Pathophysiology of diverticular disease

Association Between Colonic Diverticulosis and Colorectal Polyps, Advanced Neoplastic Lesions, and Colorectal Carcinomas: A Cross-Sectional, Retrospective Study

PURPOSE

The aim of the present study was to evaluate the association of diverticulosis with colorectal polyps, advanced neoplastic lesions (ANLs), and colorectal cancers (CRCs).

METHODS

The first-time colonoscopy records of 3496 patients were evaluated in this retrospective, cross-sectional cohort study. Data on clinical indications, presence of diverticulosis and diverticulitis, location of diverticula and polps, the size and number of polyps, and results of histopathologic examinations of polypectomies were noted. Categorical data were analyzed with χ test or the Fisher exact probability. P-values <0.05 (2 sided) were considered statistically significant. Statistical analyses were conducted with SPSS, version 18.

RESULTS

Of the 3496 patients, 1691 were male individuals (48.4%) and 1805 (51.6%) were female individuals. Diverticulosis was present in 12.6% of patients. A total of 870 polyps were detected in 716 patients. A total of 170 polyps (19.5%) were classified as ANLs. CRC was diagnosed in 112 (3.2%) patients. A significant relationship between diverticulosis and colorectal polyps (odds ratio: 1.99; 95% confidence interval: 1.59-0.2.48, P<0.001) was found. Similarly, adenomas and ANLs were more frequent in diverticulosis (P<0.05). There was no significant relationship between diverticulosis and CRCs (P=0.243).

CONCLUSIONS

Adenomatous polyps and ANLs were more frequently observed in patients with diverticulosis, but no significant relationship was found between CRC and diverticulosis. The results of this retrospective cross-sectional study need to be confirmed by longitudinal prospective cohort studies.

Possible increased risk of colonic diverticular disease from alcohol intoxication or abuse

Alcohol consumption has been suggested as a potential risk factor for diverticular diseases. This study investigated the association between alcohol intoxication or abuse and colonic diverticular disease (CDD).Using the National Health Insurance Research Database of Taiwan from January 1, 2000, to December 31, 2008, 51, 866 subjects newly diagnosed with alcohol intoxication were enrolled in this study as the alcohol intoxication cohort. The control (nonalcohol intoxication) cohort was frequency-matched 1:4 by age, sex and index year. Data were analyzed using a Cox proportional hazards model.The overall incidence of CDD (per 10,000 person-years) for the alcohol intoxication and control cohorts was 16.4 and 3.46, respectively. Compared with patients in the control cohort (95% confidence interval [CI] = 2.76-3.74), those with alcohol intoxication exhibited a 3.21-fold risk of CDD; the risk was particularly higher in male patients (adjusted hazard ratio [aHR] = 3.19, 95% CI = 2.72-3.74) and in those aged <45 years (aHR = 4.95, 95% CI = 3.91-6.27). The alcohol intoxication still had higher risk of CDD than nonalcohol intoxication, regardless of subjects without comorbidity (aHR = 3.38, 95% CI = 2.77-4.11) or with (aHR = 2.85, 95% CI = 2.25-3.61).There was a significant relationship between alcohol intoxication or abuse and CDD.

Risk of colorectal adenomas, advanced adenomas and cancer in patients with colonic diverticular disease: Systematic review and meta-analysis

BACKGROUND AND AIM

Diverticular disease and colorectal neoplasia are common digestive disorders worldwide. Both diseases share epidemiological trends and certain risk factors including advancing age, physical inactivity, and Western diet and lifestyle. Studies assessing the association between these diseases reported inconsistent results. Thus, we conducted a systematic review and meta-analysis to determine the association between diverticular disease and colorectal adenomas, advanced adenomas and cancer.

METHODS

A comprehensive search of the databases MEDLINE and EMBASE was done from inception through March 2016. Inclusion criterion was the observational studies' assessment of the association between diverticular disease and colorectal neoplasia in adult participants. Pooled OR and 95% confidence interval (CI) were calculated using a random effect.

RESULTS

Data were extracted from 14 observational studies (11 cross-sectional studies, one case-control study and two cohort studies). Diverticular disease was associated with increased odds of adenomas (OR = 1.67, 95% CI 1.27-2.21, 10 studies), but not associated with advanced adenomas (OR = 1.19, 95% CI 0.88-1.62, I²  = 52%, four studies) or colorectal cancer (OR = 1.36, 95% CI 0.47-3.92, I²  = 98%, seven studies).

CONCLUSIONS

Our meta-analysis demonstrated that diverticular disease was associated with colorectal adenomas. Colonoscopists should be aware of this association and carefully examine the entire large bowel in individuals with diverticulosis.

Prevalence and clinical features of colonic diverticulosis in a Middle Eastern population

AIM: To determine the prevalence, location, associations and clinical features of colonic-diverticulosis and its role as a cause of lower-gastroenterology-bleeding.

METHODS: We retrospectively reviewed the medical records of 3649 consecutive patients who underwent a colonoscopy for all indications between 2007 and 2011 at King Khalid University Hospital, Riyadh, Saudi Arabia. The demographic data were collected retrospectively through the hospital’s information system, electronic file system, endoscopic e-reports, and manual review of the files by two research assistants. The demographic information included the age, sex, comorbidities and indication for the colonoscopy. The association among colonic polyps, comorbidities and diverticular disease was also measured.

RESULTS: A total of 270 patients out of 3649 were diagnosed with colonic diverticulosis, with a prevalence of 7.4%. The mean age was 60.82 years ± 0.833, (range 12-110). Females comprised 38.89% (95%CI: 33-44.7) of the study population. The major symptoms were rectal bleeding in 33.6%, abdominal pain in 19.3%, constipation in 12.8% and anemia in 6%. Diverticula were predominantly left-sided (sigmoid and descending colon) in 62%, right-sided in 13% and in multiple locations in 25%. There was an association between the presence of diverticulosis and adenomatous polyps (P-value < 0.001), hypertension (P-value < 0.0001) and diabetes mellitus (P-value < 0.0016). Diverticular disease was the second most common cause of lower gastrointestinal bleeding, in 33.6% (95%CI: 27.7-39.4), after internal hemorrhoids, in 44.6% (95%CI: 40.3-48.9). On multivariable logistic regression, hypertension (OR = 2.30; 95%CI: 1.29-4.10), rectal bleeding (OR = 2.57; 95%CI: 1.50-4.38), and per year increment in age (OR = 1.05; 95%CI: 1.03-1.07) were associated with diverticulosis but not with bleeding diverticular disease. Limitations: A small proportion of the patients included had colonoscopies performed as a screening test.

CONCLUSION: Colonic-diverticulosis was found to have a low prevalence, be predominantly left-sided and associated with adenomatous-polyps. Age, hypertension and rectal bleeding predict the presence of diverticular disease.

Prevalence rates of type 2 diabetes and hypertension are elevated among middle-aged Japanese men with colonic diverticulum

OBJECTIVE

To elucidate the prevalence rate of metabolic disorders among subjects with asymptomatic colonic diverticulum.

METHODS

We carried out a cross-sectional analysis of the association between colonic diverticulum and selected metabolic disorders among the male personnel of the Self-Defense Forces who underwent total colonoscopy as part of their retirement check-up (age range, 51-59 years).

RESULTS

The prevalence rate of colonic diverticulum was 10.2% among the population studied. The scores of lifestyle factors including those of cigarette smoking and alcohol consumption were similar between the subjects with colonic diverticulum and those without it. Type 2 diabetes (21.6% vs 14.0%, P=0.047) and hypertension (30.9% vs 19.8%, P=0.011) were more prevalent among the subjects with colonic diverticulum than those without it. The prevalence rates of obesity, dyslipidemia, hyperuricemia, and impaired glucose tolerance were similar between the two groups.

CONCLUSION

The prevalence rates of type 2 diabetes and hypertension are elevated among the middle-aged male subjects with asymptomatic colonic diverticulum. The results may partly explain the reported association between colonic diverticulum and cardiovascular disease.

Endoscopic evaluation of the colon after an episode of diverticulitis: a call for a more selective approach

PURPOSE

Routine colonic evaluation is advised after an episode of diverticulitis to exclude colorectal cancer. In the recent years, the possible relation between diverticulitis and colorectal cancer has been subject of debate. The aim of this study is to evaluate the benefit of routine colonic endoscopy after an episode of diverticulitis.

METHODS

Records of all consecutive patients presenting with a radiologically confirmed episode of diverticulitis between 2007 and 2010 were retrieved from an in-hospital database. Patients who subsequently underwent colonic evaluation were included. The endoscopic detection rate of hyperplastic polyps, adenomas and advanced colonic neoplasia was assessed. Findings were categorized on the basis of the most advanced lesion identified.

RESULTS

Three hundred and seven patients presented with a radiologically confirmed primary episode of diverticulitis. Two hundred and five patients underwent colonic evaluation. Hyperplastic polyps were found in15 (6.8 %), adenomas in 18 (8.8 %) and advanced neoplastic lesions in 7 (3.4 %) patients. Only two patients had a colorectal malignancy.

CONCLUSION

There appears to be no benefit in performing routine colonic evaluation after an episode of diverticulitis as the incidence of colorectal cancer is almost equal to that of the general population. A more selective approach might therefore be justified. Potentially, only patients with persisting abdominal complaints after an episode of diverticulitis should be offered colonic evaluation to definitively exclude causal pathology.

Is diverticular disease associated with colonic malignancy?

Colon cancer and diverticular disease have common characteristics; there are increases in the incidences in both disease entities and these diseases are more common in the westernized world. There is also an increase in the age-specific incidence with advancing age. Similar dietary features have been implicated for both diseases and already during the 1960s it was postulated by Burkitt that there is an association. Observational studies initially were able to demonstrate that patients with a history of diverticular disease of the colon had an increased risk of colon cancer, especially in the left side. However, the results from these studies have not been consistent, and problems like selection bias and confounding by indication have been major drawbacks in order to interpret the results and infer causality. Recent studies, which have had a better assessment of diverticular disease by new diagnostic methods, do not support such an association to the same extent as previously. Moreover, surveillance bias has become an increasing problem as patients with diverticular disease of the colon are subjected to a higher diagnostic intensity than other individuals in a population-based setting. A critical evaluation of the studies published so far therefore clearly indicates that the proposed association between diverticular disease and colonic malignancy is not evidence based, which should have an impact on clinical practice as well as on how to deal with these patient groups within the realms of a screening program.

Colonic diverticulosis is associated with an increased adenoma detection rate in patients undergoing first-time screening colonoscopy

BACKGROUND

Diverticulosis is a common finding in patients undergoing colonoscopy. The effect of colonic diverticulosis on the colorectal adenoma detection rate (ADR) and other colonoscopy quality indicators remains unclear.

OBJECTIVES

To determine if colonic diverticulosis is associated with differences in (1) colorectal ADR and (2) other quality indicators and operating characteristics in patients undergoing first-time screening colonoscopy.

METHODS

Retrospective cohort study conducted at an outpatient surgical center affiliated with an academic medical center.

RESULTS

300 consecutive patients (190 women) with a median age of 57 years (range: 23-70 years) who underwent colonoscopy for various indications were included. 108 (36%) of these 300 patients had diverticulosis found on colonoscopy. 142 (47.3%) of these patients (88 women, median age of 52 years) underwent their first screening colonoscopy. In this population, the frequency of colonic diverticula was 39.2%, and the ADR was 47.5% for patients with diverticulosis and 27.4% for patients without diverticulosis. Multivariate analysis revealed that the presence of diverticulosis had an associated odds ratio of 2.3 (p=0.04) in favor of finding at least one adenoma. No statistically significant differences were found among the rates of total colonoscopy, median scope insertion and withdrawal times, and the amounts of midazolam and fentanyl required for sedation when patients with diverticulosis were compared to those without diverticulosis.

CONCLUSION

Colonic diverticulosis was associated with an increased ADR in patients undergoing first-time screening colonoscopy. The presence of colonic diverticulosis did not adversely affect the cecal intubation rate, scope insertion or withdrawal times, or sedation requirements.

Review article: the pathogenesis of diverticular disease--current perspectives on motility and neurotransmitters

BACKGROUND

Low-fibre diet, structural abnormalities and ageing are traditional aetiological factors implicated in the development of diverticular disease. More recently, motility disorders are implicated in its causation leading to speculation that neurotransmitters play a role in mediating these disturbances.

AIMS

To draw together studies on the role of neurotransmitters in the development of diverticular disease and its symptoms.

METHODS

Medline, GoogleScholar and Pubmed were searched for evidence on this subject using the terms neurotransmitters, motility, diverticular disease and pathogenesis. Articles relevant to the subject were cited and linked references were also reviewed.

RESULTS

Serotonin, which has been found to be an excitatory colonic neurotransmitter, has been found in early studies to be increased in colonic enterochromaffin cells. Acetylcholine, which is thought to be an excitatory neurotransmitter and cholinergic activity, has also seen to be increased in diverticular disease. These findings may suggest that an increase in excitatory neurotransmitters may result in the hypersegmentation thought to cause pulsion diverticula. Similarly, a decrease in nitric oxide which is inhibitory is found.

CONCLUSIONS

There is some evidence that neurotransmitters may play a role in the motility disturbances seen in diverticular disease; however, a clear role is yet to be ascertained.

Clinical significance of colonic diverticulosis associated with bowel symptoms and colon polyp

This study was done to evaluate prospectively the clinical significance of colonic diverticulosis. In the 1,030 consecutive outpatients undergoing colonoscopy, the information on the demographics, the patterns of bowel symptoms, and the prevalence of colon polyp were analyzed according to the presence of colonic diverticulosis. The mean age of 1,030 patients were 52.2 yr and 59.3% were male. The prevalence of diverticulosis was 19.7% (203/1,030). Of 203 diverticulosis patients 85.2% were in proximal group, 5.4% in distal group and 9.4% in both group. Six (3.0%) patients were found to have diverticulitis. Multivariate logistic regression analysis showed that an old age, diabetes and the presence of polyp were significant factors associated with proximal or both diverticulosis. A significant difference was demonstrated between the patients of distal diverticular group and the controls for the symptom frequency scores within the previous 4 weeks. The items, which showed difference, were hard stool, urgency, flatus, chest discomfort and frequent urination. In conclusion, old age, diabetes and the presence of colon polyp were associated with proximal diverticulosis. The temporal symptoms were more frequent in distal diverticulosis than in proximal diverticulosis in the study subjects.

Acromegaly is associated with an increased prevalence of colonic diverticula: a case-control study

OBJECTIVE

In acromegaly, overproduction of GH and IGF-I causes abnormal extracellular matrix regulation. We hypothesized that this may predispose to the development of colonic diverticula. Because the relation between acromegaly and colonic diverticula is unknown, the study aim was to assess the prevalence of colonic diverticula in patients with cured acromegaly.

DESIGN

This was a case-control study.

METHODS

We screened reports of colonoscopies performed for the purpose of screening for polyps in 107 patients with cured or biochemically controlled acromegaly and in 214 age- and sex-matched controls for the presence of diverticula, dolichocolon, and polyps. In patients, the findings were related to GH/IGF-I concentrations at the time of diagnosis of acromegaly and to the duration of GH/IGF-I excess.

RESULTS

In acromegaly, colonic diverticula were present in 37% of patients, dolichocolon in 34%, and adenomatous polyps in 34%, which was increased compared with controls (odds ratio 3.6, 95% confidence interval 1.4, 5.7; 12.4, 95% confidence interval 6.8, 18.0; 4.1, 95% confidence interval 1.9, 6.4, respectively). The presence of colonic diverticula was associated with both GH and IGF-I concentrations at the time of diagnosis of acromegaly, when adjusted for the duration of active disease. The presence of dolichocolon and adenomatous polyps was associated with higher IGF-I concentrations at diagnosis.

CONCLUSIONS

Acromegaly is associated with an increased prevalence of colonic diverticula. In addition to the known irreversible effect of GH excess on collagen of joints and cardiac valves, this observation indicates an irreversible effect of GH and/or IGF-I on the collagen in the colon.

The effects of mechanical forces on intestinal physiology and pathology

The epithelial and non-epithelial cells of the intestinal wall experience a myriad of physical forces including strain, shear, and villous motility during normal gut function. Pathologic conditions alter these forces, leading to changes in the biology of these cells. The responses of intestinal epithelial cells to forces vary with both the applied force and the extracellular matrix proteins with which the cells interact, with differing effects on proliferation, differentiation, and motility, and the regulation of these effects involves similar but distinctly different signal transduction mechanisms. Although normal epithelial cells respond to mechanical forces, malignant gastrointestinal epithelial cells also respond to forces, most notably by increased cell adhesion, a critical step in tumor metastasis. This review will focus on the phenomenon of mechanical forces influencing cell biology and the mechanisms by which the gut responds these forces in both the normal as well as pathophysiologic states when forces are altered. Although more is known about epithelial responses to force, information regarding mechanosensitivity of vascular, neural, and endocrine cells within the gut wall will also be discussed, as will, the mechanism by which forces can regulate epithelial tumor cell adhesion.

Diverticulosis and colorectal cancer: between lights and shadows

The prevalence of diverticulosis and colorectal cancer (CRC) is markedly increased in the last century. Both diseases are highly frequent in Western countries and in aged people. Western diet--low in fiber and rich in dietary fat--has been largely regarded to play a major role in the pathogenesis of both conditions. A causal relationship between diverticulosis and CRC has been suggested in different studies. Epidemiologic series found a more frequent rectosigmoid localization of neoplastic lesions (advanced adenoma and CRC) in patients with diverticulosis as compared with controls, particularly in those with a previous diverticulitis episode or with an extensive disease. However, data are still controversial, with other studies failing to confirm this observation. Such discrepancy could be referred to the highly heterogeneous study design and setting in the different epidemiologic series. Pathologic studies showed that either macroscopic and microscopic chronic inflammation--which is regarded as risk factor for CRC development--is present in the colonic mucosa of some patients with diverticula. Moreover, alterations in the extracellular matrix, also involved in colorectal carcinogenesis, have been depicted in diverticulosis. In addition, an upward shifting of cell proliferation occurs in diverticular mucosa, and in nondiverticular patients with advanced adenomas. Finally, aberrant crypt foci--which are considered potential markers of CRC risk in ulcerative colitis--have been detected in colonic mucosa of patients with diverticulosis. Despite this substantial amount of evidence, however, the available data are not yet strong enough to suggest a more aggressive CRC prevention in diverticular as compared with nondiverticular subjects.

Reprimo 824 G>C and p53R2 4696 C>G single nucleotide polymorphisms and colorectal cancer: a case-control disease association study

BACKGROUND

Improved survival from colorectal cancer (CRC) may result from screening for inherited genetic risk factors. Reprimo and p53R2 are p53-inducible genes involved in cell cycle surveillance and DNA repair. Single nucleotide polymorphisms (SNPs) of these genes have been discovered, but their effects on the genes' function and association with CRC is not known.

METHODS

Ninety healthy controls, 52 diverticular disease controls and 96 CRC cases were genotyped. DNA was extracted from buccal brush biopsies. Genotyping was performed by polymerase chain reaction (PCR) or polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP) methods. Tests for Hardy-Weinberg equilibrium and allelic- and genotype-disease association were performed online using the Finetti program.

RESULTS

All three populations were in Hardy-Weinberg equilibrium with respect to p53R2 4696C>G SNP, and no CRC associations were demonstrated with this SNP. The healthy and CRC populations were in Hardy-Weinberg equilibrium with respect to the Reprimo 824G>C SNP, but the diverticular disease population was not (P=0.03). No CRC were demonstrated with Reprimo 824G>C.

CONCLUSION

No association between p53R2 4696C>G and Reprimo 824G>C with CRC was shown by this study. An association between the Reprimo 824G>C heterozygote and diverticular disease may exist on the basis of deviation from Hardy-Weinberg equilibrium.

The pathology of diverticulosis: classical concepts and mucosal changes in diverticula

Left-sided diverticular disease affects upwards of 50% of the population over the age of 60 years in western countries and is becoming more common as the population ages. Studies from the 1960s to 1980s related its occurrence to the use of low fiber diets, and to the prolonged colonic transit time and increased intraluminal pressure associated with low-volume stools. Pulsion diverticula (pseudodiverticula) emerge through the muscularis propria of the left colon at points of penetration of the vasa recta that supply the submucosa and mucosa. Cardinal features of the sigmoid colon in diverticular disease are abnormalities of the muscularis propria, including thickening and elastosis of the teniae, shortening of the bowel, and thickening and folding of the circular muscle with the development of transverse semilunar ridges between the mesenteric and antimesenteric teniae. Complications of diverticular disease such as hemorrhage, diverticulitis, peridiverticular abscess, fistula, and perforation are well recognized.

Review article: uncomplicated diverticular disease of the colon

Diverticular disease of the colon is the fifth most important gastrointestinal disease in terms of direct and indirect health care costs in western countries. Uncomplicated diverticular disease is defined as the presence of diverticula in the absence of complications such as perforation, fistula, obstruction and/or bleeding. The distribution of diverticula along the colon varies worldwide being almost always left-sided and directly related to age in western countries and right-sided where diet is rich in fibre. The pathophysiology of diverticular disease is complex and relates to abnormal colonic motility, changes in the colonic wall, chronic mucosal low-grade inflammation, imbalance in colonic microflora and visceral hypersensitivity. Moreover, there can be genetic factors involved in the development of colonic diverticula. The use of non-absorbable antibiotics is the mainstay of therapy in patients with mild to moderate symptoms, and the effect of fibre-supplementation alone does not appear to be significantly different from placebo, although no definite data are available. More recently, alternative treatments have been reported. Mesalazine acts as a local mucosal immunomodulator and has been shown to improve symptoms and prevent recurrence of diverticulitis. In addition, probiotics have also been shown to be beneficial by re-establishing a normal gut microflora. In this study, the current literature on uncomplicated diverticular disease of the colon is reviewed.

Dark-lumen magnetic resonance colonography in patients with suspected sigmoid diverticulitis: a feasibility study

To assess dark-lumen magnetic resonance colonography (MRC) for the evaluation of patients with suspected sigmoid diverticulitis. Forty patients with suspected sigmoid diverticulitis underwent MRC within 72 h prior to conventional colonoscopy (CC). A three-dimensional T1-weighted volumetric interpolated breath-hold examination sequence was acquired after an aqueous enema and intravenous administration of gadolinium-based contrast agents. All MRC data were evaluated by two radiologists. Based on wall thickness and focal uptake of contrast material and pericolic reaction including mesenteric infiltration on T1-weighted sequence the sigmoid colon was assessed for the presence of diverticulitis. MRC classified 17 of the 40 patients as normal with regard to sigmoid diverticulitis. However, CC confirmed the presence of light inflammatory signs in four patients which were missed in MRC. MRC correctly identified wall thickness and contrast uptake of the sigmoid colon in the other 23 patients. In three of these patients false-positive findings were observed, and MRC classified the inflammation of the sigmoid colon as diverticulitis whereas CC and histopathology confirmed invasive carcinoma. MRC detected additionally relevant pathologies of the entire colon and could be performed in cases where CC was incomplete. MRC may be considered a promising alternative to CC for the detection of sigmoid diverticulitis.

The effect of digestion of collagen and elastin on histomorphometry and the zero-stress state in rat esophagus

To understand the physiology and pathology of the esophagus, it is necessary to know the mechanical properties and their dependence on the structural components. The aim of this study was to investigate the effect of collagenase and elastase on the morphological and biomechanical properties in the no-load and zero-stress states in the rat esophagus. Twenty tissue rings from each esophagus of seven normal rats were sectioned in an organ bath containing calcium-free Krebs solution with dextran and EGTA. After the rings were photographed in the no-load state, 8 of the 20 rings were separated into mucosa-submucosa and muscle rings and the rings were transferred to four different solutions containing collagenase, elastase, or corresponding control solutions. The rings were cut radially to obtain the zero-stress state and photographed again. The thickness, area, and opening angle were measured from the digitized images. The collagen and elastin area fractions were determined from histological slides with Van Gieson and Weigert's elastic stain. The opening angles and residual strain did not differ in the nonseparated enzyme-treated rings and control rings. However, in the separated mucosa-submucosa ring the opening angle was significantly smaller after treatment than that in control rings (P < 0.01). Collagenase and elastase reduced collagen and elastin in the mucosa-submucosa layer about 40% in the nonseparated wall and 54% in the separated mucosa-submucosa layer (P < 0.01). Collagenase and elastase increased the thickness in the separated mucosa-submucosa layer compared to the control (P < 0.05). Disconnection between the epithelia and the lamina propria was histologically observed after elastase digestion. In conclusion, collagenase and elastase caused the opening angle and the residual strain in the separated mucosa-submucosa layer to decrease. The opening angle of the separated mucosa-submucosa layer depended to some extent on the fraction of collagen and elastin.

A new mechanism for diverticular diseases: aging-related vagal withdrawal

It is widely believed that diverticulosis, a common condition among the elderly, results from repeated colonic barotrauma related to low dietary fiber and low stool bulk. Recent evidence has challenged the dietary-barotrauma hypothesis. We propose an alternative hypothesis that diverticulosis may be attributable to colonic smooth muscle dysfunction that results from vagal attrition associated with aging. We previously proposed that broad aging-related attrition of autonomic nerves may unmask intrinsic sympathetic bias of end-organs, leading to the compendium of familiar conditions associated with senility. Unexplained cholinergic hypersensitivity and receptor over-expression in bowel affected by diverticulosis have recently been observed. These findings are highly suggestive of a compensatory response to loss of vagal innervation. The resulting autonomic dysregulation may induce bowel smooth muscle dysfunction, setting the stage for diverticula formation. Thus, diverticular bowel disease may be a manifestation of the aging-related systemic vagal withdrawal. The framework may extend to diverticula formation in other parts of the gastrointestinal and genitourinary tracts. For instance, aging-related vagal attrition may represent the common upstream mechanism that induces both sphincter of Oddi dysfunction and peri-ampullary duodenal diverticula, conditions that frequently occur together. Novel approaches to preventing and treating diverticular diseases by promoting vagal activity are proposed including the electrical or pharmacologic modulation of the autonomic system.

Diverticulosis coli: update on a "Western" disease

Diverticular disease affects upwards of 50% of the population over the age of 60 years in Western countries and is becoming more common as the population ages. Studies from the 1970s and 1980s related its occurrence to the use of low-fiber diets and to the prolonged colonic transit time and increased intraluminal pressure associated with low-volume stools. Pulsion diverticula (pseudodiverticula) emerge through the thickened circular layer of the muscularis propria of the left colon at points of penetration of the vasa recta that supply the submucosa and mucosa. Complications of diverticular disease such as hemorrhage, diverticulitis, peridiverticular abscess, fistula, and perforation are well recognized. More recently, attention has been drawn to the polypoid prolapsing mucosal folds that may develop as the affected segment of bowel (usually the sigmoid) becomes shorter and to changes in the mucosa surrounding the diverticula and in the bowel wall that may result in confusion with ulcerative colitis or Crohn disease (sigmoid colitis-associated diverticulosis [SCAD]). Distinguishing SCAD from these entities is extremely important, and pathologists should be aware of the possibility of overdiagnosing chronic inflammatory bowel disease in biopsies or resection specimens of sigmoid colon with diverticular disease.

Paradigms for mechanical signal transduction in the intestinal epithelium. Category: molecular, cell, and developmental biology

Diverse physical forces including deformation or strain, pressure, and shear stress affect the intestinal mucosa during normal function, and mucosal biology is altered in pathological states in which these forces alter. Taken together with evidence in other tissues and cell types that physical forces can affect cell biology, this has led to the hypothesis that repetitively applied physical forces can initiate intracellular signals that alter intestinal epithelial proliferation and phenotype. This review outlines the nature of such forces and summarizes in vivo and in vitro evidence in support of the paradigm that repetitive force is trophic for the intestinal mucosa via a complex cascade of intracellular signals.

[Right colon diverticulitis]

Diverticulitis involving the right colon is uncommon in the Occident; only one case for every 300 cases of appendicitis occurs in Western countries compared to a ratio of 1/40-1/180 in Asia. The preferential localization of diverticula in the right colon among Asiatics is probably due to genetic factors. In Asia as in the West, a right colon diverticulum is more likely to cause hemorrhage than diverticulitis. The peak age of symptoms is 40-45 years and the sex ratio is 1:1. The patient most commonly presents with symptoms suggestive of acute appendicitis, acute localized peritonitis, or, more rarely, a psoas abscess. Clinical exam reveals an inflammatory mass in the right lower quadrant in 30% of cases; diffuse peritonitis, large abscesses, and fistulae are rare. Helical CT scan is the best tool for establishing the diagnosis and also helps to rule out other possible etiologies in the differential diagnosis-particularly a perforated right colon cancer. In noncomplicated cases with convincing evidence for the diagnosis by CT scan, a conservative (non-surgical) treatment with antibiotics is possible; a later stage colonoscopy will rule out other colonic lesions. More commonly, the correct diagnosis is only made after embarking on an appendectomy via a McBurney incision; the surgical strategy thereafter depends on the level of suspicion regarding the diagnosis and the extent and complexity of the diverticulitis. Therapeutic options may be conservative (appendectomy), limited (diverticulectomy, or extensive (ileocecal resection or right hemicolectomy). For complicated disease (abscess, localized perforation), an aggressive surgical approach is warranted. Surgical strategies need to be validated, particularly in the light of the increasing use of the laparoscopic approach for suspected appendicitis.

Diverticulosis and Diverticulitis

Diverticulosis and diverticulitis are common disorders in modern society and represent different places on the spectrum of diverticular disease. Often called a problem of western civilization, diverticular disease is rare in developing countries. This article provides an overview of the epidemiology of diverticular disease, risk factors, and clinical presentation in varying phases. Differential diagnostic testing and comprehensive management from the medical, surgical, and wound, ostomy, and continence nursing perspectives are also addressed. Nurses play a key role in supporting people with diverticular disease and referring them for appropriate assessment, treatment, and support.

Pathophysiological aspects of diverticular disease of colon and role of large bowel motility

Colonic diverticular disease (diverticulosis) is one of the most common gastrointestinal disorders in Western countries. This disorder is strictly related to aging and fibre intake, and still bears a discrete amount of morbidity. Numerous etiological co-factors have to date been implicated in the pathogenesis of the disease, yet the supporting evidence is still far from absolute. The present review considers the pathophysiology of colonic diverticular disease, with a special emphasis on factors related to abnormal colonic motility.