Variant Hirschsprung's disease

Conditions that mimic Hirschsprung's disease, but that are not Hirschsprung's disease

Hirschsprung's disease (HSCR) is widely recognized in pediatric surgery. This condition has been elucidated, and therapeutic approaches have been developed. However, even when ganglion cells are present in the rectum, some patients still experience symptoms such as bowel obstruction, intestinal dilatation, and chronic constipation, which are similar to those observed in HSCR. A consensus regarding the terminology for these diseases is yet to be established. This group of diseases was defined as 'allied disorders of Hirschsprung's disease' (ADHD). They are classified into two categories based on pathology: (1) Abnormal ganglia, including immaturity of ganglia, hypoganglionosis, and intestinal neuronal dysplasia; and (2) Normal ganglia, including megacystis microcolon intestinal hypoperistalsis syndrome (MMIHS), segmental dilatation, internal anal sphincter achalasia, and chronic idiopathic intestinal pseudo-obstruction (CIIP). Hypoganglionosis, MMIHS, and CIIP are particularly severe and not curable by surgery. Guidelines were compiled to facilitate an accurate clinical diagnosis and provide appropriate treatment strategies for each disease. A full-thickness rectal biopsy with H&E and acetylcholinesterase staining is often required for a differential diagnosis. Patients are now able to survive longer with enteral nutrition combined with long-term intravenous nutrition and decompression of the gastrointestinal tract. However, all treatment strategies are symptomatic. It is necessary to improve the results of small intestine transplantation and to develop new therapies using regenerative medicine.

Cutting-edge regenerative therapy for Hirschsprung disease and its allied disorders

Hirschsprung disease (HSCR) and its associated disorders (AD-HSCR) often result in severe hypoperistalsis caused by enteric neuropathy, mesenchymopathy, and myopathy. Notably, HSCR involving the small intestine, isolated hypoganglionosis, chronic idiopathic intestinal pseudo-obstruction, and megacystis-microcolon-intestinal hypoperistalsis syndrome carry a poor prognosis. Ultimately, small-bowel transplantation (SBTx) is necessary for refractory cases, but it is highly invasive and outcomes are less than optimal, despite advances in surgical techniques and management. Thus, regenerative therapy has come to light as a potential form of treatment involving regeneration of the enteric nervous system, mesenchyme, and smooth muscle in affected areas. We review the cutting-edge regenerative therapeutic approaches for managing HSCR and AD-HSCR, including the use of enteric nervous system progenitor cells, embryonic stem cells, induced pluripotent stem cells, and mesenchymal stem cells as cell sources, the recipient intestine's microenvironment, and transplantation methods. Perspectives on the future of these treatments are also discussed.

A novel mouse model of intestinal neuronal dysplasia: visualization of the enteric nervous system

PURPOSE

Intestinal neuronal dysplasia (IND) is a congenital anomaly affecting gastrointestinal neural innervation, but the pathogenesis remains unclear. The homozygous Ncx/Hox11L.1 knockout (Ncx-/-) mice exhibit megacolon and enteric ganglia anomalies, resembling IND phenotypes. Sox10-Venus transgenic mouse were used to visualize enteric neural crest cells in real time. This study aims to establish a novel mouse model of Sox10-Venus+/Ncx-/- mouse to study the pathogenesis of IND.

METHODS

Sox10-Venus+/Ncx-/- (Ncx-/-) (n = 8) mice and Sox10-Venus+/Ncx+/+ controls (control) (n = 8) were euthanized at 4-5 weeks old, and excised intestines were examined with fluorescence microscopy. Immunohistochemistry was performed on tissue sections with neural marker Tuj1.

RESULTS

Ncx-/- mice exhibited dilated cecum and small intestine. Body weight of Ncx-/- mice was lower with higher ratio of small intestine length relative to body weight. The neural network (Sox10-Venus) was observed along the intestine wall in Ncx-/- and control mice without staining. Ectopic and increased expression of Tuj1 was observed in both small intestine and proximal colon of Ncx-/- mice.

CONCLUSION

This study has established a reliable animal model that exhibits characteristics similar to patients with IND. This novel mouse model can allow the easy visualization of ENS in a time- and cost-effective way to study the pathogenesis of IND.

Historical Cohort Study of Congenital Isolated Hypoganglionosis of the Intestine: Determining the Best Surgical Interventions

No standard diagnostic method or surgical treatment for congenital isolated hypoganglionosis (CIHG) has been established. This study aimed to analyze the clinical outcomes of patients with CIHG and identify the best surgical interventions provided thus far. Data on surgical interventions in 19 patients were collected between 1992 and 2020, including the type of enterostomy, type of revision, and length of the intestines. Ganglion cells in the myenteric plexus were enumerated using Hu C/D staining. The ratio of the length of the small intestine to its height was defined as the intestinal ratio (IR). The outcomes were assessed using the stoma output, growth parameters including the body mass index (BMI), and parenteral nutrition (PN) dependency. All patients required a diverting enterostomy. The IR ranged from 0.51 to 1.75 after multiple non-transplant surgeries. The stoma types were tube-stoma, end-stoma, Santulli-type, and Bishop-Koop (BK)-type. Patients with Santulli- or BK-type stomas had better BMIs and less PN dependency in terms of volume than those with end-stomas or tube-stomas. Two patients with BK-type stomas were off PN, and three who underwent an intestinal transplantation (Itx) achieved enteral autonomy. The management of CIHG involves a precise diagnosis using Hu C/D staining, neonatal enterostomy, and stoma revision using the adjusted IR and Itx if other treatments do not enable enteral autonomy.

Translational research in Hirschprung's disease at the National Children's Research Centre in Dublin

Hirschsprung's disease (HD) is a congenital condition characterised by aganglionosis in the distal bowel. Over the years, at the National Children's Research Centre (NCRC), HD has been one of the most prominent and successful research areas for Prof. Prem Puri's research team. Research fellows from around the world came to the NCRC to work on both animal and human studies of HD and, cumulatively, made important discoveries in this field, publishing a total of 144 HD articles in peer-reviewed journals. Through their published work, the NCRC has been recognised as the leading international centre for the investigation of HD and its allied disorders. In this review, I will summarise the main findings from this work.

Congenital Myenteric Hypoganglionosis

Congenital myenteric hypoganglionosis is a rare developmental disorder characterized clinically by severe and persistent neonatal intestinal pseudoobstruction. The diagnosis is established by the prevalence of small myenteric ganglia composed of closely spaced ganglion cells with sparse surrounding neuropil. In practice, the diagnosis entails familiarity with the normal appearance of myenteric ganglia in young infants and the ability to confidently recognize significant deviations in ganglion size and morphology. We review clinical, histologic, and immunohistochemical findings from 12 patients with congenital myenteric hypoganglionosis in comparison with similar data from age-matched controls and clearly delineate the diagnostic features of the condition. Practical guidelines are provided to assist surgical pathologists, who are likely to encounter this condition only infrequently. The diagnosis typically requires full-thickness intestinal biopsy as the abnormality is confined to the myenteric plexus in many patients. Immunohistochemistry for Hu C/D may be used to confirm hypoganglionosis. Reduced staining for calretinin and NeuN implicates a selective deficiency of intrinsic primary afferent neurons in this disease.

Efficacy of Sox10 Promoter Methylation in the Diagnosis of Intestinal Neuronal Dysplasia From the Peripheral Blood

OBJECTIVES

Intestinal neuronal dysplasia (IND) is a common malformation of the enteric nervous system. Diagnosis requires a full-thickness colonic specimen and an experienced pathologist, emphasizing the need for noninvasive analytical methods. Recently, the methylation level of the Sox10 promoter has been found to be critical for enteric nervous system development. However, whether it can be used for diagnostic purposes in IND is unclear.

METHODS

Blood and colon specimens were collected from 32 patients with IND, 60 patients with Hirschsprung disease (HD), and 60 controls. Sox10 promoter methylation in the blood and the Sox10 expression level in the colon were determined, and their correlation was analyzed. The diagnostic efficacy of blood Sox10 promoter methylation was analyzed by receiver operating characteristic curve.

RESULTS

The blood level of Sox10 promoter methylation at the 32nd locus was 100% (90%-100%; 95% confidence interval [CI], 92.29%-96.37%) in control, 90% (80%-90%; 95% CI, 82.84%-87.83%) in HD, and 60% (50%-80%; 95% CI, 57.12%-69.76%) in IND specimens. Sox10 promoter methylation in the peripheral blood was negatively correlated with Sox10 expression in the colon, which was low in control, moderate in HD, and high in IND specimens (r = -0.89). The area under the curve of Sox10 promoter methylation in the diagnosis of IND was 0.94 (95% CI, 0.874-1.000, P = 0.000), with a cutoff value of 85% (sensitivity, 90.6%; specificity, 95.0%). By applying a cutoff value of 65%, promoter methylation was more indicative of IND than HD.

DISCUSSION

The analysis of Sox10 promoter methylation in the peripheral blood can be used as a noninvasive method for IND diagnosis.

Comparison of Acute Abdominal Surgical Outcomes of Extremely-Low-Birth-Weight Neonates according to Differential Diagnosis

BACKGROUND

Improvements in perinatal intensive care have improved survival of extremely-low-birth-weight (ELBW) neonates, although the risk of acute abdomen has increased. The differential diagnosis resulting in abdominal surgery can be categorized into necrotizing enterocolitis (NEC), spontaneous intestinal perforation (SIP), meconium-related ileus (MRI), and meconium non-related ileus (MNRI). The purpose of this study was to review our experience with abdominal surgery for ELBW neonates, and to evaluate characteristics and prognosis according to the differential diagnosis.

METHODS

Medical records of ELBW neonates treated between 2003 and 2015 were retrospectively reviewed.

RESULTS

Of 805 ELBW neonates, 65 (8.1%) received abdominal surgery. The numbers of cases by disease category were 29 for NEC, 18 for SIP, 13 for MRI, and 5 for MNRI. Ostoma formation was performed in 61 (93.8%) patients; primary anastomosis without ostoma was performed in 4 (6.2%). All patients without ostoma formation experienced re-perforation of the anastomosis site. Seven patients had 30-day postoperative mortality (6 had NEC). Long-term survival of the surgical and non-surgical groups was not statistically different. NEC was a poor prognostic factor for survival outcome (P = 0.033).

CONCLUSION

Abdominal surgery for ELBW neonates is feasible. Ostoma formation can lead to reduced complications compared to primary anastomosis.

Intestinal Neuronal Dysplasia Type B: An Updated Review of a Problematic Diagnosis

Context.—

Intestinal neuronal dysplasia type B (IND B) is a controversial histopathologic phenotype that has been associated with intestinal dysmotility, either as an isolated condition or in conjunction with established pathologic disorders (eg, Hirschsprung disease). Many factors contribute to the debate over the existence and/or clinical significance of IND B, including a large body of published data based on inconsistent diagnostic criteria and methods, which have fostered many unwarranted conclusions that lack sufficient scientific basis.

Objective.—

To critically analyze existing published data regarding IND B to provide supporting evidence-based diagnostic practice and to stimulate necessary and scientifically sound research.

Data Sources.—

This update focuses on published literature related to the pathology of IND B because without a reliable pathologic diagnosis, studies of epidemiology, pathogenesis, natural history, management, and outcome are all suspect. Problems with existing data are identified explicitly with suggestions as to how future investigations should be designed and evaluated to better understand this entity.

Conclusions.—

Inconsistencies in diagnostic criteria and methods used to define IND B justifiably encumber the universal acceptance of IND B as a neuropathologic etiology for intestinal dysmotility. IND B will remain a controversial diagnosis until rigorous, well-controlled scientific studies are conducted to establish reproducible and reliable diagnostic criteria that reliably translate from one laboratory to another.

Japanese clinical practice guidelines for allied disorders of Hirschsprung's disease, 2017

BACKGROUND

Despite the presence of ganglion cells in the rectum, some patients have symptoms similar to those of Hirschsprung's disease. A consensus has yet to be established regarding the terminology for these diseases. We defined this group of diseases as "allied disorders of Hirschsprung's disease" and compiled these guidelines to facilitate accurate clinician diagnosis and provide appropriate treatment strategies for each disease.

METHODS

These guidelines were developed using the methodologies in the Medical Information Network Distribution System (MINDS). Of seven allied disorders, isolated hypoganglionosis; megacystis-microcolon-intestinal hypoperistalsis syndrome; and chronic idiopathic intestinal pseudo-obstruction were selected as targets of clinical questions (CQ). In a comprehensive search of the Japanese- and English-language articles in PubMed and Ichu-Shi Web, 836 pieces of evidence related to the CQ were extracted from 288 articles; these pieces of evidence were summarized in an evidence table.

RESULTS

We herein outline the newly established Japanese clinical practice guidelines for allied disorders of Hirschsprung's disease. Given that the target diseases are rare and intractable, most evidence was drawn from case reports and case series. In the CQ, the diagnosis, medication, nutritional support, surgical therapy, and prognosis for each disease are given. We emphasize the importance of full-thickness intestinal biopsy specimens for the histopathological evaluation of enteric ganglia. Considering the practicality of the guidelines, the recommendations for each CQ were created with protracted discussions among specialists.

CONCLUSIONS

Clinical practice recommendations for allied disorders of Hirschprung's disease are given for each CQ, along with an assessment of the current evidence. We hope that the information will be helpful in daily practice and future studies.

Advances in understanding functional variations in the Hirschsprung disease spectrum (variant Hirschsprung disease)

Hirschsprung disease (HSCR) is a fairly well understood congenital, genetically based functional obstruction due to the congenital absence of ganglion cells in the distal bowel. However, although over 90% of Hirschsprung cases conform to the normally accepted histological diagnostic criteria, it has become increasingly clear that in addition to HSCR, there is a group of functional disturbances relating to a number of other congenital neurodysplastic conditions causing some degree of gastrointestinal tract malfunction. Although these represent a variety of possibly separate conditions of the enteric nervous system, this spectrum it would appear to be also influenced by similar developmental processes. The term "variant Hirschsprung" is commonly used to describe these conditions, but ganglion cells are mostly present if abnormal in number and distribution. These conditions are a problem group being amongst the most difficult to diagnose and treat with possible practical and legal consequences. The problem appears to be possibly one of definition which has proven difficult in the relative paucity of normal values, especially when correlated to age and gestation. It is the purpose of this paper to review the current position on these conditions and to explore possible shared common pathogenetic and genetic mechanisms. This article explores those conditions where a similar pathogenetic mechanisms to HSCR can be demonstrated (e.g. hypoganglionosis) as well as other neural features, which appear to represent separate conditions possibly linked to certain syndromes.

Genetics of enteric neuropathies

Abnormal development or disturbed functioning of the enteric nervous system (ENS), the intrinsic innervation of the gastrointestinal tract, is associated with the development of neuropathic gastrointestinal motility disorders. Here, we review the underlying molecular basis of these disorders and hypothesize that many of them have a common defective biological mechanism. Genetic burden and environmental components affecting this common mechanism are ultimately responsible for disease severity and symptom heterogeneity. We believe that they act together as the fulcrum in a seesaw balanced with harmful and protective factors, and are responsible for a continuum of symptoms ranging from neuronal hyperplasia to absence of neurons.

Rectal biopsy for Hirschsprung's disease: a review of techniques, pathology, and complications

BACKGROUND

Hirschsprung's disease (HD) is one of the most common congenital anomalies of colorectal function, affecting approximately 1 in 5000 live births, with a 4:1 male predominance. HD is characterized by aganglionosis that is most often limited to the rectosigmoid, but can extend proximally along the colon and, in rare instances, reach into the small intestine. A clinical history of delayed passage of meconium beyond 48 hours after birth, physical exam findings of abdominal distention and vomiting, and a contrast enema demonstrating a transition zone are highly suggestive of HD.

DATA SOURCES

We searched databases including PubMed, Google Scholar, and Scopus for the following key words: Hirschsprung's disease, rectal biopsy, pathology, ganglion cell, nerve trunk hypertrophy, pediatric constipation, and selected publications written in English that were relevant to the scope of this review.

RESULTS

Based on the data presented in the literature, we reviewed 1) biopsy techniques for the diagnosis of Hirschsprung's disease, addressed inadequate biopsies, and complications from rectal biopsy, and 2) pathologic and histologic interpretation of biopsy specimens for the diagnosis of Hirschsprung's disease.

CONCLUSION

A well-executed rectal biopsy with expert pathologic evaluation of the specimen remains the gold standard for the diagnosis of Hirschsprung's disease and is the subject of this review.

Current clinical features in diagnosis and treatment for immaturity of ganglia in Japan: analysis from 10-year nationwide survey

BACKGROUND

To identify the current clinical features in diagnosis and treatment for immaturity of ganglia (IG) in Japan, we retrospectively analyzed data for patients with IG from the nationwide surveys in Japan. This survey was performed by Japanese Study Group of allied disorders of Hirschsprung's disease (ADHD).

METHODS

In primary research, data on totally 355 cases of ADHD were collected for 10 years (2001-2010). Fifteen patients were IG. All IG patients were confirmed by pathological examination. In secondary research, detail questionnaires were sent and collected.

RESULTS

Male/female ratio was 9/6 and mean birth weight was 2474 g. All cases (100 %) were onset in neonatal period. Primary symptoms were abdominal distention (86.7 %), vomiting (53.3 %), and late egestion of meconium (26.7 %). An abnormal distention of intestine was recognized in 86.7 % on X-ray, and microcolon was recognized in 58.3 % on contrast enema. Caliber change was recognized in 58.3 % on laparotomy. An enterostomy was made in 13 patients (86.7 %), and an ileostomy was made in 69.2 %. Pathological diagnosis was performed in 100 %. Enterostomy was closed in 100 %.

CONCLUSIONS

Totally, 15 definitive cases of IG in 10 years were collected and analyzed. All cases were onset in the neonatal period and almost all underwent enterostomy, but no mortalities occurred.

Reevaluation of acetylcholinesterase staining for the diagnosis of Hirschsprung disease and allied disorders

OBJECTIVES

Acetylcholinesterase (AChE) staining has become the gold standard for definitively diagnosing Hirschsprung disease (HD), although some pitfalls have been reported. We reevaluated a large series at our institute in order to validate the accuracy of AChE staining for detecting HD.

METHODS

A retrospective study of the rectal mucosal specimens of all of the children with suspected HD during a 13-year period was performed. The specimens were stained according to the modified Karnovsky-Roots method for AChE staining. The final diagnosis, prognosis, and management after the histopathological diagnosis were analyzed with a questionnaire sent to the patient's original hospital.

RESULTS

Three hundred and fifty-eight specimens were collected. One hundred twenty-two (34%) specimens were diagnosed as HD, 198 (55%) as nonHD, 25 (7%) as "undetermined," and 13 (4%) as "inappropriate." The non-HD group contained 190 (96%) specimens with a normal appearance and 8 (4%) specimens with suspected intestinal neuronal dysplasia (IND). Three hundred and six of 358 questionnaires were returned. The final diagnosis showed that no specimens first diagnosed as HD were identified as non-HD and vice versa, for a sensitivity and specificity of 100%. Four cases were finally diagnosed as chronic idiopathic intestinal pseudo-obstruction (CIIP) in the non-HD group. All of the patients with HD underwent radical surgery. Most non-HD patients were managed conservatively, although some continued to have constipation.

CONCLUSIONS

AChE staining is an accurate tool for differentiating between HD and non-HD with high sensitivity and specificity. CIIP can be included in cases of non-HD; therefore, careful follow-up is mandatory.

Isolated intestinal neuronal dysplasia Type B (IND-B) in Japan: results from a nationwide survey

PURPOSE

Intestinal neuronal dysplasia Type B (IND-B) has been proposed to be an allied disorder of Hirschsprung's disease (ADHD). The original histological criteria included hyperganglionosis, giant ganglia, ectopic ganglion cells and an increased AChE activity in the lamina propria. The criteria for IND-B have been gradually revised. The present diagnostic criteria are [1] more than 20 % of the submucosal ganglia contain nine or more ganglion cells and [2] the patient is older than 1 year. To clarify the current status of IND-B in Japan, a nationwide retrospective cohort study was performed.

METHODS

Questionnaires were sent to 161 major institutes of pediatric surgery and gastroenterology in Japan.

RESULTS

A total of 355 cases of ADHD were collected, including 18 cases of IND-B (5 %). Based on original criteria, 13 out of 18 cases were diagnosed as IND-B. However, only four cases met the current criteria. Three of the four patients (75 %) required pull-through operation. All of the patients exhibited giant ganglia and ganglioneuromatosis-like hyperplasia of the myenteric plexus.

CONCLUSIONS

IND-B cases matching the current criteria are thought to be quite rare and they are associated with marked hyperplasia of the myenteric plexus. "True" IND-B is a rare and intractable disease.

Classification and diagnostic criteria of variants of Hirschsprung's disease

"Variants of Hirschsprung's disease" are conditions that clinically resemble Hirschsprung's disease (HD), despite the presence of ganglion cells in rectal suction biopsies. The diagnosis and management of these patients can be challenging. Specific histological, immunohistochemical and electron microscopic investigations are required to characterize this heterogeneous group of functional bowel disorders. Variants of HD include intestinal neuronal dysplasia, intestinal ganglioneuromatosis, isolated hypoganglionosis, immature ganglia, absence of the argyrophil plexus, internal anal sphincter achalasia and congenital smooth muscle cell disorders such as megacystis microcolon intestinal hypoperistalsis syndrome. This review article systematically classifies variants of HD based on current diagnostic criteria with an additional focus on pathogenesis, epidemiology, clinical presentation, management and outcome.

Segmental aganglionosis (zonal aganglionosis or "skip" lesions) in Hirschsprungs disease: a report of 2 unusual cases

INTRODUCTION

There is accumulating evidence that "skip" lesions or zonal aganglionosis do occur in HSCR disease, albeit rarely. They are of interest because it may cause confusion in interpreting surgical margins as well as understanding the pathophysiology of HSCR disease. Normally described as "a skip area" of normally ganglionated bowel, surrounded proximally and distally by aganglionosis with variations may occur.

CASE REPORTS

We report two cases of infants with unusual types of "skip lesions", identified within the last 5 years.

RESULTS

One patient had an area of zonal aganglionosis in the transverse colon and recto-sigmoid, bordered by areas of normally enervated bowel in the right and descending colon. In the second patient, the terminal ileum, transverse, descending and sigmoid colons and rectum were histologically aganglionic, but focal patches of ganglion cells were identified in 21 cm of the right ascending colon and the appendix, suggesting some ENS plasticity and possible incomplete apoptosis.

CONCLUSION

These cases illustrate the point that the presence of ganglion cells at the resection line is not sufficient to guarantee postoperative function and "skip" lesions may uncommonly confuse the picture. In addition, they raise questions as to its pathophysiology and favor an alternate hypothesis of local changes promoting neuroblast apoptosis as the possible cause.

Favorable surgical treatment outcomes for chronic constipation with features of colonic pseudo-obstruction

AIM: To determine long-term outcomes of surgical treatments for patients with constipation and features of colonic pseudo-obstruction.

METHODS: Consecutive 42 patients who underwent surgery for chronic constipation within the last 13 years were prospectively collected. We identified a subgroup with colonic pseudo-obstruction (CPO) features, with dilatation of the colon proximal to the narrowed transitional zone, in contrast to typical slow-transit constipation (STC), without any dilated colonic segments. The outcomes of surgical treatments for chronic constipation with features of CPO were analyzed and compared with outcomes for STC.

RESULTS: Of the 42 patients who underwent surgery for constipation, 33 patients had CPO with dilatation of the colon proximal to the narrowed transitional zone. There were 16 males and 17 females with a mean age of 51.2 ± 16.1 years. All had symptoms of chronic intestinal obstruction, including abdominal distension, pain, nausea, or vomiting, and the mean duration of symptoms was 67 mo (range: 6-252 mo). Preoperative defecation frequency was 1.5 ± 0.6 times/wk (range: 1-2 times/wk). Thirty-two patients underwent total colectomy, and one patient underwent diverting transverse colostomy. There was no surgery-related mortality. Postoperative histologic examination showed hypoganglionosis or agangliosis in 23 patients and hypoganglionosis combined with visceral neuropathy or myopathy in 10 patients. In contrast, histology of STC group revealed intestinal neuronal dysplasia type B (n = 6) and visceral myopathy (n = 3). Early postoperative complications developed in six patients with CPO; wound infection (n = 3), paralytic ileus (n = 2), and intraabdominal abscess (n = 1). Defecation frequencies 3 mo after surgery improved to 4.2 ± 3.2 times/d (range: 1-15 times/d). Long-term follow-up (median: 39.7 mo) was available in 32 patients; all patients had improvements in constipation symptoms, but two patients needed intermittent medication for management of diarrhea. All 32 patients had distinct improvements in constipation symptoms (with a mean bowel frequency of 3.3 ± 1.3 times/d), social activities, and body mass index (20.5 kg/m² to 22.1 kg/m²) and were satisfied with the results of their surgical treatment. In comparison with nine patients who underwent colectomy for STC without colon dilatation, those in the CPO group had a lower incidence of small bowel obstructions (0% vs 55.6%, P < 0.01) and less difficulty with long-distance travel (6.7% vs 66.7%, P = 0.007) on long-term follow-up.

CONCLUSION: Chronic constipation patients with features of CPO caused by narrowed transitional zone in the left colon had favorable outcomes after total colectomy.

Comparison of posterior internal anal sphincter myectomy and intrasphincteric botulinum toxin injection for treatment of internal anal sphincter achalasia: a meta-analysis

PURPOSE

Internal anal sphincter (IAS) achalasia is a clinical condition with presentation similar to Hirschsprung's disease, but with the presence of ganglion cells on rectal suction biopsy (RSB). The diagnosis is made by anorectal manometry (ARM), which demonstrates the absence of the rectosphincteric reflex on rectal balloon inflation. The recommended treatment of choice is posterior IAS myectomy. Recently, intrasphincteric botulinum toxin (Botox) injection has been effectively used for treatment of IAS achalasia. The aim of this meta-analysis was to compare the efficacy of posterior IAS myectomy with intrasphincteric Botox injection for treatment of IAS achalasia.

METHODS

A systematic literature search for relevant articles was conducted using the following databases: MEDLINE( ® ), EMBASE(®), ISI Web of Science(SM) and the Cochrane Library. A meta-analysis was performed with the studies where IAS achalasia was diagnosed based on the results of ARM and RSB. Odds ratio (OR) with 95 % confidence intervals were calculated.

RESULT

Sixteen prospective and retrospective studies, published from 1973 to 2009, were identified. A total of 395 patients with IAS achalasia were included in this meta-analysis. Fifty-eight percent of patients underwent IAS myectomy and 42 % Botox injection. Regular bowel movements were significantly more frequent after IAS myectomy (OR 0.53, [95 % CI 0.29-0.99]; p = 0.04). There was no significant difference in continued use of laxatives or rectal enemas (OR 0.92, [95 % CI 0.34-2.53], p = 0.89) and in overall complication rates between both procedures (OR 0.68, [95 % CI 0.38-1.21]; p = 0.19). Looking at specific complications, the rate of transient faecal incontinence was significantly higher after Botox injection (OR 0.07, [95 % CI 0.01-0.54]; p < 0.01). Constipation and soiling were not significantly different between both procedures (OR 0.66, [95 % CI 0.30-1.48]; p = 0.31 and OR 0.24, [95 % CI 0.03-2.07]; p = 0.25). The rate of non-response was significantly higher after Botox injection (OR 0.52, [95 % CI 0.27-0.99]; p = 0.04). Subsequent surgical treatment was significantly more frequent after Botox injection (OR 0.18, [95 % CI 0.07-0.44]; p < 0.0001). Short- and long-term improvements were significantly more frequent after IAS myectomy (OR 0.56, [95 % CI 0.32-0.97]; p = 0.04 and OR 0.25, [95 % CI 0.15-0.41]; p < 0.0001).

CONCLUSION

This meta-analysis indicates that in patients with IAS achalasia, posterior IAS myectomy appears to be a more effective treatment option compared to intrasphincteric Botox injection. After Botox injection, the rate of transient faecal incontinence, non-response and subsequent surgical procedures were significantly higher compared to IAS myectomy.

Neonatal functional intestinal obstruction and the presence of severely immature ganglion cells on rectal biopsy: 6 year experience

PURPOSE

We report our experience of managing eight babies who presented with neonatal intestinal obstruction and whose rectal biopsies showed severely immature ganglion cells.

METHODS

Neonatal unit records were reviewed to detect patients with suspected Hirschsprung's disease or functional intestinal obstruction. Those with intestinal atresia, anorectal malformation, malrotation, cystic fibrosis and prematurity were excluded.

RESULTS

We identified 73 patients born at term. Twenty-seven did not need a rectal biopsy. Twenty-one had biopsy proven Hirschsprung's disease, while 17 had a normal rectal biopsy. Eight patients, all of whom presented with severe abdominal distension, showed immature ganglion cells. Seven had failed to pass meconium after birth. X-rays in all patients showed distended loops of bowel. Two neonates underwent an emergency laparotomy and a stoma. A repeat biopsy at 3 months showed maturation of ganglion cells and the stoma was reversed. Rectal biopsy was repeated in two other patients 2-9 months after the first biopsy and showed mature ganglion cells. At follow-up, one patient still suffers from severe constipation. Seven are asymptomatic now, including the two patients who needed a stoma.

CONCLUSION

Immature ganglion cells on rectal biopsy may be an indicator of transient functional immaturity of the intestine.

Manometria anorretal em crianças com constipação intestinal crônica funcional refratária a tratamento

OBJETIVO: Descrever os resultados da manometria anorretal dos pacientes com constipação intestinal crônica funcional (CICF), refratária aos tratamentos habituais, quanto ao tônus esfincteriano, presença do reflexo inibitório retoanal (RIRA), capacidade de expulsão do balão intrarretal e comportamento durante manobra evacuatória. MÉTODOS: Estudo retrospectivo por meio de análise de prontuários médicos entre janeiro de 2003 e junho de 2007, avaliando-se 31 pacientes ambulatoriais com CICF refratária a tratamentos convencionais por manometria anorretal com cateter de quatro canais (processador MPX 816 e software Proctomaster 5.0, Dynamed). RESULTADOS: Dos 31 pacientes, 24 (77%) eram do sexo masculino. A idade média foi 8,9±2,6 anos. A média de pressão máxima fisiológica do canal anal foi 82±38mmHg. Dos 31 pacientes, 15 (48%) apresentaram esfíncter anal normotônico e 16 (52%), hipertônico. O RIRA esteve presente em todos os casos. A prova de expulsão do balão intrarretal foi positiva em 12/31pacientes, sendo 4/12 com esfíncter normotônico e 8/12 com esfíncter hipertônico (p=0,22). Anismo foi detectado em 6/15 pacientes com esfíncter normotônico (40%) e em 4/16 com esfíncter hipertônico (25%) (p=0,45). CONCLUSÕES: Houve predomínio de esfíncter anal normotônico nos casos de CICF refratária. Pouco mais de 1/3 dos pacientes conseguiram a expulsão do balão durante a prova evacuatória, independentemente da tonicidade do esfíncter anal e cerca de metade dos pacientes apresentavam anismo sem relação com a tonicidade do esfíncter anal. A manometria anorretal é apropriada para o estudo da fisiologia e dinâmica evacuatória e pode ser útil para orientar o tratamento.

Diverticular disease is associated with an enteric neuropathy as revealed by morphometric analysis

BACKGROUND

The pathogenesis of diverticular disease (DD) is attributed to several aetiological factors (e.g. age, diet, connective tissue disorders) but also includes distinct intestinal motor abnormalities. Although the enteric nervous system (ENS) is the key-regulator of intestinal motility, data on neuropathological alterations are limited. The study aimed to investigate the ENS by a systematic morphometric analysis.

METHODS

Full-thickness sigmoid specimens obtained from patients with symptomatic DD (n = 27) and controls (n = 27) were processed for conventional histology and immunohistochemistry using anti-HuC/D as pan-neuronal marker. Enteric ganglia, nerve and glial cells were quantified separately in the myenteric, external and internal submucosal plexus compartments.

KEY RESULTS

Compared to controls, patients with DD showed significantly (P < 0.05) (i) reduced neuronal density in all enteric nerve plexus, (ii) decrease of ganglionic nerve cell content in the myenteric plexus, (iii) decreased ganglionic density in the internal submucosal plexus, (iv) reduced glial cell density in the myenteric plexus, (v) decrease of ganglionic glial cell content in the myenteric plexus and increase in submucosal plexus compartments, (vi) increased glia index in all enteric nerve plexus. About 44.4% of patients with DD exhibited myenteric ganglia displaying enteric gliosis.

CONCLUSIONS & INFERENCES

Patients with DD show substantial structural alterations of the ENS mainly characterized by myenteric and submucosal oligo-neuronal hypoganglionosis which may account for intestinal motor abnormalities reported in DD. The morphometric data give evidence that DD is associated with structural alterations of the ENS which may complement established pathogenetic concepts.

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.

Diagnosis and surgical treatment of isolated hypoganglionosis

BACKGROUND

Some patients suspected with Hirschsprung's disease (HD), however, were diagnosed as having isolated hypoganglionosis according to the updated pathohistologic methods. This study was undertaken to investigate the diagnostic methods and the therapeutic results of isolated hypoganglionosis in children.

METHODS

A retrospective analysis was made on 17 patients with isolated hypoganglionosis (hypoganglionosis group) identified pathologically after operation. The data included clinical presentations, barium enema, anorectal manometry, histochemical staining for acetylcholinesterase (AChE) before operation, histological results after operation and follow-up outcomes. The data of hypoganglionosis with HD (HD group) were compared retrospectively.

RESULTS

Common complaint of the patients with hypoganglionosis and HD was intractable constipation. Barium enema showed typical narrowing and distended segment of the colon in 9 patients in the hypoganglionosis group (9/16) and in 15 patients in the HD group (15/18). In the hypoganglionosis group, in 15 patients who underwent anorectal manometry only 5 showed absent rectal anal inhibitory reflex, significantly lower than the rate in the HD group (17/18) (P<0.05). From 16 patients in hypoganglionosis group, positive staining for AChE was noted in 3 patients (3/16, 18.8%), significantly lower than that in the HD group (16/18, 88.9%) (P<0.05). Thirteen patients in the hypoganglionosis group received subtotal colectomy, while only 5 patients needed subtotal colectomy in the HD group. In the hypoganglionosis group, except 2 patients who suffered from mild enterocolitis after operation and recovered after conservative therapy, all patients recovered uneventfully without wound dehiscence, intestinal fistula, fecal incontinence or constipation recurrence. In the HD group, one patient suffered from anastomotic leak and got secondary operation, one patient had anastomotic stricture at 1 year after operation and recovered by dilatation, and other three patients suffered from mild enterocolitis after operation and recovered after conservative therapy.

CONCLUSIONS

Hypoganglionosis is a common disease, and could be finally confirmed by full-thickness biopsies in different bowel segments. The resection range can be estimated according to barium enema and 24-hour delayed X-ray findings, by which the satisfactory result in short-term follow-up can be obtained.

Interstitial cells of Cajal in the normal gut and in intestinal motility disorders of childhood

Interstitial cells of Cajal (ICCs) are pacemaker cells which are densely distributed throughout the whole gastrointestinal tract. ICCs have important functions in neurotransmission, generation of slow waves and regulation of mechanical activities in the gastrointestinal tract, especially for the coordinated gastrointestinal peristalsis. Therefore, a loss of ICCs could result in gastrointestinal motor dysfunction. In recent years c-kit labeling has been widely used to study pathological changes of ICCs in gastrointestinal motility disorders. Paediatric gastrointestinal motility disorders such as hypertrophic pyloric stenosis, Hirschsprung's disease, total colonic aganglionosis, hypoganglionosis, intestinal neuronal dysplasia, internal anal sphincter achalasia, megacystis microcolon intestinal hypoperistalsis syndrome have been reported to be associated with loss or deficiency of ICCs networks. This review describes the distribution of ICCs in the normal gastrointestinal tract and its altered distribution in intestinal motility disorders of childhood.

Enteric nervous system and developmental abnormalities in childhood

ENS consists of a complex network of neurons, organised in several plexuses, which interact by means of numerous neurotransmitters. It is capable of modulating the intestinal motility, exocrine and endocrine secretions, microcirculation and immune and inflammatory responses within the gastrointestinal tract, independent of the central nervous system. Though the embryological development of various plexuses are completed by mid-way of gestation, the maturation of neurons and nerve plexuses appear to continue well after birth. Therefore, any histological or functional abnormalities related to the gastrointestinal function must be investigated with the ongoing maturational processes in mind.

Mutation of RET proto-oncogene in Hirschsprung’s disease and intestinal neuronal dysplasia

AIM: To investigate the genetic relationship between Hirschsprung’s disease (HD) and intestinal neuronal dysplasia (IND) in Chinese population.

METHODS: Peripheral blood samples were obtained from 30 HD patients, 20 IND patients, 18 HD/IND combined patients and 20 normal individuals as control. Genomic DNA was extracted according to standard procedure. Exons 11,13,15,17 of RET proto-oncogene were amplified by polymerase chain reaction (PCR). The mutations of RET proto-oncogene were analyzed by single strand conformational polymorphism (SSCP) and sequencing of the positive amplified products was performed.

RESULTS: Eight germline sequence variants were detected. In HD patients, 2 missense mutations in exon 11 at nucleotide 15165 G→A (G667S), 2 frameshift mutations in exon 13 at nucleotide 18974 (18974insG), 1 missense mutation in exon 13 at nucleotide 18919 A→G (K756E) and 1 silent mutation in exon 15 at nucleotide 20692 G→A(Q916Q) were detected. In HD/IND combined patients, 1 missense mutation in exon 11 at nucleotide 15165 G→A and 1 silent mutation in exon 13 at nucleotide 18888 T→G (L745L) were detected. No mutation was found in IND patients and controls.

CONCLUSION: Mutation of RET proto-oncogene is involved in the etiopathogenesis of HD. The frequency of RET proto-oncogene mutation is quite different between IND and HD in Chinese population. IND is a distinct clinical entity genetically different from HD.

Long-term outcome after internal sphincter myectomy for internal sphincter achalasia

Anal internal sphincter achalasia is a rare cause of refractory constipation. It is usually treated by internal sphincter myectomy (ISM). The aim of this study was to evaluate the long-term outcome of patients who had undergone ISM for internal sphincter achalasia. Bowel habits, fecal continence, and quality of life were evaluated using a questionnaire. Fecal continence was quantitatively assessed by a score described by Holschneider. A questionnaire was sent to 13 patients (11 male, two female) operated on by ISM for intractable constipation caused by internal sphincter achalasia between 1983 and 1993. Ten patients responded and were included in the study. At the time of the study, three of the 10 patients required oral medication for constipation and had one to three bowel movements per week. One of the 10 patients had three to five bowel movements per day, and the others had one to two bowel movements per day. Four patients had normal and six patients had good continence scores. Four of the patients reported mild social problems, and one had problems associated with sports. Refractory constipation in the majority of patients with internal sphincter achalasia can be treated by ISM. However, in the long term, a significant number of patients suffer from soiling-related social problems.

Variant Hirschsprung's disease

Conditions that clinically resemble HD despite the presence of ganglion cells on suction rectal biopsy results, can be diagnosed by providing an adequate biopsy and employing a variety of histological techniques. Intestinal neuronal dysplasia is a distinct clinical entity that can be clearly proven histologically. Patients with IND not only have abnormalities of submucosal and myenteric plexuses but also defective innervation of the muscle. Internal sphincter achalasia, which is histologically characterized by nitrergic nerve depletion, can be diagnosed on anorectal manometry and successfully treated by internal sphincter myectomy. The outcome of smooth muscle disorders is generally fatal. The need for surgical intervention should be weighed carefully and individualized because most explorations have not been helpful and are probably not necessary.

Constipation and intestinal neuronal dysplasia type B: a clinical follow-up study

OBJECTIVE

Intestinal neuronal dysplasia type B (IND B) is one of the gastrointestinal motility disorders with a defined malformation of the parasympathetic submucous and myenteric ganglia. The clinical presentation of IND B is variable, ranging from intestinal obstruction in the neonatal period to acute or chronic constipation in childhood.

METHODS

Between 1993 and 1996, 105 patients (49 females and 56 males) were treated for constipation, and in all of them an IND type B was confirmed histopathologically. Twenty-two neonates, 42 infants to 6 months of age (38% of them were premature, and 5% had additional malformations), and 41 patients to the age of 4 years were included in this study. All 105 patients had been treated conservatively. Treatment consisted of diet in all patients, cisapride in 70% of them, laxatives in 52%, and repeated anal dilatations in 12% of the patients. The mean duration of their treatment lasted from 3 months to 10 months (mean, 6 months).

RESULTS

The clinical follow-up 5 to 9 years later in 89 of the 108 (85%) patients showed daily defecation in 80% of them and every second day in 14% of them. Only 5 (6%) patients experience recurrent constipation, which responds well to diet and laxatives.

CONCLUSIONS

In young patients, constipation related to IND B can be treated successfully by conservative treatment regimens, including diet, laxatives, and prokinetic drugs.

Pathogenesis of Hirschsprung's disease and its variants: recent progress

The enteric nervous system (ENS) is a complex network of interconnected neurons within the wall of the intestine that controls intestinal motility, regulates mucosal secretion and blood flow, and also modulates sensation from the gut. The cells that form the ENS in mammals are derived primarily from vagal neural crest cells. During the past decade there has been an explosion of information about genes that control the development of neural crest. Molecular-genetic analysis has identified several genes that have a role in the development of Hirschsprung's disease. The major susceptibility gene is RET, which is also involved in multiple endocrine neoplasia type 2. Recently, genetic studies have provided strong evidence in animal models that intestinal neuronal dysplasia (IND) is a real entity. HOX11L1 knockout mice and endothelin B receptor-deficient rats demonstrated abnormalities of the ENS resembling IND type B in humans. These findings support the concept that IND may be linked to a genetic defect.

Intestinal neuronal dysplasia

Intestinal neuronal dysplasia (IND) is a clinical condition that resembles Hirschsprung's disease. In the past many years investigators have raised doubts about the existence of IND as a distinct histopathologic entity. One strong piece of evidence that IND is a real entity stems from animal models. Recently, two different HOX11L1 knockout mouse models and a heterozygous endothelin B receptor-deficient rat demonstrated abnormalities of the submucous plexus similar to that observed in human IND. This review describes in detail the diagnostic criteria of IND, staining techniques, correlation between histological findings and clinical symptoms, and management of IND.

Alterations of enteric nerve plexus in experimental gastroschisis: is there a delay in the maturation?

BACKGROUND/PURPOSE

After surgical correction of gastroschisis, intestinal transitory hypoperistalsis usually occurs. Long-term parenteral nutrition often is necessary leading to a higher morbidity associated with this malformation. The etiology of this transitory intestinal hypomotility is unknown. It may be caused by a reversible inflammatory process in the intestinal wall or other causes, including an alteration of the maturation of intestinal neural plexus, because the disturbance disappears spontaneously after a variable period. The aim of this work was to study the neuronal cells of the myenteric plexus of the fetal intestine in experimental gastroschisis. The main hypothesis was that the transitory intestinal dismotility seen in gastroschisis could be secondary to alteration in the maturation of the enteric nervous plexus.

METHODS

Twenty-seven time-mated rabbits, on gestational day 25, were submitted to a midline laparotomy; the gravid bicornuate uterus was exposed and opened, and the more distal fetuses relative to the vaginal opening had the abdominal wall opened by a small incision to produce gastroschisis (n = 29). The fetuses not submitted to gastroschisis were used as controls (n = 12). The amniotic fluid was carefully aspirated from the opened uterus and saved for later repositions. On gestational day 30, the does were again submitted to general anesthesia, and the fetuses were delivered by cesarean section. The fetal intestine was removed, the adjacent mesentery excised, and intestinal specimens were harvested for histologic studies. The specimens were stained for acetyl-cholinesterase activity (AChE) to assess the maturity of the nervous enteric cells and for lactate dehydrogenase (LDH) that identify specifically immature nervous cells. The histologic sections stained by LDH were submitted to histomorphometric analysis of the nervous cells through an image system analysis (Kontron 300). The results were submitted to statistical analyses (P <.05).

RESULTS

Macroscopic alterations of the fetal gastroschisis intestine are similar to the human findings: shortening of the intestine, intestinal wall thickening, and a hypertrophied muscular layer. In the gastroschisis group, histologic AChE activity was decreased in comparison with control intestines. The histomorphometric assessment in slices stained with LDH, which identify immature nervous cells, showed that the neuronal intestinal cells of the gastroschisis group were significantly smaller and more numerous relative to the control group.

CONCLUSIONS

There were significant differences in the nervous plexus of the intestine of fetuses with gastroschisis relative to the controls. The observed morphologic changes may be caused by alteration in the maturation of the intestinal neuronal in gastroschisis. This alteration may explain the transitory intestinal hypomotility observed in infants after surgical correction of gastroschisis.

Intestinal neuronal dysplasia type A

Intestinal neuronal dysplasia is a rare cause of bowel obstruction in neonates and infants, the diagnosis of which poses a formidable challenge to both clinicians and pathologists alike. The importance of this entity lies not only in the fact that it mimics Hirschsprung's disease, but also in that untreated cases, particularly of type A, may prove fatal. The authors describe one such case of intestinal neuronal dysplasia of type A, which was diagnosed at autopsy.

Abnormalities of C-Kit-positive cellular network in isolated hypoganglionosis

BACKGROUND/PURPOSE

C-Kit-positive interstitial cells of Cajal (ICCs) have a key role in the normal motility function and development of the bowel. They are pacemaker cells, which facilitate active propagation of electrical events and neurotransmission in the bowel wall. ICCs are present in the bowel as myenteric ICCs (ICC(my)S) and muscular ICCs (ICC(mus)S). The aim of this study was to examine the distribution of c-Kit-positive ICCs and their relationship to the autonomic intrinsic innervation in bowel specimens from patients with isolated hypoganglionosis.

METHODS

Full-thickness large bowel specimens were obtained from 6 patients with hypoganglionosis and from 4 patients during bladder augmentation (controls). Frozen sections and whole-mount preparations were stained using c-Kit immunohistochemistry, nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase, and acetylcholinesterase (AChE) histochemistry and evaluated using normal brightfield and confocal laser scanning microscopy.

RESULTS

NADPH-diaphorase and AChE histochemistry findings showed characteristic histologic features of hypoganglionosis, eg, sparse and small myenteric ganglia and low or absent AChE activity in the lamina propria. Myenteric plexus in the normal bowel was surrounded by a dense network of c-Kit-positive ICC(my)S, whereas in hypoganglionosis sparse isolated ICC(my)S were found. C-Kit-positive ICC(mus)S were reduced markedly in the longitudinal and circular muscle layer and at the innermost part of the circular muscle in hypoganglionosis.

CONCLUSION

Deficient expression of c-Kit-positive myenteric and muscular ICCs in the hypoganglionic colon may contribute to the motility dysfunction in the affected bowel.

Slow transit constipation in children

Patients with chronic constipation that fails to respond to treatment remain a challenge for paediatricians and surgeons. Ongoing work in our institution suggests that a number of children with intractable symptoms have slow transit constipation, which has only been described recently in paediatrics. Common features of slow transit are: delayed passage of the first meconium stool beyond 24 h of age, symptoms of severe constipation within a year, or treatment-resistant 'encopresis' at 2-3 years, soft stools despite infrequent bowel actions, and delay in colonic transit on a transit study. A proportion of children with slow transit constipation have an abnormality of intestinal innervation associated with the dysfunctional colonic motility, recognized as intestinal neuronal dysplasia (IND). Intestinal neuronal dysplasia type B, the most common variant of IND, is defined on rectal biopsy by hyperplasia of the submucosal plexus. On laparoscopic colon muscle biopsy, many specimens show reduced numbers of excitatory substance P-immunoreactive nerve fibres in the circular muscle. Functional markers of the nerves allow new diagnostic criteria to be developed which may also allow a more rational approach to treatment. The aetiology remains obscure and the optimal management poorly defined, although subtotal colectomy, proximal colostomy or appendicostomy (for antegrade enemas) have been tried. Once the anatomy and physiology of the colon in children with slow colonic transit is better understood, we will have defined not only a new form of constipation, but also will be able to consider new therapies.

Neuropathology of paediatric chronic intestinal pseudo-obstruction and related animal models

Chronic intestinal pseudo-obstruction (CIP) in paediatric patients is due to heterogeneous aetiologies that include primary disorders of the enteric nervous system. These conditions are poorly delineated by contemporary diagnostic approaches, in part because the complex nature of the enteric nervous system may shelter significant physiological defects behind subtle or quantitative anatomical changes. Until recently, relatively few experimental animal models existed for paediatric CIP. However, the availability of rodent models, particularly novel mutants created in the last few years by genetic manipulations, has brought unprecedented opportunities to investigate molecular, cellular, physiological, and histological details of enteric neuropathology. Information gleaned from studies of these animals is likely to change diagnostic and therapeutic approaches to paediatric CIP and related conditions.

Clinicopathologic relationship of hypoganglionosis

BACKGROUND/PURPOSE

Congenital motor dysfunction of the intestine associated with a morphologically abnormal myenteric nervous plexus (MP) is known as Hirschsprung's disease allied disorder (HAD). However, the clinicopathologic features of HAD are not well understood, partially because a standardized method of histologic evaluation of MP has not been established. To elucidate the clinicopathologic relationship of HAD the authors reviewed 6 cases of HAD using a newly devised histologic evaluation method.

METHODS

Flat-mounted frozen sections of the ileum were stained for S-100 protein by fluorescent immunohistochemistry. Quantitative evaluation of MP was performed by measuring the fluorescence-positive area (MP ratio), and the results were compared with those of age-matched normal controls.

RESULTS

All of 6 patients required laparotomy within 1 month after birth and enterostomy between 23 days and 10 months. Three died of intractable enteritis by the age of 2.2 years and were totally dependent on parenteral nutrition (PN) throughout their lives. The other 3 have survived for 6 to 10 years but have required PN occasionally. MP ratio in controls was more than 0.34 at all ages, whereas that in HAD was significantly lower than that in controls according to the clinical severity.

CONCLUSION

MP size measured on 2-dimensional demonstration is suggested to be an indicator of clinical severity of HAD. J Pediatr Surg 36:898-900.

Intestinal neuronal dysplasia: results of treatment in 33 patients

PURPOSE

Intestinal neuronal dysplasia (IND) is a disease of the enteric nervous system, which clinically resembles Hirschsprung's disease. The authors reviewed their experience of IND over an 8-year period.

METHODS

Between 1992 and 1999, 418 patients underwent rectal suction biopsy for persistent constipation. Thirty-three (7.8%) patients had histologic evidence of IND. There were 26 boys and 7 girls (age range, 1 week to 10 years). The diagnosis of IND was based on the presence of hyperganglionosis of the submucous plexus and giant ganglia and at least one of the following features in rectal biopsies: (1) ectopic ganglia, (2) increased acetylcholinesterase (AChE) activity in the lamina propria, and (3) increased AChE nerve fibers around the submucosal blood vessels. All patients were started on laxatives with or without enemas after the diagnosis was made. Patients have been followed up from 1 to 8 years (mean, 2.4 years).

RESULTS

Twenty-one (64%) patients had a good response to conservative management and currently have normal bowel habits. Twelve patients (36%) underwent internal sphincter myectomy after failed conservative management. Seven of these patients now have normal bowel habits. Two patients are able to stay clean with regular enemas. Three patients who continued to have persistent constipation after myectomy and underwent resection of redundant and dilated sigmoid colon now have normal bowel habits.

CONCLUSION

The majority of patients with IND can be treated successfully with conservative treatment.

Megacystis microcolon intestinal hypoperistalsis syndrome

Megacystis microcolon intestinal hypoperistalsis syndrome (MMIHS) is a rare cause of intestinal obstruction mainly affecting female neonates. We present a case of a newborn female infant with a history of abdominal distension, bilious vomiting and decreased urine output. Barium enema showed a microcolon. Patient died soon after admission and the autopsy revealed a shortened bowel, a microcolon with abundant ganglion cells in the myenteric plexus, and an enlarged urinary bladder. An interesting finding in this case was the presence of enlarged nerve bundles containing several large ganglion cells on the lateral wall of the cervix. The salient clinical and autopsy findings in this case are presented.

Hirschsprung disease and other enteric dysganglionoses

Hirschsprung disease has become a paradigm for multigene disorders because the same basic phenotype is associated with mutations in at least seven distinct genes. As such, the condition poses distinct challenges for clinicians, patients, diagnostic pathologists, and basic scientists, who must cope with the implications of this genetic complexity to comprehend the pathogenesis of the disorder and effectively manage patients. This review focuses on the anatomic pathology, genetics, and pathogenesis of Hirschsprung disease and related conditions. The nature and functions of "Hirschsprung disease genes" are examined in detail and emphasis is placed on the importance of animal models to this field. Where possible, potential uses and limitations of new data concerning molecular genetics and pathogenesis are discussed as they relate to contemporary medical practices.