NASPGN guidelines for training in pediatric gastroenterology. NASPGN Executive Council, NASPGN Training and Education Committee

Compound Heterozygous MYO5B Mutation, a Cause of Infantile Cholestasis: A Case Report

Infantile cholestasis is a common clinical problem in early infancy characterised by impairment in bile formation and/or flow. It requires prompt evaluation for underlying aetiology to initiate appropriate management. Although biliary atresia remains the most important aetiology, metabolic and monogenic disorders are increasingly identified with advances in diagnostic genetic testing. Progressive familial intrahepatic cholestasis disorders characterised by defects in biliary canalicular transport are among the most common monogenic disorders of cholestasis. Homozygous or compound heterozygous mutation in the Myosin 5B gene leading to a progressive familial intrahepatic cholestasis-like phenotype with or without intestinal features of microvillus inclusion disease is a relatively recently identified disorder. The incidence of these newer variants of progressive familial intrahepatic cholestasis is not yet known due to the paucity of studies. We report an uncommon cause of refractory cholestasis reported in a girl who presented with severe pruritus as the primary manifestation.

Training in Paediatric Clinical Nutrition Across Europe: A Survey of the National Societies Network (2016-2019) of the European Society for Paediatric Gastroenterology, Hepatology and Nutrition

OBJECTIVES/BACKGROUND

Disease-related malnutrition is common in patients with chronic diseases and has detrimental effects, therefore, skills in nutrition care are essential core competencies for paediatric digestive medicine. The aim of this survey, conducted as part of a global survey of paediatric gastroenterology, hepatology and nutrition (PGHN) training in Europe, was to assess nutrition care-related infrastructure, staff, and patient volumes in European PGHN training centres.

METHODS

Standardized questionnaires related to clinical nutrition (CN) care were completed by representatives of European PGHN training centres between June 2016 and December 2019.

RESULTS

One hundred training centres from 17 European countries, Turkey, and Israel participated in the survey. Dedicated CN clinics exist in 66% of the centres, with fulltime and part-time CN specialists in 66% and 42%, respectively. Home tube feeding (HTF) andhome parenteral nutrition (HPN) programmes are in place in 95% and 77% of centres, respectively. Twenty-four percent of centres do not have a dedicated dietitian and 55% do not have a dedicated pharmacist attached to the training centre. Even the largest centres with >5000 outpatients reported that 25% and 50%, respectively do not have a dedicated dietitian or pharmacist. Low patient numbers on HTF and HPN of <5 annually are reported by 13% and 43% of centres, respectively.

CONCLUSIONS

The survey shows clear differences and deficits in Clinical Nutrition training infrastructure, including staff and patient volumes, in European PGHN training centres, leading to large differences and limitations in training opportunities in Clinical Nutrition.

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.

Development and Pilot Implementation of a Nutrition Curriculum and Rotation in Pediatric Gastroenterology Fellowships

Structured nutrition rotations are rarely offered in pediatric gastroenterology fellowships. The North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition (NASPGHAN) Nutrition Committee developed a curriculum to serve as the basis for a rotation in clinical nutrition. We worked directly with 5 fellowship programs to tailor the experience to individual institutions. As part of our pilot study, fellows completed knowledge assessments and self-assessment of comfort level at the start and end of the experience. We saw a trend in improvement of comfort level and increase in mean score on knowledge assessments, but the differences did not meet statistical significance. Fellows who completed the rotation had an increase in comfort level in all topics with most dramatic increases in nutrition management of cystic fibrosis, refeeding syndrome, and cholestasis. Objective measures of nutrition knowledge attainment and use of programmatic feedback to continually improve the learners' experience will help expand the nutrition curriculum to a broader audience.

Pediatric Endoscopic Procedure Complications

PURPOSE OF REVIEW

This review summarizes the current body of research, define high-risk patients and endoscopic processes, and outline evidence-based countermeasures aimed at minimizing the incidence of complications during endoscopy in children.

RECENT FINDINGS

Significant complications of endoscopy requiring emergency department or inpatient admission in otherwise healthy children are unusual, but more common with therapeutic procedures; risk from procedures increases incrementally with preoperative coexisting conditions. Duodenal hematoma is predominantly a pediatric endoscopic complication and is more likely in hematology-oncology patients. Air embolism is a well-defined endoscopic retrograde cholangiopancreatography (ERCP) complication in adults and is likely to increase in children with increased performance of pediatric ERCP. Increased physician expertise is the most often proposed countermeasure, especially in the context of endoscopy complications in the higher-risk patient and procedure. Endoscopy in children remains a very safe group of procedures, although a more detailed understanding of risk factors and ideal training and practice organization is lacking.

Therapeutic Endoscopy for the Control of Nonvariceal Upper Gastrointestinal Bleeding in Children: A Case Series

OBJECTIVES

Gastrointestinal bleeding is one of the most common indications for urgent endoscopy in the pediatric setting. The majority of these procedures are performed for control of variceal bleeding, with few performed for nonvariceal upper gastrointestinal (NVUGI) bleeding. The data on therapeutic endoscopy for NVUGI are sparse. The aims of our study were to review our experience with NVUGI bleeding, describe technical aspects and outcomes of therapeutic endoscopy, and determine gastroenterology fellows' training opportunities according to the national training guidelines.

METHODS

We performed a retrospective review of endoscopy database (Endoworks, Olympus Inc, Center Valley, PA) from January 2009 to December 2014. The search used the following keywords: bleeding, hematemesis, melena, injection, epinephrine, cautery, clip, and argon plasma coagulation. The collected data included demographics, description of bleeding lesion and medical/endoscopic therapy, rate of rebleeding, relevant laboratories, physical examination, and need for transfusion and surgery. The study was approved by the institutional review board.

RESULTS

During the study period 12,737 upper endoscopies (esophagogastroduodenoscopies) were performed. A total of 15 patients underwent 17 esophagogastroduodenoscopies that required therapeutic intervention to control bleeding (1:750 procedures). The mean ± standard deviation (median) age of patients who required endoscopic intervention was 11.6 ± 6.0 years (14.0 years). Seven out of 17 patients received dual therapy to control the bleeding lesions. All but 3 patients received medical therapy with intravenous proton pump inhibitor, and 3 received octreotide infusions. Six of the patients experienced rebleeding (40%), with 4 out of 6 initially only receiving single modality therapy. Two of these patients eventually required surgical intervention to control bleeding and both patients presented with bleeding duodenal ulcers. There were no cases of aspiration, perforation, or deaths. There were a total of 24 fellows trained in our program during the study period. Less than 1 therapeutic endoscopy per fellow for NVUGI bleeding was performed.

CONCLUSIONS

NVUGI bleeding requiring therapeutic endoscopic intervention is rare in pediatrics. A high rate (40%) of rebleeding was noted with a large proportion (66%) of patients receiving single modality therapy. Two patients required surgical intervention to control bleeding and both presented with bleeding duodenal ulcers. An insufficient number of therapeutic procedures is available for adequate fellow training requiring supplemental simulator and hands-on animal model, or adult endoscopy unit training.

Sequential incremental doses of bisacodyl increase the diagnostic accuracy of colonic manometry

BACKGROUND

Colonic manometry is the standard diagnostic modality for evaluating colonic motility in children. Intraluminal bisacodyl is routinely used to trigger high-amplitude propagating contractions (HAPCs), a feature of normal colonic motility. Usually, only a single dose (0.2 mg/kg) is suggested. We retrospectively explored whether the use of an additional higher (0.4 mg/kg) dose of bisacodyl increases the yield of colonic manometry.

METHODS

In 103 children (median age: 8.8 years, range 3.2-15.7 years) with a diagnosis of slow transit constipation, colonic motility was recorded for 1 h before and 1 h after each of two incremental doses of bisacodyl (low, L, dose: 0.2 mg/kg, max 10 mg; high, H, dose: 0.4 mg/kg, max 20 mg) and the characteristics of HAPCs analyzed.

KEY RESULTS

High-amplitude propagating contractions were seen in 85 children. H dose significantly increased the proportion of patients with fully propagated HAPCs (H dose: 57/103 [55%], L dose: 27/103 [26%], p < 0.001), paralleling the significant decrease in the proportion with partially propagated HAPCs (H dose: 29/103 [28%], L dose: 47/103 [46%], p < 0.01). Mean HAPC number significantly increased throughout the colon at H compared to L dose (7.2 ± 5.05 vs 5.6 ± 5.1, p < 0.05). Finally, the proportion of patients with normal pressure wave morphology of HAPCs significantly increased with higher dose (H dose: 55/85 [65%], L dose: 27/85 [32%], p < 0.001).

CONCLUSIONS & INTERFERENCES

An additional higher dose of bisacodyl during colonic manometry improves colonic neuromuscular function suggesting its use might improve interpretation and decision making in children with slow transit constipation.

Liver biopsy in children: position paper of the ESPGHAN Hepatology Committee

Liver biopsy (LB) is still the criterion standard procedure for obtaining liver tissue for histopathological examination and a valuable tool in the diagnosis, prognosis, and management of many parenchymal liver diseases. The aim of this position paper is to summarise the present practice of paediatric LB and make recommendations about its performance. Although histological evaluation of the liver is important in assessing prognosis and exploring treatment, noninvasive techniques (ie, imaging, laboratory markers) may replace use of liver histology. The indications for LB are changing as present knowledge of aetiologies, pathomechanism, and therapeutic options in paediatric liver disease is evolving. Adult and paediatric literature was reviewed to assess the existing clinical practice of LB with focus on the technique, indications, risk of complications, and contraindications in paediatrics. This position paper presents types of LB, indications, complications, contraindications, and an essential checklist for paediatric LB.

NASPGHAN Nutrition University as a model for continuing education within pediatric nutrition

The North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition Nutrition Committee developed the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition Nutrition University (N2U) as an education resource designed to address the nutrition topics identified by pediatric gastroenterologists. N2U was initially designed as a series of lectures. Participants completed a precourse, immediate postcourse, and 6-month postcourse assessment. The average pretest score was 74%. Participants reported learning "a great deal" and immediate postcourse test score average was 90%. Feedback from N2U participants will shape future course design, focusing on the interactive learning sessions. N2U may serve as a model for offering topic-directed continuing medical education based on targeted physician responses and feedback.

Challenges in meeting fellowship procedural guidelines in pediatric therapeutic endoscopy and liver biopsy

OBJECTIVE

The aims of this study were to assess the opportunities for therapeutic endoscopy, liver biopsies, and percutaneous endoscopic gastrostomy (PEG) placements available to fellows during a 3-year pediatric gastroenterology fellowship, and to evaluate access to ancillary procedural-training opportunities.

METHODS

Data were collected from 12 pediatric gastroenterology fellowship programs in the United States. Procedures completed in the years 2009-2011 were queried using CPT codes and endoscopy databases. The maximal opportunity for procedures was based on the total procedures performed by the institution in 3 years divided by the total number of fellows in the program. The centers completed a questionnaire regarding ancillary opportunities for endoscopic training.

RESULTS

There is significant variability in pediatric endoscopic training opportunities in specialized gastrointestinal (GI) procedures. Under the 1999 guidelines, no centers were able to meet the thresholds for polypectomy and control of nonvariceal bleeding. The 2013 guidelines allowed the number of programs reaching polypectomy thresholds to increase by 67% but made no difference for control of bleeding despite a decrease in the threshold. Training in PEG placement was not available in 42% of the surveyed centers. Elective ancillary procedural training is offered by 92% of the surveyed centers.

CONCLUSIONS

Most training programs do not have the volume of therapeutic endoscopy procedures for all of the fellows to meet the training guidelines. Training in therapeutic endoscopy, PEG placement, and liver biopsy in pediatric GI fellowships should be supplemented using all of the possible options including rotations with adult GI providers and hands-on endoscopy courses. A shift toward evaluating competency via quality measures may be more appropriate.

Effect of operator experience and frequency of procedure performance on complication rate after ultrasound-guided percutaneous liver biopsies

OBJECTIVE

The aim of the present study was to assess whether the complication rate after ultrasound-guided percutaneous liver biopsies in children is affected by how frequently the procedure is performed by the operator.

METHODS

Medical charts and ultrasound descriptions of 311 ultrasound-guided percutaneous liver biopsy procedures performed by 18 radiologists at a single center from 2000 to 2011 were reviewed. Postbiopsy ultrasound the following day was performed after 97% of the procedures.

RESULTS

There were no differences in the procedure-associated rate of major bleeding incidents (2.2% vs 0.8%, P = 0.38), minor bleeding incidents (15.2% vs 10.2%, P = 0.31), or abdominal pain (13.0% vs 10.6%, P = 0.61) among operators who performed ≤10 procedures and those who performed >10 procedures during the study period. A higher rate of minor bleeding incidents were recorded after liver biopsy when operators had performed <10 biopsies compared with operators who had performed >20 pediatric liver biopsies during the study period (odds ratio 3.4 [1.3-9.1], P = 0.02). No association between the number of biopsies performed by the operator during the 2 years preceding the date of the biopsy and complications was found.

CONCLUSIONS

Major complications are infrequent after pediatric liver biopsies and no relation between operator experience and major complications was found. We found a significant, but minor, effect of operator procedure frequency on the rate of minor bleeding incidents after ultrasound-guided pediatric liver biopsies.

An update on pediatric endoscopy

Advances in endoscopy and anesthesia have enabled gastrointestinal endoscopy for children since 1960. Over the past decades, the number of endoscopies has increased rapidly. As specialized teams of pediatric gastroenterologists, pediatric intensive care physicians and pediatric endoscopy nurses are available in many medical centers, safe and effective procedures have been established. Therefore, diagnostic endoscopies in children are routine clinical procedures. The most frequently performed endoscopies are esophagogastroduodenoscopy (EGD), colonoscopy and endoscopic retrograde cholangiopancreaticography (ERCP). Therapeutic interventions include variceal bleeding ligation, foreign body retrieval and percutaneous endoscopic gastrostomy. New advances in pediatric endoscopy have led to more sensitive diagnostics of common pediatric gastrointestinal disorders, such as Crohn's disease, ulcerative colitis and celiac disease; likewise, new diseases, such as eosinophilic esophagitis, have been brought to light.Upcoming modalities, such as capsule endoscopy, double balloon enteroscopy and narrow band imaging, are being established and may contribute to diagnostics in pediatric gastroenterology in the future.

Qualitätssicherung in der Endoskopie

Die gastrointestinale Endoskopie (im Folgenden nur noch als Endoskopie bezeichnet) unterliegt als invasives Verfahren in besonderem Maße einer Qualitätssicherung. Ziel ist, die Qualität der Endoskopie zu gewährleisten, kontinuierlich zu verbessern und unnötige Belastungen und Risiken für die Patienten sowie Komplikationen zu vermeiden bzw. zu minimieren. Gesetzliche Vorgaben sind hierfür nur teilweise vorhanden und betreffen vorwiegend die Hygiene in der Endoskopie, auf die hier nicht näher eingegangen wird (s. weiterführende Literatur; Arbeitskreis 2004; Bader et al. 2002; Beilenhoff et al. 2008; Leiß et al. 2008).

Nutrition education for pediatric gastroenterology, hepatology, and nutrition fellows: survey of NASPGHAN fellowship training programs

OBJECTIVES

The aim of the study was to assess the methodology and content of nutrition education during gastroenterology fellowship training and the variability among the different programs.

METHODS

A survey questionnaire was completed by 43 fellowship training directors of 62 active programs affiliated to the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition, including sites in the United States, Canada, and Mexico. The data were examined for patterns in teaching methodology and coverage of specific nutrition topics based on level 1 training in nutrition, which is the minimum requirement according to the published North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition fellowship training guidelines.

RESULTS

The majority of the teaching was conducted by MD-degree faculty (61%), and most of the education was provided through clinical care experiences. Only 31% of the level 1 nutrition topics were consistently covered by >80% of programs, and coverage did not correlate with the size of the programs. Competency in nutrition training was primarily assessed through questions to individuals or groups of fellows (77% and 65%, respectively). Program directors cited a lack of faculty interested in nutrition and a high workload as common obstacles for teaching.

CONCLUSIONS

The methodology of nutrition education during gastroenterology fellowship training is, for the most part, unstructured and inconsistent among the different programs. The minimum level 1 requirements are not consistently covered. The development of core curriculums and learning modules may be beneficial in improving nutrition education.

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.

Safety of pediatric percutaneous liver biopsy performed by interventional radiologists

OBJECTIVE

National data suggest that pediatric percutaneous liver biopsy is increasingly being performed by interventional radiologists rather than pediatric gastroenterologists. The objective of the present report is to describe the safety and effectiveness of percutaneous liver biopsy performed by interventional radiologists in a large cohort of children and to compare the results with the existing literature on biopsies performed by pediatric gastroenterologists.

PATIENTS AND METHODS

The medical records of 249 children undergoing ultrasound-guided percutaneous liver biopsy by interventional radiologists were reviewed for adverse events and success of obtaining tissue. Two hundred ninety-four biopsies were reviewed.

RESULTS

There were no deaths. There were 2 instances of a 2-g or greater drop in hemoglobin following biopsy, neither of which was associated with clinical signs of hemorrhage. A small, asymptomatic pneumothorax quickly resolved without treatment. One patient developed Klebsiella sepsis 48  hours after biopsy. In all but 1 case, an adequate sample size was obtained. This low incidence of adverse events compares favorably with existing published reports of morbidity and mortality following percutaneous liver biopsy performed by pediatric gastroenterologists.

CONCLUSIONS

Ultrasound-guided percutaneous liver biopsy performed by experienced pediatric interventional radiologists in a children's hospital setting is as safe and effective as biopsy performed by pediatric gastroenterologists.

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.

General considerations and updates in pediatric gastrointestinal diagnostic endoscopy

Gastrointestinal and colonic endoscopic examinations have been performed in pediatric patients in Korea for 3 decades. Endoscopic procedures are complex and may be unsafe if special concerns are not considered. Many things have to be kept in mind before, during, and after the procedure. Gastrointestinal endoscopy is one of the most frequently performed procedure in children nowadays, Since the dimension size of the endoscopy was modified for pediatric patients 15 years ago, endoscopic procedures are almost performed routinely in pediatric gastrointestinal patients. The smaller size of the scope let the physicians approach the diagnostic and therapeutic endoscopic procedures. But this is an invasive procedure, so the procedure itself may provoke an emergence state. The procedure-related complications can more easily occur in pediatric patients. Sedation-related or procedure-related respiratory, cardiovascular complications are mostly important and critical in the care. The endoscopists are required to consider diverse aspects of the procedure - patient preparation, indications and contraindications, infection controls, sedation methods, sedative medicines and the side effects of each medicine, monitoring during and after the procedure, and complications related with the procedure and medicines - to perform the procedure successfully and safely. This article presents some important guidelines and recommendations for gastrointestinal endoscopy through literature review.

Colonoscopy in Hong Kong Chinese children

AIM: To investigate the safety and diagnostic yield of colonoscopy in Chinese children in whom the procedure is not often done.

METHODS: We conducted a retrospective review of all colonoscopies in consecutive children who underwent their first diagnostic colonoscopy from Jan 2003 to 2008.

RESULTS: Seventy-nine children (48 boys, 31 girls; mean age 9.2 ± 4.2 years) were identified and reviewed with a total of 82 colonoscopies performed. Successful caecal and ileal intubation rates were 97.6% and 75.6% respectively. Forty patients (50.6%) had a positive diagnosis made in colonoscopy and that included colonic polyps (23), Crohn’s disease (12), ulcerative colitis (1), and miscellaneous causes (4). 80% of polyps were in the rectosigmoid colon. All but one were juvenile hamartomatous polyps. The exception was an adenomatous polyp. The mean ages for children with inflammatory bowel disease (IBD) and polyps were 11.3 and 4.3 years respectively. There was no procedure-related complication.

CONCLUSION: Colonoscopy is a safe procedure in our Chinese children. The increasing diagnosis of IBD in recent decades may reflect a rising incidence of the disease in our children.

Pediatric gastroenterology fellows, class of 2007: how well are they prepared for the future?

OBJECTIVES

Pediatric gastroenterology fellows are expected to acquire skills as clinicians, researchers, and educators. An e-mail survey was conducted to examine training experiences of individual fellows; to understand how graduating fellows rate their abilities as clinicians, researchers, and teachers; and to answer whether the size of a pediatric gastroenterology training program affects a fellow's training and future position choice.

MATERIALS AND METHODS

A survey was e-mailed to 76 third-year pediatric gastroenterology fellows. Respondents were ranked according to the size of their training program.

RESULTS

Completed surveys were returned by 50 respondents. Of these, 75% planned to pursue careers in academic medicine and 16% in private practice. In all, 68% of trainees participated in some type of basic research and 64% in clinical research. As attending physicians, 22% of fellows hoped to conduct basic science research and 74% clinical research. The majority thought they were competent or proficient teachers, and rated themselves as advanced beginners or competent when asked to evaluate their research skills. The North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition recommends that fellows perform 100 colonoscopies, 20 liver biopsies, and 5 paracenteses to be considered competent. We found that regardless of program size, 48% of fellows performed fewer than 100 colonoscopies, 62% performed fewer than 20 liver biopsies, and 80% performed fewer than 5 paracenteses.

CONCLUSIONS

The majority of fellows will pursue academic careers. Trainees may not be performing sufficient numbers of procedures. The number of procedures performed during fellowship was independent of program size.

Acquisition of competence in paediatric ileocolonoscopy with virtual endoscopy training

This study prospectively compared the rates of skill acquisition in ileocolonoscopy in 2 consecutive groups of trainees in paediatric gastroenterology, with 1 cohort exposed to virtual endoscopy. All paediatric gastroenterology trainees rotating through our department during a 7-year period between 1997 and 2004 were formally assessed while performing ileocolonoscopies using a trainer case-by-case method. Fourteen consecutive trainees with no previous experience of ileocolonoscopy were assessed. Comparison of rates of skill acquisition and lesion recognition using multiple linear regressions revealed a significant acceleration of achievement of endoscopic goals (P < 0.0001) in the group with prior exposure to virtual endoscopy.

Pediatric gastrointestinal motility--future directions and challenges

The study of gastrointestinal motility has evolved to a sophisticated diagnostic technique that is widely used clinically to further guide management of children with complex gastrointestinal problems. Thorough comprehension requires a multidisciplinary approach with the integration of molecular and cell biology, organ physiology, and clinical observations. During the past decade there has been a dramatic increase in our knowledge of the enteric neuromuscular system. Continued exploration of targeted gene mutations in animal models has the potential of enhancing our understanding of congenital disorders of gastrointestinal motility. Experiments studying polymorphisms in serotonin transporter gene (SERT) and different therapeutic responses to serotonergic agents in adults with irritable bowel syndrome need to be carried out in children with functional bowel disorders. Additional considerations that need to be addressed if advances are to continue include increasing the number of specialists interest in motility disorders and identifying funding sources to support the establishment of research consortiums among pediatric centers.

Normal aspects of colorectal motility and abnormalities in slow transit constipation

Human colonic motility is a relatively difficult topic to investigate. However, the refinement of manometric techniques in recent years enabled us to study both the proximal and distal segments of the viscus. The present paper reviews our knowledge about normal aspects of colorectal motility in man and the abnormalities found in slow transit constipation (STC), one of the most frequent and difficult to treat subtypes of constipation. An internet-based search strategy of the Medline and Science Citation Index was performed using the keywords colon, colonic, colorectal, constipation, slow transit, motility, rectal, rectum in various combinations with the Boolean operators AND, OR and NOT. Only articles related to human studies were used, and manual cross-referencing was also performed. Most of colonic motor activity is represented by single nonpropagated contractions, rarely organized in bursts; this activity is maximal during the day, especially after waking and following meals. In addition, a specialized propagated activity with propulsive features is detectable, represented by high- and low-amplitude propagated contractions. In the severe form of constipation represented by the slow transit type, the above motor activity is completely deranged. In fact, both basal segmental activity (especially in response to meals) and propagated activity (especially that of high amplitude) are usually decreased, and this may represent a physiologic marker of this disorder. Human colonic motor activity is quite a complex issue, still only partly understood and investigated, due to anatomic and physiological difficulties. In recent years, however, some more data have been obtained, even in proximal segments. These data have helped in elucidating, although only in part, some pathophysiological mechanisms of chronic constipation, and especially of the STC subtype.