New insights into the pathogenesis of Hirschsprung's associated enterocolitis

Outcomes Following Fecal Diversion for Intractable Hirschsprung Associated Enterocolitis: A Study From the Pediatric Colorectal and Pelvic Learning Consortium

BACKGROUND

Hirschsprung associated enterocolitis (HAEC) is a challenging problem in a subset of children with Hirschsprung disease (HD). In refractory cases, fecal diversion may be required. The aim of this study was to characterize patients who require fecal diversion for HAEC management and examine their long-term outcomes.

METHODS

A retrospective review of prospectively collected data within the Pediatric Colorectal and Pelvic Learning Consortium (PCPLC) registry was performed. All children with a history of a corrective procedure for HD and documented post-operative HAEC were included. Our primary outcome was diversion to manage HAEC after pull-through and secondary outcomes included incidence of recurrent HAEC, fecal continence following ostomy closure, and bowel management needs at last follow-up.

RESULTS

951 patients were identified with a history of HD and 852 had undergone pull-through. 339/852 (39.8 %) had documented HAEC and 75/339 (22.1 %) required an ostomy, 54 (72 %) of which underwent reversal at a median of 239.5 days. After reversal, 10/54 (18.5 %) required repeat diversion for recurrent HAEC. 30/75 (40 %) had their pull-through revised. Median age at last follow-up was 5.3 [3.4, 9] years. At time of last follow-up, 40.3 % were toilet-trained for stool and 42.9 % required long term enema-based therapy.

CONCLUSION

Fecal diversion for refractory HAEC was common in our study. Slightly more than half of the patients underwent successful closure of their stoma during over 4.5 years of follow-up, while less than half were toilet-trained for stool at their last visit. These children may represent a unique cohort that warrants further investigation.

LEVEL OF EVIDENCE

Level VI.

Toll-like receptor-8 mRNA expression as a predictor of enterocolitis in hirschsprung disease: a cross-sectional study

Introduction:

Hirschsprung-associated enterocolitis (HAEC) is an inflammatory intestinal condition occurring in patients with Hirschsprung disease (HD). While the exact pathogenesis remains unclear, factors such as intestinal mucosal barrier injury, abnormal immune responses, and pathogenic infections contribute to HAEC. Toll-like receptors (TLRs) 7 and 8 are key in viral recognition and correlate with intestinal mucosal inflammation. In particular, TLR-8 contributes to antiviral responses, and chronic inflammation, and can be targeted with adjuvants. This study investigates the relationship between TLR-8 mRNA expression and enterocolitis in HD.

Methods:

This cross-sectional study utilized simple random sampling. Histopathological analysis of colon samples from HD patients was used to assess enterocolitis severity, and RT-PCR quantified TLR-8 mRNA expression. HD diagnosis was confirmed via rectal biopsy, and enterocolitis was graded using Teitelbaum’s classification.

Results:

The study included 29 patients with an average age of 4.8 years. TLR-8 mRNA expression averaged 8.5 (fold change), ranging from 6.5 to 13.8. Subjects were divided into low (≤8.1) and high (>8.1) expression groups, with 15 (51.7%) and 14 (48.3%) patients, respectively. Enterocolitis severity distribution was 22 (75.9%) normal, 1 (3.4%) grade II, 4 (13.8%) grade III, and 2 (6.9%) IV.

Conclusion:

There is a significant association between TLR-8 mRNA expression and the incidence of enterocolitis in patients with HD. The authors found that increased TLR-8 mRNA expression in HD patients resulted in a twofold higher risk of enterocolitis. Altogether, our data indicates the potential for TLR-8 mRNA expression in biopsies as an indicator of the risk of enterocolitis development in patients with HD.

Intrasphincteric Botox injections in Hirschsprung's disease: indications and outcome in 64 procedures over a ten-year period

BACKGROUND

Intrasphincteric botulinum toxin (Botox) injection for symptomatic postoperative anal achalasia in Hirschsprung's disease (HSCR) has found wide application in the last twenty years. The aim of this study was to describe effectiveness and functional outcome of a series of patients treated over a 10-year period.

METHODS

All consecutive HSCR patients who received intrasphincteric Botox injections between January 2007 and December 2016 were included. Demographic data and clinical features were collected. A detailed questionnaire focusing on outcome in the medium and long-term was administered to all families.

RESULTS

In the study period 64 intrasphincteric Botox injections were performed in 31 patients. Completed questionnaires were returned by 27 out of 28 eligible patients (96%) reporting improvement or symptoms resolution in 16 (59%). The highest success rates were experienced by patients younger than 4, with long HSCR forms and with recurrent enterocolitis (75%, 100% and 100% of success rates, respectively). No major complications occurred. Minor complications were described by 7 patients (26%).

CONCLUSIONS

Intrasphincteric Botox injection proved to be feasible, safe and reasonably effective in children with HSCR and postoperative anal achalasia. Infants and toddlers with long HSCR forms and recurrent bouts of enterocolitis are those who would benefit most from this treatment.

Probiotics for the prevention of Hirschsprung-associated enterocolitis

BACKGROUND

Hirschsprung-associated enterocolitis (HAEC) is a leading cause of serious morbidity and potential mortality in children with Hirschsprung's disease (HD). People with HAEC suffer from intestinal inflammation, and present with diarrhoea, explosive stools, and abdominal distension. Probiotics are live microorganisms with beneficial health effects, which can optimise gastrointestinal function and gut flora. However, the efficacy and safety of probiotic supplementation in the prevention of HAEC remains unclear.

OBJECTIVES

To assess the effects of probiotic supplements used either alone or in combination with pharmacological interventions on the prevention of Hirschsprung-associated enterocolitis.

SEARCH METHODS

We searched CENTRAL, PubMed, Embase, the China BioMedical Literature database (CBM), the World Health Organization International Clinical Trials Registry, ClinicalTrials.gov, the Chinese Clinical Trials Registry, Australian New Zealand Clinical Trials Registry, and Clinical Trials Registry-India, from database inception to 27 February 2022. We also searched the reference lists of relevant articles and reviews for any additional trails.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing probiotics and placebo, or any other non-probiotic intervention, for the prevention of HAEC were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed the risk of bias of the included studies; disagreements were resolved by discussion with a third review author. We assessed the certainty of evidence using the GRADE approach. We calculated odds ratios (ORs) with 95% confidence intervals (CIs) for dichotomous outcomes.

MAIN RESULTS

We included two RCTs, with a total of 122 participants. We judged the overall risk of bias as high. We downgraded the evidence due to risk of bias (random sequence generation, allocation concealment, and blinding) and small sample size. The evidence is very uncertain about the effect of probiotics on the occurrence of HAEC (OR 0.58, 95% CI 0.10 to 3.43; I² = 74%; 2 studies, 120 participants; very low-certainty evidence). We found one included study that did not measure serious adverse events and one included study that reported no serious adverse events related to probiotics. Probiotics may result in little to no difference between probiotics and placebo in relation to the severity of children with HAEC at Grade I (OR 0.66, 95% CI 0.14 to 3.16; I² = 25%; 2 studies, 120 participants; low-certainty evidence). The effects of probiotics on the severity of HAEC at Grade II are very uncertain (OR 1.14, 95% CI 0.01 to 136.58; I² = 86%; 2 studies, 120 participants; very low-certainty evidence). Similarly, the evidence suggests that probiotics results in little to no difference in relation to the severity of HAEC at Grade III (OR 0.43, 95% CI 0.05 to 3.45; I² = 0%; 2 studies, 120 participants; low-certainty evidence). No overall mortality or withdrawals due to adverse events were reported. Probiotics may result in little to no difference in the recurrence of episodes of HAEC compared to placebo (OR 0.85, 95% CI 0.24 to 3.00; 1 study, 60 participants; low-certainty evidence).

AUTHORS' CONCLUSIONS

There is currently not enough evidence to assess the efficacy or safety of probiotics for the prevention of Hirschsprung-associated enterocolitis when compared with placebo. The presence of low- to very-low certainty evidence suggests that further well-designed and sufficiently powered RCTs are needed to clarify the true efficacy of probiotics.

Outcomes of preoperative anal dilatation for Hirschsprung disease

BACKGROUND/PURPOSE

There are some studies about the effect of postoperative anal dilatation on anastomotic stenosis and Hirschsprung-associated enterocolitis (HAEC), but we have not seen any report about preoperative anal dilatation. We hypothesized that preoperative anal dilatation could reduce the incidence of HAEC and facilitate the operation. We aim to compare the HAEC rates and postoperative complications between groups who either had or did not have anal dilatations (AD or NAD) prescribed before laparoscopic-assisted Soave pull-through procedures for Hirschsprung disease (HD); by this means, we will evaluate the benefit of dilatations before the surgery for HD.

METHODS

A retrospective review of children with HD operated in our hospital between 2014 and 2018 was performed. Those with 21 trisomy, total colonic aganglionosis, multiple stage procedures, serious congenital malformations, and lost to follow-up were excluded. Patients were divided into preoperative anal dilatation group (AD group) and no preoperative anal dilatation group (NAD group). Routine anal dilatation was performed in both groups from 2 weeks after laparoscopic-assisted Soave pull-through. The anal dilatation was carried out daily with metal anal dilators with size appropriate to the age of the child. The size of the anal dilators was increased by 1 mm every 2 weeks for at least 3 months. Demographic data, operation time, pre- and postoperative HAEC rates and postoperative obstructive symptoms between groups were compared. Significance was considered at P < 0.05.

RESULTS

There were 95 children (17 female and 78 male) included, 36 AD and 59 NAD. There was no significant difference in demographic data between the two groups. The incidence of HAEC between the groups was not different both preoperatively (14% vs. 24%, P = 0.298) and postoperatively (11% vs. 19%, P = 0.171). The postoperative obstructive symptoms rates were 19% versus 22% for the AD and NAD groups, respectively (P = 0.802). The operation time of group AD was significantly shorter than that of group NAD (P = 0.008). Preoperative anal dilatation could shorten the operation time in short and typical-segment (2.08 ± 0.39 vs. 2.67 ± 0.37, P = 0.009 and 3.05 ± 0.38 vs. 3.29 ± 0.46, P = 0.042), but has no significant effect on long-segment disease (3.85 ± 0.41 vs. 3.89 ± 0.30, P = 0.839).

CONCLUSION

We have not shown a reduced risk of developing HAEC or postoperative obstructive symptoms if anal dilatations are prescribed before surgery. However, it may decrease the difficulties of surgeries, so the operative time is shortened.

LEVEL OF EVIDENCE

Prognosis study.

LEVEL

II.

Predictive factors for the development of postoperative Hirschsprung-associated enterocolitis in children operated during infancy

PURPOSE

The risk factors for postoperative Hirschsprung-associated enterocolitis (HAEC) are still incompletely understood, especially age at which surgery is performed. Therefore, the aim of this study was to identify the risk factors for the development of postoperative HAEC in children operated during infancy.

METHODS

Thirty-five children who had undergone radical surgery for Hirschsprung disease (HD) during infancy were included in the study. They were divided into two groups; those who developed postoperative HAEC (HAEC, 14 patients) and those who did not (no HAEC, 21 patients). Their medical records were retrospectively reviewed for clinical details.

RESULTS

Developing postoperative HAEC was significantly associated with long-segment HD (p = 0.020) and the age at radical surgery (p = 0.0241). No other factors had a significant association with postoperative HAEC. In the patients who developed postoperative HAEC (n = 14), those with Trisomy 21 had significantly longer hospitalizations than those without. Patients with long-segment HD had a higher hospitalization rate than those with short-segment HD.

CONCLUSION

This study clearly showed that long-segment HD and older age at radical surgery are risk factors for developing postoperative HAEC.

Factors influencing the incidence of Hirschsprung associated enterocolitis (HAEC)

PURPOSE

This study aims to characterize risk factors for Hirschsprung-associated enterocolitis (HAEC). We hypothesize that earlier pull-through surgery is associated with lower risks of developing postoperative HAEC.

METHODS

A comparative study of 171 Hirschsprung patients treated from 1990 to 2017 was performed. Patients without HAEC were compared to patients with preoperative and/or postoperative HAEC. Results are presented as median [IQR] or frequency (%). Pearson's χ² test and Wilcoxon rank sum test were performed with a significance level at p < 0.05. Multivariable logistic regression analysis was used to adjust for potential confounders. A subanalysis was done to evaluate laparoscopic, laparotomy, and transanal surgeries.

RESULTS

Risk of developing preoperative HAEC was significantly associated with congenital malformations (OR 2.63 [1.11, 6.24]; p = 0.02). Birth weight was lower in patients with preoperative HAEC (OR 0.48 [95% CI 0.25, 0.93]; p = 0.03). On regression analysis, intestinal obstruction after surgery was significantly associated with postoperative HAEC (OR 8.2 [3.18, 21.13]; p < 0.0001). Patients with earlier pull-through surgery did not have a lower risk of developing postoperative HAEC.

CONCLUSIONS

Timing of surgery does not seem to be associated with a higher risk of developing pre- and postoperative HAEC. Predisposing factors for preoperative HAEC included associated malformations and lower birth weight, whereas intestinal obstruction was found to be associated with postoperative HAEC.

TYPE OF STUDY

Treatment study.

LEVEL OF EVIDENCE

Level III.

Risk factors for the development of post-operative enterocolitis in short segment Hirschsprung's disease

AIM OF THE STUDY

The objective of this study is to identify risk factors associated with the development of post-operative enterocolitis (HAEC), in short segment Hirschsprung's disease (HSCR-S).

METHODS

A retrospective study was carried out for post-operative patients with HSCR-S from 1997 to 2017. HSCR-S was defined as the most proximal extension of aganglionosis limited to the sigmoid colon. An episode of HAEC was defined as the presence of (1) vomiting or explosive diarrhea; (2) abdominal distension; (3) fever and (4) leukocytosis. Risk factors for the development of HACE were determined using multivariate logistic regression.

MAIN RESULTS

The medical records of 96 patients were reviewed. The overall incidence of HAEC was 20.8% (n = 20) and 65.0% (n = 13) of HAEC occurred within the first year of operation. After a univariate logistic regression analysis, three risk factors for HAEC were identified: (1) presence of other major anomalies [OR: 1.43 (1.12-2.32), p = 0.041]; (2) creation of pre-operative defunctioning stoma [OR: 2.28 (1.47-3.23), p = 0.035]; (3) extension of aganglionosis to the sigmoid colon [OR: 1.89 (1.05-3.19), p = 0.049]. After multivariate logistic regression analysis, a significant association was demonstrated for creation of pre-operative defunctioning stoma [OR: 1.81 (1.08-3.22), p = 0.045] and extension of aganglionosis to the sigmoid colon [OR: 1.91 (1.37-2.98), p = 0.038].

CONCLUSIONS

The requirement of pre-operative defunctioning stoma and a more proximal extension of aganglionosis are risk factors for the development of post-operative HAEC in HSCR-S. Patients with these risk factors should be closely followed up especially during the first year after the operation.

Gfra1 Underexpression Causes Hirschsprung's Disease and Associated Enterocolitis in Mice

BACKGROUND & AIMS

RET, the receptor for the glial cell line-derived neurotrophic factor (GDNF) family ligands, is the most frequently mutated gene in congenital aganglionic megacolon or Hirschsprung's disease (HSCR). The leading cause of mortality in HSCR is HSCR-associated enterocolitis (HAEC), which is characterized by altered mucin composition, mucin retention, bacterial adhesion to enterocytes, and epithelial damage, although the order of these events is obscure. In mice, loss of GDNF signaling leads to a severely underdeveloped enteric nervous system and neonatally fatal kidney agenesis, thereby precluding the use of these mice for modeling postnatal HSCR and HAEC. Our aim was to generate a postnatally viable mouse model for HSCR/HAEC and analyze HAEC etiology.

METHODS

GDNF family receptor alpha-1 (GFRa1) hypomorphic mice were generated by placing a selectable marker gene in the sixth intron of the Gfra1 locus using gene targeting in mouse embryonic stem cells.

RESULTS

We report that 70%-80% reduction in GDNF co-receptor GFRa1 expression levels in mice results in HSCR and HAEC, leading to death within the first 25 postnatal days. These mice mirror the disease progression and histopathologic findings in children with untreated HSCR/HAEC.

CONCLUSIONS

In GFRa1 hypomorphic mice, HAEC proceeds from goblet cell dysplasia, with abnormal mucin production and retention, to epithelial damage. Microbial enterocyte adherence and tissue invasion are late events and therefore unlikely to be the primary cause of HAEC. These results suggest that goblet cells may be a potential target for preventative treatment and that reduced expression of GFRa1 may contribute to HSCR susceptibility.

Digital pathology imaging and computer-aided diagnostics as a novel tool for standardization of evaluation of aganglionic megacolon (Hirschsprung disease) histopathology

Based on a recently introduced immunohistochemical panel (Bachmann et al. 2015) for aganglionic megacolon (AM), also known as Hirschsprung disease, histopathological diagnosis, we evaluated whether the use of digital pathology and 'machine learning' could help to obtain a reliable diagnosis. Slides were obtained from 31 specimens of 27 patients immunohistochemically stained for MAP2, calretinin, S100β and GLUT1. Slides were digitized by whole slide scanning. We used a Definiens Developer Tissue Studios as software for analysis. We configured necessary parameters in combination with 'machine learning' to identify pathological aberrations. A significant difference between AM- and non-AM-affected tissues was found for calretinin (AM 0.55% vs. non-AM 1.44%) and MAP2 (AM 0.004% vs. non-AM 0.07%) staining measurements and software-based evaluations. In contrast, S100β and GLUT1 staining measurements and software-based evaluations showed no significant differences between AM- and non-AM-affected tissues. However, no difference was found in comparison of suction biopsies with resections. Applying machine learning via an ensemble voting classifier, we achieved an accuracy of 87.5% on the test set. Automated diagnosis of AM by applying digital pathology on immunohistochemical panels was successful for calretinin and MAP2, whereas S100β and GLUT1 were not effective in diagnosis. Our method suggests that software-based approaches are capable of diagnosing AM. Our future challenge will be the improvement of efficiency by reduction of the time-consuming need for large pre-labelled training data. With increasing technical improvement, especially in unsupervised training procedures, this method could be helpful in the future.

Hirschsprung Disease beyond Infancy

Hirschsprung disease (HD) is a common cause of neonatal intestinal obstruction in which a variable segment of the distal intestinal tract lacks the normal enteric nervous system elements. Affected individuals present with varying degrees of obstructive symptoms, but today most patients are diagnosed within the first several months of life owing to the well-recognized symptoms and the ease of making the diagnosis by way of the bedside suction rectal biopsy. Thus, for the adult general or colorectal surgeon, the vast majority of patients who present for evaluation will have already undergone surgical treatment within the first year of life by a pediatric surgeon. Despite several safe operative interventions to treat patients with HD, the long-term results are far from perfect. These patients may reach adult life with ongoing defecation disorders that require a systematic evaluation by a multidisciplinary group that should be led by a surgeon with a thorough knowledge of HD operations and the potential problems. The evaluation of these patients will form the basis for the majority of this review-however, some patients manage to escape diagnosis beyond the infant and childhood period-and a section herein will briefly address the case of an older patient who is suspected of having HD.

Pathologically assessed grade of Hirschsprung-associated enterocolitis in resected colon in children with Hirschsprung's disease predicts postoperative bowel function

PURPOSE

The aim of this study was to investigate the relationship between the grade of enterocolitis on pathological assessment of resected colon and postoperative bowel function in children with Hirschsprung's disease (HD).

METHODS

Children with HD who were seen at a large tertiary center from January 2012 to December 2013 were enrolled into this study. Resected colon was assessed using the histopathologic grade scoring system for Hirschsprung-associated enterocolitis (HAEC), and the relationship of these scores to postoperative bowel function was assessed. Time of recovery to normal defecation was the primary outcome measure. The t-test, analysis of variance, and Kaplan-Meier, univariate, and multiple regression analyses were performed.

RESULTS

Eighty children with HD (median age at repair 7.9months; range 1.3months to 9years) were included in the study. Nineteen children dropped out of the study and were considered as providing censored data, giving a follow-up rate of 76.3%. A total of 21 children (34.4%) were admitted to hospital with at least one episode of enterocolitis. Multivariate Cox proportional hazards models showed that compared with patients with a normal proximal colon, those with an inflamed proximal segment had a 1.5-fold higher risk of a poor recovery. Logistic regression analyses suggested that postoperative HAEC admissions increased by 57% with each HAEC pathological grade of the transitional segment and by 50% with each grade of the overall segment. Compared with normal bowel in the transitional segment, the detection of grade ≥3 HAEC in the transitional area increased the incidence of postoperative HAEC by 4.75-fold.

CONCLUSIONS

Children whose resected proximal colon showed inflammation on pathological assessment were at risk of poor recovery after surgery. A higher pathological HAEC score for the sum of the overall three segments suggested an increased risk for the subsequent development of enterocolitis. Among three segments, the severity of enterocolitis in the transitional segment was the most significant factor in predicting postoperative HAEC.

TYPE OF STUDY

Clinical study.

LEVEL OF EVIDENCE

Moderate.

The Enteric Network: Interactions between the Immune and Nervous Systems of the Gut

Interactions between the nervous and immune systems enable the gut to respond to the variety of dietary products that it absorbs, the broad spectrum of pathogens that it encounters, and the diverse microbiome that it harbors. The enteric nervous system (ENS) senses and reacts to the dynamic ecosystem of the gastrointestinal (GI) tract by translating chemical cues from the environment into neuronal impulses that propagate throughout the gut and into other organs in the body, including the central nervous system (CNS). This review will describe the current understanding of the anatomy and physiology of the GI tract by focusing on the ENS and the mucosal immune system. We highlight emerging literature that the ENS is essential for important aspects of microbe-induced immune responses in the gut. Although most basic and applied research in neuroscience has focused on the brain, the proximity of the ENS to the immune system and its interface with the external environment suggest that novel paradigms for nervous system function await discovery.

Redo pullthrough for Hirschsprung disease

Pullthrough procedures for Hirschsprung diseases typically have favorable results. However, some children experience long-term postoperative complications comprising stooling disorders, such as intermittent enterocolitis, severe stool retention, intestinal obstruction, as well as incontinence. Reoperative Hirschsprung Disease surgery is complex. This begins with the workup after the initial presentation following primary pullthrough, continues with the definitive surgical correction with redo pullthrough, and ends with long-term follow-up of individuals. The decision tree can be varied with each patient. The operating pediatric surgeon must be able to utilize different operations and treatment options available. While lesser procedures may provide relief in a select population, those with residual aganglionosis or transition zone pathology or mechanical problems will likely require a redo pullthrough. Thus, the diagnostic workup, treatment plan, and definitive surgical care should be coordinated, and executed by an experienced, specialized team at a pediatric referral center.

Impaired Cellular Immunity in the Murine Neural Crest Conditional Deletion of Endothelin Receptor-B Model of Hirschsprung's Disease

Hirschsprung’s disease (HSCR) is characterized by aganglionosis from failure of neural crest cell (NCC) migration to the distal hindgut. Up to 40% of HSCR patients suffer Hirschsprung’s-associated enterocolitis (HAEC), with an incidence that is unchanged from the pre-operative to the post-operative state. Recent reports indicate that signaling pathways involved in NCC migration may also be involved in the development of secondary lymphoid organs. We hypothesize that gastrointestinal (GI) mucosal immune defects occur in HSCR that may contribute to enterocolitis. EdnrB was deleted from the neural crest (EdnrB^NCC-/-) resulting in mutants with defective NCC migration, distal colonic aganglionosis and the development of enterocolitis. The mucosal immune apparatus of these mice was interrogated at post-natal day (P) 21–24, prior to histological signs of enterocolitis. We found that EdnrB^NCC-/- display lymphopenia of their Peyer’s Patches, the major inductive site of GI mucosal immunity. EdnrB^NCC-/- Peyer’s Patches demonstrate decreased B-lymphocytes, specifically IgM⁺IgD^hi (Mature) B-lymphocytes, which are normally activated and produce IgA following antigen presentation. EdnrB^NCC-/- animals demonstrate decreased small intestinal secretory IgA, but unchanged nasal and bronchial airway secretory IgA, indicating a gut-specific defect in IgA production or secretion. In the spleen, which is the primary source of IgA-producing Mature B-lymphocytes, EdnrB^NCC-/- animals display decreased B-lymphocytes, but an increase in Mature B-lymphocytes. EdnrB^NCC-/- spleens are also small and show altered architecture, with decreased red pulp and a paucity of B-lymphocytes in the germinal centers and marginal zone. Taken together, these findings suggest impaired GI mucosal immunity in EdnrB^NCC-/- animals, with the spleen as a potential site of the defect. These findings build upon the growing body of literature that suggests that intestinal defects in HSCR are not restricted to the aganglionic colon but extend proximally, even into the ganglionated small intestine and immune cells.

Mucus Barriers to Microparticles and Microbes are Altered in Hirschsprung's Disease

Mucus forms a protective hydrogel layer over the intestinal epithelium, presenting a selective and robust barrier to the uptake of particulates and microbe invasion. Disease can alter mucus production and composition, thus potentially modifying mucosal barrier properties. Hirschsprung's disease (HD) is a developmental abnormality of the nervous system often complicated by intestinal infection. An investigation of colonic mucus barrier properties in an HD animal model, endothelin receptor B mutant mice, revealed significantly reduced microsphere (passive) and microbe (active) transport rates (7-fold and 3.6-fold, respectively, in proximal colonic mucus) relative to wild-type. Transport differences were evident in both the ganglionic and aganglionic colon segments, in agreement with the risk of HD-associated enterocolitis after surgery to remove aganglionic colon segments. The development of therapies aimed at altering colonic mucus barrier properties could be explored towards preventing the onset of enterocolitis in HD.

Probiotics prevent Hirschsprung's disease-associated enterocolitis: a prospective multicenter randomized controlled trial

BACKGROUND

Enterocolitis (EC) is the most common and serious postoperative complication of Hirschsprung's disease (HD). Probiotics potentially play a protective role in maintaining intestinal mucosal integrity. Based on the beneficial effects of probiotics, we hypothesized that oral probiotics could decrease the incidence and severity of Hirschsprung's disease-associated enterocolitis (HAEC).

METHODS

We conducted a prospective, multicenter, randomized, and controlled trial to assess whether oral probiotics could decrease the incidence and severity of HAEC. HD patients were randomly assigned into the control group and probiotic-treated group. All children in probiotic-treated group were fed with probiotics per day for 4 weeks. In next 3 months, the incidence and severity of HAEC were analyzed. The peripheral blood T lymphocyte subsets and cytokines, including TNF-α, IFN-γ, IL-6, and IL-10, were analyzed by flow cytometry and enzyme immunoassay (EIA).

RESULTS

Compared with the control group, the incidence of HAEC in the probiotic-treated group was significantly diminished. The severity of EC was also remarkably decreased. Furthermore, probiotics balanced T lymphocyte subsets. Moreover, pro-inflammatory cytokines TNF-α, IFN-γ, and IL-6 were significantly decreased and anti-inflammatory cytokine IL-10 was notably increased in probiotic-treated group.

CONCLUSIONS

Probiotics not only significantly diminished the incidence but also decreased the severity of HAEC. Moreover, our study revealed that probiotics decreased pro-inflammatory cytokine and increased anti-inflammatory cytokine and furthermore balanced T lymphocytes (registered with ClinicalTrials.gov, NCT number: NCT01934959).

The impact of Clostridium difficile on paediatric surgical practice: a systematic review

PURPOSE

The pathogenic potential of Clostridium difficile in children remains a controversial subject as healthy infants can be colonised by this organism. However recent analyses have clarified that C. difficile is an important enteropath in paediatric populations, particularly in antibiotic-associated diarrhoea. Paediatric surgical patients including those with Hirschsprung's disease (HD) may be especially vulnerable to C. difficile infection (CDI) and complicated C. difficile enterocolitis such as pseudomembranous colitis may require surgical management if refractory to medical therapy. Reports of increasing prevalence and emergence of hyper-virulent strains of C. difficile worldwide prompted an examination of the literature to assess the impact of CDI on current paediatric surgical practise.

METHODS

The literature was searched using a combination of the MESH terms "hirschsprung's disease", "enterocolitis", "clostridium difficile", and "children". Cases of Hirschsprung's associated enterocolitis (HAEC) investigated for C. difficile and complicated CDI in non HD patients were identified and analysed for clinical parameters, diagnostic evaluations, surgical interventions and outcome.

RESULTS

Pathogen isolation in HAEC was infrequently described. Only 98 children have been reported with C. difficile during an episode of HAEC over the last 40 years and aetiology remains unclear as asymptomatic carriage of C. difficile in HD occurs. Nonetheless 34 confirmed cases of pseudomembranous colitis complicating HD are reported in the literature with an associated 50 % mortality rate. Over 20 % of non Hirschsprung's patients with reported severe or complicated CDI required operative intervention. The need for surgery was associated with the presence of co-morbidity and high mortality occurred in this group.

CONCLUSION

Severe or complicated CDI in both HD and non HD paediatric patients is associated with high mortality and often requires surgical intervention. Although these patient cohorts represent a small number of cases, CDI should be suspected in children presenting with enterocolitis to enable early diagnosis and timely surgical intervention, particularly in patients with co-morbid conditions or preceding antibiotic use.

A practical guide for the diagnosis of primary enteric nervous system disorders

OBJECTIVE

Primary gastrointestinal neuropathies are a heterogeneous group of enteric nervous system (ENS) disorders that continue to cause difficulties in diagnosis and histological interpretation. Recently, an international working group published guidelines for histological techniques and reporting, along with a classification of gastrointestinal neuromuscular pathology. The aim of this article was to review and summarize the key issues for pediatric gastroenterologists on the diagnostic workup of congenital ENS disorders. In addition, we provide further commentary on the continuing controversies in the field.

RESULTS

Although the diagnostic criteria for Hirschsprung disease are well established, those for other forms of dysganglionosis remain ill-defined. Appropriate tissue sampling, handling, and expert interpretation are crucial to maximize diagnostic accuracy and reduce interobserver variability. The absence of validated age-related normal values for neuronal density, along with the lack of correlation between clinical and histological findings, result in significant diagnostic uncertainties while diagnosing quantitative aberrations such as hypoganglionosis or ultrashort Hirschsprung disease. Intestinal neuronal dysplasia remains a histological description of unclear significance.

CONCLUSIONS

The evaluation of cellular quantitative or qualitative abnormalities of the ENS for clinical diagnosis remains complex. Such analysis should be carried out in laboratories that have the necessary expertise and access to their own validated reference values.

Hirschsprung-associated enterocolitis: pathogenesis, treatment and prevention

Hirschsprung-associated enterocolitis (HAEC) is a common and sometimes life-threatening complication of Hirschsprung disease (HD). Presenting either before or after definitive surgery for HD, HAEC may manifest clinically as abdominal distension and explosive diarrhea, along with emesis, fever, lethargy, and even shock. The pathogenesis of HAEC, the subject of ongoing research, likely involves a complex interplay between a dysfunctional enteric nervous system, abnormal mucin production, insufficient immunoglobulin secretion, and unbalanced intestinal microflora. Early recognition of HAEC and preventative practices, such as rectal washouts following a pull-through, can lead to improved outcomes. Treatment strategies for acute HAEC include timely resuscitation, colonic decompression, and antibiotics. Recurrent or persistent HAEC requires evaluation for mechanical obstruction or residual aganglionosis, and may require surgical treatment with posterior myotomy/myectomy or redo pull-through. This chapter describes the incidence, pathogenesis, treatment, and preventative strategies in management of HAEC.

Recent developments in Hirschsprung's-associated enterocolitis

Hirschsprung's-associated enterocolitis (HAEC) continues to be a significant source of morbidity for patients with Hirschsprung's disease (HD). New clinical and histologic classification systems for HAEC will improve consistency between reports and increase the ability to compare outcomes. A complete understanding of disease pathogenesis is lacking, but evidence suggests that the intestinal microbiota may play a role in the development of HD and HAEC. The benefits of adjunctive therapies, such as anal dilations and botulinum toxin to reduce the incidence of HAEC following corrective endorectal pull-through, remain controversial. Finally, new clinical data have identified an association between HAEC and inflammatory bowel disease and will likely lead to further genetic studies to elucidate the connection between these two disease processes.

Sudden unexpected early neonatal death due to undiagnosed Hirschsprung disease enterocolitis: a report of two cases and literature review

Hirschsprung enterocolitis (HEC) is an uncommon, albeit well known, complication of Hirschsprung disease (HD). It is multifactorial and can appear in different age groups, but is particularly important in the neonatal period where it is characteristically seen in full-term neonates. Two cases of HEC are reported that were diagnosed at post-mortem examination, which presented as early sudden neonatal death, with a review the literature on fatal Hirschsprung enterocolitis. Case 1 was a 4-day old male neonate who was found unwell, struggling to breath, and with green vomitus. He was taken to hospital and pronounced dead a short time later. According to the parents meconium was passed on the first day. Post-mortem examination demonstrated necrotizing enterocolitis with isolated bowel perforation. Histology disclosed unsuspected HD. Case 2 was a 2-day old male neonate who was found wheezing with green vomitus. He arrived floppy, cyanosed, and in shock at the hospital and died a few hours later. Meconium was not passed, according to the parents. Post-mortem examination revealed necrotizing enterocolitis. There was also recto-sigmoidal aganglionosis and acetylcholinesterase staining confirmed HD. HEC is a multifactorial and sometimes recurrent complication of HD which characteristically develops in full-term neonates. Presentation with early sudden neonatal death is rare but should be considered in the diagnostic work-up of sudden deaths in this age group.

Induction of RET dependent and independent pro-inflammatory programs in human peripheral blood mononuclear cells from Hirschsprung patients

Hirschsprung disease (HSCR) is a rare congenital anomaly characterized by the absence of enteric ganglia in the distal intestinal tract. While classified as a multigenic disorder, the altered function of the RET tyrosine kinase receptor is responsible for the majority of the pathogenesis of HSCR. Recent evidence demonstrate a strong association between RET and the homeostasis of immune system. Here, we utilize a unique cohort of fifty HSCR patients to fully characterize the expression of RET receptor on both innate (monocytes and Natural Killer lymphocytes) and adaptive (B and T lymphocytes) human peripheral blood mononuclear cells (PBMCs) and to explore the role of RET signaling in the immune system. We show that the increased expression of RET receptor on immune cell subsets from HSCR individuals correlates with the presence of loss-of-function RET mutations. Moreover, we demonstrate that the engagement of RET on PBMCs induces the modulation of several inflammatory genes. In particular, RET stimulation with glial-cell line derived neurotrophic factor family (GDNF) and glycosyl-phosphatidylinositol membrane anchored co-receptor α1 (GFRα1) trigger the up-modulation of genes encoding either for chemokines (CCL20, CCL2, CCL3, CCL4, CCL7, CXCL1) and cytokines (IL-1β, IL-6 and IL-8) and the down-regulation of chemokine/cytokine receptors (CCR2 and IL8-Rα). Although at different levels, the modulation of these “RET-dependent genes” occurs in both healthy donors and HSCR patients. We also describe another set of genes that, independently from RET stimulation, are differently regulated in healthy donors versus HSCR patients. Among these “RET-independent genes”, there are CSF-1R, IL1-R1, IL1-R2 and TGFβ-1, whose levels of transcripts were lower in HSCR patients compared to healthy donors, thus suggesting aberrancies of inflammatory responses at mucosal level. Overall our results demonstrate that immune system actively participates in the physiopathology of HSCR disease by modulating inflammatory programs that are either dependent or independent from RET signaling.

The pathogenesis of Hirschsprung's disease-associated enterocolitis

Hirschsprung's disease-associated enterocolitis (HAEC) remains the most life-threatening complication in Hirschsprung disease (HD) patients. The pathogenesis of HAEC has not been determined and many hypotheses regarding the etiology of HAEC have been proposed. These include a possible causal relationship between the abnormal enteric nervous system development in HD and the development of enterocolitis. Based on the complex genetic causes of HD that have been discovered and the resultant heterogeneous group of patients that exists, the causes of HAEC are likely multiple. New insights regarding the relationship of the role of the enteric nervous system and its interaction between intestinal barrier function, innate host immunity, and commensal microflora have been discovered, which may shed light on this perplexing problem. This review presents current known risk factors of HAEC and the proposed theories and supporting evidence for the potential etiologies of HAEC.

Total colonic aganglionosis in Hirschsprung disease

Total colonic aganglionosis (TCA) is a relatively uncommon form of Hirschsprung disease (HSCR), occurring in approximately 2%-13% of cases. It can probably be classified as TCA (defined as aganglionosis extending from the anus to at least the ileocecal valve, but not >50 cm proximal to the ileocecal valve) and total colonic and small bowel aganglionosis, which may involve a very long segment of aganglionosis. It is not yet clear whether TCA merely represents a long form of HSCR or a different expression of the disease. There are many differences between TCA and other forms of HSCR, which require explanation if its ubiquitous clinical features are to be understood. Clinically, TCA appears to represent a different spectrum of disease in terms of presentation and difficulties that may be experienced in diagnosis, suggesting a different pathophysiology from the more common forms of HSCR. There is also some evidence suggesting that instead of being purely congenital, it may represent certain different pathophysiologic mechanisms. This study, in addition to reviewing current understanding and differences between TCA and the more frequently encountered rectosigmoid (or short-segment) expression, correlates them with what is currently known about the genetic and molecular biological background. Moreover, it reviews current outcomes to find consensus on management.

Reoperative surgery for Hirschsprung disease

Despite most children undergoing a successful pull through for Hirschsprung disease, a small portion of children are left with persistent stooling issues. Most of these stooling issues can be addressed by nonoperative approaches. However, in a small group of remaining children, a reoperation may be necessary. Most children who may need a redo pull-through procedure may have a persistent area of aganglionosis, unremitting enterocolitis, or a torsion or stricture of the pull-through segment. Each of these influences the approach the surgeon must take to correct the presenting problem. The chapter details the diagnostic approach as well as the operative techniques, which best deal with each of these complications.

Hirschsprung-associated enterocolitis: prevention and therapy

Hirschsprung-associated enterocolitis remains the greatest cause of morbidity and mortality in children with Hirschsprung disease. This chapter details the various approaches used to treat and prevent this disease process. This includes prevention of complications, such as stricture formation, prophylaxis with rectal washouts, and identification of high-risk individuals. The chapter also details approaches to diagnose Hirschsprung-associated enterocolitis as well as to exclude other etiologies.

[Enterocolitis as a complication of late-diagnosed Hirschsprung disease]

Enterocolitis is the most serious complication of Hirschsprung disease. Early management of these patients can decrease the severity of this complication. Hirschsprung disease is more common in patients with trisomy 21 than in the general population. Furthermore, the risk of developing enterocolitis is higher in this population. We report on an infant with trisomy 21 who developed enterocolitis as a complication of Hirschsprung disease that was diagnosed late when the infant presented with septic shock leading to death of the patient.

Re-operation for Hirschsprung's disease: experience in 24 patients from China

PURPOSE

The aim of this study is to review the authors' 12-year experience with re-operative surgery for Hirschsprung's disease (HD) including indications of re-operation and surgical technique.

METHODS

We retrospectively reviewed the data of 24 patients who underwent re-operation from 1998 to 2010. The type of initial procedure, clinical presentations, indications and details of redo surgery, and the functional results were analyzed.

RESULTS

The primary operations performed on these patients included Duhamel (nine cases), Soave (12 cases), Swenson (one case) and Rehbein (two cases). The indications for re-operation were recurrent constipation due to severe anastomotic stricture (five cases), residual aganglionic segments (five cases) and gate syndrome after Duhamel procedure (five cases); fistula formation including rectocutaneous fistula (six cases), rectovaginal fistula (one case), complex fistula (two cases). The redo procedure ranged from posterior sagittal approach combined with laparotomy (seven cases), Soave procedure (seven cases, six conventional Soave + one transanal Soave), Duhamel procedure (one case), Rehbein procedure (three cases), re-using the stapling device (five cases), repairing the rectovaginal fistula via laparotomy (one case). We have followed up the patients for 7 months to 6 years (mean 2.5 years). After re-operation, in 22 patients older than 3 years, 19 (86.4%) have normal or near normal bowel habits with a stool frequency of 1-5 times per day, two have voluntary bowel movements but occasional soiling (once or twice per week) and without significant incontinence, one presented rectosacral fistula due to careless dilatation. There were no deaths.

CONCLUSION

Re-operation can work out the anatomical or pathological problems resulted from failed initial procedure and improve the patient's quality of life. Posterior sagittal approach, Soave and Duhamel are all safe and effective, but we still need to try our best to diminish the necessity of re-operation.

Clinical impacts of delayed diagnosis of Hirschsprung's disease in newborn infants

BACKGROUND

Asian infants are at a higher risk of having Hirschsprung's disease (HD). Although HD is surgically correctable, serious and even lethal complications such as Hirschsprung's-associated enterocolitis (HAEC) can still occur. The aim of this study was to investigate the risk factors of HAEC, and the clinical impacts of delayed diagnosis of HD in newborn infants.

PATIENTS AND METHODS

By review of medical charts in a medical center in Taiwan, 51 cases of neonates with HD between 2002 and 2009 were collected. Patients were divided into two groups based on the time of initial diagnosis: Group I, diagnosis made within 1 week after birth, and Group II after 1 week. Clinical features including demographic distribution, presenting features of HD, short-term and long-term complications related to HD were compared between the two groups of patients.

RESULTS

There were 25 patients in Group I and 19 in Group II. Group II patients had more severe clinical signs and symptoms of HAEC than Group I patients. The incidence of preoperative HAEC was 12% in Group I and 63% in Group II (adjusted odds ratio = 12.81, confidence interval = 2.60-62.97). Patients with preoperative HAEC were more likely to develop adhesive bowel obstruction after operation (33% vs. 3%, p = 0.013) and failure to thrive (33% vs. 3%, p = 0.013). Also, patients with long-segment or total colonic aganglionosis were at risk of developing both postoperative HAEC (85% vs. 29%, p = 0.001) and failure to thrive (39% vs. 3%, p = 0.002).

CONCLUSION

In our study, we found that delayed diagnosis of HD beyond 1 week after birth significantly increases the risk of serious complications in neonatal patients. Patients with long-segment or total colonic aganglionosis have higher risk of postoperative HAEC and failure to thrive. Patients with preoperative HAEC are more likely to have adhesive bowel obstruction and failure to thrive.

Splenic lymphopenia in the endothelin receptor B-null mouse: implications for Hirschsprung associated enterocolitis

PURPOSE

The aim of the study was to describe and characterize a novel small spleen phenotype with splenic lymphopenia in the Ednrb-null (Ednrb-/-) mouse with aganglionosis known to also develop enterocolitis.

METHODS

We compared spleen weight as a percent of body weight from Ednrb+/+, Ednrb+/-, and Ednrb-/- mice to quantify our initial observation. Splenic microarchitecture of Ednrb+/+ and Ednrb-/- mice was assessed using both H and E staining and immunofluorescence staining for CD45R+ (B cells) and CD3+ (T cells) on tissue sections. To identify and quantify cell type, flow cytometry for CD19+ (mature B cells), CD4+ and CD8+ (T cells) was performed on the splenocytes of Ednrb+/+ and Ednrb-/- mice and compared with student's t test. A separate cohort of Ednrb+/+ and Ednrb-/- mice was killed and splenocytes were analyzed by flow cytometry, and proximal colon was histopathologically graded for enterocolitis. Spearman's rank correlations comparing total splenocyte and CD19+ cell counts with enterocolitis scores were performed.

RESULTS

We found that the mean spleen weight expressed as a percent of body weight for Ednrb+/+ and Ednrb-/- mice was 0.72 and 0.25%, respectively (P < 0.001), at 25 days of age. In addition, the Ednrb-/- spleens also had markedly abnormal splenic microarchitecture with lymphopenia, and relative reduction of B cells compared to T cells. FACS of splenocytes revealed a 5 to 20-fold reduction in total cell number, CD19+, CD4+, and CD8+ of the Ednrb-/- mice compared to the Ednrb+/+ littermates (P < 0.01). We also found a strong inverse correlation of total spleen and CD19+ cell counts with histopathological enterocolitis scores (r (s) = -0.43, P = 0.02), showing that mice with reduced cell counts also had increased severity of enterocolitis.

CONCLUSION

The small spleen immunophenotype in the Ednrb-/- mouse suggests that Ednrb-dependent signaling may be required for normal spleen development. These results raise the possibility that primary immune abnormalities may contribute at least in part to some enterocolitis. At present, our data suggest intriguing new potential explanations for HAEC in Hirschsprung patients.

Systematic review and meta-analysis of enterocolitis after one-stage transanal pull-through procedure for Hirschsprung's disease

PURPOSE

The transanal one-stage pull-through procedure (TERPT) has gained worldwide popularity over open and laparoscopic-assisted one-stage techniques in children with Hirschsprung's disease (HD). It offers the advantages of avoiding laparotomy, laparoscopy, scars, abdominal contamination, and adhesions. However, enterocolitis associated with Hirschsprung's disease (HAEC) still remains to be a potentially life-threatening complication after pull-through operation. The reported incidence of HAEC ranges from 4.6 to 54%. This meta-analysis was designed to evaluate postoperative incidence of HAEC following TERPT procedure.

METHODS

A meta-analysis of cases of TERPT reported between 1998 and 2009 was performed. Detailed information was recorded regarding intraoperative details and postoperative complications with particular emphasis on incidence of HAEC. Diagnosis of HAEC in a HD patient was based on the clinical presentation of diarrhoea, abdominal distension, and fever.

RESULTS

Of the 54 published articles worldwide, 27 articles, including 899 patients were identified as reporting entirely TERPT procedure. Postoperative HAEC occurred in 92 patients (10.2%). Recurrent episodes of HAEC were reported in 18 patients (2%). Conservative treatment of HAEC was successful in 75 patients (81.5%), whereas in 17 patients (18.5%) surgical treatment was needed.

CONCLUSIONS

This systematic review reveals that TERPT is a safe and less-invasive procedure with a low incidence of postoperative HAEC.

What is the most common complication after one-stage transanal pull-through in infants with Hirschsprung's disease?

BACKGROUND

Hirschsprung's disease (HD) is a relatively common congenital disease that could be suspected by clinical symptoms, abdominal plain X-ray, and finally diagnosed by rectal biopsy. In 80% cases, rectosigmoid junction is involved. Recently, one-stage transanal pull-through (TAPT) procedure has been popular and may have several complications.

METHODS AND PATIENTS

During a 4-year period, 86 infants (28 girls, 58 boys) with mean age 8 days (3-33) and clinically suspected to HD were admitted in our center. HD was proved by rectal biopsy. All patients after full bowel preparation and rectal washout were candidates for TAPT operation. A Swenson-like procedure was performed and the anastomosis was done between the well blood supply ganglionic colon and the rectum at 1 cm above dentate line. Interrupted suture with 5-0 Vicryl was used. Nelaton tube (12 F) inserted in the pelvis via transprineal for drainage of blood or collection. From February 2008 in 30 cases, prophylactic Hegar dilatation was performed 2 weeks after operation.

RESULTS

Anal stricture in 12 cases (14%) was treated by anal dilation in 10 cases and 2 cases corrected by surgical management. Entrocolitis in 4 cases (5%) was treated by medical management. In two cases, retrocolic abscess had spontaneous drainage via tube drain. There was no anastomotic stricture after starting prophylactic anal bouginage.

CONCLUSION

TAPT has many advantages, low complications and the results are excellent. It seems the most common complication is anastomotic stricture that responds well to prophylactic bouginage. We recommend prophylactic anal bouginage with Hegar probe at 2 weeks after operation. Long-term follow-up is needed to evaluate the outcomes of our operations.

Hirschsprung-associated enterocolitis develops independently of NOD2 variants

BACKGROUD/PURPOSE: Hirschsprung-associated enterocolitis (HAEC) represents a cause for significant pre- and postoperative morbidity and mortality in Hirschsprung disease (HD). Although multiple studies on HAEC have been performed and several mechanisms have been presumed, the pathogenesis of this condition remains unclear. As changes in colonic mucosal defense are key factors suggested in both Crohn's disease (CD) and HAEC pathogenesis, the aim of the current study was to investigate genetic alterations in the most important susceptibility gene for Crohn's enterocolitis (NOD2) to see whether carriers of polymorphisms within the NOD2 gene are predisposed to the development of HAEC.

METHODS

Genotyping for the NOD2 variants in exon 4 (p.Arg702Trp [rs2066844]), exon 8 (p.Gly908Arg [rs2066845]), and exon 11 (p.1007fs [rs2066847]) was performed in 52 white children with HD (41 boys, 11 girls), 152 healthy controls, and 152 children with CD (onset of disease <17 years; mean, 11.8 years). Seventeen patients with HD (32.7%) were carriers of a RET germline mutation, 35 children (67.3%) had short segment disease, and 17 (32.7%) had long segment disease.

RESULTS

Ten children (19.2%) with HD were heterozygous carriers of at least one NOD2 variant vs 17 (11.2%) in the healthy control group and 69 (45.4%) in the CD cohort. Hirschsprung-associated enterocolitis was observed in 7 children (13.5%), with 4 having short segment HD and 3 with long segment HD; but none of them were carriers of NOD2 variants.

CONCLUSION

Our study shows that NOD2 variants described to be causatively associated with CD do not predispose to the development of HAEC. As data on the molecular basis of HAEC are limited, the distinct mechanisms involved in the pathogenesis of this complication remain unclear.

Genomics approach to the analysis of bacterial communities dynamics in Hirschsprung's disease-associated enterocolitis: a pilot study

INTRODUCTION

The most invalidating and life-threatening complication in Hirschsprung's disease patients (HSCR) is Hirschsprung's disease-associated enterocolitis (HAEC). The mechanisms underlying enterocolitis have not been identified. The limited knowledge of the role of intestinal microflora is in part due to the complexity of the intestinal microbiome and to the limitation of cultivation-based technologies, given that less than 25% of the intestinal bacterial species can be cultured.

MATERIALS AND METHODS

We used amplified ribosomal DNA restriction analysis (ARDRA) with four different restriction enzymes to study variations of microflora composition of the stools of a selected HSCR patient in different clinical conditions (acute phase vs. remission).

RESULTS

We assessed a total of 15 stool specimens belonging to the same 3-year-old male patient suffering from HSCR, which were harvested during 4 HAEC episodes and remission phases. Restriction analysis showed that HAEC episodes seem to cluster together at ARDRA analysis, thus suggesting a sort of predisposing bacterial community for HAEC development and the need for a microflora equilibrium to maintain wellness.

CONCLUSIONS

This approach proved to be effective, useful and powerful in assessing microflora dynamics and indicated that the differences in microflora associated with acute HAEC or remission are likely to result from a combination of disease activity and different antibiotic therapies. ARDRA proved to be useful in discriminating disease versus remission. Our findings indicated that HAEC results from a change in the equilibrium between bacterial species or from altered discrimination of harmless from harmful microorganisms, challenging the definition of pathogenic and non-pathogenic species. Based on these results, we propose ARDRA as a rapid inexpensive tool to assess microflora dynamics during HAEC episodes.

Murine model of Hirschsprung-associated enterocolitis. I: phenotypic characterization with development of a histopathologic grading system

PURPOSE

The aim of the study was to characterize enterocolitis in the Ednrb-null (Ednrb-/-) mouse with aganglionosis of the colon and to develop and validate a semiquantitative histopathologic grading system to assess enterocolitis.

METHODS

We isolated colon and ileal specimens of Ednrb-/- and control mice (Ednrb+/+) and performed histochemical staining (H&E) on tissue sections. After establishing inflammation grading criteria, 2 blinded pathologists independently assessed the severity and depth of inflammation of proximal colon segments on 2 separate occasions. Interclass correlations (ICCs) and coefficient of variation (CV) were calculated to determine interrater and intrarater agreement. We then prospectively applied the enterocolitis grading system to Ednrb-/- mice that became clinically ill. A cohort of Ednrb-/- mice were observed until they developed clinical illness, at which time they were euthanized and had multiple organ homogenates cultured for bacteria, and colon and small bowel were histopathologically graded for enterocolitis. Spearman's rank correlations comparing enterocolitis scores with level of bacteremia were performed.

RESULTS

Intra- and interrater ICCs of the histologic scoring system were satisfactory (0.61 and 0.94, respectively), as were intra- and interrater CVs (18% and 9%, respectively). Of the Ednrb-/- mice, 65% developed bacteremia. Those with bacteremia had significantly higher enterocolitis scores than those without bacteremia (P < .01). Ednrb-/- mice that developed bacteremia showed a strong positive correlation between total enterocolitis scores and number of bacterial colony forming units in peritoneal lavage, liver, kidney, and aerobic spleen.

CONCLUSIONS

The Ednrb-/- mouse with aganglionosis develops enterocolitis and has features similar to Hirschsprung-associated enterocolitis in humans. Our grading system is a reliable way to assess enterocolitis. By performing microsurgical pull-through, we can now perform controlled, hypothesis-driven, mechanistic studies to evaluate etiologic factors affecting enterocolitis in the Ednrb-/- mouse.

Practical pathology and genetics of Hirschsprung's disease

Diagnosis and management of Hirschsprung's disease (HSCR) requires understanding of the malformation's anatomic features and multigenic nature. Rectal biopsies, intraoperative frozen sections, and resection specimens provide invaluable information. Extraction of these data requires thoughtful biopsy technique, adequate histologic sections, histochemistry, and collaboration of surgeon and pathologist. Critical consideration of transition zone anatomy and published studies of "transition zone pull through" indicate that more research is needed to determine how much ganglionic bowel should be resected from HSCR patients. Many HSCR-susceptibility genes have been identified, but mutational analysis has limited practical value unless family history or clinical findings suggest syndromic HSCR.

Patterns of postoperative enterocolitis in children with Hirschsprung's disease combined with hypoganglionosis

OBJECTIVE

The relationship between postoperative enterocolitis (EC) and Hirschsprung's disease (HD) combined with hypoganglionosis (HYP) has not been thoroughly reported elsewhere. The aim of this study was to investigate the incidence of EC after operation in children with HD combined with HYP and to identify new strategies to prevent postoperative EC.

METHODS

From 1998 to 2005, 97 children with HD underwent the modified Swenson's procedure in this institute. They were classified into 2 groups based on pathologic investigation as follows: group A contained 70 patients with HD and group B contained 27 patients with HD complicated with HYP. The mean follow-up time from the time of the operation was 3.4 years (range, 1.5-8 years). The incidence of postoperative EC and anorectal functions were evaluated and compared between these 2 groups.

RESULTS

Eight cases (11.4%) in group A developed postoperative EC, whereas 11 (40.7%) in group B did so. The incidence of postoperative EC in group A was significantly lower than that in group B (P < .005). According to the Rintala scoring system, the percentage of patients with an excellent score in group A (85.7%) was significantly higher than that in group B (P < .05). The recurrence rate of constipation in group B was 14.8% (4/27), whereas it was 2.8% (2/70) in group A.

CONCLUSIONS

Postoperative EC is associated with retained proximal HYP, which suggests that HYP could be, at minimum, a predictive marker for this complication. Complete resection of HYP segment could potentially minimize the incidence of postoperative EC and alleviate the severity of EC.

A novel corrective pullthrough surgery in a mouse model of Hirschsprung's disease

BACKGROUND/PURPOSE

The study aimed to develop a mouse model of post-pullthrough Hirschsprung's disease that will allow investigation of mechanisms that cause postoperative complications.

METHODS

We developed a novel microsurgical pullthrough operation on Balb/C mice and evaluated its effect on growth rate and stooling pattern. Histologic assessment of the pullthrough colon was performed. The pullthrough operation was then performed on Ednrb-/- mice that have aganglionic megacolon and Ednrb+/+ littermate controls, and the outcomes compared.

RESULTS

The Balb/C pullthrough group had 97% survival at 1 week and 70% survival at 2 weeks. Body weight of the pullthrough animals declined 15% in the first week after surgery and subsequently normalized. The stooling pattern showed consistently softer stools in the pullthrough group, but no difference in frequency compared to controls. Histopathologic analyses 4 weeks postoperatively showed well-healed coloanal anastomoses. Two-week survival after pullthrough surgery in Ednrb-/- and Ednrb+/+ mice was 50.0%, and 69.2%, respectively (P = NS). Increased mortality in the Ednrb-/- mice was related to the technical challenge of performing microsurgery on smaller-sized mice with poor baseline health status.

CONCLUSIONS

Our microsurgical pullthrough operation in mice is feasible and allows systematic investigations into potential mechanisms mediating post-pullthrough complications and poor long-term results in mouse models of Hirschsprung's disease.

Low incidence of enterocolitis and colonic mucosal inflammation in Norwegian patients with Hirschsprung's disease

BACKGROUND

Hirschsprung's disease (HD) may be associated with inflammation in the colon. Further, the etiology of Hirschsprung-associated enterocolitis (HEC) is unclear. To learn more about these features, we examined our cohort of HD patients during a period of 6 years for inflammation in their colonic mucosa as well as for signs of HEC.

MATERIALS AND METHODS

Rectal suction biopsies and operative full thickness aganglionic and ganglionic colonic specimens from 36 patients were examined. Signs of inflammation were recorded in hematoxylin/eosin/saffron (HES)-stained sections and with fluorescence conjugated polyclonal antibodies to IgA and IgG applied on serial sections. The suction biopsies were also evaluated for the presence of mucus inspissation and crypt dilatation. Clinical signs of HEC were recorded from medical files of the same 36 patients.

RESULTS

HES-staining revealed that seven patients had inflammation in the suction biopsies; these patients were significantly older than the patients without inflammation. Slight mucus inspissation was identified in suction biopsies of five out of 33 patients, but crypt abscesses or ulcerations were not found in any specimens. Virtually all very young patients (<3 months) had slight crypt dilatation. We identified inflammation in resected colonic segments from 17 out of 36 patients. Thirteen of these 17 had a diverting colostomy, and only one out of 14 patients with colostomy had no inflammation. Inflammatory changes were similar in ganglionic and aganglionic bowel. By immunofluorescence (IF) staining, inflammation was found in resected colonic segments from five patients. Four of these had a colostomy. HEC was diagnosed in three patients, and inflammation detected in resected specimens from only one of these three.

CONCLUSIONS

We have not been able to identify particular characteristics in the colonic or rectal mucosa that are linked to development of HEC. Inflammation in the resected specimen was mainly found in patients with a diverting colostomy, and then in both ganglionic and aganglionic colon.

Development of a standardized definition for Hirschsprung's-associated enterocolitis: a Delphi analysis

PURPOSE

The reported incidence of Hirschsprung's-associated enterocolitis (HAEC) is extremely variable. A standardized definition would permit comparison of different studies and provide an interpretable outcome measure for future prospective studies in patients with Hirschsprung's disease.

METHODS

The Delphi method is a technique for achieving consensus among a panel of experts. A list of 38 potential criteria from the history, physical examination, radiologic studies, and pathologic specimens was made available to pediatric surgeons and gastroenterologists who have contributed to the literature on Hirschsprung's disease. Each expert ranked the diagnostic importance of each item using a Likert scale. In subsequent surveys, the same process was used, but the means and SDs from previous rounds were included as a way of influencing the experts toward consensus. Cronbach's alpha was used after each round to measure variability among the experts. Once consensus was reached, an overall "HAEC score" was developed by assigning a value of 1 or 2 to each item that was considered important by the expert panel. The score was then validated by circulating 10 clinical cases to the panel and asking if each represented HAEC or not.

RESULTS

Twenty-seven experts completed the survey. Cronbach's alpha increased from 0.93 after the first round to 0.97 after the second. Criteria receiving the highest scores were diarrhea, explosive stools, abdominal distension, and radiologic evidence of bowel obstruction or mucosal edema. Eighteen items were included in the score. During the validation process, the score agreed with the experts in 9 of the 10 case scenarios.

CONCLUSION

The most important clinical diagnostic criteria for HAEC were identified from a larger pool of potential diagnostic items through a consensus approach using the Delphi method. A score was developed and validated and can now be used as a standardized and reproducible outcome measure for future studies in children with Hirschsprung's disease.

The ITGB2 immunomodulatory gene (CD18), enterocolitis, and Hirschsprung's disease

Hirschsprung's disease (HSCR)-associated enterocolitis (HAEC) remains a major contributor to morbidity and mortality associated with HSCR, being sometimes difficult to diagnose in its subclinical form. Its pathogenesis appears to include impaired local defense mechanisms as well as dysfunctional immune response and leukocyte function. In this context, the ITGB2 (CD18) immunomodulation-related gene is a possible candidate in HAEC pathogenesis as it codes for the beta-subunit of leukocyte adhesion molecule lymphocyte function-associated antigen 1, which has an established role in T-cell development and function. ITGB2/CD18 has also been linked to chronic colitis in both human and animal models involving defense mechanisms within colonic mucosa. There is therefore a fairly compelling case for the potential involvement of the ITGB2 (CD18) in HAEC pathogenesis.

AIM

The aim of this study was to investigate the ITGB2 immunomodulatory gene (CD18) in a cohort of patients with HSCR and explore its correlation with enterocolitis.

PATIENTS AND METHODS

Screening for mutations of the ITGB2 (CD18) gene was performed on DNA extracted from colonic tissue samples and whole blood of 33 HSCR patients controlled by analysis of 60 unaffected individuals from the diverse South African population. Polymerase chain reaction amplification was performed, followed by heteroduplex single-strand conformation polymorphism analysis and bidirectional semiautomated DNA sequencing analysis.

RESULTS

Heteroduplex single-strand conformation polymorphism banding patterns of the ITGB2 gene showed variations in 22 HSCR patients (66%), 13 of whom had severe episodes of HAEC, and 6 others had milder symptoms. Of the 13, 6 (46%) had Down's syndrome-associated HSCR. Genetic variations included 1 mutation (D77N), 2 known (V367, V441), and 4 novel polymorphisms (-111T/C, 24G/T, 295G/A, 892A/G). Significant associations were identified in the exon 5' untranslated promotor region (P < .0001), exon 10 (P < .0007), and the 3' untranslated promotor region at 122G/A (P < .0001) and 370 G/T positions (P = .04). Those regions of the gene most frequently associated with HAEC and severe symptoms were those with more than 1 variant identified in the gene.

CONCLUSIONS

This study shows that impaired CD18 leukocyte and T regulatory cell regulation can probably be linked to a genetic (ITGB2) predisposition to HAEC. It furthermore provides a possible genetic link to HAEC patient selection, identifying a potential molecular target.

Hirschsprung disease: do risk factors of poor surgical outcome exist?

INTRODUCTION

Long-term results after surgical treatment of Hirschsprung disease (HSCR) are not always as good as a surgeon may perceive. Several studies have tried to correlate preoperative features to the surgical outcome of HSCR, but none came to definitive conclusions. Our study is aimed at identifying risk factors of poorer long-term outcome after surgery for HSCR.

MATERIALS AND METHODS

One hundred two patients with HSCR were included. Eighty had rectosigmoid aganglionosis and 22 had total colonic aganglionosis (TCSA). Preoperative variables were sex, associated anomalies, delayed meconium passage, preoperative enterocolitis, preoperative bowel obstruction, age at surgery, and number of pull-through procedures performed. Outcome measures were surgical complications, postoperative enterocolitis, perineal excoriations, constipation, continence, psychological self acceptance, and patients' perspectives. These were evaluated with regard to preoperative features and length of aganglionosis.

RESULTS

Results of patients with TCSA proved to be significantly worse than those of patients with classic HSCR (constipation and poor continence excluded). Male patients with TCSA proved to have a significantly higher incidence of complications (100% vs 38.5%) and poor psychological self acceptance (100% vs 46.2%). Patients with associated anomalies (central nervous system) experienced a significantly higher incidence of postoperative constipation (43% vs 13%). Patients who described failure or delayed meconium passage complained of significantly worse continence (28.3% vs 7.1% of fair to poor continence). Preoperative enterocolitis proved to be significantly correlated to postoperative enterocolitis (16.4% vs 37.1%) and perineal excoriations (13.7% vs 30.9%). Patients with preoperative intestinal obstructions complained of significantly worse psychological self acceptance (37.8% vs 12.5%).

CONCLUSIONS

Length of aganglionosis has the greatest impact on overall surgical outcome of HSCR. Other minor risk factors have been identified, namely, male sex, associated central nervous system anomalies, failure to pass meconium, and preoperative enterocolitis occurrences. Age at surgery and redo procedures proved not to significantly interfere with the outcome. Our study provides comprehensive and useful data to inform parents and families of a baby with HSCR with regard to expected results and long-term outcomes of surgery basing on preoperative features. Further studies on larger series are strongly recommended.

Uncommon causes of postoperative chronic diarrhoea mimicking enterocolitis in Hirschsprung's disease: is there a role for digestive endoscopy?

Severe chronic diarrhoea secondary to enterocolitis is a severe complication of Hirschsprung's disease (HSCR). Persistent outlet obstruction, immunologic issues, and mucin/mucous imbalance can cooperate in the development of this complication. Furthermore, isolated reports described severe postoperative chronic diarrhoea mimicking enterocolitis in patients with sucrase-isomaltase deficiency, inflammatory bowel disease (IBD), or intestinal microvillus atrophy. This paper is aimed in describing three patients from our HSCR series who experienced severe chronic postoperative diarrhoea secondary to such uncommon associated anomalies: sucrase-isomaltase deficiency (one patient) and IBD (two patients). With an appropriate sucrose-free diet or immunosuppressive therapy these patients improved dramatically and their diarrhoea settled. These associated anomalies can be diagnosed with digestive endoscopies (both gastro-duodenoscopy and colonoscopy). Therefore, we developed a diagnostic and therapeutic algorithm for patients with chronic diarrhoea after a pull-through, which includes digestive endoscopy to be performed in selected cases.

Hirschsprung's disease: 13 years' experience in 112 patients from a single institution

Although Hirschsprung's disease is curable, a low mortality and a certain morbidity have been described by several authors. We will present our experience with the treatment of Hirschsprung's disease at Gaslini Children's Hospital. All patients who underwent a pull-through procedure since January 1993 were included. Data were obtained from a comprehensive questionnaire and from the revision of the notes. The results were subsequently described and compared with regard to age and length of aganglionosis. A total of 151 patients underwent a pull-through. One hundred and twelve of these patients completed the forms and were reviewed. Eighty patients had a classic form, 22 an ultralong. Complications occurred in 28 patients (25%). Postoperative enterocolitis was complained by 25 patients (13% colonic and 59% ultralong forms) and constipation by 15 (equally distributed). Excellent to good continence was experienced by 84% of patients with classic forms and by 68% of patients with ultralong forms. A clear improving trend during growth was evident for patients with ultralong forms. Psychological self-acceptance, patients' perspective and cosmetic results proved to be significantly better for patients with classic forms of the disease. Our study confirmed the complications and long-term sequelae that patients with Hirschsprung's can experience. Early diagnosis can minimise morbidity and mortality and prompt and adequate treatment can reduce the incidence of postoperative complications. The parents should be acknowledged regarding the progressive improvements of function that patients gain during growth, particularly in case of ultralong forms, thus strengthening the need for continuative care and close follow-up.