Functional Dyspepsia and Gastroparesis in Tertiary Care are Interchangeable Syndromes With Common Clinical and Pathologic Features

Clinical validation of the VIPUN™ gastric monitoring system versus manometry for the evaluation of gastric motility

BACKGROUND

Gastrointestinal dysmotility is frequently suspected in patients with gastroparesis, functional dyspepsia, and ileus, and in the intensive care unit. Monitoring of gastric motility in clinical practice remains challenging. A novel technology was developed to meet the medical need for a widely available bedside tool to monitor gastric motility continuously. The VIPUN™ Gastric Monitoring System (GMS) comprises a nasogastric feeding tube with intragastric balloon to allow for measuring gastric contractions.

AIMS

To compare the performance of the VIPUN GMS versus a reference technique (manometry).

METHODS

In this validation study in healthy subjects, the investigational catheter and a solid-state manometry catheter were placed in the stomach concomitantly. Motility was recorded for 2.5 h: 2 h in a fasting state, followed by a 400-kcal liquid meal, and monitoring of the fed state for the remaining half hour. The performance of both systems was compared by automated recognition and manual identification of the contractile activity. Data are presented as mean (standard deviation).

KEY RESULTS

The analysis set comprised 13 healthy subjects (6 women, age: 27.5 (8.1) years, BMI: 22.2 (2.46) kg/m2). Automatically-recognized contractility was strongly correlated between the two techniques (endpoint: contraction duration; Spearman ρ = 0.96, p < 0.001). A correlation was also observed between the number of individual contractions identified by expert gastroenterologists on both technologies independently (ρ = 0.71, p = .007) and between the contractions identified by the experts and by the GMS software (ρ = 0.87, p = 0.001). No serious or unanticipated adverse events occurred.

CONCLUSIONS & INFERENCES

The observed strong correlations with the gold standard, manometry, validate the performance of the VIPUN GMS as a gastric monitoring system.

Symptoms from the Gastroparesis Cardinal Symptom Index and clinical factors associated with delayed gastric emptying in patients with suspected gastroparesis

BACKGROUND

The association between upper gastrointestinal symptoms and delayed gastric emptying (GE) shows conflicting results. This study aimed to assess whether the symptoms of the Gastroparesis Cardinal Symptom Index (GCSI) and/or the scores were associated with the result of GE tests and whether they could predict delayed GE.

METHODS

Patients referred for suspected gastroparesis (GP) were included in a prospective database. Demographical data, medical history, and symptoms of the GCSI score were collected for each patient. A GE scintigraphy was then performed with a 4-hour recording. Delayed GE was defined as a retention rate ≥ 10% at 4 h.

RESULTS

Among 243 patients included in this study, 110 patients (45%) had delayed GE. The mean age (49.9 vs. 41.3 years; p < 0.001) and weight loss (9.4 kg vs. 5.6 kg; p = 0.025) were significantly higher in patients with delayed GE. Patients with diabetes or a history of surgery had a higher prevalence of delayed GE (60% and 78%, respectively) than patients without comorbidity (17%; p < 0.001). The GCSI score was higher in patients with delayed GE (3.06 vs. 2.80; p = 0.045), but no threshold was clinically relevant to discriminate between patients with normal and delayed GE. Only vomiting severity was significantly higher in patients with delayed GE (2.19 vs. 1.57; p = 0.01).

CONCLUSION

GE testing should be considered when there are symptoms such as a higher weight loss, comorbidities (diabetes, and history of surgery associated with GP), and the presence of vomiting. Other symptoms and the GCSI score are not useful in predicting delayed GE.

Meal effects on gastric bioelectrical activity utilizing body surface gastric mapping in healthy subjects

BACKGROUND

Gastric sensorimotor disorders are prevalent. While gastric emptying measurements are commonly used, they may not fully capture the underlying pathophysiology. Body surface gastric mapping (BSGM) recently emerged to assess gastric sensorimotor dysfunction. This study assessed varying meal size on BSGM responses to inform test use in a wider variety of contexts.

METHODS

Data from multiple healthy cohorts receiving BSGM were pooled, using four different test meals. A standard BSGM protocol was employed: 30-min fasting, 4-h post-prandial, using Gastric Alimetry® (Alimetry, New Zealand). Meals comprised: (i) nutrient drink + oatmeal bar (482 kcal; 'standard meal'); (ii) oatmeal bar alone; egg and toast meal, and pancake (all ~250 kcal). Gastric Alimetry metrics included BMI-adjusted Amplitude, Principal Gastric Frequency, Gastric Alimetry Rhythm Index (GA-RI) and Fed:Fasted Amplitude Ratio (ff-AR).

KEY RESULTS

238 participants (59.2% female) were included. All meals significantly increased amplitude and frequency during the first postprandial hour (p < 0.05). There were no differences in postprandial frequency across meals (p > 0.05). The amplitude and GA-RI of the standard meal (n = 110) were significantly higher than the energy bar alone (n = 45) and egg meal (n = 65) (all p < 0.05). All BSGM metrics were comparable across the three smaller meals (p > 0.05). A higher symptom burden was found in the oatmeal bar group versus the standard meal and pancake meal (p = 0.01, 0.003, respectively).

CONCLUSIONS & INFERENCES

The consumption of lower calorie meals elicited different postprandial responses, when compared to the standard Gastric Alimetry meal. These data will guide interpretations of BSGM when applied with lower calorie meals.

Difference in Cyclic Versus Non-cyclic Symptom Patterns in Patients with the Symptoms of Gastroparesis Undergoing Bioelectric Therapy

INTRODUCTION

Patients with gastroparesis (Gp) have symptoms with or without a cyclic pattern. This retrospective study evaluates differences in cyclic vs. non-cyclic symptoms of Gp by analyzing mucosal electrogastrogram (mEG), familial dysautonomias, and response to gastric stimulation.

METHODS

37 patients with drug refractory Gp, 7 male and 30 female, with a mean age of 41.4 years, were studied. 18 had diabetes mellitus, 25 had cyclic (Cyc), and 12 had a non-cyclic (NoCyc) pattern of symptoms. Patients underwent temporary mucosal gastric stimulator (tGES) placement, which was done as a trial before permanent stimulator (GES) placement. Electrogastrogram (EGG) by mucosal (mEG) measures, including frequency, amplitude, and frequency-amplitude ratio (FAR), were pre- and post-tGES. Patients' history of personal and familial dysautonomias, quality of life, and symptom scores were recorded. Baseline vs. follow-ups were compared by paired t tests and McNemar's tests. T tests contrasted symptom scores, gastric emptying tests (GET), and mEG measures, while chi-squared tests deciphered comorbidity differences between two groups and univariate and multivariate analyses.

RESULTS

There were significantly more patients with diabetes in the Cyc group vs. the NoCyc group. Using a 1 point in symptom outcome, 18 patients did not improve and 19 did improve with tGES. Using univariable analysis, with the cyclic pattern as a predictor, patients exhibiting a cyclic pattern had an odds ratio of 0.22 (95% CI 0.05-0.81, p = 0.054) for achieving an improvement of at least one unit in vomiting at follow-up from baseline. The mucosal electrogastrogram frequency to amplitude ratio (FAR) for the "not Improved" group was 19.6 [3.5, 33.6], whereas, for the "Improved" group, it was 54.3 [25.6, 72.5] with a p-value of 0.049. For multivariate logistic regression, accounting for sex and age squared, patients exhibiting a cyclic pattern had an adjusted odds ratio (OR) of 0.16 (95% CI 0.03-0.81, p = 0.027) for achieving an improvement of at least one unit in vomiting at follow-up from baseline. The two groups had no significant differences in the personal or inherited history of investigated familial patterns.

CONCLUSION

This study shows differences in Gp patients with Cyc vs. NoCyc symptoms in several areas. Larger studies are needed to elicit further differences between the two groups about cycles of symptoms, EGG, findings, familial patterns, and response to mucosal GES.

Epidemiology of functional dyspepsia and gastroparesis as diagnosed in Flemish-Belgian primary care: A registry-based study from the Intego database

BACKGROUND

Dyspepsia is a prevalent condition in the general population. Besides organic causes, the differential diagnosis of dyspepsia includes functional dyspepsia (FD) and gastroparesis (GP) which share similar pathophysiological mechanisms and clinical presentation. So far, no study investigated the prevalence of FD and GP in a primary care in Belgium.

METHODS

Data were obtained from Intego, a Flemish-Belgian general practice-based morbidity registration network. From 586,164 patients between 2000 and 2021, we selected patients with ICD-10 code for FD and GP. Patients with organic gastrointestinal diseases were excluded. We determined demographics and comorbidities of FD/GP. For prevalence and incidence calculation, we included those who consulted their general practitioners at least once in the given year. Pair-wise comparison was conducted to access the impact of comorbidities on risk of FD/GP.

KEY RESULTS

Between 2011 and 2021, the prevalence of FD/GP ranged from 1.03% to 1.21%. The incidence of FD/GP ranged from 109 to 142 per 100,000 adults. In total 5242 cases of FD/GP were identified. These cases shared commonly coexisting diagnoses of gastroesophageal reflux disease (18.8%), irritable bowel syndrome (17.1%), and chronic constipation (18.7%). Patients with somatization/anxiety/depression had significantly higher risk of FD/GP, compared to the control (OR 1.38, 95% CI 1.19-1.61, p < 0.01).

CONCLUSIONS AND INFERENCES

The prevalence (1.03%-1.21%) and incidence (109-142/100,000) of FD/GP in primary care over last decade appear to conflict with epidemiological research in the general population. The discrepancies suggest a potential lack of awareness of FD and GP among physicians and/or patients in Flemish-Belgium.

Gastric Alimetry® Testing and Healthcare Economic Analysis in Nausea and Vomiting Syndromes

BACKGROUND

Chronic nausea and vomiting syndromes (CNVS), gastroparesis and functional dyspepsia (FD) are complex disorders. Body Surface Gastric Mapping (BSGM), a new test of gastric function, using Gastric Alimetry® (Alimetry, New Zealand) may be useful for de-escalating healthcare utilisation. This study aimed to define healthcare costs and estimate health economic impacts of implementing this test in patients with chronic gastroduodenal symptoms.

METHODS

Consecutive patients at a tertiary referral centre evaluated with Gastric Alimetry were included. Frequency and cost data relating to medical investigations, hospital and outpatient presentations were evaluated. Costs of healthcare utilisation were calculated, and the potential cost savings of implementing Gastric Alimetry within a diagnostic decision-tree model were estimated.

RESULTS

Overall, 31 consecutive patients (mean age 36.1 years; 83.9% female; predominant symptoms: nausea [83.9%], pain [61.3%], vomiting [67.7%] and bloating [35.5%]) completed Gastric Alimetry testing. Repeat gastroscopy and abdominal CT rates were 29% (8/28) and 85% (11/13), respectively. Gastric Alimetry testing identified spectral abnormalities in 45.2% of patients, and symptom profiling classified a further 29.1% of patients. Median annualised cost difference after test introduction was NZ$-12,032. Estimated reductions in investigation-related costs when incorporating Gastric Alimetry into the diagnostic workflow model were approximately NZ$1,300 per patient.

CONCLUSIONS

Healthcare utilisation and confirmatory testing rates remain high in nausea and vomiting syndromes. This study presents real-world data, together with a decision-tree analysis, showing Gastric Alimetry can streamline clinical care pathways, resulting in reduced healthcare utilisation and cost.

Short- and long-term reproducibility of body surface gastric mapping using the Gastric Alimetry® system

BACKGROUND

Many diagnostic tests for gastroduodenal symptoms, such as gastric emptying scintigraphy (GES), gastric emptying breath tests (GEBT), and electrogastrography (EGG) show variable intra-individual reproducibility over time. This study investigated the short- and long-term reproducibility of body surface gastric mapping (BSGM), a non-invasive test for assessing gastric function, in controls and patients with chronic gastroduodenal disorders.

METHODS

Participants completed three standardized BSGM tests using Gastric Alimetry® (Alimetry, New Zealand). The test encompassed a fasting baseline (30 min), a 482 kCal standard meal, and a 4 h postprandial recording. The first two tests were >6 months apart and the last occurred ~1 week after the second test, to evaluate long and short-term reproducibility.

RESULTS

Fourteen patients with upper gastrointestinal symptoms and 14 healthy controls were recruited. There were no significant differences in any BSGM metrics between the tests at short and long term (all p > 0.180). Lin's concordance correlation coefficients (CCC) for the primary metrics were high, ranging from 0.58 to 0.96, with intra-individual coefficients of variance (CVintra) ranging from 0.2% to 1.9%. Reproducibility was higher, and intra-individual variation lower, than in previous studies of GES (CCC = 0.54-0.83, CVintra = 3%-77%), GEBT (CVintra = 8%-11%), and EGG (CVintra = 3%-78%).

CONCLUSIONS

BSGM spectral metrics demonstrate high reproducibility and low intra-individual variation at both short and long term, with superior results to comparable tests. The high reproducibility of Gastric Alimetry supports its role as a diagnostic aid for gastric dysfunction and a reliable tool for evaluating treatment outcomes and disease progression over time.

Benefits of Prokinetics, Gastroparesis Diet, or Neuromodulators Alone or in Combination for Symptoms of Gastroparesis

BACKGROUND & AIMS

Prokinetics have limited effectiveness for treating symptoms of gastroparesis. Thus, alternative or adjunct therapies, such as gastroparesis diets or neuromodulators, are often prescribed. Their therapeutic benefits alone or in combination remain unclear.

METHODS

One hundred and twenty-nine patients with symptoms of gastroparesis underwent wireless motility capsule gastric emptying time and gastric emptying scintigraphy. Based on test results, changes in therapy were recommended. Changes in Gastroparesis Cardinal Symptom Index (GCSI) and individual symptom scores over 6 months were related to recommendations for prokinetics, gastroparesis diet, or neuromodulators given as solo new therapies or in dual combinations. Multivariate analyses were performed to adjust for gastric emptying and other variables.

RESULTS

In the whole group regardless of therapy, GCSI scores decreased by 0.53 points (interquartile range, -1.25 to 0.05; P < .0001) over 6 months. GCSI did not decrease for prokinetics as solo new therapy (P = .95). Conversely, neuromodulators as solo therapy decreased GCSI scores (P = .04) and all individual symptoms except nausea/vomiting (P = .86). Prokinetics combined with gastroparesis diets or neuromodulators improved GCSI scores (P ≤ .04) and most individual symptoms. Adjusting for gastric emptying time on multivariate analyses showed greater GCSI decreases for nondelayed emptying for neuromodulators as solo new therapy (P = .01). Gastric emptying scintigraphy, gender, diabetes, and functional dyspepsia did not influence responses to any treatment.

CONCLUSIONS

Initiating prokinetics as solo new therapy had little benefit for patients with symptoms of gastroparesis. Neuromodulators as the only new therapy decreased symptoms other than nausea and vomiting, especially with nondelayed gastric emptying. Adding gastroparesis diets or neuromodulators to prokinetics offered relief, suggesting that combination therapies may be more useful in managing these patients. (ClinicalTrials.gov NCT02022826.).

Factors Associated With Delayed Gastric Emptying in Symptomatic Diabetic and Non-diabetic Patients: A Retrospective Observational Study

Background Gastroparesis, characterized by delayed gastric emptying without mechanical obstruction, is a significant complication, especially in diabetic individuals. It manifests through symptoms such as abdominal bloating, feelings of fullness, and pain. This study investigates the prevalence of gastroparesis among non-diabetic and diabetic patients, exploring associations with demographic data, hemoglobin A1C (HbA1C) levels, and symptoms. Methodology This retrospective, observational, cohort study included patients with gastroparesis symptoms who underwent a nuclear gastric emptying study from January 2021 to April 2023. The study analyzed demographic data, symptoms, and HbA1c levels to identify correlations with delayed gastric emptying. Results Of 157 patients, 34.4% exhibited delayed gastric emptying. Diabetic patients comprised 29.3% of the sample, with a notable disease duration of over 10 years in 77.3% of cases. Symptoms such as nausea, vomiting, epigastric pain, and early satiety were prevalent, with significant associations between delayed emptying and female gender, higher HbA1c, and vomiting. Conclusions Delayed gastric emptying is significantly associated with female gender, elevated HbA1c levels, and when vomiting is the presenting symptom. Highlighting the importance of awareness among healthcare providers and the community, the findings encourage collaborative efforts for further gastroparesis research to better understand the predictive factors and mechanisms.

Characterization of gastric dysfunction after fundoplication using body surface gastric mapping

BACKGROUND

Adverse gastric symptoms persist in up to 20% of fundoplication operations completed for gastroesophageal reflux disease, causing significant morbidity and driving the need for revisional procedures. Noninvasive techniques to assess the mechanisms of persistent postoperative symptoms are lacking. This study aimed to investigate gastric myoelectrical abnormalities and symptoms in patients after fundoplication using a novel noninvasive body surface gastric mapping (BSGM) device.

METHODS

Patients with a previous fundoplication operation and ongoing significant gastroduodenal symptoms and matched controls were included. BSGM using Gastric Alimetry (Alimetry Ltd) was employed, consisting of a high-resolution 64-channel array, validated symptom-logging application, and wearable reader.

RESULTS

A total of 16 patients with significant chronic symptoms after fundoplication were recruited, with 16 matched controls. Overall, 6 of 16 patients (37.5%) showed significant spectral abnormalities defined by unstable gastric myoelectrical activity (n = 2), abnormally high gastric frequencies (n = 3), or high gastric amplitudes (n = 1). Patients with spectral abnormalities had higher Patient Assessment of Upper Gastrointestinal Disorders-Symptom Severity Index scores than those of patients without spectral abnormalities (3.2 [range, 2.8-3.6] vs 2.3 [range, 2.2-2.8], respectively; P = .024). Moreover, 7 of 16 patients (43.8%) had BSGM test results suggestive of gut-brain axis contributions and without myoelectrical dysfunction. Increasing Principal Gastric Frequency Deviation and decreasing Rhythm Index scores were associated with symptom severity (r > .40; P < .05).

CONCLUSION

A significant number of patients with persistent postfundoplication symptoms displayed abnormal gastric function on BSGM testing, which correlated with symptom severity. Our findings advance the pathophysiologic understanding of postfundoplication disorders, which may inform diagnosis and patient selection for medical therapy and revisional procedures.

Gastric volumetry for the assessment of fundic compliance and visceral hypersensitivity in patients with gastroparesis: a retrospective comparative study

BACKGROUND/AIMS

The evaluation of visceral hypersensitivity and gastric accommodation in patients with gastroparesis (GP) is difficult. CT-scan gastric volumetry allows to test the distension of different regions of the stomach. We aimed to study gastric volumes and patient's sensitivity to gastric distension between in patients with GP compared to patients with GERD.

METHOD

Retrospective study including patients who had CT-scan volumetry for GP or GERD. Two CT-scan series were made after gastric distension: left lateral decubitus 30° (LLD30) for antrum and right lateral decubitus (RLD) for body. Pain and discomfort were assessed using visual analogue scale (VAS). Gastric volumes were measured for LLD30 and RLD.

RESULTS

13 patients (7 GP and 6 GERD) were included. Mean age was 35.6+/-7.3 years. Median gastric volume in the RLD was lower in GP vs GERD (927+/-208 ml vs. 1115+/-163 ml; p = 0.046) while it was similar for LLD30 (1053+/-228 ml vs. 1054+/-193 ml; p = 0.603). GP patients had significantly more pain and discomfort during the procedure: pain VAS for GP was 6[0-9] versus 0[0-2] for GERD, p = 0.004, discomfort VAS for GP was 7[4-10] versus 4[0-5] for GERD, p = 0.007. 66.7% of GERD patients felt no pain vs. 14.3% in GP, p = 0.053.

CONCLUSION

This pilot study suggests that GP could be associated with a reduced gastric volume compared to GERD in RLD after gaseous distension. In contrast, patient self-assessment of pain related to gastric distension was greater int GP patients. A lack of fundus accommodation and visceral hypersensitivity could explain some mechanisms in the genesis of GP symptoms.

Management of Gastrointestinal Symptoms in Parkinson's Disease: A Comprehensive Review of Clinical Presentation, Workup, and Treatment

Gastrointestinal symptoms in Parkinson's disease (PD) are among the most prevalent and debilitating of complications and present unique diagnostic and management challenges. Patients with PD commonly experience dysphagia, nausea, bloating, and constipation related to pathologic involvement of the enteric nervous system. In turn, gastrointestinal complications may impact motor fluctuations and the efficacy of levodopa therapy. This review will explore the common gastrointestinal manifestations of PD with an emphasis on clinical presentation, workup, and treatment strategies.

Gastric Alimetry Expands Patient Phenotyping in Gastroduodenal Disorders Compared with Gastric Emptying Scintigraphy

INTRODUCTION

Gastric emptying testing (GET) assesses gastric motility, however, is nonspecific and insensitive for neuromuscular disorders. Gastric Alimetry (GA) is a new medical device combining noninvasive gastric electrophysiological mapping and validated symptom profiling. This study assessed patient-specific phenotyping using GA compared with GET.

METHODS

Patients with chronic gastroduodenal symptoms underwent simultaneous GET and GA, comprising a 30-minute baseline, 99m TC-labelled egg meal, and 4-hour postprandial recording. Results were referenced to normative ranges. Symptoms were profiled in the validated GA App and phenotyped using rule-based criteria based on their relationships to the meal and gastric activity: (i) sensorimotor, (ii) continuous, and (iii) other.

RESULTS

Seventy-five patients were assessed, 77% female. Motility abnormality detection rates were as follows: GET 22.7% (14 delayed, 3 rapid), GA spectral analysis 33.3% (14 low rhythm stability/low amplitude, 5 high amplitude, and 6 abnormal frequency), and combined yield 42.7%. In patients with normal spectral analysis, GA symptom phenotypes included sensorimotor 17% (where symptoms strongly paired with gastric amplitude, median r = 0.61), continuous 30%, and other 53%. GA phenotypes showed superior correlations with Gastroparesis Cardinal Symptom Index, Patient Assessment of Upper Gastrointestinal Symptom Severity Index, and anxiety scales, whereas Rome IV Criteria did not correlate with psychometric scores ( P > 0.05). Delayed emptying was not predictive of specific GA phenotypes.

DISCUSSION

GA improves patient phenotyping in chronic gastroduodenal disorders in the presence and absence of motility abnormalities with increased correlation with symptoms and psychometrics compared with gastric emptying status and Rome IV criteria. These findings have implications for the diagnostic profiling and personalized management of gastroduodenal disorders.

Letter: interpretation of the BESST trial in the context of baseline antidepressant and neuromodulator use-Authors' reply

This article is linked to Parkman et al papers. To view these articles, visit https://doi.org/10.1111/apt.17479 and https://doi.org/10.1111/apt.17800

Liquid and solid gastric emptying and correlation with clinical characteristics in pediatric patients with dyspepsia

BACKGROUND

There is limited data on gastric emptying in dyspeptic children. We aimed to determine solid and liquid emptying rates in dyspeptic children and correlate with clinical characteristics.

METHODS

Charts of dyspeptic children undergoing 4-hour dual-phase gastric scintigraphy were reviewed for demographics, symptoms, and comorbidities.

KEY RESULTS

In 1078 dyspeptic patients (65% females, median age 13 years) vomiting (55%), nausea (53%), and abdominal pain (52%) were the most common symptoms. The most common comorbidities were mental health (32%), neurologic (27%), and hypermobility spectrum disorders (20%). Solid and liquid emptying rates were aligned in 61.23%. Delayed solid with normal liquid emptying were noted in 2.5%, compared to delayed liquid with normal solid emptying in 26.16%. Abdominal pain had a trend for association with delayed or normal solid emptying (p = 0.06). Nausea was mostly reported with normal solid emptying (p < 0.0001) and underreported in patients <12 years with vomiting (29%). Abnormal solid emptying (rapid and delayed) was noted more frequently in children with mental health disorders (p = 0.027). Rapid liquid emptying was more common in children with genetic disorders (p = 0.032).

CONCLUSION AND INFERENCES

Over half of children with dyspepsia had delayed liquid gastric emptying, and one quarter had delayed liquid with normal solid emptying. Dual-phase gastric emptying studies may help target therapy in dyspeptic children. Nausea is not a reliable symptom for dyspepsia in younger children. Given the significant association of abnormal gastric emptying in children with mental health disorders, we recommend screening and treating children with dyspepsia.

Letter: interpretation of the BESST trial in the context of baseline antidepressant and neuromodulator use

This article is linked to Parkman et al papers. To view these articles, visit https://doi.org/10.1111/apt.17479 and https://doi.org/10.1111/apt.17838

Ca2+ dynamics in interstitial cells: foundational mechanisms for the motor patterns in the gastrointestinal tract

The gastrointestinal (GI) tract displays multiple motor patterns that move nutrients and wastes through the body. Smooth muscle cells (SMCs) provide the forces necessary for GI motility, but interstitial cells, electrically coupled to SMCs, tune SMC excitability, transduce inputs from enteric motor neurons, and generate pacemaker activity that underlies major motor patterns, such as peristalsis and segmentation. The interstitial cells regulating SMCs are interstitial cells of Cajal (ICC) and PDGF receptor (PDGFR)α+ cells. Together these cells form the SIP syncytium. ICC and PDGFRα+ cells express signature Ca2+-dependent conductances: ICC express Ca2+-activated Cl- channels, encoded by Ano1, that generate inward current, and PDGFRα+ cells express Ca2+-activated K+ channels, encoded by Kcnn3, that generate outward current. The open probabilities of interstitial cell conductances are controlled by Ca2+ release from the endoplasmic reticulum. The resulting Ca2+ transients occur spontaneously in a stochastic manner. Ca2+ transients in ICC induce spontaneous transient inward currents and spontaneous transient depolarizations (STDs). Neurotransmission increases or decreases Ca2+ transients, and the resulting depolarizing or hyperpolarizing responses conduct to other cells in the SIP syncytium. In pacemaker ICC, STDs activate voltage-dependent Ca2+ influx, which initiates a cluster of Ca2+ transients and sustains activation of ANO1 channels and depolarization during slow waves. Regulation of GI motility has traditionally been described as neurogenic and myogenic. Recent advances in understanding Ca2+ handling mechanisms in interstitial cells and how these mechanisms influence motor patterns of the GI tract suggest that the term "myogenic" should be replaced by the term "SIPgenic," as this review discusses.

Physiological characterization of gastric emptying using high-resolution antropyloroduodenal manometry

Delayed gastric emptying (GE) has been associated with antral and pyloric dysmotility. We aimed to characterize differences in the antral, duodenal, and pyloric motility profiles associated with delayed GE, using high-resolution antropyloroduodenal manometry (HR-ADM). Patients referred for HR-ADM for dyspeptic symptoms performed a concurrent GE breath test (NCT01519180 and NCT04918329). HR-ADM involved 36 sensors 1 cm apart, placed across the pylorus. Interdigestive and postprandial periods were identified. Antral, pyloric, and duodenal motor profiles were analyzed recording the frequency, amplitude, and propagative nature of contractions for each period. Plots of patients with normal and delayed GE were compared. Sixty patients underwent both HR-ADM and GE tests. Twenty-five and 35 patients had delayed and normal GE, respectively. Antral and duodenal motor profiles were not different between the two groups during the interdigestive period. During the postprandial period, a lower frequency of antral contractions was associated with delayed GE (2.22 vs. 1.39 contractions/min; P = 0.002), but no difference in mean contraction amplitude was observed. The pyloric region was identified in all the patients and pylorospasms, defined as 3 min of repeated isolated pyloric contractions, were more frequent in patients with delayed GE (32.0% vs. 5.7%; P = 0.02) during the postprandial period. No difference in duodenal contraction profiles was observed. Manometric profile alterations were observed in 72% of the patients with delayed GE, with 56% having a low frequency of antral contractions. Using HR-ADM, patients with delayed GE displayed different postprandial antropyloric motility as compared with patients with normal GE.NEW & NOTEWORTHY High-resolution antropyloroduodenal manometry (HR-ADM) allows precise characterization of antral, pyloric, and duodenal motility, although its association with gastric emptying (GE) has been poorly investigated. Concurrent HR-ADM with GE measurement showed a lower frequency of antral postprandial contractions and an increased frequency of postprandial pylorospasms in patients with delayed GE. HR-ADM could, therefore, be useful in the future to better select patients for treatments targeting the pylorus.

Noninvasive electrical neuromodulation for gastrointestinal motility disorders

INTRODUCTION

Gastrointestinal motility disorders are highly prevalent without satisfactory treatment. noninvasive electrical neuromodulation is an emerging therapy for treating various gastrointestinal motility disorders.

AREAS COVERED

In this review, several emerging noninvasive neuromodulation methods are introduced, including transcutaneous auricular vagal nerve stimulation, percutaneous auricular vagal nerve stimulation, transcutaneous cervical vagal nerve stimulation, transcutaneous electrical acustimulation, transabdominal interference stimulation, tibial nerve stimulation, and translumbosacral neuromodulation therapy. Their clinical applications in the most common gastrointestinal motility are discussed, including gastroesophageal reflux disease, functional dyspepsia, gastroparesis, functional constipation, irritable bowel syndrome, and fecal incontinence. PubMed database was searched from 1995 to June 2023 for relevant articles in English.

EXPERT OPINION

Noninvasive neuromodulation is effective and safe in improving both gastrointestinal symptoms and dysmotility; it can be used when pharmacotherapy is ineffective. Future directions include refining the methodology, improving device development and understanding mechanisms of action.

Optimal measurement of gastric emptying of solids in gastroparesis or functional dyspepsia: evidence to establish standard test

OBJECTIVE

Symptoms in gastroparesis (Gp) and functional dyspepsia (FD) overlap; using egg protein substitute to measure gastric emptying of solids (GES), ~40% of patients are reclassified from Gp to FD, and vice versa. Our aim was to assess inter-individual and intra-individual coefficients of variation (COV) in GES in symptomatic patients with Gp or FD with documented slow or normal GES, respectively.

DESIGN

Scintigraphic GES (T1/2 and GE% at 2 and 4 hours) using a 320 kcal real egg meal (30% fat) was tested in the following: single measurements in 20 patients with diabetes mellitus (10 each type 1 and type 2); repeat GES to estimate COVintra measured: 3 days apart in 9 Gp, 4 weeks apart in 21 Gp and 18 with FD with normal GE assigned to placebo and in 70 patients at 94.3 weeks (median) apart.

RESULTS

COVinter for GE% at 4 hours and GE T1/2 were respectively 14.2% and 23.5% in FD and 27.5% and 33% in Gp; COVintra for GE% at 4 hours and GE T1/2 up to 4 weeks apart were 23.4% and 37.9% in FD and 20.1% and 33% in Gp. GE% at 2 hours showed less consistent results. However, >85% retained original diagnosis as normal or delayed. From clinical GES to baseline research for Gp group, repeat GES (after treatment) showed the COVintra for GE% at 4 hours was 37.3% at median 94.3 weeks, with 26/70 changed diagnoses.

CONCLUSION

The 320 kcal (30% fat) GES scintigraphic test provides consistent diagnosis in >85% and should be the standard test for suspected gastric emptying disorders.

Relationships among intragastric meal distribution during gastric emptying scintigraphy, water consumption during water load satiety testing, and symptoms of gastroparesis

Gastric emptying scintigraphy (GES) measures total gastric retention after a solid meal and can assess intragastric meal distribution (IMD). Water load satiety test (WLST) measures gastric capacity. Both IMD immediately after meal ingestion [ratio of proximal gastric counts after meal ingestion to total gastric counts at time 0 (IMD0)] and WLST (volume of water ingested over 5 min) are indirect measures of gastric accommodation. In this study, IMD0 and WLST were compared with each other and to symptoms of gastroparesis to gauge their clinical utility for assessing patients with symptoms of gastroparesis. Patients with symptoms of gastroparesis underwent GES to obtain gastric retention and IMD0, WLST, and filled out patient assessment of upper GI symptoms. A total of 234 patients with symptoms of gastroparesis were assessed (86 patients with diabetes, 130 idiopathic, 18 postfundoplication) and 175 (75%) delayed gastric emptying. Low IMD0 <0.568 suggesting initial rapid transit to the distal stomach was present in 8% and correlated with lower gastric retention, less heartburn, and lower volumes consumed during WLST. Low WLST volume (<238 mL) was present in 20% and associated with increased severity of early satiety, postprandial fullness, loss of appetite, and nausea. Low IMD0 is associated with less gastric retention and less heartburn. Volume of water consumed during WLST, while associated with IMD0, has associations with early satiety, postprandial fullness, loss of appetite, and nausea. Thus, IMD0 and WLST appear to overlap somewhat in their assessment of gastric physiology in adults with symptoms of gastroparesis but relate to different dyspeptic symptoms.NEW & NOTEWORTHY IMD0 and WLST were assessed for their clinical utility in assessing patients with symptoms of gastroparesis. Low IMD0 is associated with less gastric retention and less heartburn. Volume of water consumed during WLST, while associated with IMD0, has associations with early satiety, postprandial fullness, loss of appetite, and nausea. IMD0 and WLST appear to overlap somewhat in their assessment of gastric physiology in adults with symptoms of gastroparesis but relate to different dyspeptic symptoms.

Gastric Alimetry in the Management of Chronic Gastroduodenal Disorders: Impact to Diagnosis and Health Care Utilization

INTRODUCTION

Chronic gastroduodenal symptoms are frequently overlapping within existing diagnostic paradigms, and current diagnostic tests are insensitive to underlying pathophysiologies. Gastric Alimetry has emerged as a new diagnostic test of gastric neuromuscular function with time-of-test symptom profiling. This study aimed to assess the impact to diagnosis and health care utilization after the introduction of Gastric Alimetry into clinical care.

METHODS

Consecutive data of patients from 2 tertiary centers with chronic gastroduodenal symptoms (Rome-IV defined or motility disorder) having integrated care and Gastric Alimetry testing were evaluated. Changes in diagnoses, interventions, and management were quantified. Pretest and posttest health care utilization was reported. A preliminary management framework was established through experiential learning.

RESULTS

Fifty participants (45 women; median age 30 years; 18 with gastroparesis, 24 with chronic nausea and vomiting syndrome, and 6 with functional dyspepsia) underwent Gastric Alimetry testing. One-third of patients had a spectral abnormality (18% dysrhythmic/low amplitude). Of the remaining patients, 9 had symptoms correlating to gastric amplitude, while 19 had symptoms unrelated to gastric activity. Gastric Alimetry aided management decisions in 84%, including changes in invasive nutritional support in 9/50 cases (18%; predominantly de-escalation). Health care utilization was significantly lower post-Gastric Alimetry testing when compared with the average utilization cost in the year before Gastric Alimetry testing (mean ± SD $39,724 ± 63,566 vs $19,937 ± 35,895, P = 0.037).

DISCUSSION

Gastric Alimetry aided diagnosis and management of patients with chronic gastroduodenal symptoms by enabling phenotype-informed care. The high majority of results aided management decisions, which was associated with reduced health care utilization.

Meal-eating characteristics among patients with symptoms of gastroparesis: Relationships to delays in gastric emptying

BACKGROUND

Patients with symptoms of gastroparesis (Gp) often modify their diets and consume small meals. However, the relationship between patients' eating behavior and their gastric emptying is not well understood. This study describes meal-eating characteristics of patients with Gp symptoms and relates them to severity of emptying delay.

METHODS

Adult patients with Gp symptoms underwent 4-h gastric emptying scintigraphy and completed questionnaires including the Patient Assessment of GI Symptoms, a nutrition and diet questionnaire, and the Meal Patterns Questionnaire.

KEY RESULTS

Of 119 patients with Gp symptoms, 35 had normal gastric emptying (≤10% gastric retention at 4 h), 26 mildly delayed (>10%-20%), 28 moderately delayed (>20%-35%), and 30 severely delayed (>35%). Most patients (85%) reported eating small meals with an average of 2.4 meals per day. The most common reasons for stopping eating a meal were feeling full (83%), nausea (46%), and abdominal pain (31%). As gastric emptying worsened, patients increasingly made diet modifications such as low-fat, low-fiber, Gp diet, oral supplements, and blenderized meals (r = 0.309, p = 0.0007). Postprandial fullness lasted for 351 ± 451 min for patients with severely delayed emptying versus 207 ± 173 min for patients with normal emptying (p = 0.19).

CONCLUSIONS & INFERENCES

Meal-eating characteristics were found to vary with severity of gastric retention. Patients with severely delayed gastric emptying reported the longest duration of postprandial fullness. Dietary modification increased significantly with gastric retention. These meal-eating characteristics are important to understand as they impact on dietary education given to Gp patients for symptom management.

Gastrointestinal syndromes preceding a diagnosis of Parkinson's disease: testing Braak's hypothesis using a nationwide database for comparison with Alzheimer's disease and cerebrovascular diseases

OBJECTIVE

Braak's hypothesis states that Parkinson's disease (PD) originates in the gastrointestinal (GI) tract, and similar associations have been established for Alzheimer's disease (AD) and cerebrovascular diseases (CVD). We aimed to determine the incidence of GI syndromes and interventions preceding PD compared with negative controls (NCs), AD and CVD.

DESIGN

We performed a combined case-control and cohort study using TriNetX, a US based nationwide medical record network. Firstly, we compared subjects with new onset idiopathic PD with matched NCs and patients with contemporary diagnoses of AD and CVD, to investigate preceding GI syndromes, appendectomy and vagotomy. Secondly, we compared cohorts with these exposures to matched NCs for the development of PD, AD and CVD within 5 years.

RESULTS

We identified 24 624 PD patients in the case-control analysis and matched 18 cohorts with each exposure to their NCs. Gastroparesis, dysphagia, irritable bowel syndrome (IBS) without diarrhoea and constipation showed specific associations with PD (vs NCs, AD and CVD) in both the case-control (odds ratios (ORs) vs NCs 4.64, 3.58, 3.53 and 3.32, respectively, all p<0.0001) and cohort analyses (relative risks (RRs) vs NCs 2.43, 2.27, 1.17 and 2.38, respectively, all p<0.05). While functional dyspepsia, IBS with diarrhoea, diarrhoea and faecal incontinence were not PD specific, IBS with constipation and intestinal pseudo-obstruction showed PD specificity in the case-control (OR 4.11) and cohort analysis (RR 1.84), respectively. Appendectomy decreased the risk of PD in the cohort analysis (RR 0.48). Neither inflammatory bowel disease nor vagotomy were associated with PD.

CONCLUSION

Dysphagia, gastroparesis, IBS without diarrhoea and constipation might specifically predict Parkinson's disease.

Gastroparesis: time for a paradigm change

PURPOSE OF REVIEW

Gastroparesis (GP) is a syndrome defined by symptoms and delayed gastric emptying in the absence of mechanical obstruction. Typical symptoms include nausea, vomiting, abdominal pain, and early satiety. Only one medication is currently FDA-approved for the treatment of GP. This review highlights recent research findings pertaining to GP and provides evidence to support a change in the current GP diagnostic and treatment paradigm.

RECENT FINDINGS

An analysis of GP trials over the past four decades demonstrates the power of placebo and the need to perform longer studies with clearly defined patient populations. Two studies highlight the need to evaluate patients with suspected GP carefully and to perform gastric emptying studies properly. The misdiagnosis of GP symptoms is reviewed, preceded by a discussion of whether GP should be considered a disorder of gut-brain interaction. Finally, new data on therapies that target the pylorus are highlighted.

SUMMARY

Gastroparesis is frequently over-diagnosed and incorrectly diagnosed. Performing a proper gastric emptying study which adheres to standard protocol, and accurately interpreting the results in the context of the individual patient, are critical to making an accurate diagnosis of GP. The treatment paradigm needs to shift from simply aiming to accelerate gastric emptying to treating global symptoms of a chronic syndrome that may represent gut-brain dysfunction in many patients.

Gastric Alimetry® Test Interpretation in Gastroduodenal Disorders: Review and Recommendations

Chronic gastroduodenal symptoms are prevalent worldwide, and there is a need for new diagnostic and treatment approaches. Several overlapping processes may contribute to these symptoms, including gastric dysmotility, hypersensitivity, gut-brain axis disorders, gastric outflow resistance, and duodenal inflammation. Gastric Alimetry® (Alimetry, New Zealand) is a non-invasive test for evaluating gastric function that combines body surface gastric mapping (high-resolution electrophysiology) with validated symptom profiling. Together, these complementary data streams enable important new clinical insights into gastric disorders and their symptom correlations, with emerging therapeutic implications. A comprehensive database has been established, currently comprising > 2000 Gastric Alimetry tests, including both controls and patients with various gastroduodenal disorders. From studies employing this database, this paper presents a systematic methodology for Gastric Alimetry test interpretation, together with an extensive supporting literature review. Reporting is grouped into four sections: Test Quality, Spectral Analysis, Symptoms, and Conclusions. This review compiles, assesses, and evaluates each of these aspects of test assessment, with discussion of relevant evidence, example cases, limitations, and areas for future work. The resultant interpretation methodology is recommended for use in clinical practice and research to assist clinicians in their use of Gastric Alimetry as a diagnostic aid and is expected to continue to evolve with further development.

Principles and clinical methods of body surface gastric mapping: Technical review

BACKGROUND AND PURPOSE

Chronic gastric symptoms are common, however differentiating specific contributing mechanisms in individual patients remains challenging. Abnormal gastric motility is present in a significant subgroup, but reliable methods for assessing gastric motor function in clinical practice are lacking. Body surface gastric mapping (BSGM) is a new diagnostic aid, employs multi-electrode arrays to measure and map gastric myoelectrical activity non-invasively in high resolution. Clinical adoption of BSGM is currently expanding following studies demonstrating the ability to achieve specific patient subgrouping, and subsequent regulatory clearances. An international working group was formed in order to standardize clinical BSGM methods, encompassing a technical group developing BSGM methods and a clinical advisory group. The working group performed a technical literature review and synthesis focusing on the rationale, principles, methods, and clinical applications of BSGM, with secondary review by the clinical group. The principles and validation of BSGM were evaluated, including key advances achieved over legacy electrogastrography (EGG). Methods for BSGM were reviewed, including device design considerations, patient preparation, test conduct, and data processing steps. Recent advances in BSGM test metrics and reference intervals are discussed, including four novel metrics, being the 'principal gastric frequency', BMI-adjusted amplitude, Gastric Alimetry Rhythm Index™, and fed: fasted amplitude ratio. An additional essential element of BSGM has been the introduction of validated digital tools for standardized symptom profiling, performed simultaneously during testing. Specific phenotypes identifiable by BSGM and the associated symptom profiles were codified with reference to pathophysiology. Finally, knowledge gaps and priority areas for future BSGM research were also identified by the working group.

Plasticity of gastrointestinal vagal afferents in terms of feeding-related physiology and pathophysiology

Gastrointestinal vagal afferents play an important role in communicating food related information from the gut to the brain. This information initiates vago-vagal reflexes essential for gut functions, including gut motility and secretions. These afferents also play a role in energy homeostasis, signalling the arrival, amount and nutrient composition of a meal to the central nervous system where it is processed ultimately leading to termination of a meal. Vagal afferent responses to food related stimuli demonstrate a high degree of plasticity, responding to short term changes in nutritional demand, such as the fluctuations that occur across a 24-hr or in response to a fast, as well as long term changes in energy demand, such as occurs during pregnancy. This plasticity is disrupted in disease states, such as obesity or chronic stress where there is hypo- and hypersensitivity of these afferents, respectively. Improved understanding of the plasticity of these afferents will enable identification of new treatment options for diseases associated with vagal afferent function.

Comparison of Gastric Alimetry® body surface gastric mapping versus electrogastrography spectral analysis

Electrogastrography (EGG) non-invasively evaluates gastric motility but is viewed as lacking clinical utility. Gastric Alimetry® is a new diagnostic test that combines high-resolution body surface gastric mapping (BSGM) with validated symptom profiling, with the goal of overcoming EGG's limitations. This study directly compared EGG and BSGM to define performance differences in spectral analysis. Comparisons between Gastric Alimetry BSGM and EGG were conducted by protocolized retrospective evaluation of 178 subjects [110 controls; 68 nausea and vomiting (NVS) and/or type 1 diabetes (T1D)]. Comparisons followed standard methodologies for each test (pre-processing, post-processing, analysis), with statistical evaluations for group-level differences, symptom correlations, and patient-level classifications. BSGM showed substantially tighter frequency ranges vs EGG in controls. Both tests detected rhythm instability in NVS, but EGG showed opposite frequency effects in T1D. BSGM showed an 8× increase in the number of significant correlations with symptoms. BSGM accuracy for patient-level classification was 0.78 for patients vs controls and 0.96 as compared to blinded consensus panel; EGG accuracy was 0.54 and 0.43. EGG detected group-level differences in patients, but lacked symptom correlations and showed poor accuracy for patient-level classification, explaining EGG's limited clinical utility. BSGM demonstrated substantial performance improvements across all domains.

Functional and anatomical gastric regions and their relations to motility control

The common occurrence of gastric disorders, the accelerating emphasis on the role of the gut-brain axis, and development of realistic, predictive models of gastric function, all place emphasis on increasing understanding of the stomach and its control. However, the ways that regions of the stomach have been described anatomically, physiologically, and histologically do not align well. Mammalian single compartment stomachs can be considered as having four anatomical regions fundus, corpus, antrum, and pyloric sphincter. Functional regions are the proximal stomach, primarily concerned with adjusting gastric volume, the distal stomach, primarily involved in churning and propelling the content, and the pyloric sphincter that regulates passage of chyme into the duodenum. The proximal stomach extends from the dome of the fundus to a circumferential band where propulsive waves commence (slow waves of the pacemaker region), and the distal stomach consists of the pacemaker region and the more distal regions that are traversed by waves of excitation, that travel as far as the pyloric sphincter. Thus, the proximal stomach includes the fundus and different extents of the corpus, whereas the distal stomach consists of the remainder of the corpus and the antrum. The distributions of aglandular regions and of specialized glands, such as oxyntic glands, differ vastly between species and, across species, have little or no relation to anatomical or functional regions. It is hoped that this review helps to clarify nomenclature that defines gastric regions that will provide an improved basis for drawing conclusions for different investigations of the stomach.

AGA Clinical Practice Update on Evaluation and Management of Belching, Abdominal Bloating, and Distention: Expert Review

DESCRIPTION

Belching, bloating, and abdominal distention are all highly prevalent gastrointestinal symptoms and account for some of the most common reasons for patient visits to outpatient gastroenterology practices. These symptoms are often debilitating, affecting patients' quality of life, and contributing to work absenteeism. Belching and bloating differ in their pathophysiology, diagnosis, and management, and there is limited evidence available for their various treatments. Therefore, the purpose of this American Gastroenterological Association (AGA) Clinical Practice Update is to provide best practice advice based on both controlled trials and observational data for clinicians covering clinical features, diagnostics, and management considerations that include dietary, gut-directed behavioral, and drug therapies.

METHODS

This Expert Review was commissioned and approved by the AGA Institute Clinical Practice Updates Committee and the AGA Governing Board to provide timely guidance on a topic of high clinical importance to the AGA membership, and underwent internal peer review by the Clinical Practice Updates Committee and external peer review through standard procedures of Gastroenterology. These best practice advice statements were drawn from a review of the published literature based on clinical trials, the more robust observational studies, and from expert opinion. Because systematic reviews were not performed, these best practice advice statements do not carry formal ratings regarding the quality of evidence or strength of the presented considerations. Best Practice Advice Statements BEST PRACTICE ADVICE 1: Clinical history and physical examination findings and impedance pH monitoring can help to differentiate between gastric and supragastric belching. BEST PRACTICE ADVICE 2: Treatment options for supragastric belching may include brain-gut behavioral therapies, either separately or in combination, such as cognitive behavioral therapy, diaphragmatic breathing, speech therapy, and central neuromodulators. BEST PRACTICE ADVICE 3: Rome IV criteria should be used to diagnose primary abdominal bloating and distention. BEST PRACTICE ADVICE 4: Carbohydrate enzyme deficiencies may be ruled out with dietary restriction and/or breath testing. In a small subset of at-risk patients, small bowel aspiration and glucose- or lactulose-based hydrogen breath testing may be used to evaluate for small intestinal bacterial overgrowth. BEST PRACTICE ADVICE 5: Serologic testing may rule out celiac disease in patients with bloating and, if serologies are positive, a small bowel biopsy should be done to confirm the diagnosis. A gastroenterology dietitian should be part of the multidisciplinary approach to care for patients with celiac disease and nonceliac gluten sensitivity. BEST PRACTICE ADVICE 6: Abdominal imaging and upper endoscopy should be ordered in patients with alarm features, recent worsening symptoms, or an abnormal physical examination only. BEST PRACTICE ADVICE 7: Gastric emptying studies should not be ordered routinely for bloating and distention, but may be considered if nausea and vomiting are present. Whole gut motility and radiopaque transit studies should not be ordered unless other additional and treatment-refractory lower gastrointestinal symptoms exist to warrant testing for neuromyopathic disorders. BEST PRACTICE ADVICE 8: In patients with abdominal bloating and distention thought to be related to constipation or difficult evacuation, anorectal physiology testing is suggested to rule out a pelvic floor disorder. BEST PRACTICE ADVICE 9: When dietary modifications are needed (eg, low-fermentable oligosaccharides, disaccharides, monosaccharides and polyols diet), a gastroenterology dietitian should preferably monitor treatment. BEST PRACTICE ADVICE 10: Probiotics should not be used to treat abdominal bloating and distention. BEST PRACTICE ADVICE 11: Biofeedback therapy may be effective for bloating and distention when a pelvic floor disorder is identified. BEST PRACTICE ADVICE 12: Central neuromodulators (eg, antidepressants) are used to treat bloating and abdominal distention by reducing visceral hypersensitivity, raising sensation threshold, and improving psychological comorbidities. BEST PRACTICE ADVICE 13: Medications used to treat constipation should be considered for treating bloating if constipation symptoms are present. BEST PRACTICE ADVICE 14: Psychological therapies, such as hypnotherapy, cognitive behavioral therapy, and other brain-gut behavior therapies may be used to treat patients with bloating and distention. BEST PRACTICE 15: Diaphragmatic breathing and central neuromodulators are used to treat abdominophrenic dyssynergia.

Functional Dyspepsia: Current Understanding and Future Perspective

BACKGROUND

Functional dyspepsia (FD) is a common disorder characterized by chronic or recurrent upper abdominal pain or discomfort without any structural abnormalities in the gastrointestinal tract. FD is categorized into two subgroups based on symptoms: postprandial distress syndrome (PDS) and epigastric pain syndrome.

SUMMARY

The pathophysiology of FD involves several mechanisms. Delayed gastric emptying is observed in approximately 30% of FD patients but does not correlate with symptom patterns or severity. Impaired gastric accommodation is important in the pathophysiology, particularly for PDS. Visceral hypersensitivity, characterized by heightened sensitivity to normal activities, contributes to the perception of discomfort or pain in FD. Alterations to the duodenal mucosa, including impaired mucosal barrier function and low-grade inflammation, are also implicated in the pathogenesis of FD. Microbial dysbiosis and psychological factors such as stress can further exacerbate symptoms. Treatment options include dietary modifications, establishing a physician-patient relationship, acid suppressants, prokinetics, neuromodulators, and behavioral therapies. Dietary recommendations include eating smaller, more frequent meals, and avoiding trigger foods. Acid suppressants are used as the first-line treatment. Prokinetics and neuromodulators aim to improve gastric motility and central pain processing, respectively. Behavioral therapies, including cognitive behavioral therapy and hypnotherapy, have shown benefits for refractory FD. Severe and refractory cases may require combination therapies or experimental treatments.

KEY MESSAGES

FD is a disorder of gut-brain interaction involving diverse pathophysiological mechanisms. Individualized treatment based on symptoms and responses to interventions is crucial. Further research is needed to improve the understanding of FD and advance the development of effective therapies.

Imaging in Gastroparesis: Exploring Innovative Diagnostic Approaches, Symptoms, and Treatment

Gastroparesis (GP) is a chronic disease characterized by upper gastrointestinal symptoms, primarily nausea and vomiting, and delayed gastric emptying (GE), in the absence of mechanical GI obstruction. The underlying pathophysiology of GP remains unclear, but factors contributing to the condition include vagal nerve dysfunction, impaired gastric fundic accommodation, antral hypomotility, gastric dysrhythmias, and pyloric dysfunction. Currently, gastric emptying scintigraphy (GES) is considered the gold standard for GP diagnosis. However, the overall delay in GE weakly correlates with GP symptoms and their severity. Recent research efforts have focused on developing treatments that address the presumed underlying pathophysiological mechanisms of GP, such as pyloric hypertonicity, with Gastric Peroral Endoscopic Myotomy (G-POEM) one of these procedures. New promising diagnostic tools for gastroparesis include wireless motility capsule (WMC), the 13 carbon-GE breath test, high-resolution electrogastrography, and the Endoluminal Functional Lumen Imaging Probe (EndoFLIP). Some of these tools assess alterations beyond GE, such as muscular electrical activity and pyloric tone. These modalities have the potential to characterize the pathophysiology of gastroparesis, identifying patients who may benefit from targeted therapies. The aim of this review is to provide an overview of the current knowledge on diagnostic pathways in GP, with a focus on the association between diagnosis, symptoms, and treatment.

It's a helluva journey: a qualitative study of patient and clinician experiences of nausea and vomiting syndromes

Background

Chronic gastroduodenal disorders including, chronic nausea and vomiting syndrome, gastroparesis, and functional dyspepsia, are challenging to diagnose and manage. The diagnostic and treatment pathways for these disorders are complex, costly and overlap substantially; however, experiences of this pathway have not been thoroughly investigated. This study therefore aimed to explore clinician and patient perspectives on the current clinical pathway.

Methods

Semi-structured interviews were conducted between June 2020 and June 2022 with 11 patients with chronic nausea and vomiting syndrome alone (based on Rome IV criteria) and nine gastroenterologists who treat these conditions. Interviews were recorded, transcribed, and thematically analyzed using a reflexive, iterative, inductive approach. Five key patient themes were identified: (1) the impacts of their chronic gastroduodenal symptoms, (2) the complexity of the clinical journey, (3) their interactions with healthcare providers, (4) the need for advocacy, and (5) their experience of treatments. Five key clinician themes were also identified: (1) these conditions were seen as clinically complex, (2) there is an uncertain and variable clinical pathway, (3) the nuance of investigations, (4) these conditions were difficult to therapeutically manage, and (5) there are barriers to developing a therapeutic relationship.

Conclusion

Findings indicate that both patients and clinicians are dissatisfied with the current clinical care pathways for nausea and vomiting syndromes. Recommendations included the development of more clinically relevant and discriminant tests, standardization of the diagnostic journey, and the adoption of a multidisciplinary approach to diagnosis and treatment.

Gastroparesis and Gastroparesis Syndromes as Neuromuscular Disorders

Gastroparesis syndromes (GpS) are a spectrum of disorders presenting with characteristic symptoms increasingly recognized as being gastrointestinal (GI) neuromuscular disorders (NMDs). This review focuses on GpS as a manifestation of neurologic disorders of GI NMD. GpS can be associated with systemic abnormalities, including inflammatory, metabolic, and serologic disorders, as well as autoimmune antibodies via nerve and muscle targets in the GI tract, which can be treated with immunotherapy, such as intravenous immunoglobulin. GpS are associated with autonomic (ANS) and enteric (ENS) dysfunction. Disorders of ANS may interact with the ENS and are the subject of continued investigation. ENS disorders have been recognized for a century but have only recently begun to be fully quantified. Anatomic structural changes in the GI tract are increasingly recognized in GpS. Detailed descriptions of anatomic changes in GpS, and their correlation with physiologic findings, have opened a new era of investigation. The management of GpS, when viewed as GI NMD, has shifted the paradigms of both diagnosis and treatment. This article concludes with current approaches to GpS directed at underlying neuromuscular pathology.

Gastrointestinal Symptoms Profile in Gastroparesis Compared to Other Functional and Organic Gastrointestinal Diseases

OBJECTIVES

The primary objective was to compare the patient-reported gastrointestinal symptoms profiles of pediatric patients with gastroparesis to pediatric patients with 1 of 7 other functional gastrointestinal disorders and organic gastrointestinal diseases using the Pediatric Quality of Life Inventory (PedsQL) Gastrointestinal Symptoms Scales.

METHODS

The gastrointestinal symptoms profiles of 64 pediatric patients with gastroparesis who manifested abnormal gastric retention based on gastric emptying scintigraphy testing were compared to 582 pediatric patients with 1 of 7 physician-diagnosed gastrointestinal disorders (functional abdominal pain, irritable bowel syndrome, functional dyspepsia, gastroesophageal reflux disease, functional constipation, Crohn disease, ulcerative colitis). The PedsQL Gastrointestinal Symptoms Scales encompass 10 individual multi-item scales which measure stomach pain, stomach discomfort when eating, food and drink limits, trouble swallowing, heartburn and reflux, nausea and vomiting, gas and bloating, constipation, blood in poop, and diarrhea/fecal incontinence, with an overall total gastrointestinal symptoms score.

RESULTS

The gastrointestinal symptoms profile analysis identified significantly worse overall total gastrointestinal symptoms scores between pediatric patients with gastroparesis compared to all other gastrointestinal groups except for irritable bowel syndrome (most P s < 0.001), with significant differences for stomach discomfort when eating compared to all 7 other gastrointestinal groups (most P s < 0.001). Nausea and vomiting were significantly worse for gastroparesis compared to all other gastrointestinal groups except for functional dyspepsia (all P s < 0.001).

CONCLUSIONS

Pediatric patients with gastroparesis self-reported significantly worse overall total gastrointestinal symptoms compared to all other gastrointestinal diagnostic groups except for irritable bowel syndrome, with stomach discomfort when eating and nausea and vomiting symptoms exhibiting the greatest differences compared to most gastrointestinal diagnostic groups.

Paradoxical association between dyspepsia and autoimmune chronic atrophic gastritis: Insights into mechanisms, pathophysiology, and treatment options

BACKGROUND

Autoimmune gastritis (AIG) is a progressive, chronic, immune-mediated inflammatory disease characterized by the destruction of gastric parietal cells leading to hypo/anacidity and loss of intrinsic factor. Gastrointestinal symptoms such as dyspepsia and early satiety are very common, being second in terms of frequency only to anemia, which is the most typical feature of AIG.

AIM

To address both well-established and more innovative information and knowledge about this challenging disorder.

METHODS

An extensive bibliographical search was performed in PubMed to identify guidelines and primary literature (retrospective and prospective studies, systematic reviews, case series) published in the last 10 years.

RESULTS

A total of 125 records were reviewed and 80 were defined as fulfilling the criteria.

CONCLUSION

AIG can cause a range of clinical manifestations, including dyspepsia. The pathophysiology of dyspepsia in AIG is complex and involves changes in acid secretion, gastric motility, hormone signaling, and gut microbiota, among other factors. Managing dyspeptic symptoms of AIG is challenging and there are no specific therapies targeting dyspepsia in AIG. While proton pump inhibitors are commonly used to treat dyspepsia and gastroesophageal reflux disease, they may not be appropriate for AIG. Prokinetic agents, antidepressant drugs, and non-pharmacological treatments may be of help, even if not adequately evidence-based supported. A multidisciplinary approach for the management of dyspepsia in AIG is recommended, and further research is needed to develop and validate more effective therapies for dyspepsia.

Gastroparesis: Myths, Misconceptions, and Management

Gastroparesis (GP), a historically vexing disorder characterized by symptoms of nausea, vomiting, abdominal pain, early satiety, and/or bloating, in the setting of an objective delay in gastric emptying, is often difficult to treat and carries a tremendous burden on the quality of patients' lives, as well as the healthcare system in general. Though the etiology of GP has been fairly well defined, much work has been done recently to better understand the pathophysiology of GP, as well as to identify novel effective and safe treatment options. As our understanding of GP has evolved, many myths and misconceptions still abound in this rapidly changing field. The goal of this review is to identify myths and misconceptions regarding the etiology, pathophysiology, diagnosis, and treatment of GP, in the context of the latest research findings which have shaped our current understanding of GP. Recognition and dispelling of such myths and misconceptions is critical to moving the field forward and ultimately advancing the clinical management of what will hopefully become a better understood and more manageable disorder in the future.

Normative Values for Body Surface Gastric Mapping Evaluations of Gastric Motility Using Gastric Alimetry: Spectral Analysis

INTRODUCTION

Body surface gastric mapping (BSGM) is a new noninvasive test of gastric function. BSGM offers several novel and improved biomarkers of gastric function capable of differentiating patients with overlapping symptom profiles. The aim of this study was to define normative reference intervals for BSGM spectral metrics in a population of healthy controls.

METHODS

BSGM was performed in healthy controls using Gastric Alimetry (Alimetry, New Zealand) comprising a stretchable high-resolution array (8 × 8 electrodes; 196 cm 2 ), wearable Reader, and validated symptom-logging App. The evaluation encompassed a fasting baseline (30 minutes), 482 kCal meal, and 4-hour postprandial recording. Normative reference intervals were calculated for BSGM metrics including the Principal Gastric Frequency, Gastric Alimetry Rhythm Index (a measure of the concentration of power in the gastric frequency band over time), body mass index (BMI)-adjusted amplitude (μV), and fed:fasted amplitude ratio. Data were reported as median and reference interval (5th and/or 95th percentiles).

RESULTS

A total of 110 subjects (55% female, median age 32 years [interquartile range 24-50], median BMI 23.8 kg/m 2 [interquartile range 21.4-26.9]) were included. The median Principal Gastric Frequency was 3.04 cycles per minute; reference interval: 2.65-3.35 cycles per minute. The median Gastric Alimetry Rhythm Index was 0.50; reference interval: ≥0.25. The median BMI-adjusted amplitude was 37.6 μV; reference interval: 20-70 μV. The median fed:fasted amplitude ratio was 1.85; reference interval ≥1.08. A higher BMI was associated with a shorter meal-response duration ( P = 0.014).

DISCUSSION

This study provides normative reference intervals for BSGM spectral data to inform diagnostic interpretations of abnormal gastric function.

Gastric Alimetry ® improves patient phenotyping in gastroduodenal disorders compared to gastric emptying scintigraphy alone

Objectives

Gastric emptying testing (GET) assesses gastric motility, however is non-specific and insensitive for neuromuscular disorders. Gastric Alimetry® (GA) is a new medical device combining non-invasive gastric electrophysiological mapping and validated symptom profiling. This study assessed patient-specific phenotyping using GA compared to GET.

Methods

Patients with chronic gastroduodenal symptoms underwent simultaneous GET and GA, comprising a 30-minute baseline, 99m TC-labelled egg meal, and 4-hour postprandial recording. Results were referenced to normative ranges. Symptoms were profiled in the validated GA App and phenotyped using rule-based criteria based on their relationships to the meal and gastric activity: i) sensorimotor; ii) continuous; and iii) other.

Results

75 patients were assessed; 77% female. Motility abnormality detection rates were: GET 22.7% (14 delayed, 3 rapid); GA spectral analysis 33.3% (14 low rhythm stability / low amplitude; 5 high amplitude; 6 abnormal frequency); combined yield 42.7%. In patients with normal spectral analysis, GA symptom phenotypes included: sensorimotor 17% (where symptoms strongly paired with gastric amplitude; median r=0.61); continuous 30%; other 53%. GA phenotypes showed superior correlations with GCSI, PAGI-SYM, and anxiety scales, whereas Rome IV Criteria did not correlate with psychometric scores (p>0.05). Delayed emptying was not predictive of specific GA phenotypes.

Conclusions

GA improves patient phenotyping in chronic gastroduodenal disorders in the presence and absence of motility abnormalities with improved correlation with symptoms and psychometrics compared to gastric emptying status and Rome IV criteria. These findings have implications for the diagnostic profiling and personalized management of gastroduodenal disorders.

Study Highlights

1) WHAT IS KNOWN Chronic gastroduodenal symptoms are common, costly and greatly impact on quality of lifeThere is a poor correlation between gastric emptying testing (GET) and symptomsGastric Alimetry® is a new medical device combining non-invasive gastric electrophysiological mapping and validated symptom profiling 2) WHAT IS NEW HERE Gastric Alimetry generates a 1.5x higher yield for motility abnormalities than GETWith symptom profiling, Gastric Alimetry identified 2.7x more specific patient categories than GETGastric Alimetry improves clinical phenotyping, with improved correlation with symptoms and psychometrics compared to GET.

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.