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At least 19 recordsLinked to original sources
PubMed2003

A retrospective study of histopathological findings in 894 cases of megacolon: what is the relationship between megacolon and colonic cancer?

Patients with megaesophagus (ME) have increased prevalence of cancer of the esophagus. In contrast, a higher incidence of colorectal cancer is not observed in patients with megacolon (MC). MC is very common in some regions of Brazil, where it is mainly associated with Chagas disease. We reviewed the pathology records of surgical specimens of all patients submitted for surgical resection of MC in the Hospital das Clínicas of the Faculty of Medicine of Ribeirão Preto (HC-FMRP), from the University of São Paulo. We found that 894 patients were operated from 1952 until 2001 for MC resection. Mucosal ulcers, hyperplasia and chronic inflammation were frequently found, while polyps were uncommon. No patients with MC presented any type of colonic neoplasm. This observation reinforces the hypothesis that MC has a negative association with cancer of the colon. This seems to contradict the traditional concept of carcinogenesis in the colon, since patients with MC presents important chronic constipation that is thought to cause an increase in risk for colon cancer. MC is also associated with other risk factors for cancer of colon, such as hyperplasia, mucosal ulcers and chronic inflammation. In ME these factors lead to a remarkable increase in cancer risk. The study of mucosal cell proliferation in MC may provide new insights and useful information about the role of constipation in colonic carcinogenesis.

Adolescent↗
PubMed2000

Megacolon in patients with chronic spinal cord injury.

PURPOSE: To investigate the clinical and functional correlates of megacolon in individuals with chronic spinal cord injury (SCI). PATIENTS AND METHODS: This is a cross-sectional study of 128 patients consecutively admitted to a SCI in-patient service in a US Veterans Administration Medical Centre (mean age 57+/-15 years, mean years since injury 20+/-13, 97% male) who underwent plain abdominal radiography for study purposes. Participants were characterised by radiological findings. 'Megacolon' was defined as colonic dilatation of >6 cms in one or more colonic segment(s). Clinical, functional, and medication data were abstracted from the medical and nursing records. Individual interviews were conducted with study participants regarding bowel-related symptoms and treatment over the previous 1-month period. RESULTS: Seventy-three per cent of subjects (n=94) had megacolon, and 52% of these individuals had associated radiological constipation. Subjects with megacolon were compared with those without colonic dilatation (n=34). Factors significantly associated with megacolon were older age, longer duration of injury, symptom of abdominal distension, radiological constipation, urinary outlet surgery, laxative use at least once weekly, use of anticholinergic drugs, and use of calcium-containing antacids. These factors were simultaneously included in a multiple logistic regression model. Independent correlates of megacolon were more than 10 years elapsed since acute injury, age over 50 years, and use of >/=4 laxative doses per month. CONCLUSION: Megacolon is a highly prevalent disorder in individuals with chronic spinal cord injury. Our findings suggest that the presence of megacolon may be predicted in older individuals, and in those who are more than 10 years post-SCI. We also found that clinical constipation was frequently present in individuals with megacolon, despite their significantly greater use of laxatives. SPONSORSHIP: This work was supported by a grant from the Claude D Pepper Geriatric Research and Training Center from the National Institute of Ageing-AG08812-05, and a grant from the Education and Training Foundation of the Paralyzed Veterans Association in the USA. Dr Harari is currently recipient of a grant from Action Research (UK). Spinal Cord (2000) 38, 331 - 339.

Chronic Disease↗
PubMed2001

Neuron count reevaluation in the myenteric plexus of chagasic megacolon after morphometric neuron analysis.

This study was made with the objective of reevaluating the colon denervation in chronic Chagas' disease. The diameters of neuron perikaryons of the myenteric plexus were measured on paraffin sections in a ring from the sigmoid in Chagas' disease patients, 17 with and 10 without megacolon and in 10 non-chagasic controls. All neurons were counted in ten en-echelon sections. Neuron hypertrophy only occurred in the group with megacolon, and the average increase in diameter was 69.3%. This could generate an error factor in the neuron count by increasing the probability of neurons being seen in a greater number of histological sections. The original result of the neuron count gave medians of 1264, 1961, and 2665 in the groups of chagasic patients with megacolon, without megacolon, and in the control, respectively. The denervation was greater than 55% in only seven megacolon cases (41.2%). After applying a correction factor, the median in the group with megacolon was 746, and the denervation was greater than 55% in 13 cases (76.5%). This occurrence demonstrates the need to apply a correction factor when the neuron count in chagasic megacolon is being evaluated and in the other pathologies where neuron hypertrophy may be found.

Adult↗
PubMedDate not supplied

Cisapride stimulates contraction of idiopathic megacolonic smooth muscle in cats.

We have previously shown that cisapride, a substituted piperidinyl benzamide, stimulates contraction of healthy feline colonic smooth muscle. The purpose of the present investigation was to determine the effect of cisapride on feline idiopathic megacolonic smooth muscle function. Longitudinal smooth muscle strips from ascending and descending colon were obtained from cats with idiopathic megacolon, suspended in a 1.5 mM Ca(2+)-HEPES buffer solution (37 degrees C, 100% O2, pH 7.4), attached to isometric force transducers, and stretched to optimal muscle length (Lo). Control responses were obtained at each muscle site with acetylcholine (10(-8) to 10(-4) M), substance P (10(-11) to 10(-7) M), or potassium chloride (10 to 80 mM). Muscles were then stimulated with cumulative (10(-9) to 10(-6) M) doses of cisapride in the absence or presence of tetrodotoxin (10(-6) M) and atropine (10(-6) M), or in a 0 calcium HEPES buffer solution. In cats with idiopathic megacolon, cisapride stimulated contractions of longitudinal smooth muscle from both the ascending and the descending colon. Cisapride-induced contractions were similar in magnitude to those induced by substance P and acetylcholine in the ascending colon, but were less than those observed in the descending colon. Cisapride-induced contractions in megacolonic smooth muscle were only partially inhibited by tetrodotoxin and atropine, but were virtually abolished by removal of extracellular calcium. We concluded that cisapride-induced contractions of feline megacolonic smooth muscle are largely smooth muscle mediated and dependent on influx of extracellular calcium. Cisapride-induced contractions in megacolonic smooth muscle are only partially dependent on enteric cholinergic nerves. Thus, cisapride may be useful in the treatment of cats with idiopathic megacolon.

Acetylcholine↗
PubMed1983

Treatment of nontoxic megacolon by colonoscopy.

The indications for colonoscopy in a recent consecutive series of 232 examinations were analyzed. Of these examinations, 30 (13%) were performed for nontoxic megacolon. Nontoxic megacolon is defined as severe dilatation of a segment or the entire colon unaccompanied by signs or symptoms of colon toxicity. Mechanical factors (volvulus, anastomosis, diverticulosis, carcinoma) were responsible for the nontoxic megacolon in 13 of these patients. Nontoxic megacolon was classified as secondary to acute pseudoobstruction (Ogilvie's syndrome, pancolonic megacolon, acute myxedema ileus) in 17 patients. All patients were being evaluated for possible exploratory celiotomy to prevent perforation of the colon because of the massive colonic distention. Colonoscopic examination was performed at the bedside or in the intensive care unit for 11 of 30 patients. No bowel preparation was used. Evacuation of air and fecal material was more efficiently accomplished by use of an external suction device attached to the biopsy part of the endoscope. For 12 of the 13 patients who had a mechanical basis for their nontoxic megacolon the colon was successfully decompressed. All 17 patients with acute pseudoobstruction were successfully treated. There were no iatrogenic perforations. Possible emergency operation was avoided for all patients except one who had a cecal volvulus. Colonoscopy should be considered as the initial treatment for nontoxic megacolon prior to surgical intervention.

Colonoscopy↗
PubMed1996

Decreased vasoactive intestinal peptide levels and glutathione depletion in acquired megacolon.

We reported decreased vasoactive intestinal peptide levels in acquired megacolon. The origin of altered neuropeptide levels is unknown, but recent work suggested that tissue antioxidants may function as neuroprotectants. Our hypothesis was that altered levels of inhibitory neurotransmitters in human colon are associated with depletion of the tripeptide thiol, glutathione. Normal colon samples (N = 10; from patients 41-80 years old) and acquired megacolon samples (N = 10; from patients 31-98 years old) were obtained at surgery. Vasoactive intestinal peptide levels were decreased in muscularis externa from acquired megacolon (P = 0.01), while there was a modest increase in NADPH diaphorase activity in muscularis externa from megacolon (P = 0.10). Glutathione in acquired megacolon was detectable in muscularis externa from only five specimens (P < 0.05), but was not significantly different (P > 0.05) in the mucosal-submucosal layer. The results supported the presence of vasoactive intestinal peptide and NADPH diaphorase in distinct subpopulations of nerves in human colon. The results also supported the hypothesis that glutathione functions as a neuroprotectant in a subset of patients with acquired megacolon.

Adult↗
PubMed1996

Alterations in colonic smooth muscle function in cats with idiopathic megacolon.

OBJECTIVE: To determine whether colonic smooth muscle dysfunction is involved in the pathogenesis of idiopathic megacolon in cats. DESIGN: In vitro smooth muscle mechanical measurements. ANIMALS: Colon from healthy cats and cats with idiopathic megacolon. PROCEDURE: Colonic smooth muscle strips were suspended in physiologic buffer solution, attached to isometric force transducers, and contracted with acetylcholine (ACh; 10(-9) to 10(-4)M), substance P (SP; 10(-10) to 10(-6)M), cholecystokinin (CCK; 10(-11) to 10(-8)M), potassium chloride (KCl; 10 to 80 mM), or electrical field stimulation (EFS; 25 V, 1 to 30 Hz, 0.5-millisecond duration). Isometric stress responses were compared with those obtained from healthy controls. Colonic smooth muscle strips were also evaluated histologically for neuronal and smooth muscle cell morphology. RESULTS: Passive isometric stress was not altered, but the active isometric stress responses of megacolon smooth muscle to ACh, SP, CCK, KCl, and EFS were significantly (P < 0.05) diminished, compared with healthy controls. Differences were observed in longitudinal and circular smooth muscle from proximal and distal portions of the colon. Histologic evaluation revealed few abnormalities of smooth muscle cells or of myenteric or submucosal plexus neurons. The contractile response of megacolon smooth muscle to EFS, and the inhibition of this response by tetrodotoxin, suggest that myenteric and submucosal plexus neurons in megacolon smooth muscle are functional. CONCLUSIONS: Idiopathic megacolon is a generalized dysfunction of colonic smooth muscle in cats. The diminished isometric stress responses to receptor occupancy (ACh, SP, and CCK) and membrane depolarization (KCl) further suggest that the disorder involves disturbance in the activation of smooth muscle myofilaments.

Acetylcholine↗
PubMed1997

[Myotonic dystrophy with marked megacolon: report of a case].

A 45-year-old woman was incidentally suspected to have megacolon. Chest X-rays showed elevated left diaphragm due to colonic gas, and the heart was deviated to the midline. Barium enema revealed marked dilation of the sigmoid colon, confirming the diagnosis of megacolon. Maximal diameter of the sigmoid colon was 23 cm, but she had no gastrointestinal symptoms. During the work up for megacolon, the presence of myotonic dystrophy was suspected. She had hatchet face, but was not bald. Muscles of the neck and extremities were slightly atrophic. There was percussion myotonia of the tongue and both hands, and grip myotonia of the hands. Laboratory examinations showed impaired glucose tolerance and low level of serum IgG. EMG showed myotonic discharges and myopathic units in the limbs. Brain CT imaging revealed a thick skull. Cases of myotonic dystrophy associated with marked megacolon are rare in Japan. Megacolon presents a high risk for ileus, volvulus, and rupture, and myotonic dystrophy is associated with a high operative and anesthesic risk. Megacolon, therefore, is an important complication to look for in the management of myotonic dystrophy.

Female↗
PubMed1998

[Febrile state, bloody diarrhea and megacolon].

We report about a forty year old female patient with severe bloody diarrhoea and fever over a period of 14 days due to an infection with Salmonella enteritidis. X-ray of the abdomen showed a toxic megacolon. With the diagnosis of an infectious colitis we started therapy with ciprofloxacin i/v. The toxic megacolon progressed despite intensive care and parenteral nutrition. Additionally the patient received metronidazole i/v and in combination with a roll technique in bed in the knee-elbow-position the leucocytosis and the megacolon decreased. A toxic megacolon is in about 3% associated with an infection with Salmonella enteritidis. It is essentially diagnosed by X-ray. Patients should receive intensive care, and because of the high mortality rate an interdisciplinary management is required. The article discusses the major differential diagnosis of the toxic megacolon, as well as the pathogenesis and therapy of Salmonella ent, infection. In case of an infection with Salmonella ent. physicians should acknowledge the possibility of development of a toxic megacolon.

Adult↗
PubMed1987

Megacolon in third-phase malrotation with delayed migration and degeneration of intramural ganglionic cells and nerves.

A woman of 36 was admitted to hospital because of griping abdominal pain which occurred especially during the night when turning in bed. She had a history of constipation and bloating since birth. Irrigoscopy revealed megacolon extending from the middle of the transverse colon to the rectum. A rectal biopsy excluded Hirschsprung's disease. When surgery was performed, megacolon combined with malrotation of the colon was found, only the ascending colon being attached to the abdominal wall. Hemicolectomy was performed. In the megacolon, a cropolith, the size of a foetal head, was found which along with malrotation of the large intestine had caused the woman's symptoms. The nerve supply of the ascending colon was normal but in the megacolon there was evidence of delayed migration of ganglion nerve cells and varying degrees of degeneration of ganglion nerve cells and intraganglionic nerve fibres. Malrotation of the colon associated with megacolon and delayed migration of ganglion nerve cells and degeneration of nerve elements has not been reported previously.

Adult↗
PubMed2000

Nitric oxide production is diminished in colonic circular muscle from acquired megacolon.

PURPOSE: Nitric oxide modulates human colonic smooth muscle function. To determine whether nitric oxide production is altered in colon from acquired megacolon, we measured cholinergic nerve-mediated contractions in vitro before and after inhibition of nitric oxide synthase. METHODS: Intramural nerves in circular smooth muscle from histologically normal colon (n = 12) and acquired megacolon (n = 3) were activated by electrical field stimulation. RESULTS: In controls blockade of nitric oxide synthase by N(G)-Nitro-L-Arginine induced increases (P < 0.05) in amplitude of contractions; these increases in amplitudes were blocked by L-Arginine (analysis of variance; P < 0.05). By contrast, blockade of nitric oxide synthase did not increase amplitudes of contractions with circular smooth muscle from acquired megacolon. An immediate phasic contraction was blocked by atropine sulfate. CONCLUSIONS: The results support the concept that nitric oxide production modulates cholinergic nerve-mediated contractions in normal colonic circular muscle, whereas acquired megacolon is associated with altered release of this inhibitory neurochemical. Potential explanations include depletion of tissue L-Arginine, decreased capacity to recycle citrulline to arginine, or decreased release of vasoactive intestinal peptide from circular smooth muscle in acquired megacolon.

Aged↗
PubMed2001

Toxic megacolon due to Salmonella: a case report and review of the literature.

BACKGROUND AND AIMS: Salmonella colitis is an unusual cause of toxic megacolon. We provide an overview of this condition and report a single case. PATIENTS AND METHODS: A 62-year-old man underwent subtotal colectomy with ileostomy formation for toxic megacolon due to Salmonella enteritidis phage type 4 colitis, followed by reversal with an ileorectal anastomosis. RESULTS: Twenty-seven cases have been described in the literature. These were first treated conservatively, with antibiotics and systemic/local steroids, and some proceded to surgery. CONCLUSION: Salmonella is a rare cause of toxic megacolon, but it can behave opportunistically in patients with ulcerative colitis. S. enteritidis phage type 4 is typically transmitted via raw or uncooked eggs in most cases of salmonellosis attributed to this organism. The disease is rapidly progressive, and death may ensue due to septicaemia and/or perforation. Toxic megacolon is treated aggressively, initially medically, with high-dose steroids and attention to fluid balance, ulcerative colitis being the usual working diagnosis. Once Salmonella is cultured, appropriate antibiotics are commenced. Non-surgical decompression may be appropriate in some cases, but early surgical intervention is required for failed response to these measures or rapid deterioration in the patient's condition. Following initial surgery - often subtotal colectomy and ileostomy formation - continuity may be restored. For most patients with ulcerative colitis ileal pouch anal anastomosis is the operation of choice, but ileorectal anastomosis may be safely performed for Salmonella-induced toxic megacolon. Prevention is better than cure, and therefore health education needs to reinforce avoidance of use of raw or uncooked eggs.

Humans↗
PubMed2000

A deficiency of interstitial cells of Cajal in Chagasic megacolon.

Disordered gut motor activity is a feature of patients with Chagas' disease: colonic involvement leads to the development of megacolon and symptoms of constipation. Interstitial cells of Cajal are thought to modulate gut motility. The aim of this study was to test the hypothesis that there is an abnormality of the density of distribution of interstitial cells of Cajal in Chagasic megacolon. Interstitial cells of Cajal were identified by immunohistochemistry using an anti-c-kit antibody. Six patients with Chagasic megacolon were compared with normal controls. The density of distribution of interstitial cells of Cajal was assessed in the longitudinal and circular muscle layers, and in the intermuscular plane of the Chagasic and normal colon. Statistical analysis was performed using Fisher's exact test. The interstitial cells of Cajal density in Chagasic megacolon was much reduced in comparison to normal colonic tissue in the longitudinal muscle layer (P=0.0084), intermuscular plane (P<0.0001), and circular muscle layer (P=0.0051). The lack of interstitial cells of Cajal may play a role in the pathophysiology of the disease, leading to the development of megacolon and symptoms of constipation.

Aged↗