Visceral hypersensitivity and electromechanical dysfunction as therapeutic targets in pediatric functional dyspepsia

Percutaneous Electrical Nerve Field Stimulation in Children and Adolescents With Functional Dyspepsia-Integrating a Behavioral Intervention

OBJECTIVES

Functional dyspepsia (FD) includes postprandial distress and epigastric pain syndrome. Percutaneous electrical nerve field stimulation (PENFS) in addition to behavioral interventions (BI) has shown benefits in children with functional abdominal pain but not specifically in FD. We aimed to assess the efficacy of PENFS for treating FD and compare the outcomes with those who received the combination of PENFS + BI.

MATERIALS AND METHODS

Charts of patients with FD who completed four weeks of PENFS were evaluated. A subset of patients received concurrent BI. Demographic data, medical history, and symptoms were documented. Outcomes at different time points included subjective symptom responses and validated questionnaires collected clinically (Abdominal Pain Index [API], Nausea Severity Scale [NSS], Functional Disability Inventory [FDI], Pittsburgh Sleep Quality Index [PSQI], Children's Somatic Symptoms Inventory [CSSI], Patient-Reported Outcomes Measurement Information Systems [PROMIS] Pediatric Anxiety and Depression scales).

RESULT

Of 84 patients, 61% received PENFS + BI, and 39% received PENFS alone. In the entire cohort, API (p < 0.0001), NSS (p = 0.001), FDI (p = 0.001), CSSI (p < 0.0001), PSQI (p = 0.01), PROMIS anxiety (p = 0.02), and depression (p = 0.01) scores improved from baseline to three weeks and at three months. Subjective responses showed nausea improvement (p = 0.01) and a trend for improvement in abdominal pain (p = 0.07) at week three. Abdominal pain subjectively improved at week three and three months (p = 0.003 and 0.02, respectively), nausea at week three and three months (p = 0.01 and 0.04, respectively), and a trend for improvement in sleep disturbances at week three and three months (p = 0.08 and p = 0.07, respectively) in the PENFS + BI group vs PENFS alone.

CONCLUSION

Abdominal pain, nausea, functioning, somatization, sleep disturbances, anxiety, and depression improved at three weeks and three months after PENFS in pediatric FD. Subjective pain and nausea improvement were greater in the PENFS + BI group than in the group with PENFS alone, suggesting an additive effect of psychologic therapy.

Association of vitamin D and functional dyspepsia: a case-control study

Background

Vitamin D plays a key role in responses of brain-gut axis. It has been suggested that functional dyspepsia (FD) may be associated with decreased levels of vitamin D. Hence this study wished to find the association between vitamin D in patients with FD.

Materials and methods

This case-control study was done at a tertiary care hospital with 150 cases and 150 controls. FD was diagnosed by the ROME IV criteria. Demographic profile and serum vitamin D levels including Perceived Stress Score (PSS) and salivary amylase were determined for both cases and controls.

Results

Majority of the FD cases were males (57.3%). Post-prandial distress syndrome represented the major type of FD cases (69.3%). A higher mean BMI was found among the control group (23.2 vs. 21.2, P<0.05) and higher percentage of obese individuals in the control group (42.7% vs. 29.3%, P= 0.05). Majority of the cases are from rural background (89.3% vs. 74%, P<0.001). Comparison of PSS showed that cases had significantly higher grades of PSS than control (P<0.001). However, no significant association was found in the levels of salivary amylase between the groups (P=0.728). Hypovitaminosis D (<30 ng/ml) was found significantly more among cases than controls (73.3% vs. 60%; P<0.05) with an odds ratio of 1.833 (CI 95%= 1.126-2.985). After adjustment of age, place of residence and BMI, vitamin D levels were significantly associated with FD in the regression analysis.

Conclusion

This study shows significant association of vitamin D deficiency in FD patients. It also opens up new avenues for further research into the role of vitamin D supplementation to further improve the management of such cases.

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.

An Update on the Assessment and Management of Pediatric Abdominal Pain

Chronic abdominal pain is very common in children and adolescent and results in high personal and social costs. Most youth with chronic abdominal pain fulfill criteria for a functional abdominal pain disorder (FAPD) as defined by Rome criteria. These are complex conditions with a wide array of biological, psychological, and social factors contributing to the experience of pain. The purpose of the current review is to provide an overview of the pathophysiology of FAPDs and an up-to-date summary of the literature related to FAPDs in children and adolescents, with additional focus on several areas (eg, diet and probiotics) where patients and families frequently have questions or implement self-directed care. We also provide an approach to the assessment and treatment of pediatric FAPDs focusing on the robust literature regarding psychological interventions and much sparser literature regarding medication treatment.

Functional dyspepsia in children: A study of pathophysiological factors

BACKGROUND AND AIM

Functional dyspepsia (FD) is common in children, and treatment targeted towards the altered pathophysiology can improve outcome. We evaluated FD children for abnormality of gastric accommodation and emptying, psychological stressors (PS), Helicobacter pylori (HP) infection, and post-infectious FD.

METHODS

Diagnosis of FD was based on ROME III criteria. Clinical evaluation including dyspeptic symptom scoring and assessment for PS was performed. Satiety drink test for gastric accommodation, gastroscopy with biopsy for HP infection, and solid meal gastric emptying were performed. Sixty-seven healthy children were enrolled for assessing PS and satiety drink test.

RESULTS

Fifty-five FD children (33 boys, age 12 [6-18] years) with symptoms for 4 (2-48) months and dyspeptic score of 5 (1-13) were enrolled. PS were more common in FD than in controls (46/55 vs 9/67; P < 0.001). Median satiety drink volume was 360 mL (180-1320 mL); no patients had satiety drink volume of < 5th centile of healthy children. The frequency (98% vs 85%; P = 0.01) and severity (65 [10-175] vs 50 [5-130]; P < 0.001) of postprandial symptoms were higher in FD than in controls. Of the postprandial symptoms, pain (20.3% vs 0%; P = 0.000) was present only in FD. Delayed gastric emptying was present in 6.5%, HP infection in 11%, and post-infectious FD in 13% cases. Etiological factor was identified in 87% children, with 20% having multiple factors.

CONCLUSIONS

Abnormality of gastric sensorimotor function is seen in one-fourth of FD cases. HP infection and post-infectious FD are present in 11% and 13% cases, respectively.

Electrogastrographic and autonomic nervous system responses to solid and liquid meals in youth with functional dyspepsia

BACKGROUND

Meal-related symptoms are common in paediatric functional dyspepsia (FD). There are only a small number of paediatric studies assessing mechanisms for meal-related symptoms, and these have not utilized Rome IV criteria. The aim of the current study was to assess gastric myoelectric and autonomic nervous system (ANS) responses to both liquid and solid meals in youth with Rome IV-defined FD.

METHODS

In healthy controls (N = 14) and youth with FD (N = 12), we recorded electrocardiograph (to assess heart rate variability; HRV) and electrogastrograph (EGG) signals before and after two test meals, one liquid and one solid. EGG parameters and HRV were assessed for the entire pre- and postprandial periods and in short time intervals. Additionally, liquid gastric emptying was assessed utilizing a ¹³ C-acetate breath test.

KEY RESULTS

During the EGG, the dominant power increased with both meals in controls but not patients with FD. During HRV assessment, the low frequency to high frequency ratio was higher after the liquid meal in controls, despite being similar preprandial, as compared to patients with FD. In controls, both standard deviation of normal to normal waves (SDNN) and root mean square of successive ECG R peaks (R-R interval) differences (rMSSD) increased after the liquid meal (but not after the solid meal) in controls but not patients with FD.

CONCLUSIONS AND INFERENCES

Youth with Rome IV-defined FD lacks the normal postprandial EGG dominant power response or autonomic nervous system response following a liquid meal. The latter appears to indicate a lack of ANS flexibility.

Pharmacological treatments for functional nausea and functional dyspepsia in children: a systematic review

INTRODUCTION

Chronic idiopathic nausea (CIN) and functional dyspepsia (FD) cause considerable strain on many children's lives and their families. Areas covered: This study aims to systematically assess the evidence on efficacy and safety of pharmacological treatments for CIN or FD in children. CENTRAL, EMBASE, and Medline were searched for Randomized Controlled Trials (RCTs) investigating pharmacological treatments of CIN and FD in children (4-18 years). Cochrane risk of bias tool was used to assess methodological quality of the included articles. Expert commentary: Three RCTs (256 children with FD, 2-16 years) were included. No studies were found for CIN. All studies showed considerable risk of bias, therefore results should be interpreted with caution. Compared with baseline, successful relief of dyspeptic symptoms was found for omeprazole (53.8%), famotidine (44.4%), ranitidine (43.2%) and cimetidine (21.6%) (p = 0.024). Compared with placebo, famotidine showed benefit in global symptom improvement (OR 11.0; 95% CI 1.6-75.5; p = 0.02). Compared with baseline, mosapride versus pantoprazole reduced global symptoms (p = 0.011; p = 0.009). One study reported no occurrence of adverse events. This systematic review found no evidence to support the use of pharmacological drugs to treat CIN or FD in children. More high-quality clinical trials are needed.

ABBREVIATIONS

AP-FGID: Abdominal Pain Related Functional Gastrointestinal Disorders; BART: Biofeedback-Assisted Relaxation Training; CIN: Chronic Idiopathic Nausea; COS: Core Outcomes Sets; EPS: Epigastric Pain Syndrome; ESPGHAN: European Society for Pediatric Gastroenterology Hepatology and Nutrition; FAP: Functional Abdominal Pain; FD: Functional Dyspepsia; GERD: Gastroesophageal Reflux Disease; GES: Gastric Electrical Stimulation; H2RAs: H2 Receptor Antagonists; IBS: irritable bowel syndrome; NASPGHAN: North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition; PDS: Postprandial Distress Syndrome; PPIs: Proton Pump Inhibitor; PROMs: Patient Reported Outcome Measures; RCTs: Randomized Controlled Trials; SSRIs: selective serotonin reuptake inhibitors; TCAs: tricyclic antidepressants.

Gastrointestinal symptoms in children: Primary care and specialist interface

AIMS

Gastrointestinal symptoms and diseases represent one of the major reasons for paediatricians' requests for specialist consultations and hospital admissions. One fourth of annual medical consultations for children younger than 6 years can be attributed to gastrointestinal symptoms. High-quality guidelines have been validated worldwide to provide clinical recommendations and support healthcare providers' practice. Nevertheless, overall compliance to standards of care is unsatisfactory, and children with gastrointestinal symptoms frequently undergo expensive, useless specialist consultations and laboratory evaluations. The aim of this study is to review the main epidemiological and clinical aspects, together with management strategies, of the most common gastrointestinal symptoms in children, pointing out pitfalls and practical tips in primary care management, and providing correct indications for specialist consultations.

METHODS

For this review, articles published in English from 2000 to January 2018 were identified from the PubMed/Medline (http://www.ncbi.nlm.nih.gov/pubmed/) database and selected on the basis of quality, relevance to the illness and importance in illustrating current management pathways. The search used the following keywords: gastrointestinal symptoms, functional gastrointestinal symptoms, children, primary care, specialist consultations and management. Particular emphasis was placed on evidence-based guidelines and high-quality studies.

RESULTS

Functional gastrointestinal symptoms have a high impact on the quality of life of children and families and on healthcare costs. A complete medical history and clinical examination are often sufficient to guide the primary care provider in the diagnosis, further workup or referral to a paediatric gastroenterologist.

CONCLUSION

Paediatric gastroenterology outpatients' clinics are among the most crowded specialists, and functional gastrointestinal symptoms and disorders are the most frequent reason for counselling. The number of specialist consultations could be reduced if guidelines were applied in primary care settings.

Choosing an Animal Model for the Study of Functional Dyspepsia

Functional dyspepsia (FD) is a common functional gastrointestinal disorder with pain or discomfort in the upper abdomen as the main characteristic. The prevalence of FD worldwide varies between 5% and 11%. This condition adversely affects attendance and productivity in the workplace. Emerging evidence is beginning to unravel the pathophysiologies of FD, and new data on treatment are helping to guide evidence-based practice. In order to better understand the pathophysiologies of FD and explore better treatment options, various kinds of animal models of FD have been developed. However, it is unclear which of these models most closely mimic the human disease. This review provides a comprehensive overview of the currently available animal models of FD in relationship to the clinical features of the disease. The rationales, methods, merits, and disadvantages for modelling specific symptoms of FD are discussed in detail.

Functional Dyspepsia: An Enigma in a Conundrum

As defined by Rome III, there are 4 abdominal pain-related functional gastrointestinal disorders in children: irritable bowel syndrome, functional dyspepsia (FD), abdominal migraine, and functional abdominal pain. Dyspepsia is a constellation of symptoms referable to the gastroduodenal region of the upper gastrointestinal tract. FD refers to dyspeptic symptoms that cannot currently be explained by an organic cause, and affects 25% to 40% of the adult population over a lifetime. In children, this condition results in increased specialist consultations, with reported prevalence between 3% and 27%. The Rome III criteria for pediatric FD include the presence or persistence of recurrent pain or discomfort centered in the upper abdomen, without evidence of organic disease or change in frequency of stools. Symptoms must be chronic, occurring at least weekly and over a period of at least 6 months. The goal of this article is to provide a narrative review of diagnosis and management of the FD in the pediatric population. A comprehensive search of published literature using the PubMed (http://www.ncbi.nlm.nih.gov/pubmed/) database was carried out to identify all articles published in English from 1998 to November 2015, using 3 key terms; "FD," "functional gastrointestinal disorders," and "children."

Enhanced sympathetic nerve activity induced by neonatal colon inflammation induces gastric hypersensitivity and anxiety-like behavior in adult rats

Gastric hypersensitivity (GHS) and anxiety are prevalent in functional dyspepsia patients; their underlying mechanisms remain unknown largely because of lack of availability of live visceral tissues from human subjects. Recently, we demonstrated in a preclinical model that rats subjected to neonatal colon inflammation show increased basal plasma norepinephrine (NE), which contributes to GHS through the upregulation of nerve growth factor (NGF) expression in the gastric fundus. We tested the hypothesis that neonatal colon inflammation increases anxiety-like behavior and sympathetic nervous system activity, which upregulates the expression of NGF to induce GHS in adult life. Chemical sympathectomy, but not adrenalectomy, suppressed the elevated NGF expression in the fundus muscularis externa and GHS. The measurement of heart rate variability showed a significant increase in the low frequency-to-high frequency ratio in GHS vs. the control rats. Stimulus-evoked release of NE from the fundus muscularis externa strips was significantly greater in GHS than in the control rats. Tyrosine hydroxylase expression was increased in the celiac ganglia of the GHS vs. the control rats. We found an increase in trait but not stress-induced anxiety-like behavior in GHS rats in an elevated plus maze. We concluded that neonatal programming triggered by colon inflammation upregulates tyrosine hydroxylase in the celiac ganglia, which upregulates the release of NE in the gastric fundus muscularis externa. The increase of NE release from the sympathetic nerve terminals concentration dependently upregulates NGF, which proportionately increases the visceromotor response to gastric distention. Neonatal programming concurrently increases anxiety-like behavior in GHS rats.

Functional Nausea in Children: A Review of the Literature and Need for Diagnostic Criteria

Nausea is common amongst children with functional gastrointestinal disorders and is associated with a high burden of somatic and psychosocial comorbidities in both the short and long-term. Current treatments including medications, phytotherapy, stress-reduction techniques, and gastric electrical stimulation for recalcitrant cases, are reviewed. Functional nausea merits its own diagnostic criteria as a pediatric functional gastrointestinal disorder.

Therapeutic effect of melatonin on pediatric functional dyspepsia: A pilot study

AIM: To study the effectiveness of melatonin vs placebo in children with functional dyspepsia (FD).

METHODS: The study was conducted as a double blind, randomized, placebo controlled crossover trial. Subjects were aged 8-17 years and diagnosed with FD based on Rome III criteria. All subjects had failed to respond to 4 wk of acid suppression. Subjects receive a continuous two weeks of placebo and a continuous two weeks of melatonin in an order blinded to the participant and the study team. A Global Clinical Score was obtained to assess changes in abdominal pain. Pain was self-reported to be worse (grade 1), no change (grade 2), moderate improvement (grade 3), good (grade 4; minimal pain and not interfering with daily activities), or excellent (grade 5; no pain), respectively. A positive clinical response was defined as a grade 3 or greater response. Subjects wore an actigraph to assess sleep during a one week baseline period and during each treatment period. Subjects’ sleep latency and total sleep time were recorded throughout the duration of the study.

RESULTS: Fourteen subjects were enrolled and 12 completed the study. One withdrew prior to starting both melatonin and placebo and the other before starting melatonin. A positive clinical response (grade 3-5) was achieved in 42% of subjects on melatonin vs 50% of subjects on placebo (NS). Effect size was calculated and revealed a Cohen’s D of 0.343 which demonstrates a medium effect favoring placebo. A grade 4 or grade 5 response was seen in 4 patients on melatonin and 5 patients on placebo. Baseline sleep parameters were in the healthy range with the longest sleep latency being just over 20 min (mean 7.46 ± 8.53 min) and the shortest sleep duration just over 7 h (mean 10.09 ± 2.72 h). The mean latency did not differ between periods of treatment with melatonin as compared to placebo (4.48 ± 6.45 min vs 3.58 ± 4.24 min; NS). The mean sleep duration did not differ between periods of treatment with melatonin as compared to placebo (9.90 ± 3.53 h vs 9.41 ± 2.70 h; NS).

CONCLUSION: Melatonin does not appear to have efficacy in relieving pain in unselected pediatric FD. Future studies should consider FD subtypes, pathophysiologic mechanisms, and baseline sleep disturbances.

Noninflammatory upregulation of nerve growth factor underlies gastric hypersensitivity induced by neonatal colon inflammation

Gastric hypersensitivity is one of the key contributors to the postprandial symptoms of epigastric pain/discomfort, satiety, and fullness in functional dyspepsia patients. Epidemiological studies found that adverse early-life experiences are risk factors for the development of gastric hypersensitivity. Preclinical studies found that neonatal colon inflammation elevates plasma norepinephrine (NE), which upregulates expression of nerve growth factor (NGF) in the muscularis externa of the gastric fundus. Our goal was to investigate the cellular mechanisms by which NE upregulates the expression of NGF in gastric hypersensitive (GHS) rats, which were subjected previously to neonatal colon inflammation. Neonatal colon inflammation upregulated NGF protein, but not mRNA, in the gastric fundus of GHS rats. Western blotting showed upregulation of p110γ of phosphatidylinositol 4,5-bisphosphate 3-kinase (PI3K), phosphoinositide-dependent kinase-1 (PDK1), pAKT(Ser473), and phosphorylated 4E-binding protein (p4E-BP1)(Thr70), suggesting AKT activation and enhanced NGF protein translation. AKT inhibitor MK-2206 blocked the upregulation of NGF in the fundus of GHS rats. Matrix metalloproteinase 9 (MMP-9), the major NGF-degrading protease, was suppressed, indicating that NGF degradation was impeded. Incubation of fundus muscularis externa with NE upregulated NGF by modulating the protein translation and degradation pathways. Yohimbine, an α2-adrenergic receptor antagonist, upregulated plasma NE and NGF expression by activating the protein translation and degradation pathways in naive rats. In contrast, a cocktail of adrenergic receptor antagonists suppressed the upregulation of NGF by blocking the activation of the protein translation and degradation pathways. Our findings provide evidence that the elevation of plasma NE induces NGF expression in the gastric fundus.

Present state and future challenges in pediatric abdominal pain therapeutics research: Looking beyond the forest

At the present time, it is nearly impossible to treat pediatric functional gastrointestinal disorders associated with pain in an evidence based fashion. This is due to the overall lack of controlled studies and, even more importantly, the complexity of the contributors to disease phenotype which are not controlled or accounted for in most therapeutic trials. In this manuscript, we review the challenges of defining entry criteria, controlling for the large number of biopsychosocial factors which may effect outcomes, and understanding pharmacokinetic and pharmacodynamic factors when designing therapeutic trials for abdominal pain in children. We also review the current state of pediatric abdominal pain therapeutics and discuss trial design considerations as we move forward.

Perspectives on the clinical significance of functional pain syndromes in children

Functional pain syndromes (FPS) characterize a subset of individuals who experience pain and related symptoms and disability without clear structural or disease etiology. In the pediatric population, FPS hold high clinical importance due to significant prevalence rates and potential to persist into adulthood. Although extensive research has been executed to disambiguate FPS, the syndromes that fall within its spectrum remain conceptually complex and sometimes ill-defined. This paper provides an overview of available research on the classification and multifaceted etiology of FPS in youth and their effects on interpersonal, psychological, and familial function. Vital aspects of a successful multidisciplinary approach to treating this population are described; however, it is evident that future research requires more longitudinal studies.

Plasma ghrelin and liquid gastric emptying in children with functional dyspepsia consistent with post-prandial distress syndrome

BACKGROUND

Adult studies indicate a role for ghrelin in functional dyspepsia (FD) mediated through ghrelin's effect on gastric emptying (GE). This study examines the relationship between ghrelin, liquid GE, and pain in children with FD.

METHODS

Thirteen FD patients reporting symptoms consistent with post-prandial distress syndrome (PDS) and 17 healthy controls were enrolled. All participants received a liquid meal containing (13) C-sodium acetate. Pain severity, liquid GE utilizing exhaled (13) CO2 from the sodium acetate breath tests (ABT), plasma acyl ghrelin (AG), and des-acyl ghrelin concentrations were measured at specific intervals over 240 min following ingestion.

KEY RESULTS

FD-PDS patients demonstrated lower mean baseline AG (14.8 ± 9.7 vs 27.2 ± 14.0 fmol/mL; p = 0.013), AG Cmax (24.6 ± 8.2 vs 40.5 ± 16.8 fmol/mL; p = 0.007), and AG flux (18.2 ± 7.8 vs 32.7 ± 17.3 fmol/mL; p = 0.015) than controls. The time to reach maximum exhaled (13) CO2 concentration (T max ) was longer in FD patients than controls (47.5 ± 18.5 vs 35.8 ± 11.8 min; p = 0.046). Significant relationships between ghrelin analyte ratios and ABT parameters were largely confined to control participants.

CONCLUSIONS & INFERENCES

FD-PDS in children is associated with lower fasting and maximum AG concentrations, and dampened AG flux. These data suggest a possible role for altered ghrelin physiology in the pathogenesis of PDS.