Age-related changes in colon motility

Testing in functional constipation-What's new and what works

BACKGROUND

Constipation is among the most common symptoms prompting a consultation with a paediatric gastroenterologist. While most patients will respond to lifestyle and dietary changes and conventional therapy, some may require diagnostic studies.

AIM

To review the diagnostics studies used to evaluate children with functional constipation.

MATERIALS AND METHODS

There is no evidence to support the routine use of abdominal X-rays in the evaluation of paediatric constipation. Colon transit by radiopaque markers (ROM) should be indicated when medical history does not match clinical findings, to guide colon manometry (CM) performance and to discriminate between faecal incontinence from functional constipation and non-retentive faecal incontinence. Colon scintigraphy may be useful as an alternative to ROM. Lumbar spine MRI may be indicated to evaluate for spinal abnormalities. The role of defecography has not been properly evaluated in children. Anorectal manometry in children is indicated primarily to evaluate anal resting pressure, presence and quality of the recto-anal inhibitory reflex and simulated defecation manoeuvres. The CM is indicated to guide surgical interventions after failing medical therapy.

CONCLUSIONS

The goal of these studies is to identify treatable causes of constipation. Most of these studies are designed to evaluate anatomy, transit and/or colon/rectum motility function and are primarily indicated in those who fail to respond to conventional therapy.

Utility of colonic manometry in children with Hirschsprung disease

OBJECTIVES

Abnormal motility of the residual colon has been reported in post-pull-through Hirschsprung disease (PT-HSCR) patients with persistent defecation problems. We reviewed the role of colonic manometry (CM) in the management of defecation disorders in these patients.

METHODS

We retrospectively reviewed the medical record of PT-HSCR children who underwent CM for persistent symptoms of abnormal defecation. We reviewed their clinical course and its relation to CM findings.

RESULTS

Thirty PT-HSCR patients underwent CM, of which five were diagnosed with transition zone pull-through and were excluded. Of the remaining 25 patients, 16 had colonic dysmotility, 8 had normal CM, and one had colonic hypermotility. In patients with dysmotility, five responded to ongoing medical management, three required surgical intervention (ileostomy), three remained symptomatic with medical management but not yet received surgical intervention, and five were lost to follow-up. In patients with normal CM, four responded to ongoing medical therapy, two required additional surgery (antegrade enema procedure), and two were lost to follow-up. The patient with hypermotility improved with adding loperamide.

CONCLUSIONS

Colonic dysmotility can occur in PT-HSCR patients with persistent defecation problems. CM was helpful in delineating the degree of colonic neuromuscular dysfunction. CM results were used in conjunction with other clinical data to determine optimal management. Our findings support that medical management should first be optimized before consideration of colonic manometry and surgical interventions.

Diagnostic Utility of Mucosal Biopsies Taken During Colonoscopy-Guided Colonic Manometry Catheter Placement

OBJECTIVES

The diagnostic utility of mucosal biopsies taken during colonoscopy-guided colonic manometry catheter placement is unknown. The aims of our study were to determine the frequency and histopathology results of mucosal biopsies during these procedures and to assess whether there were any associations between the histology or gross findings with manometry results.

METHODS

We performed a retrospective chart review of children who had a colonic manometry study completed between 2008 and 2020 at a quaternary children's hospital. We captured patient demographics, biopsy locations, histopathology results, gross endoscopy findings, and manometry results. The chi-squared test and when appropriate Fisher exact test was used to evaluate categorical associations.

RESULTS

One hundred forty-eight patients were included. One hundred eighteen (80%) had colonic biopsy and 63 (43%) had ileal biopsy. Colonic histology findings, which patients could have multiple, included lymphonodular hyperplasia (34%), normal (27%), chronic inflammation (24%), melanosis coli (21%), colonic eosinophilia (10%), and acute inflammation (8%). Ileal histology findings included increased Peyer patches (44%), normal (44%), acute inflammation (11%), chronic inflammation (3%), eosinophilia (5%), and eosinophilic ileitis (3%). The majority of acute and chronic inflammation was graded as mild. There were no statistically significant associations of histology to gross endoscopy or manometry findings.

CONCLUSIONS

Colonic biopsies are obtained in the majority of patients presenting for colonic manometry evaluation with ileal biopsies obtained less frequently. Histopathology findings are noted frequently, but the majority are the result of or did not impact clinical care. There were no associations between abnormal histopathology or abnormal gross endoscopy findings with colonic manometry results.

Novel sensory trigger for gastrocolonic response

BACKGROUND

Gastrocolonic response (GCR) is a physiologic increase in motor activity of the colon following meal ingestion. The presence of GCR, in colonic manometry (CM) studies, is used as a marker of normal colonic motor activity. Our aim was to investigate whether GCR could be induced by sensory stimulation (visual or olfactory) prior to food ingestion, and to describe the characteristics of patients with this response.

METHODS

We prospectively marked time of meal presence and initiation on CM tracings of patients with idiopathic constipation. We reviewed electronic medical records and normal CM studies. Presence of sensory GCR was defined as an increase by at least 25% of the baseline motility index (MI) after exposure to meal, prior to food ingestion. Manometry characteristics of patients with a sensory GCR response were compared to those without.

KEY RESULTS

Eighty-nine patients, (47% females, median age 9 years) met the inclusion criteria. Forty-seven (52.8%) patients had a positive sensory GCR. This cohort had a higher proportion of postprandial GCR (93.6% vs. 76.2%, p-value = 0.02) and lower fasting MI (2.08 mm Hg vs. 3.54 mm Hg, p < 0.01). Thirteen (14.6%) patients who had no postprandial GCR had higher baseline MI (median of 3.69 vs. 2.46 mm Hg, p < 0.05).

CONCLUSIONS & INFERENCES

Visualizing or smelling food resulted in a significant increase in baseline MI in more than 50% of patients. Our findings propose a novel, alternate pathway that can induce GCR. This central sensory pathway may have clinical relevance in the diagnosis and management of patients with colonic dysmotility.

Gastrocolonic Response

PURPOSE OF REVIEW

The gastrocolonic response (GCR), is a physiologic increase in motor activity of the colon, which usually occurs within minutes following meal ingestion. Over the years several triggers that provoke GCR were recognized including gastric dilation, caloric intake, and fat component of the meal. The response is mediated by the vagal nerve and neurohumoral mechanisms, and it can be modified by several pharmacological factors. Assessment of GCR is part of high-resolution colonic manometry studies, performed in patients with suspected colonic dysmotility. This review highlights the physiologic basis of GCR as well as its clinical and diagnostic features and implementation in variable pathological conditions and clinical practice.

RECENT FINDINGS

GCR has a role in patients with constipation, diabetes, dumping syndrome, bowel hyper and hypomotility and irritable bowel syndrome. Novel sensory triggers for GCR were recently recognized. GCR is a physiological response which is evaluated during colonic manometry studies. Abnormal GCR is a marker of an underlying pathology, which can provide a potential target for treatment.

Diagnosis of colonic dysmotility associated with autonomic dysfunction in patients with chronic refractory constipation

We report the first study assessing human colon manometric features and their correlations with changes in autonomic functioning in patients with refractory chronic constipation prior to consideration of surgical intervention. High-resolution colonic manometry (HRCM) with simultaneous heart rate variability (HRV) was performed in 14 patients, and the resulting features were compared to healthy subjects. Patients were categorized into three groups that had normal, weak, or no high amplitude propagating pressure waves (HAPWs) to any intervention. We found mild vagal pathway impairment presented as lower HAPW amplitude in the proximal colon in response to proximal colon balloon distention. Left colon dysmotility was observed in 71% of patients, with features of (1) less left colon HAPWs, (2) lower left colon HAPW amplitudes (69.8 vs 102.3 mmHg), (3) impaired coloanal coordination, (4) left colon hypertonicity in patients with coccyx injury. Patients showed the following autonomic dysfunction: (1) high sympathetic tone at baseline, (2) high sympathetic reactivity to active standing and meal, (3) correlation of low parasympathetic reactivity to the meal with absence of the coloanal reflex, (4) lower parasympathetic and higher sympathetic activity during occurrence of HAPWs. In conclusion, left colon dysmotility and high sympathetic tone and reactivity, more so than vagal pathway impairment, play important roles in refractory chronic constipation and suggests sacral neuromodulation as a possible treatment.

Individualized precision dosing approaches to optimize antimicrobial therapy in pediatric populations

Introduction:Severe infections continue to impose a major burden on critically ill children and mortality rates remain stagnant. Outcomes rely on accurate and timely delivery of antimicrobials achieving target concentrations in infected tissue. Yet, developmental aspects, disease-related variables, and host factors may severely alter antimicrobial pharmacokinetics in pediatrics. The emergence of antimicrobial resistance increases the need for improved treatment approaches.Areas covered:This narrative review explores why optimization of antimicrobial therapy in neonates, infants, children, and adolescents is crucial and summarizes the possible dosing approaches to achieve antimicrobial individualization. Finally, we outline a roadmap toward scientific evidence informing the development and implementation of precision antimicrobial dosing in critically ill children.The literature search was conducted on PubMed using the following keywords: neonate, infant, child, adolescent, pediatrics, antimicrobial, pharmacokinetic, pharmacodynamic target, Bayes dosing software, optimizing, individualizing, personalizing, precision dosing, drug monitoring, validation, attainment, and software implementation. Further articles were sought from the references of the above searched articles.Expert opinion:Recently, technological innovations have emerged that enabled the development of individualized antimicrobial dosing approaches in adults. More work is required in pediatrics to make individualized antimicrobial dosing approaches widely operationalized in this population.

1907-2020: more than one century of colonic mass movements in humans

Motility of the large bowel may be grossly subdivided in two types of contractile activity: low-amplitude single or cyclic propagated waves and high-amplitude propagated activity. The latter is mainly apt to shift relatively large amounts of colonic contents, and it is related to defecation. The main component of this propagated activity is represented by the radiologically identified mass movements that have a manometric equivalent known as high-amplitude propagated contractions (HAPC). The present article reviews origins and characterization of HAPC in the time course of colonic motility investigations, and correlates it with technological advancements in recent years, putting into perspective the future possible options to better detect and investigate these important physiological events.

Observing postprandial bowel movements in diaper-dependent toddlers

The gastrocolic reflex is a response of the colon to the presence of food in the stomach. Our goal was to observe bowel movements in healthy infants and toddlers not yet toilet trained, in response to a meal. Stool behavior of 40 toddlers, aged 18-27 months, was monitored. We observed a bowel movement within the first hour after a meal in 75% of the children. This occurred 15, 30 or 60 minutes after a meal in, respectively, 25%, 48% and 66% of the observations. If we limit to the ones that actually defecated, 37% would defecate within 15 minutes and 72% within half an hour. Fifty-nine percent of all children defecated in the morning, 54% at noon and 28% in the evening. In conclusion, we believe the gastrocolic reflex can be used as a facilitating factor to help a child to defecate on the potty, 15-30 minutes after a meal. In 50% of the cases, a child will have a bowel movement on the potty and learn to defecate on it much easier.

First translational consensus on terminology and definitions of colonic motility in animals and humans studied by manometric and other techniques

Alterations in colonic motility are implicated in the pathophysiology of bowel disorders, but high-resolution manometry of human colonic motor function has revealed that our knowledge of normal motor patterns is limited. Furthermore, various terminologies and definitions have been used to describe colonic motor patterns in children, adults and animals. An example is the distinction between the high-amplitude propagating contractions in humans and giant contractions in animals. Harmonized terminology and definitions are required that are applicable to the study of colonic motility performed by basic scientists and clinicians, as well as adult and paediatric gastroenterologists. As clinical studies increasingly require adequate animal models to develop and test new therapies, there is a need for rational use of terminology to describe those motor patterns that are equivalent between animals and humans. This Consensus Statement provides the first harmonized interpretation of commonly used terminology to describe colonic motor function and delineates possible similarities between motor patterns observed in animal models and humans in vitro (ex vivo) and in vivo. The consolidated terminology can be an impetus for new research that will considerably improve our understanding of colonic motor function and will facilitate the development and testing of new therapies for colonic motility disorders.

Identification of juvenility-associated genes in the mouse hepatocytes and cardiomyocytes

Young individuals possess distinct properties that adults do not. The juvenile animals show higher activities for growth, healing, learning and plasticity than adults. The machinery for establishing these juvenile properties is not fully understood. To better understand the molecular constituents for the above properties, we performed a comprehensive transcriptome analysis of differently aged cells of mice by high-throughput sequencing and identified the genes selectively highly expressed in the young cells. These genes, collectively called as juvenility-associated genes (JAGs), show significant enrichments in the functions such as alternative splicing, phosphorylation and extracellular matrix (ECM). This implies the juvenescence might be achieved by these functions at the cell level. The JAG mutations are associated with progeria syndromes and growth disorders. Thus, the JAGs might organize the juvenile property of young animals and analysis of JAGs may provide scientific and therapeutic approaches toward treating the genetic diseases.

An ANMS-NASPGHAN consensus document on anorectal and colonic manometry in children

BACKGROUND

Over the last few years, the study of the colon and anorectal function has experienced great technical advances that have facilitated the performance of the tests and have allowed a more detailed characterization of reflexes and motor patterns. As a result, we have achieved a much better understanding of the pathophysiology of children with defecation problems. Anorectal and colonic manometry are now commonly used in all major pediatric referral centers as diagnostic tools and to guide the management of children with intractable constipation and fecal incontinence, particularly when a surgical intervention is being considered.

PURPOSE

This review highlights some of the recent advances in pediatric colon and anorectal motility testing including indications and preparation for the studies, and how to perform and interpret the tests. This update has been endorsed by the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition (NASPGHAN).

Pharmacokinetic considerations when prescribing in children

Before prescribing, the pediatrician typically considers recommended dosing guidelines and issues related to safety. Rarely does (s)he consider the impact of normal growth and development on drug disposition and by extension drug action. This paper reviews how the processes of absorption, distribution, metabolism and elimination differ between healthy children and adults and briefly discusses considerations for medication prescribing in children where these processes are altered secondary to comorbidities.

Pharmacokinetics in neonatal prescribing: evidence base, paradigms and the future

Paediatric patients, particularly preterm neonates, present many pharmacological challenges. Due to the difficulty in conducting clinical trials in these populations dosing information is often extrapolated from adult populations. As the processes of absorption, distribution, metabolism and excretion of drugs change throughout growth and development extrapolation presents risk of over or underestimating the doses required. Information about the development these processes, particularly drug metabolism pathways, is still limited with weight based dose adjustment presenting the best method of estimating pharmacokinetic changes due to growth and development. New innovations in pharmacokinetic research, such as population pharmacokinetic modelling, present unique opportunities to conduct clinical trials in these populations improving the safety and effectiveness of the drugs used. More research is required into this area to ensure the best outcomes for our most vulnerable patients.

Pediatric pharmacokinetics: human development and drug disposition

Human development is described by the various anatomic and physiologic changes that occur as the single-celled zygote matures into an adult human being. Concomitant with bodily maturation are changes in the complex interactions between pharmacologic agents and the biologic matrix that is the human body. Profound changes in the manner by which drugs traverse the body during development can have significant implications in drug efficacy and toxicity. Although not a replacement for well-conducted, pediatric, pharmacokinetic studies, an understanding of developmental biology and the mechanisms for drug disposition invariably assists the pediatric clinician with the judicious use of medications in children.

The physiology of human defecation

Human defecation involves integrated and coordinated sensorimotor functions, orchestrated by central, spinal, peripheral (somatic and visceral), and enteric neural activities, acting on a morphologically intact gastrointestinal tract (including the final common path, the pelvic floor, and anal sphincters). The multiple factors that ultimately result in defecation are best appreciated by describing four temporally and physiologically fairly distinct phases. This article details our current understanding of normal defecation, including recent advances, but importantly identifies those areas where knowledge or consensus is still lacking. Appreciation of normal physiology is central to directed treatment of constipation and also of fecal incontinence, which are prevalent in the general population and cause significant morbidity.

Physiological basis of food intolerance in VLBW

To provide an overview on the role of gut immunity, nervous system and motility patterns in the development of feeding intolerance in newborns. Maturation of the GI is important not only for digestion and absorption, but for endocrine and exocrine function as well. There is little data available about the development of the motility function and of the mucosal barrier of the human gut, and in particular about the motility patterns and mucosal changes in newborns during early days of life. It is known that functional maturation of the gastrointestinal tract is quite different over time with respect to its anatomical development. Besides, the gastrointestinal tract through innate and specific immunologic factors, acts as a defense against ingested antigens. In addition to the mucous membrane integrity and digestion, numerous specific immunologic cells and mediators orchestrate such defensive mechanisms. In case of food antigens, the outcome is usually in favor of tolerance. Defects in that barrier, however, can lead to the development of aberrant immunologic responses, including hypersensitivity reactions. It is obvious that an appropriate feeding regimen during early infancy is in favor of food tolerance. However, in addition to genetic predisposition, development of tolerance is facilitated by an adequate gut barrier (immune or nonimmune), well-coordinated GI motility and nervous network, and appropriate food regimen.

Effect of ageing on colonic mucosal regeneration

The physiologic and pathologic cellular and molecular changes occurring with age in the human colon affect both the inflammatory process leading to mucosal injury and the regenerative capacity of the epithelium. On the one hand, age-related telomere shortening and inflamm-ageing may lead to the development of colonic inflammation, which results in epithelial damage. On the other hand, the altered migration and function of regenerative stem cells, the age-related methylation of mucosal healing-associated genes, together with the alterations of growth factor signaling with age, may be involved in delayed mucosal regeneration. The connections of these alterations to the process of ageing are not fully known. The understanding and custom-tailored modification of these mechanisms are of great clinical importance with regard to disease prevention and modern therapeutic strategies. Here, we aim to summarize the age-related microscopic and molecular changes of the human colon, as well as their role in altered mucosal healing.

Colonic hyperactivity results in frequent fecal soiling in a subset of children after surgery for Hirschsprung disease

BACKGROUND AND AIM

Fecal soiling is a challenging problem in some children after pull-through surgery for Hirschsprung disease (HSCR). The prevailing perception is that soiling results from overflow incontinence; however, its treatment with laxatives yields mixed results. Colonic manometry studies are reported to be normal in most patients in this population. The interpretation of these findings does not support the physiology of fecal overflow incontinence in these children. The aim of the present study was to define the physiology underlying daily, frequent fecal soiling in children after surgery for HSCR using manometric techniques.

PATIENTS AND METHODS

Four pediatric motility centers in the United States participated in the study; medical records and manometric tracings (anorectal and colonic) of children (n = 59; 6.5 years; 48 boys) who had pull-through surgery for HSCR and presented with daily, frequent fecal soiling were examined. Children referred for evaluation of constipation who had normal colonic manometry served as controls (n = 25; 6.7 years; 12 boys). The patients with HSCR were divided into 2 groups (Hirschsprung disease groups 1 and 2 [HD1, HD2]) based on the absence or presence of high-amplitude propagated contractions (HAPCs). A control group that included children with chronic constipation was also studied. We compared the mean HAPC frequency between the HD2 and control groups.

RESULTS

HD1 included 21 patients who had no HAPCs in fasting or postprandial periods. HD2 included 38 patients who had an average of 0.07 HPACs/min while fasting and 0.13/min in the postprandial state. In this subset the number of HAPCs in the fasting state (P = 0.04) and the postprandial state (P < 0.001) was greater when compared with controls. Additionally, there was a significant increase in HAPCs/min from the fasting to the postprandial state (P = 0.01). In the HD2 group 40% had colonic hyperactivity.

CONCLUSIONS

Daily, frequent fecal soiling after pull-through surgery for HSCR may be due to colonic hyperactivity in some children. It is imperative that this unique subset be identified because the management strategy would include avoidance of laxatives, contrary to standard current practice.

Colonic dysmotility in constipation

Constipation is a common and distressing condition with major morbidity, health care burden, and impact on quality of life. Colonic motor dysfunction remains the leading hypothesis to explain symptom generation in the most severe cases of chronic constipation and physiological testing plays a role in identifying the colonic dysmotility and the subsequent patient management. Measurement of colonic motor patterns and transit has enhanced our knowledge of normal and abnormal colonic motor physiology. The scope of this review encompasses the latest findings that improve our understanding of the motility disorders associated with colonic dysfunction in both the paediatric and adult population suffering from constipation.

Paediatric and adult colonic manometry: A tool to help unravel the pathophysiology of constipation

Colonic motility subserves large bowel functions, including absorption, storage, propulsion and defaecation. Colonic motor dysfunction remains the leading hypothesis to explain symptom generation in chronic constipation, a heterogeneous condition which is extremely prevalent in the general population, and has huge socioeconomic impact and individual suffering. Physiological testing plays a crucial role in patient management, as it is now accepted that symptom-based assessment, although important, is unsatisfactory as the sole means of directing therapy. Colonic manometry provides a direct method for studying motor activities of the large bowel, and this review provides a contemporary understanding of how this technique has enhanced our knowledge of normal colonic motor physiology, as well as helping to elucidate pathophysiological mechanisms underlying constipation. Methodological approaches, including available catheter types, placement technique and recording protocols, are covered, along with a detailed description of recorded colonic motor activities. This review also critically examines the role of colonic manometry in current clinical practice, and how manometric assessment may aid diagnosis, classification and guide therapeutic intervention in the constipated individual. Most importantly, this review considers both adult and paediatric patients. Limitations of the procedure and a look to the future are also addressed.

The nervous system and gastrointestinal function

The enteric nervous system is an integrative brain with collection of neurons in the gastrointestinal tract which is capable of functioning independently of the central nervous system (CNS). The enteric nervous system modulates motility, secretions, microcirculation, immune and inflammatory responses of the gastrointestinal tract. Dysphagia, feeding intolerance, gastroesophageal reflux, abdominal pain, and constipation are few of the medical problems frequently encountered in children with developmental disabilities. Alteration in bowel motility have been described in most of these disorders and can results from a primary defect in the enteric neurons or central modulation. The development and physiology of the enteric nervous system is discussed along with the basic mechanisms involved in controlling various functions of the gastrointestinal tract. The intestinal motility, neurogastric reflexes, and brain perception of visceral hyperalgesia are also discussed. This will help better understand the pathophysiology of these disorders in children with developmental disabilities.

American Neurogastroenterology and Motility Society consensus statement on intraluminal measurement of gastrointestinal and colonic motility in clinical practice

Tests of gastric, small intestinal and colonic motor function provide relevant physiological information and are useful for diagnosing and guiding the management of dysmotilities. Intraluminal pressure measurements may include concurrent measurements of transit or intraluminal pH. A consensus statement was developed and based on reports in the literature, experience of the authors, and discussions conducted under the auspices of the American Neurogastroenterology and Motility Society in 2008. The article reviews the indications, methods, performance characteristics, and clinical utility of intraluminal measurements of pressure activity and tone in the stomach, small bowel and colon in humans. Gastric and small bowel motor function can be measured by intraluminal manometry, which may identify patterns suggestive of myopathy, neuropathy, or obstruction. Manometry may be most helpful when it is normal. Combined wireless pressure and pH capsules provide information on the amplitude of contractions as they traverse the stomach and small intestine. In the colon, manometry assesses colonic phasic pressure activity while a barostat assesses tone, compliance, and phasic pressure activity. The utility of colonic pressure measurements by a single sensor in wireless pressure/pH capsules is not established. In children with intractable constipation, colonic phasic pressure measurements can identify patterns suggestive of neuropathy and predict success of antegrade enemas via cecostomy. In adults, these assessments may be used to document severe motor dysfunction (colonic inertia) prior to colectomy. Thus, intraluminal pressure measurements may contribute to the management of patients with disorders of gastrointestinal and colonic motility.

Erythromycin lacks colon prokinetic effect in children with functional gastrointestinal disorders: a retrospective study

Background

Motilin, a peptide hormone has a direct excitatory effect on circular smooth muscle strips derived from the human colon. Reduced plasma motilin concentration has been reported in adults with chronic constipation. Erythromycin, a non-peptide motilin receptor agonist, induces phase 3 of the migrating motor complex (MMC) in the antro-duodenum and also reduces oro-cecal transit time. A pediatric study has reported an improvement in clinical symptoms of constipation following erythromycin administration, but the effect on colon motility in children has not been formally evaluated. We used colon manometry to study the effect of intravenous erythromycin lactobionate at 1 mg/kg on colon motiltiy in ten children.

Methods

We selected patients with normal antroduodenal and colon manometry studies that were performed simultaneously. All studies were performed for clinically indicated reasons. We quantified the effect of erythromycin on colon contraction by calculating the area under the curve (AUC).

Results

The mean (SE of mean) AUC in the colon during the fasting, post-erythromycin and postprandial phases of the study was 2.1 mmHg/sec (0.35), 0.99 mmHg/sec (0.17) and 3.05 mmHg/sec (0.70) respectively. The AUC following erythromycin was significantly less compared to the fasting phase of the study (p < 0.01).

Conclusion

Erythromycin lacks colon prokinetic effect in children with chronic constipation evaluated by colon manometry.

24-Hour colonic manometry in pediatric slow transit constipation shows significant reductions in antegrade propagation

BACKGROUND

The physiological basis of slow transit constipation (STC) in children remains poorly understood. We wished to examine pan-colonic motility in a group of children with severe chronic constipation refractory to conservative therapy.

METHODS

We performed 24 h pan-colonic manometry in 18 children (13 boys, 11.6 +/- 0.9 yr, range 6.6-18.7 yr) with scintigraphically proven STC. A water-perfused, balloon tipped, 8-channel, silicone catheter with a 7.5 cm intersidehole distance was introduced through a previously formed appendicostomy. Comparison data were obtained from nasocolonic motility studies in 16 healthy young adult controls and per-appendicostomy motility studies in eight constipated children with anorectal retention and/or normal transit on scintigraphy (non-STC).

RESULTS

Antegrade propagating sequences (PS) were significantly less frequent (P < 0.01) in subjects with STC (29 +/- 4 per 24 h) compared to adult (53 +/- 4 per 24 h) and non-STC (70 +/- 14 per 24 h) subjects. High amplitude propagating sequences (HAPS) were of a normal frequency in STC subjects. Retrograde propagating sequences were significantly more frequent (P < 0.05) in non-STC subjects compared to STC and adult subjects. High amplitude retrograde propagating sequences were only identified in the STC and non-STC pediatric groups. The normal increase in motility index associated with waking and ingestion of a meal was absent in STC subjects.

CONCLUSIONS

Prolonged pancolonic manometry in children with STC showed significant impairment in antegrade propagating motor activity and failure to respond to normal physiological stimuli. Despite this, HAPS occurred with normal frequency. These findings suggest significant clinical differences between STC in children and adults.

Assessment of Age-Related Changes in Abdominal Organ Structure and Function With Computed Tomography and Positron Emission Tomography

With the size of the aged population in the United States expected to grow considerably during the next several decades, the number of imaging studies performed on such aged individuals will similarly increase. Thus, it is important to understand normal age-related changes in the structural and functional imaging appearance of the abdominal organs. We therefore present preliminary data and a review of the literature relevant to structural and functional changes in the abdominal organs of children and older adults. In a retrospective study of both adult and pediatric populations, we used computed tomography (CT), positron emission tomography (PET), and PET/CT imaging to investigate age-associated changes in size, attenuation, and metabolic function of the abdominal organs. Organs of interest include the liver, spleen, pancreas, kidneys, adrenal glands, stomach, small bowel, colon, and rectum. Although volumes of adult liver, spleen, pancreas, and kidneys do not change significantly with age, adult left and right adrenal gland volumes do significantly increase with age (r = 0.2823, P = 0.0334, and r = 0.3676, P = 0.0049, respectively). Also, the attenuation of adult liver (r = -0.2122, P = 0.0412), spleen (r = -0.4508, P < 0.0001), pancreas (r = -0.5124, P = 0.0007), and left and right adrenal gland (r = -0.5835, P < 0.0001 and r = -0.6135, P < 0.0001, respectively) decrease significantly with increasing age. Every organ studied in the pediatric population demonstrates a positive association between organ volume and age. Significant age-related changes in organ function are noted in the adult liver and small bowel, with the liver demonstrating a positive association between metabolic activity and age (r = 0.4434, P = 0.0029) and the small bowel showing an inverse association between mean small bowel standardize uptake value and age (r = -0.2435, P = 0.0174). Also, the maximum overall small bowel and colon metabolic activity in children increases with age (r = 0.6478, P = 0.0008). None of the other organs studied (ie, spleen, pancreas, adrenal glands, stomach, colon, rectum) demonstrate significant changes in metabolism with advancing age. The metabolic volumetric product (calculated as the product of organ volume and mean organ SUV) of the liver and spleen does not change significantly with age. In conclusion, various abdominal organs demonstrate differential changes in volume, attenuation, and/or metabolism with increasing age in pediatric and adult populations.

Considerations in the rational design and conduct of phase I/II pediatric clinical trials: avoiding the problems and pitfalls

Over the past decade, there has been a heightened awareness of the need to include children in the drug development process. With this awareness has come an expansion of the infrastructure for conducting studies in children and an increase in the sponsorship of pediatric clinical trials. However, the growth in pediatric research has, in many cases, not been accompanied by an increase in the involvement of trained pediatric investigators when it comes to trial design and/or interpretation. Pediatric phase I/II protocols continue to span a spectrum from those that are carefully constructed to those that are poorly designed. This paper highlights the basic elements of phase I/II protocols that merit unique consideration when the clinical trial involves children. Illustrations are provided from our experience, which highlight problems that may arise when trials are not designed with the pediatric patient in mind.

Colon motility during a panic attack

OBJECTIVE

To document the temporal relationship between a panic attack and high amplitude propagating contractions.

METHODS

Colon manometry was used to discriminate between functional defecation problems and colon neuromuscular disease. By chance, the patent developed a panic attack during the test session.

RESULTS

Coincident with the panic attack, there was a continuous series of high amplitude propagating contractions. There were 15 high amplitude propagating contractions over 45 minutes, initially at a rate of 4 per 10 minutes, gradually slowing to 1.5 per 10 minutes.

CONCLUSIONS

These data may explain the cause for gastrointestinal distress and diarrhea in some patients with panic attacks.

Assessment of small intestinal bacterial overgrowth in uncomplicated acute diverticulitis of the colon

AIM: Small intestinal bacterial overgrowth (SIBO) may contribute to the appearance of several gastrointestinal nonspecific symptoms. Acute diverticulitis is affected by some similar symptoms and bacterial colonic overgrowth. We assessed the prevalence of SIBO in acute uncomplicated diverticulitis and evaluated its influence on the clinical course of the disease.

METHODS: We studied 90 consecutive patients (39 males, 51 females, mean age 67.2 years, range 32-91 years). Sixty-one patients (67.78%) and 29 patients (32.22%) were affected by constipation-or diarrhea-prevalent diverticulitis respectively. All subjects were investigated by lactulose H₂-breath test at the entry and at the end of treatment. We also studied a control group of 20 healthy subjects (13 males, 7 females, mean age 53 years, range 22-71 years).

RESULTS: Oro-cecal transit time (OCTT) was delayed in 67/90 patients (74.44%) (range 115-210 min, mean 120 min). Fifty-three of ninety patients (58.88%) showed SIBO, while OCTT was normal in 23/90 patients (25, 56%). In the control group, the mean OCTT was 88.2 min (range 75-135 min). The difference between diverticulitic patients and healthy subjects was statistically significant (P<0.01). OCTT was longer in constipation-prevalent disease than in diarrhea-prevalent disease [180.7 min (range 150-210 min) vs 121 min (range 75-180 min) (P<0.001)], but no difference in bacterial overgrowth was found between the two forms of diverticulitis.After treatment with rifaximin plus mesalazine for 10 d, followed by mesalazine alone for 8 wk, 70 patients (81.49%) were completely asymptomatic, while 16 patients (18.60%) showed only slight symptoms. Two patients (2.22%) had recurrence of diverticulitis, and two other patients (2.22%) were withdrawn from the study due to side-effects. Seventy-nine of eighty-six patients (91.86%) showed normal OCTT (range 75-105 min, mean 83 min), while OCTT was longer, but it was shorter in the remaining seven (8.14%) patients (range 105-115 min, mean of 110 min). SIBO was eradicated in all patients, while it persisted in one patient with recurrence of diverticulitis.

CONCLUSION: SIBO affects most of the patients with acute diverticulitis. SIBO may worsen the symptoms of patients and prolong the clinical course of the disease, as confirmed in the case of persistence of SIBO and diverticulitis recurrence. In this case, we can hypothesize that bacteria from small bowel may re-colonize in the colon and provoke recurrence of symptoms.

Chronic constipation in children: organic disorders are a major cause

Diagnostic tools for paediatric chronic constipation have been limited, leading to over 90% of patients with treatment-resistant constipation being diagnosed with chronic idiopathic constipation, with no discernible organic cause. Work in our institution suggests that a number of children with intractable symptoms actually have slow colonic transit leading to slow transit constipation. This paper reviews recent data suggesting that a significant number of the children with chronic treatment-resistant constipation may have organic causes (slow colonic transit and outlet obstruction) and suggests new approaches to the management of children with chronic treatment-resistant constipation.

A pilot study using total colonic manometry in the surgical evaluation of pediatric functional colonic obstruction

BACKGROUND/PURPOSE

Total colonic manometry (TCM) can directly measure intraluminal pressures and contractile function of the entire colon. The utility of TCM to guide the surgical management of functional colonic obstruction has not been reported.

METHODS

Total colonic manometry was performed on all patients referred for surgical evaluation of refractory functional colonic obstruction. Manometric tracings were obtained while fasting, after feeding, and after pharmacologic stimulation.

RESULTS

Nine patients were referred for refractory colonic obstruction. The mean age was 4.8 years, and the mean duration of follow-up was 29 months. Two patients had functional obstruction after repair of Hirschsprung's disease, and 7 patients had idiopathic functional obstruction. In the idiopathic group, 4 distinct motility patterns were identified: (1) normal colonic motility, (2) dysmotility with massive distension, (3) persistent segmental dysmotility, and (4) global neuropathy/myopathy. Both Hirschsprung's patients showed globally abnormal motility. Surgical management was guided by TCM results. There was significant improvement in bowel function and weight gain after manometry-guided intervention. An unnecessary laparotomy was avoided in 2 patients.

CONCLUSIONS

TCM can be valuable in deciding the need for and timing of diversion, the extent of resection required, and the suitability of the patient for restoring bowel continuity in refractory functional obstruction.

Pathophysiological aspects of diverticular disease of colon and role of large bowel motility

Colonic diverticular disease (diverticulosis) is one of the most common gastrointestinal disorders in Western countries. This disorder is strictly related to aging and fibre intake, and still bears a discrete amount of morbidity. Numerous etiological co-factors have to date been implicated in the pathogenesis of the disease, yet the supporting evidence is still far from absolute. The present review considers the pathophysiology of colonic diverticular disease, with a special emphasis on factors related to abnormal colonic motility.

Colonic manometry in children with defecatory disorders. role in diagnosis and management

OBJECTIVE

The aim of this study was to evaluate the role of colonic manometry in clarifying pathophysiology of childhood defecatory disorders and to evaluate its impact on management.

METHODS

We conducted a retrospective review of medical records of children referred to undergo colonic manometry to a tertiary care Motility Center from 1996 to 2001. Families were followed up a median of 20 months after evaluation (range 3-60 months).

RESULTS

A total of 150 colonic manometries were performed in 146 children (74 male, median age 79 months, range 4-225 months). Colonic manometry had been requested to clarify the pathophysiology of lower GI symptoms in 68%; as part of diagnostic workup for chronic intestinal pseudo-obstruction in 11%; to decide about reanastomosis of a diverted colon in 7%; and to clarify the pathophysiology of persisting symptoms after surgery for Hirschsprung's disease in 14%. Normal motility was found in the entire colon in 38% of children. In 17%, there was normal motility in the proximal colon with abnormality limited to the dilated distal colon. Abnormal motility was found in 45% of children. After colonic manometry, treatment changes were recommended in 93% of patients. We were able to follow up 65% of the families. When recommendations were followed (96% of the contacted patients), the symptoms improved in 78%, were unchanged in 18%, and were worse in 4% of patients. Among the parents, 88% believed that the suggestions given after colonic manometry had been helpful in improving their children's health.

CONCLUSIONS

Colonic manometry may provide information useful in guiding therapy in a subgroup of patients with defecatory disorders.

Ileal manometry in children following ileostomies and pull-through operations

Our aim was to analyse the patterns of ileal contractions in children. We reviewed the charts of 23 children who had ileal manometry studies (16 males), mean age 7 years (range 2 months to 17 years). We positioned the manometry catheters with 4-8 recording sites, 5 or 15 cm apart, through ileostomies fashioned for clinically indicated reasons. We studied six additional children with persistent faecal soiling following endorectal pull through for Hirschsprung's disease; the catheters were positioned through the anus and colon into the ileum. We recorded phasic and tonic intermittent contractions in all the subjects, clustered contractions (rate 5-9 min-1, duration 20-120 s) in 19 subjects with ileostomies and four with endorectal pull throughs. In 13 children there were prolonged propagated contractions, > 60 mmHg in amplitude, > 15 s in duration, propagating at rates of 2-6 cm s-1 over at least 20 cm. The migrating motor complex was rare; in 55 h of fasting recording there were two phase III sequences. There are four distinctive features of ileal manometry recordings in children: random intermittent contractions, clustered contractions, prolonged propagated contractions and tonic contractions. The features of ileal motility differ from motility in the proximal small bowel.

The physiology of continence: idiopathic fecal constipation and soiling

The anatomic and functional elements contributing to fecal continence and defecation are explored. The high incidence and importance of chronic idiopathic constipation as an entity in itself and a contributing factor to fecal incontinence are emphasized, and its management is discussed. The importance of a proper clinical history and examination is highlighted, and investigative modalities including radiology, transit studies, and anorectal manometry are described and placed in the context of practical clinical management.

Motility disorders. Diagnosis and treatment for the pediatric patient

Motility disorders are common in children and may affect any area of the GI tract. The past decade has brought significant advances in the understanding of motility disorders in pediatrics. More sophisticated testing techniques have helped to differentiate normal from abnormal motility in children of different ages. Manometry now may be used to clarify the pathophysiologic defect underlying chest pain, dysphagia, rumination, gastroparesis, chronic intestinal pseudo-obstruction, and colonic neuromuscular disorders. Motility testing also may be used to identify the motor defect responsible for persistence of symptoms after surgery for GER or HD. New investigational techniques and prokinetic agents likely to be available in the future also were discussed.

Total colonic manometry as a guide for surgical management of functional colonic obstruction: Preliminary results

BACKGROUND/PURPOSE

Functional colonic obstruction (pseudo-obstruction) encompasses a broad group of motility disorders. Medical management of colonic pseudo-obstruction is complex and often fails, leading to surgical referral. In most cases (excepting Hirschsprung's disease) the surgeon is unable to precisely localize the area of functional obstruction. Total colonic manometry can directly measure intraluminal pressures and contractile function along the entire length of the colon. The authors propose that total colonic manometry can be used by the pediatric surgeon to guide the timing and extent of surgical therapy in refractory functional colonic obstruction.

METHODS

Four patients were evaluated for functional colonic obstruction. All underwent barium enema and rectal biopsy with a diagnosis of Hirschsprung's disease in one patient. All patients underwent colonoscopy and total colonic manometry. Manometric tracings were obtained while fasting, after feeding, and after pharmacologic stimulation both preoperatively (n = 4) and postoperatively (n = 3).

RESULTS

Total colonic manometry identified an abrupt end of normal peristalsis in 2 of the non-Hirschsprung's patients (one in the proximal colon and one in the transverse colon). Medical therapy failed in both of these patients, and they underwent diverting ostomy proximal to the loss of normal peristalsis. The third non-Hirschsprung's patient essentially had normal manometry and was able to have her colon decompressed successfully on a laxative regimen. Repeat manometry after colonic decompression showed return of normal peristalsis in 2 of these patients and continued abnormal peristaltic activity in the third. Definitive surgical intervention based on the results of total colonic manometry was performed on the latter. All 3 patients achieved normal continence. A fourth patient had Hirschsprung's disease confirmed by rectal biopsy and underwent a 1-stage neonatal modified Duhamel procedure, which was complicated by postoperative functional obstruction. Manometry showed a lack of peristaltic function beginning in the right colon. An ileostomy was performed, and timing of ileostomy closure was guided by the return of normal colonic peristalsis seen on manometry.

CONCLUSIONS

These initial cases show the utility of total colonic manometry in the management of colonic pseudo-obstruction syndromes. In addition to its diagnostic utility, direct measurement of colonic motor activity can be valuable in deciding the need for and timing of diversion, the extent of resection, and the suitability of the patient for restoring bowel continuity. In Hirschsprung's disease, total colonic manometry can potentially be used to determine suitability for primary neonatal pull-through versus a staged approach. J Pediatr Surg 36:1757-1763.

Pediatric anorectal disorders

Anorectal disorders are common in children. It has been estimated that 10% of children are brought to medical attention because of a defecation disorder, and constipation is the chief complaint in 3% to 5% of all visits to pediatricians. Most of these children suffer from functional constipation. There are substantial differences in the approach to children and adults with anorectal disorders. This article discusses the commonest pediatric anorectal disorders, emphasizing the differences between children and adults in terms of clinical presentations, pathophysiology, diagnosis, and treatment.

Alterations in rectal sensitivity and motility in childhood irritable bowel syndrome

BACKGROUND & AIMS

Children with chronic abdominal pain have a heterogeneous clinical presentation, but no organic cause can be identified in most of them. Some children present with symptoms of irritable bowel syndrome (IBS). We hypothesized that visceral hypersensitivity and motor abnormalities may be underlying mechanisms in these children.

METHODS

Rectal sensation and rectal contractile response to a meal were studied in 8 children with IBS and 8 children with functional abdominal pain (FAP) and were compared with those of 9 healthy volunteers (HVs).

RESULTS

The threshold for pain, but not that for first sensation and urge to defecate, was significantly decreased in IBS patients (6 +/- 1 mm Hg) compared with FAP patients and HVs (17 +/- 1 and 22 +/- 2 mm Hg, respectively). In HVs and patients with FAP, ingestion of a meal induced a decrease in rectal volume with an early and late component. This motor pattern was absent in children with IBS. In IBS patients, no rapid volume waves were observed during fasting in contrast to FAP patients (2.7 +/- 0.3/10 min) and HVs (1.8 +/- 0.5/10 min).

CONCLUSIONS

Children fulfilling the Rome II criteria for IBS have a significantly lowered threshold for pain and a disturbed contractile response to a meal. Comparable to results reported in adults, sensory and motor abnormalities might play a pathophysiologic role in childhood IBS.

Colonic motility after surgery for Hirschsprung's disease

OBJECTIVE

Years after surgery for Hirschsprung's disease, many children continue to suffer from fecal incontinence or constipation. The purpose of the present investigation was to define the physiology underlying the persistent symptoms in children after surgery for Hirschsprung's disease, and to determine the outcome of interventions based on the results of the motility testing.

METHODS

We studied 46 symptomatic patients (5.5+/-3.3 yr old, 35 male) >10 months after surgery for Hirschsprung's disease. We performed a colonic manometry with a catheter placed with the tip in the proximal colon. We used a structured questionnaire and phone interview to follow up the patients an average of 34 months after the manometry.

RESULTS

We identified four motility patterns: 1) high-amplitude propagating contractions (HAPCs) migrating through the neorectum to the anal sphincter, associated with fecal soiling (n = 18); 2) normal colonic manometry associated with fear of defecation and retentive posturing (n = 9); 3) absence of HAPCs or persistent simultaneous contractions over two or more recording sites (n = 15), associated with constipation (n = 13); and 4) normal colonic motility and a hypertensive internal anal sphincter (>80 mm Hg) (n = 4). We based treatment on results of the motility studies. There was improvement in global health (mean score, 3.9+/-1.1 vs 2.8+/-1.3 at the time of initial evaluation, p < 0.001) and emotional health (3.8+/-1.1 vs 2.6+/-1.1, p < 0.0001). Improvement in the number of bowel movements occurred in 72% of children. Resolution or decreased abdominal pain was reported in 80%.

CONCLUSIONS

Colonic manometry clarifies the pathophysiology and directs treatment in symptomatic children after surgery for Hirschsprung's disease.

Colonic motility in man: features in normal subjects and in patients with chronic idiopathic constipation

The human colon is still a relatively unknown viscus, especially concerning its motor activity. However, in recent years, techniques have been perfected that allow a better understanding of colonic motility, especially through prolonged recording periods. In this way, it has been demonstrated that the viscus contracts according to a circadian trend, is responsive to physiological stimuli (meals, sleep), and features high amplitude, propulsive contractions that are part of the complex dynamic of the defecatory process. These physiological properties and their alterations in patients with chronic idiopathic constipation are reviewed in this article.

Bisacodyl and high-amplitude-propagating colonic contractions in children

BACKGROUND

The purpose of these studies was to determine the suitability of bisacodyl for stimulating high-amplitude-propagating contractions in pediatric studies of colonic manometry.

METHODS

Water-perfused manometry catheters were inserted into the right colon of children referred for evaluations related to defecation disorders. Colonic motility was measured in a 3-hour test session: an hour fasting, an hour after a meal, and 30 minutes after administration of a provocative agent.

RESULTS

Bisacodyl was superior to edrophonium as a stimulant for inducing high-amplitude-propagating contractions. Bisacodyl-induced high-amplitude-propagating contractions were similar in amplitude, duration, propagation velocity, and sites of origin and extinction to naturally occurring high-amplitude-propagating contractions. The effect of intrarectal bisacodyl was similar to that of intracecal bisacodyl, except for a delay of 10 minutes in onset. Bisacodyl induced high-amplitude-propagating contractions in all 28 children (22 with spontaneous high-amplitude-propagating contractions) without evidence of neuromuscular disease and in 2 of 9 children with a colonic neuromuscular disorder and no spontaneous high-amplitude-propagating contractions.

CONCLUSIONS

Bisacodyl-induced high-amplitude-propagating contractions were quantitatively and qualitatively similar to naturally occurring high-amplitude-propagating contractions. In selected cases, such as in children receiving total parenteral nutrition or restricted fluid intake, it may be possible to shorten diagnostic colonic manometry using bisacodyl rather than waiting for spontaneous high-amplitude-propagating contractions.

Gastrointestinal motility in neonatal and pediatric practice

Caring for children with gastrointestinal motility disorders requires an understanding of age-related changes in gastrointestinal function and in the clinical expression of disease. Successful evaluation of the child with a gastrointestinal motility disorder necessitates an approach that takes into account not only the child's symptoms, but also the stage of development. This article reviews the ontogeny of gastrointestinal motility; the techniques available for the study of gastrointestinal motility in children; and the presentation, pathophysiology, and treatment of pediatric functional bowel diseases. Differences in children compared to adults in performing and analyzing motility testing and in evaluating motility disorders are emphasized. A more complete understanding of pediatric motility disorders may provide important insights in approaching functional bowel diseases in adults.