Oral colon transit scintigraphy using indium-111 DTPA: variability in healthy subjects

Colonic transit in patients after anterior resection: prospective, comparative study using single-photon emission CT/CT scintigraphy

BACKGROUND

Bowel dysfunction after anterior resection is well documented, but its pathophysiology remains poorly understood. No study has assessed whether postoperative variation in colonic transit contributes to symptoms. This study measured colonic transit using planar scintigraphy and single-photon emission CT (SPECT)/CT in patients after anterior resection, stratified according to postoperative bowel function.

METHODS

Symptoms were assessed using the low anterior resection syndrome (LARS) score. Following gallium-67 ingestion, scintigraphy was performed at predefined time points. Nine regions of interest were defined, and geometric centre (GC), percentage isotope retained, GC velocity index and colonic half-clearance time (T_½ ) determined. Transit parameters were compared between subgroups based on LARS score using receiver operating characteristic (ROC) curve analyses.

RESULTS

Fifty patients (37 men; median age 72·6 (range 44·4-87·7) years) underwent planar and SPECT scintigraphy. Overall, 17 patients had major and nine had minor LARS; 24 did not have LARS. There were significant differences in transit profiles between patients with major LARs and those without LARS: GCs were greater (median 5·94 (range 2·35-7·72) versus 4·30 (2·12-6·47) at 32 h; P = 0·015); the percentage retained isotope was lower (median 53·8 (range 6·5-100) versus 89·9 (38·4-100) per cent at 32 h; P = 0·002); GC velocity indices were greater (median 1·70 (range 1·18-1·92) versus 1·45 (0·98-1·80); P = 0·013); and T_½ was shorter (median 38·3 (17·0-65·0) versus 57·0 (32·1-160·0) h; P = 0·003). Percentage tracer retained at 32 h best discriminated major LARS from no LARS (area under curve (AUC) 0·828).

CONCLUSION

Patients with major LARS had accelerated colonic transit compared with those without LARS, which may help explain postoperative bowel dysfunction in this group. The percentage tracer retained at 32 h had the greatest AUC value in discriminating such patients.

Sacral Nerve Stimulation Fails to Offer Long-term Benefit in Patients With Slow-Transit Constipation

BACKGROUND

Sacral nerve stimulation is proposed as a treatment for slow-transit constipation. However, in our randomized controlled trial we found no therapeutic benefit over sham stimulation. These patients have now been followed-up over a long-term period.

OBJECTIVE

The purpose of this study was to assess the long-term efficacy of sacral nerve stimulation in patients with scintigraphically confirmed slow-transit constipation.

DESIGN

This study was designed for long-term follow-up of patients after completion of a randomized controlled trial.

SETTINGS

It was conducted at an academic tertiary public hospital in Sydney.

PATIENTS

Adults with slow-transit constipation were included.

MAIN OUTCOME MEASURES

At the 1- and 2-year postrandomized controlled trial, the primary treatment outcome measure was the proportion of patients who reported a feeling of complete evacuation on >2 days per week for ≥2 of 3 weeks during stool diary assessment. Secondary outcome was demonstration of improved colonic transit at 1 year.

RESULTS

Fifty-three patients entered long-term follow-up, and 1 patient died. Patient dissatisfaction or serious adverse events resulted in 44 patients withdrawing from the study because of treatment failure by the end of the second year. At 1 and 2 years, 10 (OR = 18.8% (95% CI, 8.3% to 29.3%)) and 3 patients (OR = 5.7% (95% CI, -0.5% to 11.9%)) met the primary outcome measure. Colonic isotope retention at 72 hours did not differ between baseline (OR = 75.6% (95% CI, 65.7%-85.6%)) and 1-year follow-up (OR = 61.7% (95% CI, 47.8%-75.6%)).

LIMITATIONS

This study only assessed patients with slow-transit constipation.

CONCLUSIONS

In these patients with slow-transit constipation, sacral nerve stimulation was not an effective treatment.

Regional gastrointestinal transit and pH studied in 215 healthy volunteers using the wireless motility capsule: influence of age, gender, study country and testing protocol

BACKGROUND

The wireless motility capsule (WMC) offers the ability to investigate luminal gastrointestinal (GI) physiology in a minimally invasive manner.

AIM

To investigate the effect of testing protocol, gender, age and study country on regional GI transit times and associated pH values using the WMC.

METHODS

Regional GI transit times and pH values were determined in 215 healthy volunteers from USA and Sweden studied using the WMC over a 6.5-year period. The effects of test protocol, gender, age and study country were examined.

RESULTS

For GI transit times, testing protocol was associated with differences in gastric emptying time (GET; shorter with protocol 2 (motility capsule ingested immediately after meal) vs. protocol 1 (motility capsule immediately before): median difference: 52 min, P = 0.0063) and colonic transit time (CTT; longer with protocol 2: median 140 min, P = 0.0189), but had no overall effect on whole gut transit time. Females had longer GET (by median 17 min, P = 0.0307), and also longer CTT by (104 min, P = 0.0285) and whole gut transit time by (263 min, P = 0.0077). Increasing age was associated with shorter small bowel transit time (P = 0.002), and study country also influenced small bowel and CTTs. Whole gut and CTTs showed clustering of data at values separated by 24 h, suggesting that describing these measures as continuous variables is invalid. Testing protocol, gender and study country also significantly influenced pH values.

CONCLUSIONS

Regional GI transit times and pH values, delineated using the wireless motility capsule (WMC), vary based on testing protocol, gender, age and country. Standardisation of testing is crucial for cross-referencing in clinical practice and future research.

Treatment efficacy of sacral nerve stimulation in slow transit constipation: a two-phase, double-blind randomized controlled crossover study

OBJECTIVES

Sacral nerve stimulation (SNS) is a potential treatment for constipation refractory to standard therapies. However, there have been no randomized controlled studies examining its efficacy. In patients with slow transit constipation, we evaluated the efficacy of suprasensory and subsensory SNS compared with sham, in a prospective, 18-week randomized, double-blind, placebo-controlled, two-phase crossover study. The primary outcome measure was the proportion of patients who, on more than 2 days/week for at least 2 of 3 weeks, reported a bowel movement associated with a feeling of complete evacuation.

METHODS

After 3 weeks of temporary peripheral nerve evaluation (PNE), all patients had permanent implantation and were randomized to subsensory/sham (3 weeks each) and then re-randomized to suprasensory/sham (3 weeks each) with a 2-week washout period between each arm. Daily stool dairies were kept, and quality of life (QoL; SF36) was measured at the end of each arm.

RESULTS

Between November 2006 and March 2012, 234 constipated patients were assessed, of whom 59 were willing and deemed eligible to participate (4 male; median age 42 years). Of the 59 patients, 16 (28%) responded to PNE. Fifty-five patients went on to permanent SNS implantation. The proportion of patients satisfying the primary outcome measure did not differ between suprasensory (30%) and sham (21%) stimulations, nor between subsensory (25%) and sham (25%) stimulations. There were no significant changes in QoL scores.

CONCLUSIONS

In patients with refractory slow transit constipation, SNS did not improve the frequency of complete bowel movements over the 3-week active period.

Colonic motor abnormalities in slow transit constipation defined by high resolution, fibre-optic manometry

BACKGROUND

Slow transit constipation (STC) is associated with colonic motor abnormalities. The underlying cause(s) of the abnormalities remain poorly defined. In health, utilizing high resolution fiber-optic manometry, we have described a distal colonic propagating motor pattern with a slow wave frequency of 2-6 cycles per minute (cpm). A high calorie meal caused a rapid and significant increase in this activity, suggesting the intrinsic slow wave activity could be mediated by extrinsic neural input. Utilizing the same protocol our aim was to characterize colonic meal response STC patients.

METHODS

A fiber-optic manometry catheter (72 sensors at 1 cm intervals) was colonoscopically placed with the tip clipped at the ascending or transverse colon, in 14 patients with scintigraphically confirmed STC. Manometric recordings were taken, for 2 h pre and post a 700 kCal meal. Data were compared to 12 healthy adults.

KEY RESULTS

Prior to and/or after the meal the cyclic propagating motor pattern was identified in 13 of 14 patients. However, the meal, did not increase the cyclic motor pattern (preprandial 7.4 ± 7.6 vs postprandial 8.3 ± 4.5 per/2 h), this is in contrast to the dramatic increase observed in health (8.3 ± 13.3 vs 59.1 ± 89.0 per/2 h; p < 0.001).

CONCLUSIONS & INFERENCES

In patients with STC a meal fails to induce the normal increase in the distal colonic cyclic propagating motor patterns. We propose that these data may indicate that the normal extrinsic parasympathetic inputs to the colon are attenuated in these patients.

Interpretation of overall colonic transit in defecation disorders in males and females

BACKGROUND

There is little information regarding gender-specific measurements of colonic transit and anorectal function in patients with defecation disorders (DD). To compare overall colonic transit by gender in DD.

METHODS

In 407 patients with constipation due to DD diagnosed by a single gastroenterologist (1994-2012), DD was characterized by anorectal manometry, balloon expulsion test, and colonic transit by scintigraphy. The primary endpoint was overall colonic transit (geometric center, GC) at 24 h (GC24). Effects of gender in DD on colonic transit, and comparison with transit in 208 healthy controls were assessed by Mann-Whitney rank sum test. Secondary endpoints were maximum anal resting (ARP) and squeeze (ASP) pressures. We also tested association of the physiological endpoints among DD females by pregnancy history and among DD patients by colectomy history.

KEY RESULTS

The DD patients were 67 males (M) and 340 females (F). Significant differences by gender in DD patients were observed in GC24 (median: M: 2.2; F: 1.8; P = 0.01), ARP (median: M: 87.8 mmHg; F: 82.4 mmHg; P = 0.04), and ASP (median: M: 182.4 mmHg; F: 128.7 mmHg; P < 0.001). GC24 was slower in DD compared with same-gender healthy controls. GC24 did not differ among DD females by pregnancy history. Anorectal functions and upper GI transit did not differ among DD patients by colectomy history.

CONCLUSIONS & INFERENCES

Patients with DD have slower colonic transit compared with gender-matched controls. Among DD patients, males have higher ARP and ASP, and females have slower colonic transit. Although the clinical significance of these differences may be unclear, findings suggest that interpretation of these tests in suspected DD should be based on same-gender control data.

Differential effects of selective and non-selective muscarinic antagonists on gastrointestinal transit and bowel function in healthy women

BACKGROUND

The gastrointestinal effects of antimuscarinic drugs used to treat overactive bladder may be related to the selectivity of these agents for M(3) -muscarinic receptor subtypes. We compared the effects of non-selective (fesoterodine) and M(3)-selective (solifenacin) antimuscarinics on gastrointestinal transit in healthy women.

METHODS

Gastric emptying (GE), small-intestinal transit (colonic filling at 6 h), colonic transit [geometric center at 24 h (GC24; primary endpoint) and 48 h (GC48)], and bowel habits were assessed by scintigraphy and bowel diaries before and after randomization to fesoterodine 8 mg, solifenacin 10 mg, or placebo (2 : 2 : 1) for 14 days. An interim analysis to finalize sample size was conducted.

KEY RESULTS

After 60 subjects [placebo (n = 12), fesoterodine (n = 25), solifenacin (n = 23)] completed the study, the study was terminated due to a prespecified criterion (sample size ≥ 452.5 needed to provide ≥ 80% power to demonstrate superiority of fesoterodine over solifenacin in GC24). Compared with baseline, (i) placebo delayed small-intestinal, but not colonic, transit, (ii) fesoterodine significantly increased GE t(1/2) vs placebo (17.0 min; P = 0.027), and (iii) fesoterodine and solifenacin delayed small-intestinal (-36.8% and -21.8%, respectively, P < 0.001 vs placebo) and colonic transit (GC24: -0.44 and -0.49, respectively, P < 0.05 vs placebo; GC48: -0.25 and -0.65, respectively, P > 0.05 vs placebo). Solifenacin increased stool hardness from baseline (P = 0.010 for difference vs fesoterodine); stool frequency was comparable.

CONCLUSIONS & INFERENCES

In healthy women, fesoterodine had greater effects on small-intestinal transit and solifenacin had greater effects on colonic transit; the latter finding may explain why solifenacin, but not fesoterodine, increased stool hardness.

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.

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.

Epidemiology of constipation in children and adults: a systematic review

We aimed to review the published literature regarding the epidemiology of constipation in the general paediatric and adult population and to assess its geographic, gender and age distribution, and associated factors. A search of the Medline database was performed. Study selection criteria included: (1) studies of population-based samples; (2) containing data on the prevalence of constipation without obvious organic aetiology; (3) in paediatric, adult or elderly population; (4) published in English and full manuscript form. Sixty-eight studies met our inclusion criteria. The prevalence of constipation in the worldwide general population ranged from 0.7% to 79% (median 16%). The epidemiology of constipation in children was investigated in 19 articles and prevalence rate was between 0.7% and 29.6% (median 12%). Female gender, increasing age, socioeconomic status and educational level seemed to affect constipation prevalence.

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.

The evaluation of constipation

Constipation is a major medical problem in the United States, affecting 2% to 28% of the population. Individual patients may have different conceptions of what constipation is, and the findings overlap with those in other functional gastrointestinal disorders. In 1999, an international panel of experts laid out specific criteria for the diagnosis of constipation known as the Rome II criteria. When patients present with complaints of constipation, a complete history and physical examination can elicit the cause of constipation. It is imperative to rule out a malignancy or other organic causes of the patient's symptoms prior to making the diagnosis of functional constipation. Many patients' symptoms can be relieved with lifestyle and dietary modification, both of which should be implemented before other potentially unnecessary tests are performed. Functional constipation is divided into two subtypes: slow transit constipation and obstructive defecation. Because many different terms are used interchangeably to describe these subtypes of constipation, physicians need to be comfortable with the language. Slow transit constipation is due to abnormal colonic motility. The diagnosis is made with the use of a colonic transit study. We continue to use a single-capsule technique as first described in the literature, but modifications of the capsule technique as well as scintigraphic techniques are validated and can be substituted in place of the capsule. Obstructive defecation is a much more complex problem, with etiologies ranging from rare diseases such as Hirschsprung's to physiologic abnormalities such as paradoxical puborectalis contraction. To fully evaluate the patient with obstructive defecation, anorectal manometry, defecography, and electromyography should be utilized. The different techniques available for each test are fully covered in this article. When evaluating each patient with constipation, it is important to keep in mind that the disease may be specific to one subtype or a combination of both subtypes. Because it is difficult to differentiate the subtypes from the patient's history, we feel it is imperative to evaluate patients fully for both slow transit and obstructive defecation prior to any surgical intervention. Furthermore, we have described many tests that need to be applied to one's population of patients on the basis of the capabilities and expertise the institution offers.

Performance characteristics of scintigraphic colon transit measurement in health and irritable bowel syndrome and relationship to bowel functions

BACKGROUND

The inter- and intra-subject variations of scintigraphy, which are used to identify colonic transit disturbances in irritable bowel syndrome (IBS), are unclear. The relationship between colonic transit and bowel functions is incompletely understood. To assess inter- and intra-subject variations of scintigraphic colonic transit measurements in 86 IBS patients and 17 healthy subjects and to quantify the relationship between colonic transit and bowel symptoms in 147 IBS patients and 46 healthy subjects.

METHODS

Data from participants with multiple colonic transit measurements were analysed. Primary end points were colonic filling at 6 h (CF6h) and geometric center (GC) at 24 and 48 h for colonic transit. Bowel functions were assessed by daily stool diaries.

KEY RESULTS

Inter- and intra-subject variations were greater for small intestinal than colonic transit. Overall, inter- and intra-subject variations were relatively narrow for colonic transit (both GC24h and GC48h, with lower COV at 48 h); there was little intra-subject variation in health and IBS-constipation over a period of <or=3 weeks and over 2.0 years (median, range 0.1, 11.0 years). Significant intra-individual differences in GC24h were observed only in IBS-D patients. Colonic transit was significantly associated with stool form (accounting for 19-27% of the variance), frequency (19%), and ease of stool passage (12%).

CONCLUSIONS & INFERENCES

Despite inter-subject variation in scintigraphic colonic transit results, the intra-subject measurements are reproducible over time in healthy volunteers and patients with IBS; significant changes in colonic transit at 24 h were observed only in IBS-D. Colonic transit is associated with stool form, frequency and ease of passage.

Pathophysiology of colonic causes of chronic constipation

Colonic sensorimotor dysfunction is recognized as the principal pathophysiological mechanism underpinning chronic constipation. This review addresses current understanding derived from both human and animal studies, with particular reference made to methods of investigation.

Spatio-temporal analysis reveals aberrant linkage among sequential propagating pressure wave sequences in patients with symptomatically defined obstructed defecation

Available evidence implicates abnormal colonic contractility in patients suffering from constipation. Traditional analysis of colonic manometry focuses on the frequency, extent and amplitude of propagating sequences (PS). We tested the hypotheses that the spatio-temporal linkage among sequential PSs exists throughout the healthy human colon and is disrupted during constipation. In eight patients with severe constipation and eight healthy volunteers, we recorded colonic pressures from 16 regions (caecum-rectum) for 24 h. Sequential PSs were regionally linked if the two PSs originated from different colonic regions but the segments of colon traversed by each PS overlapped. In order to determine whether this linkage occurred by chance, a computer program was used to randomly rearrange all PSs in time. Data were re-analysed to compare regional linkage between randomly re-ordered PSs (expected) and the natural distribution of PSs (observed). In controls the observed regional linkage (82.5 +/- 9.0%) was significantly greater than the expected value (60.5 +/- 4.3%; P = 0.0001). In patients the observed and expected regional linkage did not differ. The (observed - expected) delta value of regional linkage in controls was significantly greater than in patients (21.7 +/- 8.5%vs-2.3 +/- 7.0%; P = 0.01). Regional linkage among sequential PSs in the healthy colon appears to be a real phenomenon and this linkage is lost in patients with constipation. Regional linkage may be important for normal colonic transit and loss of linkage might have pathophysiological relevance to and provide a useful biomarker of severe constipation.

Colonic movements in healthy subjects as monitored by a Magnet Tracking System

The Magnet Tracking System (MTS) is a minimally-invasive technique of continuous evaluation of gastrointestinal motility. In this study, MTS was used to analyse colonic propulsive dynamics and compare the transit of a magnetic pill with that of standard radio-opaque markers. MTS monitors the progress in real time of a magnetic pill through the gut. Ten men and 10 women with regular daily bowel movements swallowed this pill and 10 radio-opaque markers at 8 pm. Five hours of recordings were conducted during 2 following mornings. Origin, direction, amplitude and velocity of movements were analysed relative to space-time plots of the pill trajectory. Abdominal radiographs were taken to compare the progress of both pill and markers. The magnetic pill lay idle for 90% of its sojourn in the colon; its total retrograde displacement accounted for only 20% of its overall movement. Analysis of these movements showed a bimodal distribution of velocities: around 1.5 and 50 cm min(-1), the latter being responsible for 2/3 of distance traversed. There were more movements overall and more mass movements in males. Net hourly forward progress was greater in the left than right colon, and greater in males. The position of the magnetic pill correlated well with the advancement of markers. MTS showed patterns and propulsion dynamics of colonic segments with as yet unmet precision. Detailed analysis of slow and fast patterns of colonic progress makes it possible to specify the motility of colonic segments, and any variability in gender. Such analysis opens up promising avenues in studies of motility disorders.

Colonic transit studies: normal values for adults and children with comparison of radiological and scintigraphic methods

The sitz or plastic marker study for colonic transit has been around for many years. It is applicable where an X-ray machine exists, is widely used and is accepted as the gold standard for diagnosing constipation. Recently, radiopharmaceutical methods have been developed. The theme of this review is their possible roles in the assessment of paediatric bowel motility disorders in patients presenting to paediatric surgeons. This review presents data on total and segmental transit in normal adults and children and comparing the two techniques in adults. Reliability and reproducibility are presented. Normative data for colonic transit in adults and children are discussed and parameters for assessing abnormal transit are reviewed. Normal colonic transit takes 20-56 h. Plastic marker studies are more readily accessible, but the assessment may be misleading with current methods. Plastic markers show faster transit than scintigraphy. It is difficult to compare the two techniques because methods of reporting are different. Using scintigraphy, repeatability is good. Separation of normal from slow transit in the ascending colon is apparent at 24 and 48 h, but the determination of transit through the distal colon/rectum in adults may require studies of more than 7 days. In conclusion, plastic marker studies and scintigraphy show similar transit rates in young adults and children. However, scintigraphy has advantages of allowing transit through the stomach and small intestine to be measured and has proved useful in the diagnostic workup of children with intractable constipation.

Standard medical therapies do not alter colonic transit time in children with treatment-resistant slow-transit constipation

BACKGROUND

Slow transit constipation (STC) is a form of chronic constipation characterised by prolonged passage of faecal matter through the colon. It is diagnosed by demonstrating delayed colonic transit on gastrointestinal transit studies. Traditionally, radio-opaque marker studies are performed. Recently, radioisotope nuclear transit studies (NTS) have been used in our centre to assess gastrointestinal transit time. This study aimed to evaluate if there are changes in colonic transit in STC children resistant to standard medical treatment over a prolonged period.

METHODS

Children with STC resistant to standard medical therapy for > or =2 years who had undergone two separate NTS to assess their colonic transit (where the first study had identified slow colonic transit without anorectal retention) were identified after ethical approval. The geometric centre (GC) of radioisotope activity at 6, 24, 30 and 48 h was compared in the two transit studies to determine if changes occurred.

RESULTS

Seven children (4 males) with proven STC resistant to standard medical therapy and two transit studies performed at different times were identified. Mean age was 7.0 years (5.4-10.8 years) at first study, and 11.4 years (9.7-14.2 years) at second study, with a mean of 4.4 years (1-8.5 years) between studies. There was no significant difference in colonic transit at any timepoint in the two tests (paired t test).

CONCLUSIONS

We conclude that nuclear transit studies are reproducible in assessing slow colonic transit in children with treatment-resistant STC and demonstrate that conventional medical treatment over many years has no effect on underlying colonic motility.

Slow-transit constipation: evaluation and treatment

Slow-transit constipation is characterized by delay in transit of stool through the colon, caused by either myopathy or neuropathy. The severity of constipation is highly variable, but may be severe enough to result in complete cessation of spontaneous bowel motions. Diagnostic tests to assess colonic transit include radiopaque marker or radioisotope studies, and intraluminal tests (colonic and small bowel manometry). Most patients with functional constipation respond to laxatives, but a small proportion are resistant to this treatment. In some patients biofeedback is helpful although the mechanism by which this works is still uncertain. Other patients are resistant to all conservative modes of therapy and require surgical intervention. Extensive clinical and physiological preoperative assessment of patients with slow colonic transit is essential before considering surgery, including an assessment of small bowel motility and identification of coexistent obstructed defecation. The psychological state of the patient should always be taken into account. When surgery is indicated, subtotal colectomy and ileorectal anastomosis is the operation of choice. Segmental colonic resection has been reported in a few patients, but methods of identifying the affected segment need to be developed further. Less invasive and reversible surgical options include laparoscopic ileostomy, antegrade colonic enema and sacral nerve stimulation.

Sacral nerve stimulation induces pan-colonic propagating pressure waves and increases defecation frequency in patients with slow-transit constipation

OBJECTIVE

Colonic propagating sequences are important for normal colonic transit and defecation. The frequency of these motor patterns is reduced in slow-transit constipation. Sacral nerve stimulation (SNS) is a useful treatment for fecal and urinary incontinence. A high proportion of these patients have also reported altered bowel function. The effects of SNS on colonic propagating sequences in constipation are unknown. Our aims were to evaluate the effect of SNS on colonic pressure patterns and evaluate its therapeutic potential in severe constipation.

METHOD

In eight patients with scintigraphically confirmed slow-transit constipation, a manometry catheter (16 recording sites at 7.5 cm intervals) was positioned colonoscopically and the tip fixed in the caecum. Temporary electrodes (Medtronic) were implanted in the S2 and S3 sacral nerve foramina under general anaesthesia. In the fasted state, 14 Hz stimulation was administered and four sets of parameters (pulse width 300 or 400 micros; S2 and S3) were tested in four 2-h epochs, in random order, over 2 days. Patients were then discharged home with the sacral wires in situ and a 3-week trial stimulation commenced during which patients completed a daily stool diary.

RESULTS

When compared with basal activity, electrical stimulation to S3 significantly increased pan-colonic antegrade propagating sequence (PS) frequency (5.4 +/- 4.2 vs 11.3 +/- 6.6 PS/h; P=0.01). Stimulation at S2 significantly increased retrograde PSs (basal 2.6 +/- 1.8 vs SNS 5.6 +/- 4.8 PS/h; P=0.03). During the subsequent three-week trial (continuous stimulation), six of eight reported increased bowel frequency with a reduction in laxative usage.

CONCLUSION

These data demonstrate that SNS induces pan-colonic propagating pressure waves and therefore shows promise as a potential therapy for severe refractory constipation.

Validation of a semi-automated scintigraphic technique for detecting episodic, real-time colonic flow

The relationships between the movement of colonic content and regional pressures have only been partially defined. During the analysis of a combined colonic scintigraphic and manometric study, a quantitative technique for determining discrete, episodic, real-time colonic flow was developed. Our aim was to validate this technique through the construction of a computer-generated phantom model of known antegrade and retrograde motility. The anthropoid phantom was rasterized into a 6-mm voxel model to create a 3D voxel phantom of the colon with four distinct colonic segments. Associating a time/activity curve with each segment simulated dynamic behaviour. Activity in the model was based on data obtained from human colonic scintigraphic recordings using 30 MBq of (99m)Tc sulphur colloid. The flow was simulated by modifying the input time/activity functions to represent episodes of net flow of 2%, 5% or 10% of segmental content. Our quantitative technique was applied to the phantom model to measure the accuracy with which simulated flows were detected. Our quantitative technique proved to be a sensitive and specific means of detecting the presence and the magnitude of discrete episodes of colonic flow and therefore, should improve our ability to correlate colonic flow and motor patterns.

Impaired proximal colonic motor response to rectal mechanical and chemical stimulation in obstructed defecation

PURPOSE

Both motor and sensory dysfunction have been implicated in the pathogenesis of obstructed defecation. We have found that despite preservation of a defecatory urge, patients with obstructed defecation have lost the normal predefecatory augmentation in frequency and amplitude of colonic propagating pressure waves. This observation might be explainable by either altered rectal sensory thresholds or by dysfunction in the colonic motor apparatus. By measuring rectal sensory thresholds and proximal colonic motor responses to rectal mechanical and chemical stimuli, we tested the hypotheses that central perception of rectal stimuli is enhanced and that the proximal colonic motor response to rectal stimulation is attenuated.

METHODS

In seven patients with obstructed defecation and ten healthy volunteers we measured proximal colonic motor responses and sensory thresholds in response to both rectal balloon distention and rectal instillation of chenodeoxycholic acid.

RESULTS

In controls, but not in patients, rectal mechanical distention significantly reduced and chemical stimulation significantly increased the frequency of proximal colonic propagating sequences (P = 0.01). There was no significant difference in rectal sensory thresholds between patients and controls. Prior instillation of chenodeoxycholic acid significantly reduced (P < 0.03) maximum tolerated balloon volume and defecatory urge volume to comparable degree in both patients and controls.

CONCLUSIONS

In obstructed defecation, 1) the normal rectocolonic pathways mediating stimulation-induced proximal colonic propagating pressure waves are nonfunctioning, and. 2) central perception of these rectal stimuli is normal.

Abnormal predefecatory colonic motor patterns define constipation in obstructed defecation

BACKGROUND & AIMS

The pathophysiology of constipation in the syndrome of obstructed defecation is unknown. Using 24-hour pancolonic manometric recordings of the unprepared colon to record basal pressures and spontaneous defecation episodes, we tested the hypothesis that the frequency, timing, or spatial distribution of propagating colonic pressure waves is abnormal in patients with obstructed defecation.

METHODS

In 11 patients with obstructed defecation and 16 healthy controls, pressures were recorded using a nasocolonic catheter that was positioned such that 16 recording sites spanned the unprepared colon at 7.5-cm intervals.

RESULTS

The overall frequency of propagating sequences (PS) in the colon did not differ between patients and controls. When compared with controls, patients had a significant increase in the frequency of retrograde and antegrade PS (P < 0.05) in the left colon and a significant reduction in the amplitude of propagating pressure waves throughout the entire colon (P < 0.03). Defecation occurred in 6 of 11 patients and 9 of 16 controls. In the 15 minutes before defecation, controls showed a highly significant increase in frequency (P = 0.001) and amplitude (P = 0.01) of PS. In contrast, patients did not demonstrate this or the typical spatiotemporal organization of PS normally observed before expulsion of stool.

CONCLUSIONS

Patients with obstructed defecation lack the normal predefecatory augmentation in frequency and amplitude of propagating pressure waves and lack the normal stereotypic spatiotemporal patterning of colonic pressure waves that would normally culminate in effective expulsion of stool.

Principles of motility and sensation testing

Motility of the gastrointestinal tract includes the phenomena of contractile activity, tone, compliance, flow, and transit. Sensitivity of the gastrointestinal tract is intimately related to motility. A range of techniques, both invasive and noninvasive, can be applied to evaluate enteric sensorimotor function in health and disease. This article reviews the physiologic principles underpinning these techniques. Altertions in both sensitivity and motility are believed to be important in the origin of symptoms in the functional gastrointestinal disorders. The evolution of studies investigating motility and sensitivity in these disorders, using the previously mentioned techniques, is also considered.

The pharmacokinetics of glycyrrhizic acid evaluated by physiologically based pharmacokinetic modeling

Glycyrrhizic acid is widely applied as a sweetener in food products and chewing tobacco. In addition, it is of clinical interest for possible treatment of chronic hepatitis C. In some highly exposed subjects, side effects such as hypertension and symptoms associated with electrolyte disturbances have been reported. To analyze the relationship between the pharmacokinetics of glycyrrhizic acid in its toxicity, the kinetics of glycyrrhizic acid and its biologically active metabolite glycyrrhetic acid were evaluated. Glycyrrhizic acid is mainly absorbed after presystemic hydrolysis as glycyrrhetic acid. Because glycyrrhetic acid is a 200-1000 times more potent inhibitor of 11-beta-hydroxysteroid dehydrogenase compared to glycyrrhizic acid, the kinetics of glycyrrhetic acid are relevant in a toxicological perspective. Once absorbed, glycyrrhetic acid is transported, mainly taken up into the liver by capacity-limited carriers, where it is metabolized into glucuronide and sulfate conjugates. These conjugates are transported efficiently into the bile. After outflow of the bile into the duodenum, the conjugates are hydrolyzed to glycyrrhetic acid by commensal bacteria; glycyrrhetic acid is subsequently reabsorbed, causing a pronounced delay in the terminal plasma clearance. Physiologically based pharmacokinetic modeling indicated that, in humans, the transit rate of gastrointestinal contents through the small and large intestines predominantly determines to what extent glycyrrhetic acid conjugates will be reabsorbed. This parameter, which can be estimated noninvasively, may serve as a useful risk estimator for glycyrrhizic-acid-induced adverse effects, because in subjects with prolonged gastrointestinal transit times, glycyrrhetic acid might accumulate after repeated intake.

Scintigraphic assessment of colonic transit in women with slow-transit constipation arising de novo and following pelvic surgery or childbirth

BACKGROUND

Colonic transit has not been compared between patients with slow-transit constipation (STC) arising de novo (idiopathic) and those whose symptoms followed pelvic surgery or childbirth (acquired).

METHODS

In 48 women, with either idiopathic (n = 36) or acquired (n = 12) STC, 111In-radiolabelled diethylene-triamine penta-acetic acid colonic scintigraphy was performed to determine patterns of delay (generalized or left sided), the 'severity' of transit disturbance between subgroups, and the association with age or duration of symptoms. Results were compared with those in healthy women. Patterns of colonic transit disturbance were assessed using previously defined criteria. In those with a generalized delay, variables reflecting the overall rate of isotope progression throughout the colon were calculated: gradient of geometric centre of isotope progression and estimated evacuation time of the isotope.

RESULTS

The pattern of transit delay was similar between the subgroups, but the 'severity' of the transit abnormality was significantly worse in those with chronic idiopathic symptoms. In the chronic idiopathic STC subgroup only, there was a significant correlation between both age and duration of symptoms and severity of transit disturbance.

CONCLUSION

This study demonstrates that differences in colonic transit exist between subgroups of patients with STC. These might be explained by differences in duration of symptoms or differences in aetiology.

A population physiologically based pharmacokinetic/pharmacodynamic model for the inhibition of 11-beta-hydroxysteroid dehydrogenase activity by glycyrrhetic acid

Glycyrrhizic acid is widely applied as a sweetener in food products and chewing tobacco. Habitual consumption of this compound may lead to hypertension and electrolyte disturbances due to inhibition of 11-beta-hydroxysteroid dehydrogenase by the metabolite glycyrrhetic acid. The effect of 130 mg glycyrrhetic acid/day for 5 days on 11-beta-hydroxysteroid dehydrogenase activity was studied by measuring the cortisol-cortisone ratio in 24-h urine. A twofold increase in this ratio was observed. It took 4 days for the elevated urinary cortisol-cortisone ratio to return to the baseline ratio after cessation of the treatment. The pharmacokinetics of glycyrrhetic acid were studied after the first and last dose. Using data from a previously performed single-dose study and present multiple-dose treatment, a physiologically based pharmacokinetic model for glycyrrhetic acid was developed. The variability of the pharmacokinetics of glycyrrhetic acid in the population studied could be explained for a considerable part by interindividual differences in gastrointestinal transit of glycyrrhetic acid metabolites. The relationship between glycyrrhetic acid exposure and changes in urinary cortisol-cortisone ratio was described by a pharmacodynamic model, using nonlinear mixed-effect modeling. Literature data on the inhibitory effect of glycyrrhetic acid on 11-beta-hydroxysteroid dehydrogenase activity under various exposure scenarios could be adequately described by the model. Due to the relationship between the pharmacokinetics of glycyrrhetic acid and its inhibitory effect on 11-beta-hydroxysteroid dehydrogenase activity, reflected by a change in the urinary cortisol-cortisone ratio, this ratio might serve as a noninvasive marker to identify individuals at risk for glycyrrhizic acid over-consumption.

Results of colectomy for severe slow transit constipation

PURPOSE

This study assesses the outcome of a standardized operation performed by two surgeons for severe idiopathic slow transit constipation that was resistant to laxative treatment.

METHODS

Fifty-nine consecutive patients, 4 men and 55 women, with a mean age of 42.3 years, underwent colectomy with ileorectal anastomosis. Slow colonic transit was demonstrated in each case. Fifty-two patients were available for follow-up, with median time to follow-up being 42 (range, 3-81) months.

RESULTS

Median bowel frequency was 4 per 24 hours. Sixty-nine percent had four or less bowel movements daily. Ten percent used antidiarrheal medication regularly. One patient had a stoma for recurrent severe constipation. Mean continence score was 1.8 (on a scale of 0-20); six patients were incontinent, and four of these six had normal preoperative anal manometry. Fourteen patients (27 percent) had difficulty with rectal evacuation. Preoperative defecating proctography was a poor predictor of postoperative evacuation difficulties. Twenty-seven patients (52 percent) had persisting abdominal pain, but there was a significant improvement in the degree of pain (P <0.00001). Forty-seven patients (90 percent) were satisfied with the outcome of the operation (and would elect to have it done again). Dissatisfied patients had recurrent constipation or diarrhea and incontinence.

CONCLUSION

Colectomy with ileorectal anastomosis produces a satisfactory functional outcome in the majority of patients undergoing surgery for severe constipation with proven slow colonic transit.

Colon transit scintigraphy using oral indium-111-labeled DTPA. Can scan pattern predict final diagnosis?

Colon transit scintigraphy (CTS) was performed in 100 consecutive patients with idiopathic constipation using oral indium-111-labeled DTPA. Criteria were defined to allow classification of studies as normal, slow transit constipation (STC), or obstructed defecation (OD). Results were compared with final clinical diagnosis in 100 and findings of defecating proctography in 70. Of those with a scintigraphic diagnosis of STC, this was also the final diagnosis in 75% (33 of 44), and the scintigraphic diagnosis of OD was confirmed in 61% (17 of 28). Of 28 normal or equivocal scans, the final diagnosis was STC in only two (4%) but OD in 10 (21%). Fifty-four percent of patients with STC and 71% with OD had abnormal proctograms. The correlation between CTS and proctography was mediocre, occurring in 54% of patients. CTS has a valuable role in the diagnostic work-up of patients with idiopathic constipation.

Role of nuclear medicine in evaluating patients with suspected gastrointestinal motility disorders

Functional symptoms caused by gastrointestinal motility disorders are relatively common in the general population. Knowledge of the relationship between symptoms and the underlying gastrointestinal dysmotility provides physicians with a framework for successful evaluation and treatment of patients with possible motor disorders of the gastrointestinal tract. Scintigraphy provides for noninvasive and quantitative assessment of physiological transit throughout the gastrointestinal tract, and it is extremely useful for diagnosing gastrointestinal motor dysfunction. The wide range of scintigraphic studies now available supplement other diagnostic tests for evaluation of all segments of the gastrointestinal tract.

Obstructed defecation: current status of pathophysiology and management

Obstructed defecation poses a challenging clinical problem and in many patients presenting with this syndrome the underlying pathophysiology cannot be determined. Up to now, attempts to diagnose and treat obstructed defecation (anismus) have focused on the function of the somatic pelvic floor musculature surrounding the anorectum, and concepts such as 'puborectalis paradox' and 'spastic pelvic floor' have gained widespread acceptance despite there being no objective data to support such concepts. New evidence showing that defecation is an integrated process of colonic and rectal emptying suggests that anismus may be much more complex than a simple disorder of the pelvic floor muscles. In a small number of patients obstructed defecation is caused by a more simple mechanism, such as internal sphincter hypertonia or a large rectocele, which is easily corrected surgically. Careful selection of patients for treatment, based on identifying the underlying pathophysiological disorder, is emphasized.

Surgery for severe constipation: the use of radioisotope transit scan and barium evacuation proctography in patient selection

Nineteen women aged 19-64 years (median 38) with intractable constipation were assessed by Indium-111 DTPA colonic transit scan and barium evacuation proctogram. Patients were classified as having an isolated (I) or predominant disorder of colonic transit (II), a mixed disorder of colonic transit and rectal evacuation (III), a predominant disorder of rectal evacuation (IV) or normal colorectal emptying (V). Twelve patients fell into categories I and II and were considered suitable for surgery. Three responded to further vigorous aperient therapy and nine (32-55 years, median 38) underwent subtotal colectomy with ileorectal anastomosis at the level of the sacral promontory. Two patients required re-operation for suspected anastomotic leak. One patient required readmission on two occasions for small bowel obstruction. Follow up has been 2-21 months (median 16). Eight of the nine patients no longer take oral aperients. Eight patients have a satisfactory stool frequency of 2-8 per 24 h; the other patient has an ileostomy and incapacitating postprandial abdominal pain. Abdominal pain is troublesome in two other patients. Two patients require antidiarrhoeal therapy but none experience faecal incontinence. In severely constipated patients with a proven disorder of colonic transit but normal or near normal rectal evacuation subtotal colectomy provides excellent symptomatic relief.