life, returning the patient to employment and functional social status.

Adolescent rumination syndrome

Rumination syndrome is the non-purposeful regurgitation of recently ingested food from the stomach to the mouth, where it is either expelled or reswallowed. Adolescent rumination syndrome (ARS) is a rare condition of which many physicians are unaware. Patients often are misdiagnosed or undergo costly testing, and as a result, diagnosis and treatment are often delayed. While ARS is not life-threatening, it does have medical and emotional effects on the patient and the patient's family. Diagnosis of ARS is based upon the Rome III diagnostic criteria. Antroduodenal manometry, while not required for a diagnosis, can be helpful to confirm the diagnosis. The pathogenesis of this disorder is complex and not well understood. However, because of its behavioral component, treatment of ARS requires a multidisciplinary approach that includes both medical management of symptoms and implementation of strategies that address behavioral, psychological, and general quality-of-life components of the disorder.

Chronic vomiting and diarrhea in a young adult female

Patient: Female, 25

Final Diagnosis: Rumination syndrome

Symptoms: Diarrhea • nausea • vomiting

Medication: —

Clinical Procedure: —

Specialty: Psychology

Rumination syndrome in children and adolescents: a school survey assessing prevalence and symptomatology

BACKGROUND

Rumination syndrome (RS) is a functional gastrointestinal disorder (FGD) increasingly recognized in children and adolescents. The epidemiology of this condition in school aged children is poorly understood. The main objective of this study was to assess the prevalence of rumination and other related associations in a cohort of Sri Lankan children.

METHODS

Children aged 10-16 years were randomly selected from 8 schools in 4 provinces in Sri Lanka. RS was diagnosed using Rome III criteria. Data was collected using a self administered questionnaire distributed in an examination setting. It was translated into Sinhala, the native language and pretested before distribution.

RESULTS

A total of 2163 children were included in the study (55% boys, mean age 13.4 years, SD 1.8 years). Prevalence of RS was 5.1% (n = 110); boys 5.1% and girls 5.0%. When symptoms were analyzed, 73.6% reported re-swallowing of regurgitated food, while the rest spat it out. In 94.5% regurgitation occurred during the first hour after the meal. Only 8.2% had daily symptoms while 62.7% had symptoms weekly. Abdominal pain, bloating and weight loss were the commonest symptoms associated with RS (19.1%, 17.3% and 11.8% respectively). No significant association was observed between exposure to stressful events and rumination (p > 0.05). Twenty (18.2%) with RS fulfilled Rome III criteria for at least one other FGD. School absenteeism was seen in 11.8% of affected children.

CONCLUSION

RS was reasonably common in this cohort of school-aged children and adolescents in Sri Lanka. However, symptoms were severe enough to affect schooling only in 12% of affected children. Around one fifth with RS had at least one other overlapping FGD.

Adult rumination syndrome: Differentiation from psychogenic intractable vomiting

Rumination syndrome is known to exist in infants and mentally retarded adults since long time. In past few years, some reports appeared that showed its existence in adult patients also. It is frequently confused with the intractable vomiting in adults and misdiagnosis leads to delay in appropriate management. We are here describing the case of a female patient with rumination syndrome where specific points in the history delineated the presence of this illness and helped in appropriate management. The patient became symptom free soon after the diagnosis was reached.

Management of diabetic gastroparesis

Symptoms suggestive of gastroparesis occur in 5% to 12% of patients with diabetes. Such a complication can affect both prognosis and management of the diabetes; therefore, practicing clinicians are challenged by the complex management of such cases. Gastroparesis is a disorder characterized by a delay in gastric emptying after a meal in the absence of a mechanical gastric outlet obstruction. This article is an evidence-based overview of current management strategies for diabetic gastroparesis. The cardinal symptoms of diabetic gastroparesis are nausea and vomiting. Gastroesophageal scintiscanning at 15-minute intervals for 4 hours after food intake is considered the gold standard for measuring gastric emptying. Retention of more than 10% of the meal after 4 hours is considered an abnormal result, for which a multidisciplinary management approach is required. Treatment should be tailored according to the severity of gastroparesis, and 25% to 68% of symptoms are controlled by prokinetic agents. Commonly prescribed prokinetics include metoclopramide, domperidone, and erythromycin. In addition, gastric electrical stimulation has been shown to improve symptoms, reduce hospitalizations, reduce the need for nutritional support, and improve quality of life in several open-label studies.

Rumination syndrome: an emerging case scenario

This article describes the case of a 19-year-old woman presenting with repetitive episodes of effortless vomiting, which started within 3 weeks of her naval boot camp training. She underwent a battery of costly investigations before the diagnosis of rumination syndrome could be made. One of the reasons for her delayed diagnosis is that many physicians are unaware of, or are reluctant to make the diagnosis of rumination syndrome. The purpose of this article is to make the general physician aware of the possibility of rumination syndrome in adolescents and adults of normal intelligence, even though it was initially considered only in infants and mentally retarded individuals. The key to diagnosis is a thorough patient history. Reassurance and behavioral therapy is the mainstay of treatment, with a reported success of >80%.

Gastric compliance in bulimia nervosa

Bulimia nervosa (BN) is a psychiatric illness characterized by eating binges followed by inappropriate behavioral attempts to compensate for the binges, usually vomiting or laxative abuse. Patients with BN have disturbances in the development of satiety during a meal as well as disturbances in functions of the upper gastrointestinal tract such as slowed gastric emptying, impaired gastric accommodation reflex and blunted cholecystokinin release. The present study examined gastric compliance and sensory responses to gastric distention in women with BN and controls. Sixteen women with BN and 13 healthy control subjects swallowed an inflatable bag that was placed in the proximal stomach. The bag was inflated to produce increasing steps of pressure against the stomach wall, before and after consumption of a 200 ml (200 Kcal) liquid meal. Pressure and volume were recorded for 2-min periods, beginning at 0 mm Hg pressure and increasing in steps of 2 mm Hg until subjects reported discomfort, gastric volume reached 600 ml, or pressure reached 20 mm Hg. At each pressure step subjects made sensory ratings. Gastric compliance was calculated as the slope of the best-fit straight line of each subject's gastric volume vs. gastric pressure. There was a significant postmeal increase in gastric compliance in both groups of subjects but there was no difference in compliance between patients with BN and controls. Patients with BN appeared to have diminished sensitivity to gastric distention. In conclusion, although other studies have described gastrointestinal abnormalities associated with BN, the current study found gastric compliance of patients with BN to be normal.

Effect of modulation of serotonergic, cholinergic, and nitrergic pathways on murine fundic size and compliance measured by ultrasonomicrometry

Reduced fasting or postprandial gastric volumes have been implicated in the pathophysiology of functional dyspepsia. The mechanisms that underlie the control of gastric fundic volume are incompletely understood, partly because of an inability to accurately measure fundic volume in vivo in small animals. Small animals are useful models to evaluate mechanisms, e.g., in knockout animals. The aim of this study was to determine whether an ultrasonometric technique accurately monitors fundic contraction and relaxation in mice in vivo and to determine the effect of modulation of cholinergic, nitrergic, and serotonergic pathways on fundic size and compliance in the intact mouse innervated stomach. Two to four piezoelectric crystals (diameter 1 mm, 24-microm resolution) were glued to the serosal side of fundus and used to measure distance. Validation studies showed excellent correlation between measured changes and actual changes in distances between crystals and excellent reproducibility. The expected responses to pharmacological modulation with bethanechol and nitroglycerin were demonstrated. Atropine increased the distance between the crystals, suggesting a baseline cholinergic regulation of fundic volume. Bethanechol, Nomega-nitro-L-arginine, and the 5-HT1B/D agonist sumatriptan decreased the distance between the crystals, suggesting fundic contraction. Atropine, nitroglycerin, and buspirone caused an increase in intercrystal distance consistent with fundic relaxation. Fundic compliance was investigated by changing intragastric pressure via an implanted catheter. Sumatriptan increased compliance, whereas buspirone increased the distance between crystals but did not change compliance. The data suggest that ultrasonomicrometry is a useful tool that can reproducibly and accurately measure changes in fundic size and the response to pharmacological agents.

Gastric electrical stimulation inhibits postprandial antral tone partially via nitrergic pathway in conscious dogs

Gastric electrical stimulation (GES) has recently been explored as a therapeutic option for gastrointestinal motility disorders or obesity. The mechanism behind it is not fully elucidated. The aims of this study were to assess the effects of GES with different parameters on antral tone and to explore the involvement of the nitrergic pathway. Eight dogs equipped with a gastric cannula and one pair of serosal electrodes in the greater curvature 4 cm above the pylorus were studied on separate days. The study was composed of seven randomized sessions in the fed state [control, GES with different parameters, and GES plus neuronal nitric oxide synthase (nNOS) inhibitor]. Each session included three consecutive 30-min periods (baseline, GES, and recovery). GES was performed with long pulses or pulse trains. The antral volume was measured using an intragastric balloon connected with a barostat device. Behaviors of the dogs during each stimulation period were also noted. We found that 1) postprandial antral tone was reduced with GES with all tested parameter settings, reflected as a significant and substantial increase in antral volume ranging from 179 to 309%; 2) the inhibitory effect of GES on antral tone was partially blocked (decreased by 39.5%) with an nNOS inhibitor; and 3) mild symptoms were induced with GES and found to be correlated with the GES-induced increase in antral volume. We conclude that retrograde GES with long pulses or pulse trains inhibits antral tone, and this inhibitory effect is partially mediated via the nitrergic pathway. These results suggest that retrograde GES may have a therapeutic potential for obesity.

Selective effects of serotonergic psychoactive agents on gastrointestinal functions in health

This study evaluated the effects of serotonergic psychoactive agents on gastrointestinal functions in healthy human subjects. Participants received one of four regimens in a randomized, double-blind manner: buspirone, a 5-HT(1A) receptor agonist (10 mg twice daily); paroxetine, a selective serotonin reuptake inhibitor (20 mg daily); venlafaxine-XR, a selective serotonin and norepinephrine reuptake inhibitor (75 mg daily); or placebo for 11 days. Physiological testing performed on days 8-11 included scintigraphic assessment of gastrointestinal and colonic transit, the nutrient drink test, and assessment of the postprandial change in gastric volume. Fifty-one healthy adults (40 females, 11 males) participated in this study. No effects on gastric emptying or colonic transit were identified with any agent. Small bowel transit of a solid meal was accelerated by paroxetine. Buspirone decreased postprandial aggregate symptom and nausea scores. Venlafaxine-XR increased the postprandial change in gastric volume. Buspirone, paroxetine, and venlafaxine-XR affect upper gastrointestinal functions in healthy humans. These data support the need for clinical and physiological studies of these agents in functional gastrointestinal disorders.

Rumination syndrome in children and adolescents: diagnosis, treatment, and prognosis

OBJECTIVES

To characterize the clinical features, results of diagnostic testing, and treatment outcomes for children and adolescents with rumination syndrome.

METHODS

Review of the medical records for all 147 patients ages 5 to 20 diagnosed with rumination syndrome at our institution between 1975 and 2000. Data are presented as mean +/- the standard error of the mean.

RESULTS

Sixty-eight percent were female. Age at diagnosis was 15.0 +/- 0.3 years. Symptom duration before diagnosis was 2.2 +/- 0.3 years, 73% missed school/work, and 46% had been hospitalized because of symptoms. Before diagnosis, 16 (11%) underwent surgery for evaluation or management of symptoms. Twenty-four (16%) had psychiatric disorders; 3.4% had anorexia or bulimia nervosa. All patients described postprandial regurgitation after almost every meal (2.7 +/- 0.1 meals per day). Weight loss was described by 42.2% (median: 7 kg). Additional symptoms included: abdominal pain, 38%; constipation, 21%; nausea, 17%; and diarrhea, 8%. Structural studies were normal. Gastric emptying of solids at 4 hours was delayed in 26 of 56 patients. Esophageal pH testing in 24 patients showed reflux/regurgitation in 54%. Gastroduodenal manometry in 65 patients showed characteristic rumination-waves in 40%. Outcome data (at median follow-up 10 months) were available for 54 patients. Symptoms resolved in 16 (30%) and improved in 30 (56%).

CONCLUSIONS

Recognition of the clinical features of rumination syndrome in children and adolescents is essential; the diagnosis is often delayed and associated with morbidity. Extensive diagnostic testing is unnecessary. Early behavioral therapy is advocated, and patient outcomes are generally favorable.

Effect of intragastric barostat bag on proximal and distal gastric accommodation in response to liquid meal

The barostat is the gold standard for measurement of proximal gastric accommodation. Ultrasonography can be used to measure gastric volume. The aim was to investigate the effects of the barostat bag on gastric accommodation and transpyloric flow. Accommodation after a liquid meal (300 ml, 450 kcal) was measured twice at random in eight healthy volunteers. Proximal accommodation was measured once using barostat and once using ultrasound (US). Antrum accommodation was measured using US. Bag volume (BV), antral area (AA), proximal gastric area, and proximal gastric diameter (PGD) data were assessed before and 1, 5, 15, 30, 40, 50, and 60 min postprandially. Transpyloric flow was measured using Doppler 1-5 min postprandially. Fasted, AA size was not affected by the barostat bag (1 mmHg > minimal distension pressure; 2.7 +/- 0.5 vs. 2.6 +/- 0.3 cm(2)). Postprandially, AAs were larger with the bag present (ANOVA, P < 0.04). Maximum AA was reached with the bag in 5 min, without the bag in 1 min postprandially (15.1 +/- 2.3 vs. 9.4 +/- 1.5 cm(2); P < 0.03). Furthermore, AAs were related to BVs (r = 0.57; P < 0.01). After bag deflation, AA decreased (11.9 +/- 1.8 to 7.0 +/- 0.9 cm(2); P = 0.02) and was comparable with the 60-min AA size without the bag (7.1 +/- 1.2 cm(2); P = 0.76) present. Proximal gastric radius calculated from the BVs and PGDs was larger with the bag present (ANOVA, P < 0.001). No effect on early gastric emptying was observed. Postprandially, the barostat bag causes dilatation of the antrum due to meal displacement without influencing early gastric emptying. This antral dilatation is likely to induce exaggerated proximal gastric relaxation observed in studies using the barostat to evaluate fundic accommodation.

Gastroduodenal motility

Several major themes emerged over the past year in the area of gastroduodenal motility. Mostly, these themes represented extensions of research areas discussed in prior reviews in this series rather than the emergence of completely new concepts. Thus, for example, considerable emphasis has again been placed on regional gastric motor function in dyspepsia and on the role of fundic relaxation and accommodation, in particular. Not surprisingly, basic physiologic research has also shown a keen interest in the regulation of fundic relaxation. One new and exciting development is the recognition of the stomach's role in satiety. The spectrum of gastric motor dysfunction in diabetes mellitus continues to be explored, and the important role of hyperglycemia in regulating gastric function has been further emphasized. More data have been provided on noninvasive alternatives to gastric motor function testing, and several studies have looked at factors that may influence variability in these various tests. There have been few innovations over the past year in the therapeutic arena; rather, the indications and limitations of current therapies have been further developed.