Brain processing of rectal sensation in adolescents with functional defecation disorders and healthy controls

Interoceptive Processing in Functional Gastrointestinal Disorders

Functional gastrointestinal disorders (FGIDs) are characterized by chronic gastrointestinal symptoms in the absence of overt pathology and affect a significant percentage of the worldwide population. They are commonly accompanied by co-morbid psychiatric symptomatology and are associated with significant suffering and great healthcare services utilization. There is growing evidence that dysregulation of the gut-brain axis and disturbances in the processing of afferent interoceptive signals lie at the heart of these disorders. In this context, the aim of the current review was to detect and critically review original articles focusing on the role of interoception in the pathophysiology of FGIDs. Our search yielded 38 relevant studies. FGID patients displayed increased visceral sensitivity, enhanced attention to gastrointestinal interoceptive cues, and greater emotional arousal when coping with gut-derived sensations. Neuroimaging studies have shown significant structural and functional changes in regions of the interoceptive network, while molecular and genetic studies have revealed significant associations between interoceptive signaling and deficits in excitatory neurotransmission, altered endocrine and immune physiological pathways, and aberrant expression of transient receptor potential channel genes. Finally, there were emerging data suggesting that interoception-based interventions may reduce physical symptoms and improve quality of life and should be integrated into FGID clinical management practices.

Faecal incontinence: Retentive, non-retentive and when to suspect organic pathology

BACKGROUND

Faecal incontinence is a highly prevalent and very distressing condition that occurs throughout the entire paediatric age.

AIM

To summarise advances in the understanding of the epidemiology, pathophysiology, evaluation and treatment of children with faecal incontinence due to either disorders of gut-brain interaction or organic diseases.

METHODS

Literature review on prevalence, impact, diagnosis and treatment options for children with faecal incontinence, interspersed with observations from the author's lifelong career focused on evaluation of children with motility disorders.

RESULTS

Faecal incontinence in children is most commonly due to unrecognised or insufficiently treated functional constipation with overflow incontinence. Non-retentive faecal incontinence (NRFI) is probably more common than previously thought and is particularly challenging to treat. Organic diseases such as anorectal malformations (ARMs), Hirschsprung disease and spinal defects are often associated with faecal incontinence; in these conditions, faecal incontinence has a profound impact on quality of life. Recognition of the different pathophysiologic mechanisms causing the incontinence is essential for a successful treatment plan. A thorough physical examination and history is all that is needed in the diagnosis of the causes of faecal incontinence related to disorders of gut-brain interaction. Colonic transit studies or x-rays may help to differentiate retentive from NRFI. Manometry tests are helpful in determining the mechanisms underlying the incontinence in children operated on for ARMs or Hirschsprung diseases. Multiple behavioural, medical and surgical interventions are available to lessen the severity of faecal incontinence and its impact on the daily life of affected individuals.

CONCLUSIONS

Recent advances offer hope for children with faecal incontinence.

Imaging in pediatric disorders of the gut-brain interactions: current best practice and future directions

INTRODUCTION

Disorders of Gut-Brain Interactions (DGBI) are a common clinical problem in children and pose significant challenges to the attending pediatrician. Radiological investigations are commonly ordered to evaluate these children.

AREA COVERED

This review focuses on the current best practice of using radiological investigations in DGBIs and how novel radiological investigations could revolutionize the assessment and therapeutic approach of DGBI in children.

EXPERT OPINION

We believe imaging in DGBI is still in its early stages, but it has the potential to revolutionize how we diagnose and treat children with DGBI. As the understanding of the gut-brain axis continues to grow, we can expect to see the disappearance of conventional imaging techniques and the emergence of more sophisticated imaging techniques with less radiation exposure in the future which provide more clinically meaningful information regarding the gut-brain axis and its influence on intestinal function. Some of the novel imaging modalities will be able to broaden our horizon of understanding DGBI in children providing more useful therapeutic options to minimize their suffering.

Association between childhood constipation and exposure to stressful life events: a systematic review

BACKGROUND

Several cross-sectional studies have reported an association between childhood constipation and exposure to stressful events. We planned to systematically review the literature on constipation and its associated stressful events.

METHODS

PubMed, Embase, and PsycINFO databases were searched (until February 2021) using standard search terms related to "constipation" and "stress" from 0 to 18 years that describe the association between psychological stressors and constipation. Studies were screened using pre-designed eligibility criteria. Studies that fulfilled the criteria were reviewed in a full-text format. The quality assessment of selected articles was conducted using standard methods.

KEY RESULTS

Of 2296 titles and abstracts screened, 38 were included in the full-text review. Out of that, 15 articles were included in this systematic review. There were 2954 children with constipation, and the age range was from 6 months to 16 years. Exposure to home-related stressors (divorce or separation of parents, severe illness in family, and parental job loss) school-related stressors (including being bullied at school, change in school, separation from the best friend at school, and failure in an examination), exposure to child maltreatments and exposure to war/civil unrest were associated with childhood constipation.

CONCLUSIONS AND INFERENCES

Exposure to day-to-day home- and school-related stressors, to child maltreatment, and to civil unrest is associated with constipation in children and adolescents. These factors need to be explored during clinical evaluation of children with constipation.

Functional Constipation and Dyssynergic Defecation in Children

Defecation is a complex physiological process, which relies on intricate mechanisms involving the autonomic and somatic nervous system, the pelvic floor muscles, and the anal sphincter complex. Anorectal dysfunction may result in constipation, a bothersome defecation disorder that can severely affect daily lives of children and their families. In this review, we focus on different mechanisms underlying anorectal dysfunction and specific treatment options aimed at improving defecation dynamics in children with functional constipation.

Management Approach of Pediatric Constipation

Constipation is a common challenge in pediatrics. Abdominal radiographs are frequently taken in the pediatric emergency department for diagnosis despite their inadequate reliability to detect the pathology or the degree of constipation. Misdiagnosis of constipation may cause multiple vague physician visits, deployment of emergency medical services, use of radiation, unnecessary laboratory tests, and even surgical procedures. The primary evidence-based suggestions are based on published guidelines that include management of constipation in children divided into three stages of therapy: (1) disimpaction, (2) maintenance therapy, and (3) behavior modification, and special care should be given to neonates and to children with pre-existing medical problems.

Roles of Gut Microbiota and Metabolites in Pathogenesis of Functional Constipation

Functional constipation (FC), a condition characterized by heterogeneous symptoms (infrequent bowel movements, hard stools, excessive straining, or a sense of incomplete evacuation), is prevalent over the world. It is a multifactorial disorder and can be categorized into four subgroups according to different pathological mechanisms: normal transit constipation (NTC), slow transit constipation (STC), defecatory disorders (DD), and mixed type. Recently, growing evidence from human and animals has pointed that there was a strong association between gut microbiota and FC based on the brain-gut-microbiome axis. Studies have reported that the main characteristics of gut microbiota in FC patients were the relative decrease of beneficial bacteria such as Lactobacillus and Bifidobacterium, the relative increase of potential pathogens, and the reduced species richness. Gut microbiota can modulate gut functions through the metabolites of bacterial fermentation, among which short-chain fatty acids (SCFAs), secondary bile salts (BAs), and methane occupied more important positions and could trigger the release of gut hormones from enteroendocrine cells (EECs), such as 5-hydroxytryptamine (5-HT), peptide YY (PYY), and glucagon-like peptide-1 (GLP-1). Subsequently, these gut hormones can influence gut sensation, secretion, and motility, primarily through activating specific receptors distributed on smooth muscle cells, enteric neurons, and epithelial cells. However, research findings were inconsistent and even conflicting, which may be partially due to various confounding factors. Future studies should take the associated confounders into consideration and adopt multiomics research strategies to obtain more complete conclusions and to provide reliable theoretical support for exploring new therapeutic targets.

Lifestyle Habits Associated with Poor Defecation Habit among Pupils in Japan

PURPOSE

Not enough attention has been paid to defecation habits in Japan. This study aimed to emphasize the importance of defecation habits on health and function in Japanese pupils.

METHODS

Using multiple regression analysis, 2,722 questionnaires obtained from pupils in grades 5 to 12 were analyzed to determine lifestyle habits associated with defecation frequency.

RESULTS

Significant regression formulae for defecation scores were obtained for all school types: elementary school (ES) (adjusted R2=0.08, p<0.001), junior high school (JHS) (0.09, p<0.001), and senior high school (SHS) (0.15, p<0.001). The following factors were associated with poorer defecation scores, according to school type: female gender (all 3 school types), breakfast skipping (elementary and JHSs), lower physical activity (JHSs and SHSs), and longer school-day screen time (elementary and SHSs). In addition, poorer self-reported academic performance scores in ES, less standardized body mass index (BMI) in JHS, and shorter non-school- day screen time scores in SHS, were associated with poorer defecation scores.

CONCLUSION

Poor defecation frequency showed significant associations with various lifestyle habits, such as breakfast skipping, physical activity, and screen time, among pupils. Academic performance and standardized BMI were also associated with defecation frequency. More attention should be paid to defecation frequency to sustain health and function in pupils.

Management of functional constipation in children and adults

Functional constipation is common in children and adults worldwide. Functional constipation shows similarities in children and adults, but important differences also exist regarding epidemiology, symptomatology, pathophysiology, diagnostic workup and therapeutic management. In children, the approach focuses on the behavioural nature of the disorder and the initial therapeutic steps involve toilet training and laxatives. In adults, management focuses on excluding an underlying cause and differentiating between different subtypes of functional constipation - normal transit, slow transit or an evacuation disorder - which has important therapeutic consequences. Treatment of adult functional constipation involves lifestyle interventions, pelvic floor interventions (in the presence of a rectal evacuation disorder) and pharmacological therapy. When conventional treatments fail, children and adults are considered to have intractable functional constipation, a troublesome and distressing condition. Intractable constipation is managed with a stepwise approach and in rare cases requires surgical interventions such as antegrade continence enemas in children or colectomy procedures for adults. New drugs, including prokinetic and prosecretory agents, and surgical strategies, such as sacral nerve stimulation, have the potential to improve the management of children and adults with intractable functional constipation.

The complex relationship between urinary and defecatory disorders in young and adolescent girls

PURPOSE OF REVIEW

Scientific advancements have led to enhanced clarity about the interrelationship between urinary tract pathology and functional bowel disturbances. The present article will review the current literature regarding the cause, pathophysiology, diagnosis, and treatment of lower urinary tract dysfunction and abnormal bowel habits in young and adolescent girls.

RECENT FINDINGS

Complex neurological, physiological mechanisms and functional behaviors exist that contribute to the development of coexisting urinary symptoms and defecatory disorders in young and adolescent girls. Bladder bowel dysfunction (BBD) in childhood and adolescence is carried into adulthood creating a lifetime health burden.

SUMMARY

Practitioners should be aware and actively screen for conditions mimicking BBD with time-efficient and effective history-taking and physical exams that reduce anxiety and fear. The present review provides guide to comprehensive treatment strategies for managing complex pelvic floor disorders including urinary incontinence, defecatory disorders, pelvic and perineal pain, and constipation. More research is needed to elucidate pathophysiology and optimal treatment strategies of the BBD.

Barriers in Neurogastroenterology and Motility Training Experience for Pediatric Gastroenterology Fellows

BACKGROUND

Neurogastroenterology and motility (NGM) disorders are common and have a high health care burden. Although pediatric gastroenterology fellows are expected to obtain comprehensive training in the diagnosis and management of NGM disorders, there is ongoing concern for unmet training needs and lack of exposure in treating patients who suffer from NGM problems.

METHODS

We conducted a cross-section survey of trainees listed as pediatric gastroenterology fellows in North American training programs in 2018 via direct E-mail and the pediatric gastroenterology listserv. Eighty-one pediatric gastroenterology fellows responded to the anonymous survey.

RESULTS

A total of 53.1% of the fellows reported interest in NGM; however, 75.1% of the fellows believed they had not been adequately trained in NGM during their fellowship. Eighty percent of fellows with 2 weeks or less of dedicated motility training reported that they received inadequate NGM training, compared to 46.2% fellows who received 1 or more months of dedicated motility training (P = 0.0148). The majority of fellows reported not being comfortable in performing gastrointestinal (GI) motility studies. The majority of fellows also reported not being comfortable in interpreting GI motility studies.

CONCLUSIONS

Although most pediatric gastroenterology fellows expressed interest in NGM, the lack of exposure and dedicated training in motility during fellowship were identified as barriers to pursuing motility-focused careers. Furthermore, most fellows reported limited comfort with performing and/or interpreting motility studies. Changes are needed to encourage fellows to develop their interest and expertise in NGM.

Brain MRI Lesions are Related to Bowel Incontinence in Multiple Sclerosis

BACKGROUND AND PURPOSE

Bowel incontinence in multiple sclerosis might be associated with specific lesion sites. This study intended to determine associations between bowel incontinence and cerebral multiple sclerosis lesions using a voxel-wise lesion symptom mapping analysis.

METHODS

We conducted a retrospective study of multiple sclerosis patients with self-reported bowel incontinence and matched controls. Lesions were manually outlined on T2-weighted MRI scans and transformed into stereotaxic space. We performed a voxel-wise subtraction analysis subtracting the lesion overlap of patients without from patients with bowel incontinence. Finally, we compared the absence or presence of bowel incontinence between patients with and without lesions in a given voxel using the Liebermeister test.

RESULTS

A total of 51 patients were included in the study. The analysis yielded associations between bowel incontinence and lesions in the supramarginal gyrus of the left secondary somatosensory cortex and another lesion cluster in the right parahippocampal gyrus and amygdala.

CONCLUSIONS

Our analysis indicates associations between bowel incontinence and lesions in the left supramarginal gyral area contributing to integrating anorectal-visceral sensation and in the right parahippocampal gyrus and amygdala contributing to generating visceral autonomic arousal states. Moreover, our results suggest left hemispheric dominance of sensory visceral integration, while limbic areas of the right hemisphere seem to contribute to the autonomic component of the defecation process. A limitation of our study is the retrospective evaluation of the bowel incontinence status based on medical records. Further research should evaluate the bowel incontinence status in multiple sclerosis patients prospectively to overcome the limitations of the current study.

FUNCTIONAL CONSTIPATION AND OVERACTIVE BLADDER IN WOMEN: A POPULATION-BASED STUDY

ABSTRACT BACKGROUND: An association between urinary disorders and functional constipation has been registered in children and adults, with functional constipation being a common complaint in individuals with overactive bladder. OBJECTIVE: To evaluate the prevalence of functional constipation, overactive bladder and its dry/wet subtypes in women and to determine which bowel symptoms predict overactive bladder. METHODS: A cross-sectional study of women randomly approached in public spaces. Exclusion criteria: neurological/anatomical abnormalities of the bowel or urinary tract. Constipation was defined as ≥2 positive symptoms of those listed in the Rome criteria. Urinary abnormalities (frequent urination, urgency, incontinence, nocturia) were defined by a score ≥2 in the respective item of the International Consultation on Incontinence Questionnaire - Overactive Bladder. Dry overactive bladder was defined as urgency without incontinence, while wet overactive bladder included incontinence. RESULTS: A total of 516 women with a mean age of 35.8±6 years were interviewed. Rates of functional constipation, overactive bladder, dry overactive bladder and wet overactive bladder were 34.1%, 15.3%, 8.9% and 6.4%, respectively. Functional constipation was associated with overactive bladder and dry overactive bladder, with functional constipation predicting dry overactive bladder (OR=2.47). Quality of life was poorer in constipated women compared to non-constipated and even worse in constipated women with wet overactive bladder (median 22.5; 95%CI: 17.25-35.25). Manual maneuvers were significantly associated with both overactive bladder subtypes. Independent predictive factors for overactive bladder were manual maneuvers (OR=2.21) and <3 defecations/week (OR=2.18), with the latter being the only predictive factor for dry overactive bladder (OR=3.0). CONCLUSION: Functional constipation is associated with overactive bladder and its dry subtype, particularly in the younger population. In addition, this association is responsible for lower quality of life scores, especially when urinary incontinence is present. The presence of manual maneuvers and less than three defecations per week should direct us to look for overactive bladder.

Prevalence of Functional Defecation Disorders in Children: A Systematic Review and Meta-Analysis

OBJECTIVE

To systematically review the literature regarding the epidemiology of functional constipation and functional nonretentive fecal incontinence (FNRFI) in children. Secondary objectives were to assess the geographical, age, and sex distribution of functional constipation and FNRFI and to evaluate associated factors.

STUDY DESIGN

The Cochrane Library, PubMed, and Embase databases were searched from 2006 until September 2017. The following inclusion criteria were applied: (1) prospective studies of population-based samples; (2) reporting on the prevalence of functional constipation or FNRFI according to the Rome III/IV criteria; (3) in children aged 0-18 years; and (4) published in full manuscript form. A quality assessment of included studies was conducted. Random effect meta-analyses with meta-regression analyses of study characteristics were performed.

RESULTS

Thirty-seven studies were included, of which 35 reported on the prevalence of functional constipation and 15 of FNRFI. The reported prevalence of functional constipation ranged from 0.5% to 32.2%, with a pooled prevalence of 9.5% (95% CI 7.5-12.1). The prevalence of FRNFI ranged from 0.0% to 1.8%, with a pooled prevalence of 0.4% (95% CI 0.2-0.7). The prevalence of functional constipation was 8.6% in boys compared with 8.9% in girls (OR 0.99, 95% CI 0.9-1.4). Geographical location, dietary habits, and exposure to stressful life events were reported to be associated with the prevalence of functional constipation. Data on FNRFI were scarce and no associated factors were identified.

CONCLUSION

Functional constipation is common in childhood and is associated with geographical location, lifestyle factors, and stressful life events. FNRFI is rare, and no associated factors were identified.