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.     

Chronic Intestinal Pseudoobstruction as a Possible Sequel to Encephalitis

A patient is reported who presented with a typical intestinal pseudoobstruction syndrome. Before this illness, the patient had suffered from measles encephalitis at the age of 15 months. A postencephalitic syndrome was present which included severe mental retardation, parkinsonism, and epilepsy. There were no relatives with a similar disease. Clinically, there was a frank recurrent pseudoobstruction syndrome with occasional diarrhea. Radiographic barium studies showed delayed transit, hypomotility of the intestines, and gross distension of the esophagus, stomach, small intestine, and colon. Histological examination of the gastrointestinal tract revealed a normal appearance of the mucosa; however, there was a hypertrophic muscle layer with abnormalities of the plexuses. Both the submucosal and the myenteric plexuses were reduced in number and size. They showed a decreased number of ganglion cells, proliferation of Schwann cells and infiltration by lymphocytes. The abnormalities were most strikingly present in the esophagus and the small intestine. The intestinal neuropathy resulting in clinical pseudoobstruction is proposed to be part of the generalised neurological pathology as a late sequel to the measles encephalitis.     

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.     

Distributions of neuropeptides in the human esophagus

The distributions of nerve cells and fibers with immunoreactivity for the peptides substance P, somatostatin, enkephalin, vasoactive intestinal peptide, gastrin-releasing peptide, and neuropeptide Y and the enzyme tyrosine hydroxylase were examined in 25 samples of human esophagus. These were compared with samples of stomach and intestine. In the smooth muscle of the muscularis externa, the muscularis mucosae, and beneath the epithelium, the most abundant nerve fibers contained vasoactive intestinal peptide and neuropeptide Y, in contrast to the scarcity of substance P, enkephalin, somatostatin, and gastrin-releasing peptide. Gastric and intestinal samples contained dense populations of fibers containing vasoactive intestinal peptide, neuropeptide Y, substance P, and enkephalin in the equivalent layers, but somatostatin- and gastrin-releasing peptide-immunoreactive fibers were scarce. Complete coexistence of vasoactive intestinal peptide and neuropeptide Y in nerve fibers within the muscle layers was demonstrated in the esophagus, but not in gastric and intestinal samples. The myenteric plexus along the length of the esophagus contained cell bodies and fibers reactive for vasoactive intestinal peptide, neuropeptide Y, enkephalin, and substance P. Somatostatin-immunoreactive cell bodies were very rare in the myenteric plexus, no gastrin-releasing peptide-immunoreactive cell bodies were seen, and both somatostatin and gastrin-releasing peptide-immunoreactive fibers were rare. In the upper esophagus, striated muscle bundles did not contain nerve fibers reactive for these peptides but immunoreactive fibers were seen in the muscularis mucosae and subepithelium. It is concluded that the esophagus has a different pattern of innervation by peptide-containing neurons than the stomach and intestines. Esophageal neurons can be classified into separate classes on the basis of their peptide content.     

Chronic intestinal pseudoobstruction as a complication of Duchenne's muscular dystrophy

We report a case of Duchenne's muscular dystrophy complicated by intestinal pseudoobstruction. The patient had recurrent attacks of nausea, vomiting, and abdominal distention for many years, and abdominal films repeatedly showed a dilated and fluid-filled small intestine and colon. Barium studies showed an esophageal diverticulum, reduced esophageal and gastric motility, and a dilated small bowel and colon. Pathologically, the entire gastrointestinal tract had smooth muscle fibrosis, but this was most marked in the esophagus and stomach. We conclude that Duchenne's muscular dystrophy may involve intestinal smooth muscle and produce pseudoobstruction.     

Hereditary visceral myopathy: an entity in idiopathic intestinal pseudo-obstruction

A 17 year-old girl with chronic idiopathic intestinal pseudo-obstruction is reported. Abnormalities of smooth intestinal muscle were shown on light and electron microscopic studies of the excised small intestine and led to the diagnosis of visceral myopathy based on the following features: vacuolar degeneration of intestinal smooth muscle cells with replacement by fibrous preferential involvement of the external longitudinal muscle layer normal myenteric plexus. For the first time similar ultrastructural changes were found on histological study of the colon. Manometric studies revealed a diffuse disease involving the esophagus, small bowel, and bladder. Anorectal abnormalities, never described before, were reported. Family involvement was shown by abnormal esophageal and anorectal manometries in the patient's brother and by paternal history of fatal small intestine occlusion without mechanical obstruction. The prognosis of severe forms of visceral myopathy is generally poor because of the inefficiency of drugs. In this case, after a long period of parenteral nutrition with maintenance of a good nutritional status, a terminal ileostomy (with a special procedure to avoid evagination) associated with a second stage total colectomy allowed to stop parenteral nutrition.     

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.     

Intestinal pseudoobstruction caused by a new form of visceral neuropathy: palliation by radical small bowel resection

We report a case of chronic intestinal pseudoobstruction caused by a newly recognized type of degenerative neuropathy of the myenteric plexus. Failure to improve despite aggressive medical management led to radical resection of the clinically involved small intestine. At follow-up 10 mo later, the patient is doing well without the need for parenteral nutrition. Radical resection of the small intestine may be necessary for palliation in rare patients with intractable pseudoobstruction.     

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.     

The colon in the pseudoobstructive syndrome

Colonic pseudoobstruction can occur as part of a generalized chronic intestinal pseudoobstruction syndrome or as an isolated entity. Isolated colonic pseudoobstruction can occur in two unrelated forms: the acute and chronic forms. Acute colonic pseudoobstruction is frequently a hospital-acquired disease that arises as a complication of other illnesses. The syndrome must be recognized and treated with early colonoscopic decompression to prevent cecal or colonic perforation. Chronic colonic pseudoobstruction is a syndrome of many causes. The prognosis of patients with chronic colonic pseudoobstruction is much better than that of generalized chronic intestinal pseudoobstruction, because the patients become asymptomatic with appropriate operations. The pathogenesis of acute colonic pseudoobstruction and several types of chronic colonic pseudoobstruction is not known. Further investigations should include bacteriologic study, histopathologic studies (examinations of smooth muscle and myenteric plexus), and examination of extrinsic nerves of the colon. With these approaches, a better understanding of the pathogenesis of these syndromes will be achieved.     

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.     

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.     

Electron microscopic study of neuropeptide Y-containing nerve elements of the guinea pig small intestine

Neuropeptide Y-containing nerve cell bodies and processes were identified by electron microscopic immunocytochemistry in the guinea pig small intestine. Labeled nerve processes were numerous in the myenteric plexus. However, a few immunoreactive nerve fibers were found in all layers of the small intestine. Some of the immunoreactive nerve processes were found in close apposition to the epithelial cells of the crypts of Lieberkühn and to endothelial and smooth muscle cells. The neuropeptide Y-containing nerve cell bodies were preferentially located in the submucous ganglia. In the myenteric plexus many synaptic connections were observed between the neuropeptide Y-immunoreactive nerve fibers and unlabeled nerve cell bodies and other nerve fibers. These findings provide a morphologic basis for the possibility that neuropeptide Y may act as a transmitter and exert postsynaptic effects on intrinsic neurons, in addition to participating in the regulation of smooth muscle activity and epithelial cell functions.     

Chronic intestinal pseudoobstruction in young children

We studied 8 young children (4 boys and 4 girls) with chronic intestinal pseudoobstruction. Intestinal pseudoobstruction, recurrent urinary tract infections, and dysuria occurred between the ages of a few weeks to 5 yr old. All had marked dilatation of the entire gastrointestinal tract distal to the esophagus, and megacystis. Conventional pathologic examinations of the full-thickness specimens of the gastrointestinal tract were normal in 5 and abnormal in 2 patients. The abnormalities included increased fibrosis and lipofuscin pigment in the smooth muscle cells. Myenteric plexus examination, using the Smith's method in 2 patients, was normal. Biopsy specimens from urinary bladders examined in 3 patients revealed separation of individual smooth muscle cells by collagen fibers. Intestinal manometric studies performed in 3 patients showed only weak and infrequent contractions during fasting and after feeding. Severe and extensive dysfunction of the gastrointestinal and urinary tracts with relatively normal histologic appearance are typical for these children.     

Intestinal Auerbach plexus structures with NADH histochemistry in three strains of spontaneous diabetic rats

The enteric nervous system comprises two major systems: the submucosal and the myenteric plexus. The aim of this study was to describe the myenteric plexus from three strains of spontaneous diabetic rats from the histological point of view. Samples of small intestine and of proximal and distal colon were obtained fom three spontaneous diabetic rats i.e., eSS, eSMT, beta strains and 1-year old Wistar rats. Specimens were stained with NADH (beta-nicotinamide adenine dinucleotide, reduced form) histochemical technique and examined with light microscope. Microscopically little modifications in mesh-like structure of intestinal Auerbach's plexus from eSS were detected in comparison with Wistar rats samples. Intestinal plexus of eSMT and beta rats showed disruption of mesh-like structures, modifications in the slightly colored background (smooth muscle) and augmented vascularization. Small intestine and colon are affected. In short: In our spontaneously diabetic rat models, mesh-like structure of Auerbach's plexus is strain dependent.     

Enteric nerves in diabetic rats: increase in vasoactive intestinal polypeptide but not substance P

The distribution of vasoactive intestinal polypeptide (VIP) and substance P-like immunoreactivities was studied by immunohistochemistry in the myenteric plexus and circular muscle layer of the ileum and proximal colon of rats 8 wk after induction of diabetes with streptozotocin. A consistent increase was observed in fluorescence intensity of VIP-like immunoreactivity in the nerve fibers, and intensely stained cell bodies were significantly more frequent in the myenteric plexus of the ileum (p less than 0.001) from diabetic animals. Some varicosities of VIP-like immunoreactive fibers in the myenteric plexus appeared to be enlarged. Vasoactive intestinal polypeptide-like immunoreactivity was increased and VIP-like immunoreactive nerves appeared thicker in the circular muscle layer of both diabetic ileum and proximal colon. The VIP levels were measured biochemically in tissue consisting of the smooth muscle layers and myenteric plexus. A significant increase in the VIP content per centimeter of intestine was found in both the ileum (p less than and proximal colon (p less than 0.01) from diabetic rats. In contrast, no apparent change in substance P innervation was observed immunohistochemically in the myenteric plexus and circular muscle layer of either diabetic ileum or proximal colon when compared with controls. The results are discussed in relation to the symptoms of autonomic neuropathy of the gut in diabetes.     

Migration of the myoelectric complex after interruption of the myenteric plexus: intestinal transection and regeneration of enteric nerves in the guinea pig

The effects of surgical interruption of the myenteric plexus (myectomy), extrinsic denervation of a length of small intestine, or transection and reanastomosis of the intestinal wall on migration of phase III of the migrating myoelectric complex was studied in guinea pigs. In addition, the recovery of phase III migration and the regrowth of intestinal nerves and muscle across the reanastomosis was studied at various times up to 60 days after surgery. At 6-9 days after surgery, phase III did not migrate past the myectomy during 50%-60% of recorded migrating myoelectric complexes and transection and reanastomosis of the intestinal wall blocked aboral progression of phase III in 90% of cases. Extrinsic denervation did not alter phase III migration through the denervated segment. Phase III migration past the reanastomosis recovered with time after surgery; 80% recovery occurred by 60 days after surgery. Immunoreactivities for vasoactive intestinal peptide, gastrin-releasing peptide, and somatostatin were used as markers for intestinal nerves that were cut by transaction. Immunoreactivities for vasoactive intestinal peptide and gastrin-releasing peptide are contained in myenteric neurons that project in an oral to anal direction to other myenteric ganglia and to the circular muscle. Immunoreactivity for somatostatin is contained in nerve fibers projecting aborally to other myenteric ganglia. At 7-15 days after surgery, there were accumulations of immunoreactivities for vasoactive intestinal peptide, gastrin-releasing peptide, and somatostatin in nerve fibers on the oral side of the reanastomosis, but nerve fibers containing these peptides were not observed in myenteric ganglia or circular muscle close to the anal edge. At 23-28 days, immunoreactivities for vasoactive intestinal peptide, gastrin-releasing peptide, and somatostatin nerve fibers were traced across the reanastomosis and nerve terminals were detected in ganglia and muscle close to the lesion on the anal side. Nerve fibers traversed the lesion in all cases at 57-60 days and vasoactive intestinal peptide-, gastrin-releasing peptide-, and somatostatin-immunoreactive nerve terminals were detected in the first two to three rows of myenteric ganglia on the anal side. Regrowth of intestinal muscle followed a similar time-course to that observed for nerves. These data suggest that interruption of the myenteric plexus alone does not completely block phase III migration. In addition, recovery of phase III migration past a reanastomosis is associated with a restoration of both nervous and mechanical connections.     

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.     

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.     

Submucosal hypoganglionosis causing chronic idiopathic intestinal pseudo-obstruction.

A 39-year-old woman presented with recurrent symptoms suggestive of intestinal obstruction. She was put on total parenteral nutrition (TPN) and consequently developed sepsis and endocarditis. TPN was stopped and a venting enterostomy was performed. Biopsies of mucosa and submucosa were taken at surgery; immunohistochemistry for neuronal proteins, protein gene product 9.5 (PGP 9.5) and the glial S-100-protein was done. Many enlarged nerve fiber strands were found in the submucosa. Few small ganglia containing a small number of nerve cells could be observed, suggesting hypoganglionosis. This patient with chronic idiopathic intestinal pseudoobstruction of neurogenic type had a defect in the submucous plexus, whereas visceral neuropathies are usually characterized by defects of the myenteric plexus with normal submucous plexus.