Chronic constipation: overview and challenges

Prospective randomized double-blind study of temporary sacral nerve stimulation in patients with rectal evacuatory dysfunction and rectal hyposensitivity

OBJECTIVE

Prospective randomized double-blind placebo-controlled crossover trial of 14 female patients (median age 52 [30-69] years) with proctographically defined evacuatory dysfunction (ED) and demonstrable rectal hyposensitivity (elevated thresholds to balloon distension in comparison with age- and sex-matched controls).

BACKGROUND

Sacral nerve stimulation (SNS) is an evolving treatment for constipation. However, variable outcomes might be improved by better patient selection. Evidence that the effect of SNS may be mediated by modulation of afferent signaling promotes a role in patients with ED associated with rectal hyposensation.

METHODS

SNS was performed by the standard 2-stage technique (temporary then permanent implantation). During a 4-week period of temporary stimulation, patients were randomized ON-OFF/OFF-ON for two 2-week periods. Before insertion (PRE), and during each crossover period, primary (rectal sensory thresholds) and secondary (bowel diaries, constipation, and GIQoL [gastrointestinal quality of life] scores) outcome variables were blindly assessed.

RESULTS

Thirteen patients completed the trial. Following stimulation, defecatory desire volumes to rectal balloon distension were normalized in 10 of 13 patients (PRE: mean 277 mL [234-320] vs ON: 163 mL [133-193] vs OFF: 220 mL [183-257 mL]; P = 0.006) and maximum tolerable volume in 9 of 13 (PRE: mean 350 mL [323-377] vs ON: 262 mL [219-305] vs OFF: 298 mL [256-340 mL]; P = 0.012). There was a significant increase in the percentage of successful bowel movements (PRE: median 43% [0-100] vs ON: 89% [11-100] vs OFF: 83% [11-100]; P = 0.007) and Wexner constipation scores improved (PRE: median 19 [9-26] vs ON: 10 [6-27] vs OFF: 13 [5-29]; P = 0.01). There were no significant changes in disease-specific or generic quality of life measures. Eleven patients progressed to permanent stimulation (9/11 success at 19 months).

CONCLUSIONS

Most patients with chronic constipation secondary to ED with rectal hyposensitivity responded to temporary SNS. The physiological results presented support a mechanistic role for rectal afferent modulation.

Use acupuncture to treat functional constipation: study protocol for a randomized controlled trial

BACKGROUND

Whether acupuncture is effective for patients with functional constipation is still unclear. Therefore, we report the protocol of a randomized controlled trial of using acupuncture to treat functional constipation.

DESIGN

A randomized, controlled, four-arm design, large-scale trial is currently undergoing in China. Seven hundred participants are randomly assigned to three acupuncture treatment groups and Mosapride Citrate control group in a 1:1:1:1 ratio. Participants in acupuncture groups receive 16 sessions of acupuncture treatment, and are followed up for a period of 9 weeks after randomization. The acupuncture groups are: (1) Back-Shu and Front-Mu acupoints of Large Intestine meridians (Shu-Mu points group); (2) He-Sea and Lower He-Sea acupoints of Large Intestine meridians (He points group); (3) Combining used Back-Shu, Front-Mu, He-Sea, and Lower He-Sea acupoints of Large Intestine meridians (Shu-Mu-He points group). The control group is Mosapride Citrate group. The primary outcome is frequency of defecation per week at the fourth week after randomization. The secondary outcomes include Bristol stool scale, the extent of difficulty during defecating, MOS 36-item Short Form health survey (SF-36), Self-Rating Anxiety Scale (SAS), and Self-rating Depression Scale (SDS). The first two of second outcomes are measured 1 week before randomization and 2, 4, and 8 weeks after randomization. Other second outcomes are measured 1 week before randomization and 2 and 4 weeks after randomization, but SF-36 is measured at randomization and 4 weeks after randomization.

DISCUSSION

The result of this trial (which will be available in 2012) will confirm whether acupuncture is effective to treat functional constipation and whether traditional acupuncture theories play an important role in it.

TRIALS REGISTRATION

Clinical Trials.gov NCT01411501.

The physiology of human defecation

Human defecation involves integrated and coordinated sensorimotor functions, orchestrated by central, spinal, peripheral (somatic and visceral), and enteric neural activities, acting on a morphologically intact gastrointestinal tract (including the final common path, the pelvic floor, and anal sphincters). The multiple factors that ultimately result in defecation are best appreciated by describing four temporally and physiologically fairly distinct phases. This article details our current understanding of normal defecation, including recent advances, but importantly identifies those areas where knowledge or consensus is still lacking. Appreciation of normal physiology is central to directed treatment of constipation and also of fecal incontinence, which are prevalent in the general population and cause significant morbidity.

Effects and possible mechanisms of acupuncture at ST36 on upper and lower abdominal symptoms induced by rectal distension in healthy volunteers

Background acupuncture (AP) has been shown to have a therapeutic potential for gastrointestinal motility disorders. The aims of this study were to investigate the effects and possible mechanisms of acupuncture on postprandial upper and lower abdominal symptoms induced by rectal distension (RD). Twenty healthy volunteers were involved in a two-session study (AP and sham-AP, AP and no-AP, or sham-AP and no-AP). In 12 of the volunteers, RD was performed for 60 min in the postprandial state, and AP at ST36 or sham-AP was performed during the second 30-min period of RD. Gastric slow waves and heart rate variability (HRV) were recorded using the electrogastrogram and electrocardiogram, respectively. Upper and lower abdominal symptoms were scored during RD with AP and sham-AP. In five of the subjects, an additional experiment with two sessions (with AP and no-AP) was performed. In the remaining eight volunteers, the same experiment was performed with sham-AP and no-AP was performed. The results were, first, RD at an average volume of 171 ml induced upper and lower abdominal symptoms (P < 0.01). AP, but not sham-AP or no-AP, reduced both upper and lower abdominal symptoms (P < 0.05). Second, RD decreased the percentage of normal gastric slow waves (P < 0.05). AP improved gastric slow waves compared with sham-AP or no-AP (P < 0.05). Third, in the larger, but not smaller, sample size experiment, the vagal activity during the RD plus AP period was significantly higher than that during the RD alone period in the same session and the corresponding period with sham-AP or no-AP in other sessions (P < 0.05). Neither sham-AP nor no-AP showed any effects on vagal activity (P > 0.05). Finally, in the experiment with eight volunteers, neither sham-AP nor no-AP showed any effects on RD-induced impairment in gastric slow waves, abdominal symptoms, or vagal activity (P > 0.05). The conclusions are RD induces upper or lower abdominal symptoms and impairs gastric slow waves in healthy volunteers. AP at ST36 is able to improve upper and lower abdominal symptoms and impaired gastric slow waves induced by RD, possibly mediated via the vagal pathway.

Factors associated with persistent and nonpersistent chronic constipation, over 20 years

BACKGROUND & AIMS

The prevalence of chronic constipation (CC) has been reported to be as high as 20% in the general population, but little is known about its natural history. We estimated the natural history of CC and characterized features of persistent CC and nonpersistent CC, compared with individuals without constipation.

METHODS

In a prospective cohort study, we analyzed data collected from multiple, validated surveys (minimum of 2) of 2853 randomly selected subjects, over a 20-year period (median, 11.6 years). Based on responses, subjects were characterized as having persistent CC, nonpersistent CC, or no constipation. We assessed the association between constipation status and potential risk factors using logistic regression models, adjusting for age and sex.

RESULTS

Of the respondents, 84 had persistent CC (3%), 605 had nonpersistent CC (21%), and 2164 had no symptoms of constipation (76%). High scores from the somatic symptom checklist (odds ratio [OR] = 2.1; 95% confidence interval [CI], 1.3-3.4) and frequent doctor visits (OR = 2.0; 95% CI, 1.0-3.8) were significantly associated with persistent CC, compared with subjects with no constipation symptoms. The only factor that differed was increased use of laxatives or fiber among subjects with persistent CC (OR = 3.0; 95% CI, 1.9-4.9).

CONCLUSIONS

The prevalence of constipation might be exaggerated-the proportion of the population with persistent CC is low (3%). Patients with persistent and nonpersistent CC have similar clinical characteristics, although individuals with persistent CC use more laxatives or fiber. CC therefore appears and disappears among certain patients, but we do not have enough information to identify these individuals in advance.

The impact of laxative use upon symptoms in patients with proven slow transit constipation

Background

Constipation severity is often defined by symptoms including feelings of complete evacuation, straining, stool frequency and consistency. These descriptors are mostly obtained in the absence of laxative use. For many constipated patients laxative usage is ubiquitous and long standing. Our aim was to determine the impact of laxative use upon the stereotypic constipation descriptors.

Methods

Patients with confirmed slow transit constipation completed 3-week stool diaries, detailing stool frequency and form, straining, laxative use and pain and bloating scores. Each diary day was classified as being under laxative affect (laxative affected days) or not (laxative unaffected days). Unconditional logistic regression was used to assess the affects of laxatives on constipation symptoms.

Results

Ninety four patients with scintigraphically confirmed slow transit constipation were enrolled in the study. These patients reported a stool frequency of 5.6 ± 4.3 bowel motions/week, only 21 patients reported <3 bowel motions/week. Similarly, 21 patients reported a predominant hard stool at defecation. The majority (90%) of patients reported regular straining. A regular feeling of complete evacuation was reported in just 7 patients. Daily pain and/or bloating were reported by 92% of patients. When compared with laxative unaffected days, on the laxative affected days patients had a higher stool frequency (OR 2.23; P <0.001) and were more likely to report loose stools (OR 1.64; P <0.009). Laxatives did not increase the number of bowel actions associated with a feeling of complete evacuation. Laxative use had no affect upon straining, pain or bloating scores

Conclusions

The reporting of frequent and loose stools with abdominal pain and/or bloating is common in patients with slow transit constipation. While laxative use is a significant contributor to altering stool frequency and form, laxatives have no apparent affect on pain or bloating or upon a patients feeling of complete evacuation. These factors need to be taken into account when using constipation symptoms to define this population.

Randomised clinical trial: The ileal bile acid transporter inhibitor A3309 vs. placebo in patients with chronic idiopathic constipation--a double-blind study

BACKGROUND

One half of patients with constipation are not satisfied with available therapies, hence there is a need for more effective and well-tolerated drugs.

AIM

To evaluate the effects of a specific inhibitor of the Ileal Bile Acid Transporter (IBAT; syn apical sodium-dependent bile acid transporter; ASBT) in patients with chronic idiopathic constipation (CIC) with focus on safety, colonic transit and efficacy signals.

METHODS

This was a single-centre, prospective, randomised, double-blind, placebo-controlled study with a dose-escalating design in patients with CIC. In addition to evaluation of conventional safety and tolerability parameters, (i) colonic transit time (CTT) was measured using radio-opaque markers, (ii) metabolic parameters [lipid profile, C4 (7α-hydroxy-4-cholesten-3-one) and FGF19 (Fibroblast Growth Factor 19)] were evaluated, and (iii) constipation parameters, such as changes in stool frequency and consistency, were analysed.

RESULTS

Thirty patients were randomised into five dose-levels (range: 0.1-10 mg/day) or to placebo. All patients completed a 14-day treatment period, and the safety/tolerability analysis was favourable. A3309, present in picomolar concentrations in plasma, induced up to a three-fold increase in bile acid synthesis (C4) and a reduction of plasma FGF19, as well as reduction in total and LDL cholesterol. CTT was reduced in the highest dose groups; the main acceleration was identified in the left colon. Efficacy parameters showed trends for increased number of spontaneous bowel movements and improved stool consistency.

CONCLUSIONS

Ileal Bile Acid Transporter inhibition is a novel mechanism for treatment of patients with chronic idiopathic constipation and has additional benefits of improving metabolic parameters (EudraCT 2008-003255-72).

Chronic constipation: Facilitator factor for development of varicocele

AIM: To evaluate the possible relationship between varicocele and chronic constipation.

METHODS: Between April 2009 and May 2010, a total of 135 patients with varicocele or constipation and 120 healthy controls were evaluated. Patients were divided into two groups. In both groups detailed medical history was taken and all patients were examined physically by the same urologist and gastroenterologist. All of them were evaluated by color Doppler ultrasonography. All patients with constipation, except for the healthy controls of the second group, underwent a colonoscopy to identify the etiology of the constipation. In the first group, we determined the rate of chronic constipation in patients with varicocele and in the second group, the rate of varicocele in patients with chronic constipation. In both groups, the rate of the disease was compared with age-matched healthy controls. In the second group, the results of colonoscopies in the patients with chronic constipations were also evaluated.

RESULTS: In the first group, mean age of the study and control groups were 22.9 ± 4.47 and 21.8 ± 7.21 years, respectively (P < 0.05). In the second group, mean age of the study and control groups were 52.8 ± 33.3 and 51.7 ± 54.3 years, respectively (P < 0.05). In the first group, chronic constipation was observed in 8 of the 69 patients with varicocele (11.6%) and 3 out of 60 in healthy controls (5%), respectively. In this regard, there was no statistical significance between varicocele patients and the healthy control (P = 0.37). In the second group, varicocele was observed in 16 of the 66 patients with chronic constipation (24.24%) and 12 out of 60 in healthy controls (20%) respectively. Similarly, there was no statistical significance between chronic constipation and healthy controls (P = 0.72). Internal/external hemorrhoids were detected in 4 of the 16 patients with chronic constipation and varicocele, in the second group. In the remaining 50 patients with chronic constipation 9 had internal/external hemorrhoids. In this regard, there was no statistical significance between chronic constipation and healthy controls (P = 0.80).

CONCLUSION: Chronic constipation may not be a major predictive factor for the development of varicocele, but it may be a facilitator factor for varicocele.

Factor analysis identifies subgroups of constipation

AIM: To determine whether distinct symptom groupings exist in a constipated population and whether such grouping might correlate with quantifiable pathophysiological measures of colonic dysfunction.

METHODS: One hundred and ninety-one patients presenting to a Gastroenterology clinic with constipation and 32 constipated patients responding to a newspaper advertisement completed a 53-item, wide-ranging self-report questionnaire. One hundred of these patients had colonic transit measured scintigraphically. Factor analysis determined whether constipation-related symptoms grouped into distinct aspects of symptomatology. Cluster analysis was used to determine whether individual patients naturally group into distinct subtypes.

RESULTS: Cluster analysis yielded a 4 cluster solution with the presence or absence of pain and laxative unresponsiveness providing the main descriptors. Amongst all clusters there was a considerable proportion of patients with demonstrable delayed colon transit, irritable bowel syndrome positive criteria and regular stool frequency. The majority of patients with these characteristics also reported regular laxative use.

CONCLUSION: Factor analysis identified four constipation subgroups, based on severity and laxative unresponsiveness, in a constipated population. However, clear stratification into clinically identifiable groups remains imprecise.

Colonic dysmotility in constipation

Constipation is a common and distressing condition with major morbidity, health care burden, and impact on quality of life. Colonic motor dysfunction remains the leading hypothesis to explain symptom generation in the most severe cases of chronic constipation and physiological testing plays a role in identifying the colonic dysmotility and the subsequent patient management. Measurement of colonic motor patterns and transit has enhanced our knowledge of normal and abnormal colonic motor physiology. The scope of this review encompasses the latest findings that improve our understanding of the motility disorders associated with colonic dysfunction in both the paediatric and adult population suffering from constipation.

Childhood constipation; an overview of genetic studies and associated syndromes

Constipation is a common problem in children but little is known about its exact pathophysiology. Environmental, behavioural but also genetic factors are thought to play a role in the aetiology of childhood constipation. We provide an overview of genetic studies performed in constipation. Until now, linkage studies, association studies and direct gene sequencing have failed to identify mutations in specific genes associated with constipation. We show that along with functional constipation, there are numerous clinical syndromes associated with childhood constipation. These syndromic forms of constipation appear to be the result of mutations in genes affecting all aspects of the normal physiology of human defecation. We stress that syndromic causes of childhood constipation should be considered in the evaluation of a constipated child.

Rectal sensorimotor dysfunction in constipation

The pathophysiological mechanisms underlying chronic constipation in both adults and children remain to be unravelled. This is a not inconsiderable challenge, but is fundamental to improving management of such patients. Rectal sensorimotor function, which encompasses both sensation and motility, as well as biomechanical components (compliance, capacity), is now strongly implicated in the pathogenesis of constipation. Rectal hyposensitivity, rectal hypercompliance, increased rectal capacity, rectal motor dysfunction (phasic contractility and tone), and altered rectoanal reflex activity are all found in constipated patients, particularly in association with 'functional' disorders of defaecation (i.e. pelvic floor dyssynergia). This review covers contemporary understanding of how components of rectal sensorimotor function may contribute to symptom development in both adult and paediatric populations. The complex interaction between sensory/motor/biomechanical domains, and how best to measure these functions are addressed, and where data exist, the impact of sensorimotor dysfunction on therapeutic outcomes is highlighted.

Accurate localization of a fall in pH within the ileocecal region: validation using a dual-scintigraphic technique

Stereotypical changes in pH occur along the gastrointestinal (GI) tract. Classically, there is an abrupt increase in pH on exit from the stomach, followed later by a sharp fall in pH, attributed to passage through the ileocecal region. However, the precise location of this latter pH change has never been conclusively substantiated. We aimed to determine the site of fall in pH using a dual-scintigraphic technique. On day 1, 13 healthy subjects underwent nasal intubation with a 3-m-long catheter, which was allowed to progress to the distal ileum. On day 2, subjects ingested a pH-sensitive wireless motility capsule labeled with 4 MBq (51)Chromium [EDTA]. The course of this, as it travelled through the GI tract, was assessed with a single-headed γ-camera using static and dynamic scans. Capsule progression was plotted relative to a background of 4 MBq ¹¹¹Indium [diethylenetriamine penta-acetic acid] administered through the catheter. Intraluminal pH, as recorded by the capsule, was monitored continuously, and position of the capsule relative to pH was established. A sharp fall in pH was recorded in all subjects; position of the capsule relative to this was accurately determined anatomically in 9/13 subjects. In these nine subjects, a pH drop of 1.5 ± 0.2 U, from 7.6 ± 0.05 to 6.1 ± 0.1 occurred a median of 7.5 min (1-16) after passage through the ileocecal valve; location was either in the cecum (n = 5), ascending colon (n = 2), or coincident with a move from the cecum to ascending colon (n = 2). This study provides conclusive evidence that the fall in pH seen within the ileocolonic region actually occurs in the proximal colon. This phenomenon can be used as a biomarker of transition between the small and large bowel and validates assessment of regional GI motility using capsule technology that incorporates pH measurement.

Pancolonic spatiotemporal mapping reveals regional deficiencies in, and disorganization of colonic propagating pressure waves in severe constipation

BACKGROUND

The morphology, motor responses and spatiotemporal organization among colonic propagating sequences (PS) have never been defined throughout the entire colon of patients with slow transit constipation (STC). Utilizing the technique of spatiotemporal mapping, we aimed to demonstrate 'manometric signatures' that may serve as biomarkers of the disorder.

METHODS

In 14 female patients with scintigraphically confirmed STC, and eight healthy female controls, a silicone catheter with 16 recording sites spanning the colon at 7.5 cm intervals was positioned colonoscopically with the tip clipped to the cecum. Intraluminal pressures were recorded for 24 h.

KEY RESULTS

Pan-colonic, 24 h, spatiotemporal mapping identified for the first time in STC patients: a marked paucity of propagating pressure waves in the midcolon (P = 0.01), as a consequence of a significant (P < 0.0001) decrease in extent of propagation of PS originating in the proximal colon; an increase in frequency of retrograde PS in the proximal colon; a significant reduction in the spatiotemporal organization among PS (P < 0.001); absence of the normal nocturnal suppression of PS.

CONCLUSIONS & INFERENCES

Pancolonic, 24 h, spatiotemporal pressure mapping readily identifies characteristic disorganization among consecutive PS, regions of diminished activity and absent or deficient fundamental motor patterns and responses to physiological stimuli. These features are all likely to be important in the pathophysiology of slow transit constipation.

Paediatric and adult colonic manometry: A tool to help unravel the pathophysiology of constipation

Colonic motility subserves large bowel functions, including absorption, storage, propulsion and defaecation. Colonic motor dysfunction remains the leading hypothesis to explain symptom generation in chronic constipation, a heterogeneous condition which is extremely prevalent in the general population, and has huge socioeconomic impact and individual suffering. Physiological testing plays a crucial role in patient management, as it is now accepted that symptom-based assessment, although important, is unsatisfactory as the sole means of directing therapy. Colonic manometry provides a direct method for studying motor activities of the large bowel, and this review provides a contemporary understanding of how this technique has enhanced our knowledge of normal colonic motor physiology, as well as helping to elucidate pathophysiological mechanisms underlying constipation. Methodological approaches, including available catheter types, placement technique and recording protocols, are covered, along with a detailed description of recorded colonic motor activities. This review also critically examines the role of colonic manometry in current clinical practice, and how manometric assessment may aid diagnosis, classification and guide therapeutic intervention in the constipated individual. Most importantly, this review considers both adult and paediatric patients. Limitations of the procedure and a look to the future are also addressed.