Intestinal neuronal dysplasia

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.

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.

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.

Allergic proctitis and abdominal distention mimicking Hirschsprung's disease in infants

AIM

To determine the incidence and clinical aspects of allergic proctitis (AP) in infants with symptoms that mimic Hirschsprung's disease (HD).

METHODS

One hundred and five patients less than 6 months of age, who underwent barium enema, anorectal manometry and rectal suction biopsy due to suspicion of HD, were enrolled. Comparison of the patient characteristics associated with each disease was based on the results of the triple testing. The sensitivity and specificity of the three tests, for the diagnosis of HD, were evaluated.

RESULTS

The mean age of enrolled patients was 2.1+/-0.9 months. Based on the three tests, 39 patients (37.1%) were diagnosed with HD, seven patients (6.7%) with AP, and 53 (50.5%) had normal results. Of the 54 patients with transitional zone and a reversed rectosigmoid index on the barium enema, four (7.4%) were patients with AP. The mean age of the AP patients (3.1+/-1.5 months old) was older than the HD children (1.4+/-0.9 months old). The sensitivity of the three tests for HD was 97.4%, 87.2% and 92.3% and the specificity was: 74.2%, 78.8% and 100%, respectively.

CONCLUSIONS

In the infants with severe abdominal distention, the incidence of AP mimicking HD was relatively high. Therefore, consideration of AP should be part of the differential diagnosis in infants with severe abdominal distention or findings that mimic HD. For differentiation of these disorders, a rectal suction biopsy is very useful.

Controversies concerning diagnostic guidelines for anomalies of the enteric nervous system: a report from the fourth International Symposium on Hirschsprung's disease and related neurocristopathies

Intestinal Dysganglionoses (IDs) represent a heterogeneous group of Enteric Nervous System anomalies including Hirschsprung's disease (HD), Intestinal Neuronal Dysplasia (IND), Internal Anal Sphincter Neurogenic Achalasia (IASNA) and Hypoganglionosis. At present HD is the only recognised clinico-pathological entity, whereas the others are not yet worldwide accepted and diagnosed. This report describes the areas of agreement and disagreement regarding definition, diagnosis, and management of IDs as discussed at the workshop of the fourth International Meeting on "Hirschsprung's disease and related neurochristopathies." The gold standards in the preoperative diagnosis of IDs are described, enlighting the importance of rectal suction biopsy in the diagnostic workup. The most important diagnostic features of HD are the combination of hypertrophic nerve trunks and aganglionosis in adequate specimens. Acetylcholinesterase staining is the best diagnostic technique to demonstrate hypertrophic nerve trunks in lamina propia mucosae, but many pathologist from different centers still use H&E staining effectively. Moreover, the importance of an adequate intraoperative pathological evaluation of the extent of IDs to avoid postoperative complications is stressed. Although it is not clear whether IND is a separate entity or some sort of secondary acquired condition, it is concluded that both IND and IASNA do exist. Other interesting conclusions are provided as well as detailed results of the discussion. Further investigation is needed to resolve the many controversies concerning IDs. The fourth International Conference in Sestri Levante stimulated discussion regarding these entities and led to the International guidelines to serve the best interest of our patients.

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.

Abnormal vasculature in intestinal neuronal dysplasia

Intestinal neuronal dysplasia (IND) is an intestinal motility disorder, which clinically resembles Hirschsprung's disease (HD). Adventitial fibromuscular dysplasia (AFMD) consists of proliferation of smooth muscle cells and collagen fibers in the adventitia of blood vessels. The purpose of this study was to investigate vascular abnormalities in large bowel biopsies from patients with isolated HD, IND associated with HD and isolated IND. Large bowel biopsies from patients presenting with isolated HD ( n=23), IND associated with HD ( n=11), isolated IND ( n=16) and normal bowel as controls ( n=6) were investigated using acetylcholinesterase (AChE) histochemistry, van Gieson staining and alpha-smooth muscle actin (alpha-SMA) immunohistochemistry. Increased AChE activity around submucosal vessels was found in 9/16 (56%) cases with isolated IND, 3/11 (27%) cases of IND associated with HD, 5/23 (21%) isolated HD cases and 0/6 controls. AFMD was found in 10/16 (62%) of the isolated IND cases, 4/11 (362) of the cases with IND associated with HD and 4/23 (17%) cases of HD without IND using van Gieson staining. None of the control specimens revealed AFMD. Increased alpha-SMA immunoreactivity filaments were demonstrated in the submucosal vessel wall in 9/16 (56%) of isolated IND and 2/11(18%) of IND associated with HD cases. Normal alpha-SMA immunoreactivity around submucosal vessels was seen in isolated HD and controls. Abnormal submucosal vasculature is a common histological finding in isolated IND and IND associated with HD and may be a useful additional diagnostic feature in these patients.

The enteric nervous system I: organisation and classification

Major advances have been made in our understanding of the nervous system in the gastrointestinal tract, the enteric nervous system. Because of its importance, neurogastroenterology is being increasingly recognised in clinical pharmacology. The enteric nervous system is a collection of neurones that can function more or less independently of the central nervous system and controls or modulates motility, exocrine and endocrine secretions, microcirculation and immune and inflammatory processes. Increasing knowledge of the physiology, pathophysiology, and pharmacology of the enteric nervous system will provide a basis for creation of new approaches to the treatment of gastrointestinal disorders. This review is part one of three and will describe the organisation and classification of the enteric nervous system.

Molecular etiology of gut malformations and diseases

This review describes recent advances using animal models in the analysis of the molecular controls of gastrointestinal development, with specific attention to mutations causing maldevelopment similar to those seen in human gut malformations. By focusing on specific human gut pathologic conditions and maldevelopment, we describe the probable roles of signaling pathways, including the hedgehog pathway, the bone morphogenic protein pathway, and the role of the homeotic genes.

Enteric nervous system: development and developmental disturbances--part 1

This review, which is presented in two parts, summarizes and synthesizes current views on the genetic, molecular, and cell biological underpinnings of the early embryonic phases of enteric nervous system (ENS) formation and its defects. In the first part, we describe the critical features of two principal abnormalities of ENS development: Hirschsprung's disease (HSCR) and intestinal neuronal dysplasia type B (INDB) in humans, and the similar abnormalities in animals. These represent the extremes of the diagnostic spectrum: HSCR has agreed and unequivocal diagnostic criteria, whereas the diagnosis and even existence of INDB as a clinical entity is highly controversial. The difficulties in diagnosis and treatment of both these conditions are discussed. We then review the genes now known which, when mutated or deleted, may cause defects of ENS development. Many of these genetic abnormalities in animal models give a phenotype similar or identical to HSCR, and were discovered by studies of humans and of mouse mutants with similar defects. The most important of these genes are those coding for molecules in the GDNF intercellular signaling system, and those coding for molecules in the ET-3 signaling system. However, a range of other genes for different signaling systems and for transcription factors also disturb ENS formation when they are deleted or mutated. In addition, a large proportion of HSCR cases have not been ascribed to the currently known genes, suggesting that additional genes for ENS development await discovery.

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.

Colonic motility after surgery for Hirschsprung's disease

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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