Chronic idiopathic intestinal pseudo-obstruction caused by a degenerative disorder of the myenteric plexus: the use of Smith's method to define the neuropathology

In this paper we report the pathologic basis of chronic idiopathic intestinal pseudo-obstruction in a patient who had a subtotal colectomy and ileorectal anastomosis for severe obstipation. Conventional light microscopy of the resected intestine showed an increased thickness of the longitudinal muscle, minimal amounts of smooth muscle fibrosis, and normal smooth muscle cells. The morphology of the myenteric plexus was difficult to interpret with this technique, but quantification of colonic neurons revealed a significantly decreased number compared with controls. Silver stains of the myenteric plexus by Smith's method showed: (a) patchy loss of nerve tracts with replacement by Schwann cells, (b) degeneration and decreased numbers of both argryophilic and argyrophobic neurons, (c) fragmentation and dropout of many axons, and (d) increased thickness and disorganized spatial arrangement of other axons. The pathology of this intestinal neuropathy could be missed by conventional light microscopy and may be apparent only when a silver technique is used to visualize the myenteric plexus.     

Jejunal diverticulosis with perforation as a complication of Fabry's disease

This study presents the case of a patient who had jejunal diverticulosis with perforation and abscess formation as a complication of Fabry's disease. Light microscopy disclosed glycolipid deposition in the neurons and nerve fibers of the intestinal nerve plexuses and smooth muscle. Silver stains of the myenteric plexus in the involved segment of the bowel showed enlarged, granular argyrophobic neurons and a marked decrease in the number of argyrophilic neurons, with those remaining being enlarged and distorted by the cytoplasmic glycolipid accumulation. These abnormalities of the myenteric plexus suggest that jejunal diverticulosis may be the result of a variety of disorders of the smooth muscle or myenteric plexus, or both. We propose that jejunal diverticulosis in our patient was a consequence of uncoordinated smooth muscle activity resulting from Fabry's involvement of myenteric plexus neurons, with mucosal protrusion through the smooth muscle.     

Paraneoplastic visceral neuropathy as a cause of severe gastrointestinal motor dysfunction

The purpose of this study was to define the cause of severe gastrointestinal motor dysfunction in 7 patients with lung cancer. Six patients had small cell carcinoma and 1 patient had pulmonary carcinoid. Their ages ranged from 58 to 74 yr. All had intestinal pseudoobstruction and obstipation/constipation; 6 of 7 patients had gastroparesis; 4 of 4 patients had esophageal peristaltic abnormalities; and 2 patients had neurogenic bladders, autonomic insufficiency, and peripheral neuropathy. Five of 7 patients had dilated small bowel with 4 of them showing slow transit of barium; 2 of 7 patients had dilated colons; and 3 of 7 patients had slow colonic transit. Five patients died 4-9 mo after onset of gastrointestinal symptoms, and 2 survived. Post-mortem or surgical samples of the esophagus, stomach, small bowel, and colon showed neuron and axon degeneration and dropout, lymphoplasmacytic infiltration, and glial cell proliferation within the myenteric plexus of 6 patients. The antrum from the seventh patient had inflammatory cells within the myenteric plexus but without neuron dropout. Neuron numbers were significantly less than normal in each area of the gastrointestinal tract. Thus, we conclude that lung cancer may be complicated by severe gastrointestinal motor dysfunction resulting from visceral neuropathy of the myenteric plexus, a paraneoplastic effect of the cancer.     

伴高脂血症急性坏死性胰腺炎大鼠胃肠传输与肠肌间神经丛形态改变研究

目的 探讨肠肌间神经丛形态改变与伴高脂血症急性坏死性胰腺炎(ANP)大鼠胃肠传输延迟的关系.方法 将40只雄性SD大鼠均分为4组(正常对照组、单纯ANP组、高脂对照组、高脂ANP组),分组采用高脂饲料喂养4周建立大鼠高脂血症模型,应用逆行胰胆管注射3.5%牛磺胆酸钠制作ANP大鼠模型.用墨汁灌胃法测量各组大鼠胃肠传输距离,计算胃肠传输率,以Karnovsky-Root直接法和NADPH组织化学法观察回肠肌间神经丛胆碱能和氮能神经的组织形态学改变.结果 高脂ANP组较单纯ANP组胰腺炎病理损伤加重(病理学评分12.8±0.63比10.8±1.93,P<0.01),胃肠传输明显延迟(传输率27%±5%比38%±6%,P<0.01),胆碱能神经元密度下降(4.80±1.23比5.80±0.79,P<0.05),氮能神经元密度明显升高(8.70±0.75比6.80±1.48,P<0.01).肌间神经丛乙酰胆碱脂酶和一氧化氮合酶改变与胃肠传输率有线性回归关系(R2=0.531,P<0.01).结论 伴高脂血症ANP的大鼠存在明显胃肠动力障碍,肠肌间神经丛形态改变与其密切相关.

Abstract：

Objective To explore association between the changes of myenteric nerve plexus and the delayed gastrointestinal transit in acute necrotic pancreatitis (ANP) rat complicated with hyperlipemia. Methods Atotal of 40 male Sprague-Dawley (SD) rats were randomly divided into 4 groups (normal control group, ANP group, hyperlipemia (HL) control group and HL with ANP group). HL rat model was established by fed with high-fat diet for 4 weeks, and ANP rat model was induced by retrograde injection of 3.5% sodium taurocholate into pancreatic duct. Gastrointestina1 transit distance was measured by ink gavage method. The histological changes of cholinergic and nitriergic nerves in myenteric plexus were observed by Karnovsky-Root method and NADPH histochemistry method. Results Pathological injuries were more severe in HL with ANP group than in ANP group (12.8±0.63 vs. 10.8±1.93,P<0.01), gastrointestinal transit was obviously delayed (transmission rate was 27%±5% vs. 38%±6%,P<0.01), the density of cholinergic neurons decreased (4.80±1.23 vs. 5.80±0.79, P<0.05), and the density of nitriergic neurons significantly increased (8.70±0.75 vs. 6.80±1.48, P<0.01). There was a linear regression between changes of cholinergic and nitrievgic nerves in myenteric nerve plexus and gastrointestinal transit (R2=0.531, P<0.01). Conclusion There was significant gastrointestinal motility disorder in the ANP rat complicated with hyperlipemia, which may be closely related with the changes of myenteric nerve plexus.     

Familial enteric neuropathy with pseudoobstruction

We report a case of autosomal dominant chronic intestinal pseudoobstruction secondary to a familial enteric neuropathy. Esophagogastrointestinal manometry studies in the index case showed decreased postprandial contractile frequency with normal amplitude of pressure activity in the stomach and small bowel. Pupillary function and autonomic reflexes were all normal, excluding an extrinsic autonomic neuropathy of the viscera. Histologic examination of the small intestine by hematoxylin and eosin stains revealed normal smooth muscles but a reduced number of neurons in the myenteric plexus without inflammatory cells or neuroNal intranuclear inclusions. Histologic examination of the myenteric plexus using the sections taken along the longitudinal axis of the intestine, stained with silver by the Smith technique, disclosed decreased numbers of argyrophilic neurons and degeneration of neurons and axons; however, there was no reactive increase in the number of glial cell nuclei. The patient's mother had suffered from chronic intestinal pseudoobstruction, which did not abate following extensive small bowel resection. This is the third family reported with an autosomal dominant enteric neuropathy unassociated with evidence of extrinsic autonomic or peripheral neuropathy. Subtotal resection of the small bowel was followed by recurrence of the pseudoobstruction syndrome in both affected members of the family.     

Megacolon in myotonic dystrophy caused by a degenerative neuropathy of the myenteric plexus

A 32-yr-old man with myotonic dystrophy had a left hemicolectomy performed because of a megacolon. The colonic mucosa, smooth muscle, and connective tissue appeared normal by hematoxylin and eosin and trichrome stains and transmission electron microscopy. In contrast, the myenteric plexus had markedly fewer neurons than normal on the hematoxylin and eosin stains. Silver staining of the plexus revealed degeneration and decreased numbers of argyrophilic neurons, which were smaller and had fewer processes and a more uneven staining quality than controls. Many axons were fragmented, and increased numbers of glial cell nuclei were present in the plexus. Degenerative changes in the neurons were present in a patchy distribution on transmission electron microscopy. Immunohistochemistry revealed a decrease of the substance P- and enkephalin-immunoreactive fibers in the muscularis externa. This suggests that colonic motor dysfunction associated with myotonic dystrophy may be caused by a visceral neuropathy that involves the substance P- and enkephalin-immunoreactive fibers of the smooth muscle.     

The pathogenesis of idiopathic megacolon

BACKGROUND: Even today, the pathogenesis of idiopathic megacolon is still a subject of controversy. Anomalies of the gastrointestinal autonomous nervous system or of the smooth muscle of the muscularis propria are being considered. METHODS: Sixty-three idiopathic megacolon resections between 1997 and June 2004 were investigated. The native specimens were coiled caudo-cranially and cryostat-cut. Connective tissue was stained with picric acid/Sirius red after Delauney fixation. Immunohistochemistry was performed for collagen types I, II, III and IV, as well as smooth muscle actin, vimentin, desmin fibronectin and CD117 for interstitial cells of Cajal. The enteric nervous system was examined by enzyme histochemistry for acetylcholine-esterase, lactate dehydrogenase, succinic dehydrogenase and nitroxide synthase. RESULTS: Histologically, idiopathic megacolon was characterized by a total atrophy of the collagenous tendinous connective tissue membrane of the myenteric plexus and the tendinous collagen fibre net of the muscularis propria. Immunohistochemically, mainly collagen type III was missing in the muscularis propria. Interestingly, the incidence of idiopathic megacolon in those of the female sex was seven times more frequent than in the male sex. The myenteric plexus was normal in the majority of patients. Interstitial cells of Cajal, collagen II and IV, as well as smooth muscle actin, desmin and fibronectin showed no consistent alteration. CONCLUSION: A normally structured tendinous fibre net of muscularis propria is an essential prerequisite for effective gut peristalsis. Atrophy of the tendinous fibre net abolishes peristalsis and allows for unlimited distension of the colon. A diagnosis of idiopathic megacolon can reliably be made on a collagen stain. The normal findings of myenteric plexus support the hypothesis that a primary metabolic defect of muscularis propria may be the underlying cause of idiopathic megacolon.     

Notable postnatal alterations in the myenteric plexus of normal human bowel

BACKGROUND: Nitric oxide is the most important transmitter in non-adrenergic non-cholinergic nerves in the human gastrointestinal tract. Impaired nitrergic innervation has been described in Hirschsprung's disease, hypertrophic pyloric stenosis, and intestinal neuronal dysplasia (IND). Recent findings indicate that hyperganglionosis, one of the major criteria of IND, is age dependent. However, information is scanty regarding the neurone density in normal human bowel in the paediatric age group. AIMS: To determine neurone density, morphology, and nitric oxide synthase distribution of the normal myenteric plexus at different ages during infancy and childhood. METHODS: Specimens were obtained from small bowel and colon in 20 children, aged one day to 15 years, at postmortem examination. Whole mount preparations were made of the myenteric plexus, which were subsequently stained using NADPH diaphorase histochemistry (identical to nitric oxide synthase) and cuprolinic blue (a general neuronal marker). The morphology of the myenteric plexus was described and the neurone density estimated. RESULTS: The myenteric plexus meshwork becomes less dense during the first years of life. The density of ganglion cells in the myenteric plexus decreases significantly with age during the first three to four years of life. The NADPH diaphorase positive (nitrergic) subpopulation represents about 34% of all neurones in the myenteric plexus. CONCLUSIONS: The notable decrease in neurone density in the myenteric plexus during the first years of life indicates that development is still an ongoing process in the postnatal enteric nervous system. Applied to the clinical situation, this implies that interpretation of enteric nervous system pathology is dependent on the age of the patient.     

Immunohistochemical study of the colonic muscle and innervation in idiopathic chronic constipation

PURPOSE: This study was designed to investigate neural and muscular features of the colonic wall in patients with severe idiopathic constipation. METHODS: By using quantitative immunohistochemistry, resected specimens from 14 patients with idiopathic chronic constipation and 17 nonobstructed cancer controls were studied. RESULTS: Routine histology revealed no significant histologic abnormality throughout the colon apart from four cases of melanosis coli. Ratio of the thickness of circular to longitudinal muscle was significantly lower in the left colon in constipated subjects. The myenteric plexus appeared morphologically normal in all subjects. S-100 protein, which stains neuronal supporting tissues, demonstrated an increase in the proportion of neural tissue in the myenteric plexus. There was an increased number of PGP-9.5 immunoreactive nerve fibers in the muscularis propria in constipated patients, and this was significantly higher in the ascending and descending colon. CONCLUSION: Intractably constipated patients have alterations in the neural composition of the colonic myenteric plexus and innervation of the circular muscle.Supported by a grant from Yonsei University Research Foundation, Seoul, Korea. Dr. Talbot is supported in part by the Imperial Cancer Research Fund.     

There are no morphologic abnormalities of the gastric wall or abdominal vagus in patients with diabetic gastroparesis

Because there is evidence for vagal autonomic neuropathy as the cause of diabetic gastroparesis, we hypothesized that this disorder should be associated with morphologic abnormalities of the abdominal vagus nerve or gastric myenteric plexus, or both. We studied the smooth muscle and myenteric plexus of the stomach in 18 nondiabetic controls and 16 patients with long-standing diabetes. Five of the diabetics had gastroparesis and 11 did not. We utilized conventional histology and Smith's silver technique for visualizing the myenteric plexus. Neurons within the myenteric plexus were quantified in sections stained with each technique. The abdominal vagus nerves from 5 diabetics (2 with gastroparesis) and 12 nondiabetic controls were stained with hematoxylin and eosin, Gomori trichrome, luxol-fast blue, and Holmes' silver stains. There were no abnormalities in the numbers or appearance of neurons or axons in the myenteric plexus of the stomach of diabetics, with or without gastroparesis. Also absent were abnormalities of the smooth muscle or vagus nerve. Thus, no morphologic abnormalities of the gastric wall or abdominal vagus were identified in diabetic gastroparesis.     

Idiopathic myenteric ganglionitis underlying intractable vomiting in a young adult

Inflammatory infiltration of intestinal myenteric plexuses (i.e. myenteric ganglionitis), along with severe intestinal motor abnormalities, may accompany paraneoplastic syndromes, neurological disorders and gastrointestinal infections, although rare cases can be idiopathic. In this report, we describe the case of a patient who presented with chronic intractable vomiting and weight loss associated with idiopathic myenteric ganglionitis mainly involving the stomach. Tissue analysis showed that the inflammatory infiltrate comprised T lymphocytes (CD4+ and CD8+), and peptide immunolabelling revealed a marked decrease of substance P/tachykinin immunoreactive staining in nerve fibres and myenteric neurones. Following systemic steroid therapy, the patient's symptoms dramatically improved, and after one year of follow-up his general condition remains satisfactory. The possible mechanisms leading to symptom generation and gastric dysmotility in the context of an idiopathic myenteric ganglionitis are discussed.     

Eosinophilic myenteric ganglionitis: a case of intestinal pseudo-obstruction in a 93-year-old female

Eosinophilic myenteric ganglionitis is a disorder characterized by infiltration of the Auerbach plexus by eosinophils. It can be associated with a bowel dysmotility and a few cases of intestinal pseudo-obstructive syndrome have been described in children. In this case report, we present an elderly 93-year-old woman who presented with episodes of functional bowel obstruction of unknown etiology. After several admissions for recurrent obstipation requiring fecal disimpaction, she had a Hartmann procedure performed with a resection of the sigmoid colon. The sigmoid colon was markedly dilated and the only significant finding on histology was infiltration of the Auerbach plexus by eosinophils. The mucosa and the muscular layers appeared unremarkable. Her symptoms resolved after the resection and the patient is currently well after 5 months. Recurrent gastrointestinal pseudo-obstruction can arise secondary to eosinophilic myenteric ganglionitis even in adults. Clinical improvement is likely if this disease entity is promptly recognized and treated.     

Expression of c-fos in gastric myenteric plexus and spinal cord of rats with cervical spondylosis

AIM: To determine the expression of c-fos in gastric myenteric plexus and spinal cord of rats with cervical spondylosis and its clinical significance. METHODS: A cervical spondylosis model was established in rats by destroying the stability of cervical posterior column, and the cord segments C4-6 and gastric antrum were collected 3, 4 and 5 mo after the operation. Rats with sham operation were used as controls, c-fos neuronal counter-staining was performed with an immunohistochemistry method. Every third sections from C4-6 segments were drawn. The 10 most labeled c-fos-immunoreactive (Fos-IR) neurons were counted, and the average number was used for statistical analysis. The mean of Fos-IR neurons in myenteric plexus was calculated after counting Fos-IR neurons in 25 ganglia from each antral preparation, and expressed as a mean count per myenteric ganglion. RESULTS: There were a few c-fos-positive neurons in the cervical cord and antrum in the control group. There was an increased c-fos expression in model group 3, 4 and 5 mo after operation, whereas there was no significant increase in c-fos expression in the control group at 3, 4 and 5 mo. More importantly, there was a significant difference in c-fos expression between rats followed up for 3 mo and those for 5 mo in the model group (11.20±2.26 vs 27.68±4.36, P<0.05, for the cervical cord; and 11.3±2,3 vs 29.3±4.6, P<0.05, for the gastric antrum). There was no significant difference between rats followed up for 3 mo and those for 4 mo and between rats followed up for 4 mo and those for 5 mo in the model group. CONCLUSION: c-fos expression in gastric myenteric plexus was dramatically associated with that in the spinal cord in rats with cervical spondylosis, suggesting that the gastrointestinal function may be affected by cervical spondylosis. If this hypothesis is confirmed by further studies, functional gastrointestinal diseases such as functional dyspepsia and irritable bowel syndrome could be explained by neurogastroenterology.     

Autoradiographic localization of mu- and delta-type opioid receptors in the gastrointestinal tract of the rat and guinea pig

The distribution of delta- and mu-type opioid binding sites in the gastrointestinal tract of the rat and guinea pig was studied by autoradiography after in vitro incubation of tissue slices with 3H-D-Ala2,D-Leu5-enkephalin, and 3H-naloxone or 3H-dihydromorphine to locate delta- and mu-type opioid receptors, respectively. In the gastric fundus, both mu- and delta-type binding sites were found to occur associated with the circular muscle, muscularis mucosae, and submucosal plexus, whereas in the corpus and antrum, binding was located primarily in the submucosal plexus, deep muscular plexus, and mucosa. Some mu-type opioid receptor sites were present in the myenteric plexus. A dense distribution of both mu- and delta-type binding sites was observed throughout the mucosa of the duodenum and ileum of the rat. In guinea pig ileal tissue, however, only mu-type binding could be demonstrated, occurring in the submucosal plexus and diffusely over the muscle layers. Endogenous opioid peptides, acting at these receptors sites, might be involved in the control of gastrointestinal motility, endocrine and exocrine secretions, as well as intestinal fluid and electrolyte transport.     

Intestinal pseudoobstruction caused by diffuse lymphoid infiltration of the small intestine

Four young women presented with diarrhea, malabsorption, and intestinal pseudoobstruction. Intestinal biopsy specimens (both peroral and full-thickness) showed flat small intestinal mucosa, sparsity of crypts, and a widespread lymphoid infiltrate in the lamina propria, muscularis propria, and myenteric plexus. There was no neuron or nerve fiber loss or damage in the plexus; muscle cell absence in the vicinity of lymphoid cell infiltration in the muscularis propria probably accounted for the pathogenesis of pseudoobstruction. Immunochemical stains showed that the infiltrate was polyclonal, and none of the patients has developed lymphoma on clinical follow-up of 4-16 yr. Transient improvement in symptoms occurred after antibiotic therapy in 3 patients, and 1 patient had improvement after treatment with cyclophosphamide and prednisone; however, symptoms of pseudoobstruction persist in all. These cases illustrate yet another cause of intestinal pseudoobstruction which is histologically distinct from visceral myopathies and neuropathies. The pathogenesis of this illness may be related to that of diffuse immunoproliferative diseases seen in Third World countries.     

Age-related functional gastrointestinal disorders

The demographic development will lead to a disproportionate increase of older people and to a significant increase of functional gastrointestinal disorders including dysphagia due to motility and reflux-related disorders, nausea and vomiting by gastrointestinal dysfunction and abdominal and pelvic pain caused by chronic obstipation, stool impaction and incontinence. This implies significant consequences with regard to the development of weight loss, anorexia, social disadvantages and increased mortality with serious socio-economic burden. Ageing processes are determined by differentiated neurogeneration of the myenteric plexus (cholinergic degeneration) through reactive oxygen and nitrogen species and alteration of protective and regenerative processes. Age-related gastrointestinal dysfunctions may be caused by the ageing gastrointestinal tract itself or by other age-related diseases such as tumour, neurological or inflammatory diseases, anatomic changes, therapeutic medication, polymorbidity or malnutrition. Because of the significant therapeutic options, differential diagnostic work-up is mandatory also in elderly patients.     

Isolation, identification and culture of myenteric plexus cells from ovine esophagus

Background/aims

The myenteric plexus of the esophagus consists of two major cell types, neurons and enteric glial cells, and functions to coordinate peristaltic waves. The aim of this study was to develop a protocol for the isolation of myenteric plexus and dissociation and culture of myenteric plexus cells.

Methods

The myenteric plexus was isolated from the ovine esophagus through treatment with collagenase, followed by dissociation of cells with trypsin/EDTA. Myenteric plexus cells were cultured in vitro and the different cell components were identified by immunohistochemical staining.

Results

Isolated myenteric plexi expressed enteric glial cell markers S-100 and GFAP and enteric neuronal cell marker PGP 9.5. Furthermore, c-kit positive cells were also detected, which may represent the interstitial cells of Cajal. Despite the successful isolation of a wide range of myenteric plexus cells, dissociation of cells was poor and requires further optimization.

Conclusion

This study reports on the isolation and dissociation of the principle cells of the myenteric plexus from ovine esophagus. As the ovine model is a clinically relevant large animal model for esophageal disease, the isolation of ovine myenteric plexus cells is of significant importance for the understanding of pathologies of the enteric nervous system and application in gastrointestinal tissue engineering.     

Pathophysiological significance of neuronal nitric oxide synthase in the gastrointestinal tract

It has been demonstrated that nitric oxide (NO) is a major inhibitory nonadrenergic, noncholinergic (NANC) neurotransmitter in the gastrointestinal (GI) tract. NO released in response to nerve stimulation of the myenteric plexus causes relaxation of the smooth muscle. NO is synthesized by the activation of neuronal NO synthase (nNOS) in the myenteric plexus. Released NO plays an important physiological role in various parts of the GI tract. NO regulates the muscle tone of the sphincter in the lower esophagus, pylorus, sphincter of Oddi, and anus. NO also regulates the accommodation reflex of the fundus and the peristaltic reflex of the intestine. Previous studies have shown that NOS inhibitors delay gastric emptying and colonic transit. The reduction of nNOS expression, associated with impaired local production of NO, may be responsible for motility disorders in the GI tract. There is accumulated evidence that dysfunction of NO neurons in the myenteric plexus may cause various GI diseases. These reports are reviewed and possible mechanisms of altered nNOS expression are discussed in this article. In particular, impaired nNOS synthesis of the myenteric plexus seems to be an important contributing factor to the pathogenesis of achalasia, diabetic gastroparesis, infantile hypertrophic pyloric stenosis, Hirschsprung's disease, and Chagas' disease. Reduced NO release and/or nNOS expression are suspicious in a subset of patients with functional dyspepsia. Although the etiology of intestinal pseudo-obstruction remains unknown, it is conceivable that extrinsic denervation may upregulate nNOS expression, resulting in enhanced muscular relaxation and disturbed peristalsis. An animal model of colitis showed impaired nNOS expression in the colonic myenteric plexus. Antecedent infection may be associated with the impaired NO pathways observed in functional dyspepsia, colitis, and Chagas' disease.     

Intestinal pseudo-obstruction as the presenting manifestation of small-cell carcinoma of the lung. A paraneoplastic neuropathy of the gastrointestinal tract

A 58-year-old woman who had presented with intestinal pseudo-obstruction died 9 months later from rapidly progressive neurologic symptoms and autonomic insufficiency. Her gastric emptying had been markedly delayed and transit of markers had been slowed throughout the small bowel. A 5-hour manometric recording of the antrum and duodenum had shown absence of the normal interdigestive motor complex, which was replaced by irregular contractile activity of reduced amplitude. A small-cell carcinoma of the lung was found at autopsy. Pathologic study of the gut showed widespread degeneration of the myenteric plexus, which was infiltrated by plasma cells and lymphocytes and contained significantly reduced numbers of neurons. The extra-intestinal nervous system had neuronal loss and lymphocytic infiltrates in dorsal root ganglia. Thus, a gastrointestinal neuropathy causing intestinal pseudo-obstruction may be the presenting manifestation of a paraneoplastic syndrome associated with small-cell carcinoma.     

Chronic primary intestinal pseudo-obstruction from visceral myopathy.

Chronic intestinal pseudo-obstruction is an uncommon syndrome characterized by relapsing episodes suggesting intestinal obstruction during which no mechanical causes are identified to account for symptoms. Etiologic factors may be manifold. Among them a number of neurologic conditions, gastrointestinal smooth muscle myopathies, endocrino-metabolic and autoimmune diseases, and the use of selected drugs stand out. We report a case of chronic intestinal pseudo-obstruction originating in a sporadic, primary intestinal myopathy that corresponds to no type thus far described. A histological study of the intestinal wall showed disrupted muscle bundles and the presence of interstitial edema. Myocytes had severe degenerative changes, and no alterations were seen in submucosal and myenteric plexus neurons. The activity of enzyme complexes in the mitochondrial respiratory chain, and of thymidine phosphorylase was normal. No mitochondrial DNA changes were seen.