Defecation disorders: neuromuscular aspects and treatment

Digital Rectal Examination Is a Valuable Bedside Tool for Detecting Dyssynergic Defecation: A Diagnostic Study and a Meta-Analysis

BACKGROUND

Accurate dyssynergic defecation (DD) diagnosis depends on anorectal physiological tests that are not widely available.

AIM

The purpose of this study is to evaluate the diagnostic yield of digital rectal examination (DRE) compared with anorectal physiological tests in diagnosing DD in patients with constipation.

METHODS

A total of 218 chronic constipation patients who fulfilled the Rome IV diagnostic criteria for functional constipation (FC) and underwent a standardized DRE and high-resolution anorectal manometry (HRAM) test were enrolled in this study. The diagnostic accuracy of DRE compared with HRAM was evaluated, and the agreement between DRE and HRAM was calculated. Furthermore, a comprehensive literature search on PubMed, Web of Science, Cochrane Library, and Embase database was conducted to further elucidate the pooled diagnostic accuracy of DRE in DD patients.

RESULTS

A total of 101 patients (46.33%) had a DD pattern using HRAM, while 117 patients (53.67%) were diagnosed without DD. The sensitivity of DRE in diagnosing dyssynergia was 71.3%, and the specificity was 76.1%. There was a moderate agreement between DRE and HRAM for diagnosing DD (κ-coefficient = 0.474, P < 0.001). Meanwhile, six studies (including our study) comprising 964 constipated patients were included in our meta-analysis. The outcomes demonstrated that the AUC was 0.85 (95% CI 0.82-0.88) with 77% summary sensitivity (95% CI 65-86) and 80% summary specificity (95% CI 71-86) to diagnose DD.

CONCLUSIONS

DRE could be a valuable tool for screening DD. Our study revealed acceptable sensitivity and specificity of DRE in detecting dyssynergia compared with the physiological tests. Meanwhile, our study highlights that DRE remains an important tool in clinical practice.

High-resolution Anorectal Manometry in the Diagnosis of Functional Defecation Disorder in Patients With Functional Constipation: A Retrospective Cohort Study

Background/Aims

High-resolution anorectal manometry (HRAM) has been considered a first-line diagnostic tool for functional defecation disorder. However, clinical studies on HRAM used in constipation patients are very limited and few studies have reported the characteristics of anorectal pressure in Chinese patients. The aim of this study is to investigate the characteristics of motility data in a cohort of Chinese patients with functional constipation.

Methods

A total of 82 consecutive patients with functional constipation who underwent a standardized HRAM were retrospectively enrolled in this study. The functional defecation disorder was classified into Rao’s types.

Results

The mean age of 82 patients was 51 years (range, 16–83 years). Indications for anorectal manometry were functional constipation for all patients. The mean resting pressure was 69.2 ± 21.2 mmHg (range, 24.5–126.9 mmHg). The mean maximum squeezing pressure was 198.4 ± 75.6 mmHg (range, 54.2–476.9 mmHg). The mean length of the anal high pressure zone was 3.4 ± 1.0 cm (range, 0.6–4.9 cm). Sixty (73.2%) patients were diagnosed as functional defecation disorder. In attempted defecation, type I was most common (n = 24), followed by type II (n = 12), type III (n = 11), and type IV (n = 13) that were present on HRAM according to Rao’s classification. In all 60 patients with functional defecation disorder, 37 were women and 23 were men. Men were significantly more likely than women to have functional defecation disorder (92.0% vs 64.9%, P = 0.014).

Conclusion

HRAM could be used as a test for the diagnosis of functional defecation disorder and functional defecation disorder is common in Chinese patients with functional constipation.

High-resolution and high-definition anorectal manometry: rediscovering anorectal function

Anorectal motor and functional disorders are common among the general population. Anorectal manometry allows the study of anorectal motor activity both at rest and mimicking different physiological situations. High-resolution anorectal manometry (HR-ARM) and high-definition anorectal manometry (HD-ARM) are increasingly used in clinical practice. In comparison with the conventional technique, HR-ARM and HD-ARM catheters provide a higher number of recording points because of their many, closely packed circumferential sensors. This allows time-space visualization (topographic or 2-3-plane mode) as spatially continuous measurements are obtained by interpolation between near sensors. HR-ARM and HD-ARM allow a more standardized, reproducible technique, and a better assessment and understanding of the functional anatomy of the sphincter complex. Newer specific parameters are now being developed for use with these systems. They are being currently assessed by multiple research teams, and many of them remain unavailable for clinical practice as of today. However, they provide highly relevant information, which is now prompting a redefinition of anorectal anatomy and physiology. The goal of the present review was to describe the currently available HR-ARM and HD-ARM techniques, to discuss the normal values so far reported, and to analyze the newer parameters that may be assessed with these techniques, and which will likely be highly useful for clinical practice in the upcoming future.

The diagnostic value of a digital rectal examination compared with high-resolution anorectal manometry in patients with chronic constipation and fecal incontinence

OBJECTIVES

Digital rectal examination (DRE) is a simple clinical method to diagnose anorectal disorders. High-resolution antorectal manometry (HRAM) based on a spatiotemporal plot is expected to promote improved diagnostic accuracy. However, there are no reports comparing the effectiveness of DRE and HRAM. The aim of our study was therefore to evaluate the diagnostic value of DRE compared with HRAM.

METHODS

A total of 309 consecutive patients with chronic constipation (n=268) or fecal incontinence (n=41) who underwent a standardized DRE, HRAM, and balloon expulsion test were enrolled in this study. The diagnostic yield of DRE compared with HRAM was determined, and agreement between DRE and HRAM data was evaluated.

RESULTS

Of the constipated patients, 207 (77.2%) were diagnosed with dyssynergia using HRAM. The sensitivity, specificity, and positive predictive value of DRE in the diagnosis of dyssynergia were 93.2%, 58.7%, and 91.0%, respectively, and moderate agreement was seen between the two modalities (κ-coefficient =0.542, P<0.001). In patients with fecal incontinence, there was moderate agreement in terms of anal squeeze pressure between the two modalities (κ-coefficient =0.418, P=0.006); however, there was poor agreement for anal resting tone (κ-coefficient =0.079, P=0.368).

CONCLUSIONS

DRE shows high sensitivity and positive predictive value in detecting dyssynergia compared with HRAM, and could therefore be used as a bedside screening test for the diagnosis of this disorder. Further studies are warranted to evaluate the correlation between DRE and HRAM in assessing anal sphincter pressure.

Smoothelin expression in the gastrointestinal tract: implication in colonic inertia

Colonic inertia is a frustrating motility disorder to patients, clinicians, and pathologists. The pathogenesis is largely unknown. The aims of this study were to: (1) characterize the expression of smoothelin, a novel smooth muscle-specific contractile protein expressed only by terminally differentiated smooth muscle cells, in the normal gastrointestinal (GI) tract; and (2) determine whether smoothelin is aberrantly expressed in patients with colonic inertia. A total of 57 resections of the normal GI tract (distal esophagus to left colon) were obtained from patients without GI motor dysfunction. Sixty-one colon resections were obtained from patients with a clinical diagnosis of colonic inertia. Smoothelin immunostaining was conducted on full-thickness tissue sections. In the nondysmotile controls, strong and diffuse cytoplasmic staining for smoothelin was observed in both the inner circular and outer longitudinal layers of the muscularis propria (MP) throughout the entire GI tract. The muscularis mucosae (MM) and muscular vessel walls were either completely negative or only patchily and weakly stained. The 1 exception to this pattern was observed in the distal esophagus, in which the MM was also diffusely and strongly stained. In cases with colonic inertia, a moderate to marked reduction of smoothelin immunoreactivity was observed in 15 of 61 (24.6%) colon resections, selectively seen in the outer layer of the MP. The data demonstrate that smoothelin is differentially expressed in the MP and MM of the normal GI tract and suggest that defective smoothelin expression may play a role in the pathogenesis of colonic inertia in a subset of patients.

Advances in diagnostic assessment of fecal incontinence and dyssynergic defecation

Disorders of the anorectum and pelvic floor affect approximately 25% of the population. Their evaluation and treatment have been hindered by a lack of understanding of underlying mechanism(s) and a working knowledge of the diagnostic advances in this field. A meticulous evaluation of anorectal structure and its function can provide invaluable insights to the practicing gastroenterologist regarding the pathogenic mechanism(s) of these disorders. Also, significant new knowledge has emerged over the past decade that includes the development of newer diagnostic tools such as high-resolution manometry and magnetic resonance defecography as well as a better delineation of the clinical and pathophysiologic subtypes of constipation and incontinence. This article provides an up-to-date review on the role of diagnostic tests in the evaluation of fecal incontinence and constipation with dyssynergic defecation.

Constipation and obstructed defecation

Difficulties with bowel function are common and may be due to several causes including slow colonic transit and obstructed defecation. The anatomical and pathophysiological changes associated with these conditions are varying, often incompletely understood, and in many cases have limited treatment outcomes. Patients present with variable complaints and have previously tried a plethora of over-the-counter medications in an effort to relieve their symptoms. Physicians need an organized approach to manage these patients optimally. Improvements over the past few years in our understanding of the complex process of defecation, along with the increasing use of radiological and anorectal physiology studies, have led to improved treatment results.

Neurophysiological testing in anorectal disorders

Neurophysiological tests of anorectal function can provide useful information regarding the integrity of neuronal innervation, as well as neuromuscular function. This information can give insights regarding the pathophysiological mechanisms that lead to several disorders of anorectal function, particularly fecal incontinence, pelvic floor disorders and dyssynergic defecation. Currently, several tests are available for the neurophysiological evaluation of anorectal function. These tests are mostly performed on patients referred to tertiary care centers, either following negative evaluations or when there is lack of response to conventional therapy. Judicious use of these tests can reveal significant and new understanding of the underlying mechanism(s) that could pave the way for better management of these disorders. In addition, these techniques are complementary to other modalities of investigation, such as pelvic floor imaging. The most commonly performed neurophysiological tests, along with their indications and clinical utility are discussed. Several novel techniques are evolving that may reveal new information on brain-gut interactions.

Cholestyramine--a useful adjunct for the treatment of patients with fecal incontinence

AIM/BACKGROUND

Cholestyramine may improve fecal incontinence, but its use has not been assessed. We report our experience with the use of cholestyramine in the treatment of fecal incontinence.

MATERIALS AND METHODS

Twenty-one patients (19 female, mean age 65 years) with fecal incontinence (>/=1 episode/week) received cholestyramine along with biofeedback therapy (group A). Stool frequency, stool consistency (Bristol scale), number of incontinent episodes, satisfaction with bowel function (VAS), and anorectal physiology were assessed at 3 months and at 1 year after treatment. Data were compared with a matched group of 21 incontinent subjects (19 female, mean age 64 years) who received biofeedback alone (group B).

RESULTS

At 3 months and at 1 year, group A patients showed decreased stool frequency (p < 0.01), stool consistency (p = 0.001), and number of incontinent episodes (p < 0.04). In contrast, stool frequency (p = 0.8) and stool consistency (0.23) were not different from baseline in group B subjects. In both groups, there was improvement in the satisfaction with bowel function (p < 0.05), anal sphincter pressures (p < 0.05) and ability to retain saline infusion (p < 0.05). Mean dose of cholestyramine used was 3.6 g; 13 subjects (62%) required dose titration, and 7 (33%) subjects reported minor side effects.

CONCLUSION

Cholestyramine is safe and useful adjunct for the treatment of diarrhea and fecal incontinence. Most patients require small doses, and dose titration is important. The improvement in stool characteristics favors a drug effect, over and above the benefits of biofeedback therapy.

Diagnostic testing in patients with chronic constipation

During the past few years, significant developments have taken place in the understanding and diagnosis of defecation disorders. Several innovative manometric, neurophysiologic, and radiologic techniques have been discovered, which have improved the accuracy of identifying the neuromuscular and pathophysiologic mechanisms of chronic constipation. Such approaches have led to improved management of these patients. In this review, we summarize and highlight recent advances in the utility of diagnostic testing of chronic constipation.

Managing fecal incontinence in long-term care

Fecal incontinence is common among long-term care residents. It increases mortality and is an overall marker for health status. Its etiology is associated with weakened sphincter muscles, comorbid disorders, and medication side effect profiles. Assessment and diagnostic issues are reviewed along with treatment interventions. Prompted toileting, dietary changes, and avoiding or minimizing fecal incontinence-inducing medications remain the most viable and effective interventions for long-term care residents.