Modulation of the rectoanal inhibitory reflex (RAIR): qualitative and quantitative evaluation in multiple sclerosis

Transcutaneous Electrical Acustimulation Improves Constipation by Enhancing Rectal Sensation in Patients With Functional Constipation and Lack of Rectal Sensation

INTRODUCTION

Reduced rectal sensation is involved in the pathophysiology of constipation. The aim of this study was to investigate the effects of transcutaneous electrical acustimulation (TEA) at acupuncture point ST36 on constipation and rectal sensation as well as autonomic functions in patients with constipation and reduced rectal sensation.

METHODS

In an acute study, anorectal motility and sensation tests were performed in constipation patients (N = 53) who were treated with TEA at ST36 or sham points. In a chronic study, patients (N = 18) underwent 2 weeks of TEA or sham-TEA in a crossover design.

RESULTS

Chronic TEA increased spontaneous bowel movements (3.72 vs 2.00 per week with sham-TEA, P < 0.0001) and significantly reduced constipation symptoms and increased quality of life in comparison with sham-TEA (P < 0.05). Acute TEA reduced the sensation threshold in response to rectal distention for the urge of defecation and maximum tolerable volume (P < 0.05, vs baseline); chronic TEA reduced the sensation thresholds for first sensation and desire of defecation, and decreased the threshold volume to an elicit rectal anal inhibitory reflex (P < 0.05). Both acute and chronic TEA increased parasympathetic activity (P < 0.05).

DISCUSSION

TEA at ST36 improves chronic constipation by enhancing rectal sensation possibly mediated by the reinforcement of parasympathetic activity in patients with functional constipation and reported lack/absence of rectal sensation.

Tools for fecal incontinence assessment: lessons for inflammatory bowel disease trials based on a systematic review

BACKGROUND

Fecal incontinence is a disabling condition affecting up to 20% of women.

OBJECTIVE

We investigated fecal incontinence assessment in both inflammatory bowel disease and non-inflammatory bowel disease patients to propose a diagnostic approach for inflammatory bowel disease trials.

METHODS

We searched on Pubmed, Embase and Cochrane Library for all studies on adult inflammatory bowel disease and non-inflammatory bowel disease patients reporting data on fecal incontinence assessment from January 2009 to December 2019.

RESULTS

In total, 328 studies were included; 306 studies enrolled non-inflammatory bowel disease patients and 22 studies enrolled inflammatory bowel disease patients. In non-inflammatory bowel disease trials the most used tools were the Wexner score, fecal incontinence quality of life questionnaire, Vaizey score and fecal incontinence severity index (in 187, 91, 62 and 33 studies). Anal manometry was adopted in 41.2% and endoanal ultrasonography in 34.0% of the studies. In 142 studies (46.4%) fecal incontinence evaluation was performed with a single instrument, while in 64 (20.9%) and 100 (32.7%) studies two or more instruments were used. In inflammatory bowel disease studies the Wexner score, Vaizey score and inflammatory bowel disease quality of life questionnaire were the most commonly adopted tools (in five (22.7%), five (22.7%) and four (18.2%) studies). Anal manometry and endoanal ultrasonography were performed in 45.4% and 18.2% of the studies.

CONCLUSION

Based on prior validation and experience, we propose to use the Wexner score as the first step for fecal incontinence assessment in inflammatory bowel disease trials. Anal manometry and/or endoanal ultrasonography should be taken into account in the case of positive questionnaires.

Inhibitory Effects and Sympathetic Mechanisms of Distension in the Distal Organs on Small Bowel Motility and Slow Waves in Canine

Rectal distension (RD) is known to induce intestinal dysmotility. Few studies were performed to compare effects of RD, colon distension (CD) and duodenal distension (DD) on small bowel motility. This study aimed to investigate effects and underlying mechanisms of distensions in these regions on intestinal motility and slow waves. Eight dogs chronically implanted with a duodenal fistula, a proximal colon fistula, and intestinal serosal electrodes were studied in six sessions: control, RD, CD, DD, RD + guanethidine, and CD + guanethidine. Postprandial intestinal contractions and slow waves were recorded for the assessment of intestinal motility. The electrocardiogram was recorded for the assessment of autonomic functions. (1) Isobaric RD and CD suppressed intestinal contractions (contractile index: 6.0 ± 0.4 with RD vs. 9.9 ± 0.9 at baseline, P = 0.001, 5.3 ± 0.2 with CD vs. 7.7 ± 0.8 at baseline, P = 0.008). Guanethidine at 3 mg/kg iv was able to partially block the effects. (2) RD and CD reduced the percentage of normal intestinal slow waves from 92.1 ± 2.8 to 64.2 ± 3.4 % (P < 0.001) and from 90 ± 2.7 to 69.2 ± 3.7 % (P = 0.01), respectively. Guanethidine could eliminate these inhibitory effects. (3) DD did not induce any changes in small intestinal contractions and slow waves (P > 0.05). (4) The spectral analysis of the heart rate variability showed that both RD and CD increased sympathetic activity (LF) and reduced vagal activity (HF) (P < 0.05). Isobaric RD and CD could inhibit postprandial intestinal motility and impair intestinal slow waves, which were mediated via the sympathetic pathway. However, DD at a site proximal to the measurement site did not seem to impair small intestinal contractions or slow waves.

Anorectal dysfunction in multiple sclerosis: a systematic review

Constipation and fecal incontinence are common in patients with neuromuscular diseases. Despite their high prevalence and potential impact on overall quality of life, few studies have addressed anorectal dysfunction in patients with multiple sclerosis (MS). The goal of this paper is to define the prevalence, pathophysiology, impact, and potential treatment of constipation and incontinence in MS patients. Methods. The PubMed database was searched for English language publications between January 1973 and December 2011. Articles were reviewed to assess the definition of the study population, duration, type and severity of MS, sex distribution, prevalence, impact, results of physiologic testing, and treatments. Results. The reported prevalence of constipation and fecal incontinence ranged around 40%. Anorectal dysfunction significantly affected patients with nearly 1 in 6 patients limiting social activities or even quitting work due to symptoms. Caregivers listed toileting as a common and significant burden. The only randomized controlled trial showed a marginal improvement of constipation with abdominal massage. All other reports lacked control interventions and only demonstrated improvement in individuals with milder symptoms. Conclusion. Anorectal dysfunction is a common manifestation in MS that significantly affects quality of life. Therapies are at best moderately effective and often cumbersome, highlighting the need for simple and more helpful interventions.

Morphological abnormalities of the recto-anal inhibitory reflex reflects symptom pattern in neurogenic bowel

BACKGROUND

Bowel dysfunction amongst multiple sclerosis (MS) and spinal cord injury (SCI) patients often manifests as fecal incontinence (FI) or constipation, but the pathophysiology is poorly understood. Anorectal physiology provides an objective assessment of lower bowel functions and is increasingly being used in clinical practice.

AIM

The purpose of this study was to correlate symptoms of bowel dysfunction in patients with spinal cord disease with findings in anorectal physiology. We hypothesized that specific abnormalities will correlate with symptoms: prolonged recto-anal inhibitory reflex in patients with incontinence and decreased rectal mucosal blood flow in patients with constipation.

METHODS

Forty-nine patients with MS (35 with predominant FI and 14 constipation), 46 supraconal SCI (mixed symptom load), and 21 healthy volunteers matched for age and sex were studied. Subjects completed validated constipation and FI symptom questionnaires. Patients underwent standard anorectal physiology, including assessment of rectal mucosal blood flow and recto-anal inhibitory reflex (RAIR).

RESULTS

Severity of constipation correlates significantly with distension sensitivity (urge volume [r = 0.68, p = 0.002] and maximal volume [r = 0.39, p = 0.03]). Severity of constipation also correlated with diminished rectal mucosal blood flow in both patient groups (r = -0.51, p = 0.006). In both groups, constipation correlated with diminished relaxation of the sphincters in the RAIR whilst fecal incontinence correlated with a prolonged duration of RAIR (r = 0.33, p = 0.009) and recovery phase (r = 0.37, p = 0.05).

CONCLUSION

Bowel symptoms in patients with MS and SCI correlate with specific alterations of anorectal physiology. This provides objective assessment of bowel symptoms and may allow tailored treatment to individual patients.