Technologies in the evaluation of irritable bowel syndrome

During a meeting in The Hague, The Netherlands, the IBiS Club evaluated the most important techniques that can be used in the investigation of irritable bowel syndrome, either in the context of scientific research or as a clinical diagnostic tool. In each of these, the relevance of findings made in irritable bowel syndrome was balanced against the applicability of the technique. The discussion of the group is summarized in this paper.

The rectum: a window to irritable bowel syndrome?

This report summarizes current concepts and information gathered to date about the rectum in the irritable bowel syndrome (IBS) that were presented at the 10th meeting of IBiS Club held in Leuven, Belgium. A working group of experts in the field of IBS discussed whether the rectum or the whole colon is the better site to test in IBS patients and provided suggestions for a number of areas where further advances are required.

Epidemiological aspects of irritable bowel syndrome in Europe and North America

The epidemiology of irritable bowel syndrome (IBS) in Europe and North America was analyzed from published material. The percentage of the population of Western civilisation with IBS symptoms is between 10 and 15% in most studies. The proportion of a Western population visiting a doctor for IBS symptoms is around 5%. The prevalence of IBS and the proportion of consulters do not seem to depend on age in an adult population. The female-to-male ratio of IBS in the population is close to 2. It is higher in IBS consulters in primary care and may be as high as 3 or 4 in tertiary referral centers. At least in patients from these centers, the number of physician visits and colonoscopies is considerable. Most of the consulters get a drug prescription.

Tegaserod, a 5-HT(4) receptor partial agonist, relieves symptoms in irritable bowel syndrome patients with abdominal pain, bloating and constipation

AIM

To investigate the efficacy and safety of tegaserod, a novel 5-HT(4) receptor partial agonist, in a randomized, double-blind, placebo-controlled, 12-week treatment, multicentre study.

METHODS

Eight hundred and eighty-one patients with irritable bowel syndrome, characterized by abdominal pain, bloating and constipation, received tegaserod, 2 mg b.d. or 6 mg b.d., or placebo for 12 weeks.

RESULTS

Tegaserod, 2 mg b.d. and 6 mg b.d., showed a statistically significant relief of overall irritable bowel syndrome symptoms, measured by a weekly, self-administered questionnaire. At end-point, treatment differences from placebo were 12.7% and 11.8% for 2 mg b.d. and 6 mg b.d., respectively. The effect of tegaserod was noted as early as week 1, and was sustained over the 12-week treatment period. Individual irritable bowel syndrome symptoms assessed daily also showed a statistically significant improvement of abdominal discomfort/pain, number of bowel movements and stool consistency, and a favourable trend for reducing days with significant bloating. Adverse events were similar in all groups, with transient diarrhoea being the only adverse event seen more frequently with tegaserod than placebo.

CONCLUSIONS

Based upon the results of this study, tegaserod offers rapid and sustained relief of the abdominal pain and constipation associated with irritable bowel syndrome. Tegaserod is also well tolerated.

Dysplasia of the submucous nerve plexus in slow-transit constipation of adults

AIM

A clinicopathological entity, intestinal neuronal dysplasia type B (IND) has been described in children with severe constipation. The present study was designed to evaluate whether IND could be identified in adult patients with idiopathic slow-transit constipation.

METHODS

Rectal biopsies were taken from 27 constipated patients with documented slow colonic transit and 23 controls and stained for S100 protein, acetylcholine esterase and lactate dehydrogenase. The mean and maximal number of ganglion cells per ganglion, mean number of ganglia and mean number of ganglion cells per mm2 of submucosal tissue, mean and maximal diameter of ganglion cells, maximal thickness of submucosal nerve fibres, and number of S100-positive cells per mm2 mucosal tissue were quantified. The density of submucosal ganglia, presence of heterotopic ganglion cells, intensity of staining of the adventitial layer of submucosal arteries, and density of nerve fibres in submucosa and lamina propria were evaluated qualitatively. In addition, subjective evaluation by an experienced pathologist was performed.

RESULTS

There were no major differences between patients and controls, except that patients had slightly thicker submucosal nerves than controls (30.8 +/- 1.6 versus 25.5 +/- 2.0 microm, P < 0.05) and more frequent heterotopic ganglion cells (32 versus 6%, P < 0.05). Neither discriminant analysis of the morphometric data nor subjective evaluation was able to correctly classify the slides as originating from patients or controls.

CONCLUSIONS

The existence of the clinicopathological entity IND in adults with slow-transit constipation is unlikely. For further classification of slow-transit constipation, rectal biopsies do not appear to be useful at present.

Functional bowel disorders and functional abdominal pain

The Rome diagnostic criteria for the functional bowel disorders and functional abdominal pain are used widely in research and practice. A committee consensus approach, including criticism from multinational expert reviewers, was used to revise the diagnostic criteria and update diagnosis and treatment recommendations, based on research results. The terminology was clarified and the diagnostic criteria and management recommendations were revised. A functional bowel disorder (FBD) is diagnosed by characteristic symptoms for at least 12 weeks during the preceding 12 months in the absence of a structural or biochemical explanation. The irritable bowel syndrome, functional abdominal bloating, functional constipation, and functional diarrhea are distinguished by symptom-based diagnostic criteria. Unspecified FBD lacks criteria for the other FBDs. Diagnostic testing is individualized, depending on patient age, primary symptom characteristics, and other clinical and laboratory features. Functional abdominal pain (FAP) is defined as either the FAP syndrome, which requires at least six months of pain with poor relation to gut function and loss of daily activities, or unspecified FAP, which lacks criteria for the FAP syndrome. An organic cause for the pain must be excluded, but aspects of the patient's pain behavior are of primary importance. Treatment of the FBDs relies upon confident diagnosis, explanation, and reassurance. Diet alteration, drug treatment, and psychotherapy may be beneficial, depending on the symptoms and psychological features.

Interobserver agreement in defecography--an international study

BACKGROUND

Defecography is considered to be an essential investigation in the evaluation of functional anorectal disorders, but the agreement between observers from different clinical centers has never been evaluated.

METHODS

14 defecographic studies were selected aimed to cover the most relevant defecographic findings responsible for disordered defecation. Eight studies were considered unequivocal, but six were thought to be controversial. All were sent to the ten participants in Europe and the US (five proctosurgeons, three radiologists, two gastroenterologists). They evaluated the studies using a previously agreed upon questionnaire. Interobserver agreement was quantified by kappa statistics and by the proportions of positive and negative agreement as compared to chance agreement, respectively.

RESULTS

Overall, only the completeness of rectal emptying and the presence of a rectocele achieved acceptable kappa values above 0.4. When restricting the evaluation to the studies considered to be unequivocal, agreement improved considerably and was moderate to good for all items describing the images (kappa 0.43-0.63). However, whether proctosurgery should be performed and whether defecography contributed to the management of the particular patient remained controversial with very low kappa.

CONCLUSIONS

It is doubtful whether defecography contributes substantially to the management of patients with disordered defecation.

Paradoxical sphincter contraction is rarely indicative of anismus

BACKGROUND

Anismus is thought to be a cause of chronic constipation by producing outlet obstruction. The underlying mechanism is paradoxical contraction of the anal sphincter or puborectalis muscle. However, paradoxical sphincter contraction (PSC) also occurs in healthy controls, so anismus may be diagnosed too often because it may be based on a non-specific finding related to untoward conditions during the anorectal examination.

AIMS

To investigate the pathophysiological importance of PSC found at anorectal manometry in constipated patients and in patients with stool incontinence.

METHODS

Digital rectal examination and anorectal manometry were performed in 102 chronically constipated patients, 102 patients with stool incontinence, and in 18 controls without anorectal disease. In 120 of the 222 subjects defaecography was also performed. Paradoxical sphincter contraction was defined as a sustained increase in sphincter pressure during straining. Anismus was assumed when PSC was present on anorectal manometry and digital rectal examination and the anorectal angle did not widen on defaecography.

RESULTS

Manometric PSC occurred about twice as often in constipated patients as in incontinent patients (41.2% versus 25.5%, p < 0.017) and its prevalence was similar in incontinent patients and controls (25.5% versus 22.2%). Oroanal or rectosigmoid transit times in constipated patients with and without PSC did not differ significantly (total 64.6 (8.9) hours versus 54.2 (8.1) hours; rectosigmoid 14.9 (2.4) hours versus 13.8 (2.5) hours).

CONCLUSIONS

Paradoxical sphincter contraction is a common finding in healthy controls as well as in patients with chronic constipation and stool incontinence. Hence, PSC is primarily a laboratory artefact and true anismus is rare.

Clinical response to dietary fiber treatment of chronic constipation

OBJECTIVES

To determine the clinical outcome of dietary fiber therapy in patients with chronic constipation.

METHODS

One hundred, forty-nine patients with chronic constipation (age 53 yr, range 18-81 yr, 84% women) at two gastroenterology departments in Munich, Germany, were treated with Plantago ovata seeds, 15-30 g/day, for a period of at least 6 wk. Repeated symptom evaluation, oroanal transit time measurement (radiopaque markers), and functional rectoanal evaluation (proctoscopy, manometry, defecography) were performed. Patients were classified on the basis of the result of dietary fiber treatment: no effect, n = 84; improved, n = 33; and symptom free, n = 32.

RESULTS

Eighty percent of patients with slow transit and 63% of patients with a disorder of defecation did not respond to dietary fiber treatment, whereas 85% of patients without a pathological finding improved or became symptom free.

CONCLUSION

Slow GI transit and/or a disorder of defecation may explain a poor outcome of dietary fiber therapy in patients with chronic constipation. A dietary fiber trial should be conducted before technical investigations, which are indicated only if the dietary fiber trial fails.

Decreased substance P levels in rectal biopsies from patients with slow transit constipation

OBJECTIVE

Previous studies in patients with chronic constipation found abnormalities in the nervous tissue of the large intestine, predominantly in the muscularis externa. Since there is evidence that the nervous system of mucosa and submucosa is also involved in the control of colonic motility we investigated the contents of vasoactive intestinal polypeptide (VIP), somatostatin and substance P in rectal biopsies of patients with slow colonic transit constipation.

DESIGN AND METHODS

Twenty-two patients (17 females, 5 males) with chronic slow transit constipation (oro-anal transit with radio-opaque markers on high fibre diet > 70 h) and long-term use of laxatives, and 20 controls (12 females, 8 males) with no history of constipation, were included in this study. Large rectal biopsy specimens including the submucosa were obtained from 5 cm above the dentate line and frozen in liquid nitrogen. After microdissection of the biopsies into mucosa and submucosa the neuropeptides were extracted by boiling and homogenizing the tissue in acetic acid and determined using validated radioimmunoassays.

RESULTS

Patients with slow transit constipation showed, compared to healthy controls, significantly lower levels of the excitatory neurotransmitter substance P in the mucosa and submucosa of rectal biopsies. There was no difference between the two groups concerning the levels of the inhibitory neurotransmitters, VIP and somatostatin.

CONCLUSION

Slow transit constipation is associated with abnormalities of the substance P content of the enteric nervous system of mucosa and submucosa. This seems not to be related to chronic laxative use, since anthranoids cause a reduction in the levels of inhibitory neurotransmitters (VIP, somatostatin), but not of substance P, in the rat colon.

Diagnostic value of histology in non-erosive gastro-oesophageal reflux disease

BACKGROUND

In the absence of oesophageal erosions longterm pH monitoring is the present gold standard for diagnosing gastro-oesophageal reflux disease (GORD). This method, however, is invasive, time consuming, expensive, and not generally available.

AIMS

As histological changes have been described in GORD, this study looked at the possibility of whether the diagnosis of non-erosive reflux disease could be made by histological examination routinely during endoscopy.

SUBJECTS

A total of 24 prospectively selected patients with symptoms suggestive of GORD and seven healthy volunteers.

METHODS

Oesophageal erosions and other peptic lesions were excluded by oesophago-gastroduodenoscopy. Oesophageal pinch biopsy specimens were taken 2 cm and 5 cm above the oesophagogastric junction and evaluated blindly for the histological parameters cellular infiltration, basal zone hyperplasia, and papillary length. Twenty four hour pH monitoring was used as gold standard for the definition of reflux disease. It was abnormal in 13 patients (reflux patients) and normal in 11 patients (symptomatic controls) and in seven healthy volunteers.

RESULTS

Sparse infiltration of the epithelium with lymphocytes in at least one biopsy specimen was found in all patients and volunteers, with neutrophils in three reflux patients, and with eosinophils in two reflux patients and in two healthy volunteers. The basal zone thickness was increased in three reflux patients, in one symptomatic control, and in one healthy volunteer. The papillary length was greater than two thirds of total epithelium in six of 13 reflux patients in contrast with none in 11 symptomatic controls (p < 0.05) and to one healthy volunteer. The sensitivity of the parameter papillary length hence was only 46%.

CONCLUSIONS

Although gastro-oesophageal reflux produces slight histological changes apart from oesophageal erosions in a few subjects, none of the established histological parameters can fulfil the for the diagnosis of GORD in patients without visible oesophageal erosions.

Functional diagnostic work-up in patients with irritable bowel syndrome

The first aim of the study was to find a cause of symptoms in patients suffering from "irritable bowel syndrome" using diagnostic tests aimed at functional disorders of lower gut. A second aim was to test, whether the presence of irritable bowel syndrome (or, synonymously, absence of classic organic disease) can be predicted by specific symptoms. 134 consecutive patients (50 +/- 16 SD years, range 17 to 88, 94 women) presenting in our gastroenterological outpatient department with abdominal pain and altered bowel habits were included. A conventional diagnostic work-up aimed at classic organic diseases and, if negative, a functional diagnostic work-up aimed at gastrointestinal malfunction such as dietary fibre trial, functional proctoscopy, defecography, colonic transit of radiopaque markers, anorectal manometry, and lactose tolerance test were done. A classic organic disease was found in only 15 of 134 patients by conventional diagnostic tests. Functional diagnostic work-up yielded a diagnosis in 70 of the remaining 119 patients that else would have been labeled to suffer from IBS (25 slow transit constipation, 20 disordered defecation, nine low fibre intake, and nine lactose intolerance among them). When symptoms were evaluated with a standardized questionnaire, "constipation" and the "necessity of straining to open bowels" were very specific for functional bowel disorder (92% and 100%), but sensitivity of both symptoms was only about 60%. The so-called "Manning criteria" had a very low prevalence in our sample and so were not discriminatory. Since in more than half of the patients with "irritable bowel syndrome" a specific diagnosis can be reached, functional tests should be considered in such patients. The symptom "constipation" in patients with lower gut complaints predicted a functional disorder rather than a classic organic disease with a high specificity.

Empiric therapy for gastroesophageal reflux disease

BACKGROUND

In the absence of highly specific symptoms and without esophageal erosions, long-term pH monitoring is necessary for diagnosing gastroesophageal reflux disease. This method, however, is not generally available.

OBJECTIVE

To determine whether gastroesophageal reflux disease can be diagnosed empirically by acid suppression in patients with normal results of endoscopy.

METHODS

We studied 33 consecutive outpatients with pathologic findings on pH monitoring who had symptoms compatible with gastroesophageal reflux disease and normal results of esophagogastroduodenoscopy, particularly a normal appearance of the esophageal mucosa. The severity of symptoms was graded on a visual analog scale from 1 to 10 by the patient. The patients were treated for at least 7 days with either ranitidine, 150 mg twice daily (patients 1 through 10), omeprazole, 40 mg/d (patients 11 through 21), or omeprazole, 40 mg twice daily (patients 22 through 33). A reassessment of symptoms and second pH monitoring were performed during the last day of treatment.

RESULTS

Omeprazole, 40 mg/d, significantly reduced the severity of symptoms from 7.1 (range, 4 to 9) to 3.7 (0 to 8) and the reflux measure mean acidity from 0.98 mmol/L (0.21 to 76 mmol/L) to 0.02 mmol/L (0 to 0.47 mmol/L). Omeprazole, 40 mg twice daily, significantly reduced the severity of symptoms from 6.8 (3 to 10) to 0.6 (0 to 2) and the mean acidity from 0.38 mmol/L (0.13 to 8.5 mmol/L) to 0.01 mmol/L (0 to 0.14 mmol/L). Both doses of omeprazole were superior to ranitidine, 150 mg twice daily. When a 75% reduction of symptoms was defined as positive, the "omeprazole test" with 40 mg twice daily had a sensitivity of 83.3%, whereas the sensitivity with 40 mg/d was only 27.2%.

CONCLUSION

In practice, the diagnosis of gastroesophageal reflux disease can be ruled out if symptoms do not improve with a limited course of high-dose proton pump inhibitors.

The influence of arginine-vasopressin on stool output and gastrointestinal transit time in healthy volunteers

OBJECTIVE

It was asked whether continuous infusion of arginine-vasopressin (AVP) could decrease stool output and gastrointestinal transit time in healthy volunteers.

DESIGN

Randomised single blind cross-over-design.

SUBJECTS

5 healthy male volunteers.

INTERVENTIONS

Continuous s.c. infusion of AVP (7.5 micrograms/d) for one week vs. 0.9% NaCl-solution (placebo). Some days before the experiment started, the volunteers underwent a two-day-thirsting-period (< 500 ml/day).

MEASUREMENTS

AVP-levels in serum, urine output, AVP-urine-excretion, stool frequency, stool weight, colonic transit time.

RESULTS

As compared to saline infusion both serum-levels of AVP and AVP-excretion in urine were about four times higher during AVP-infusion whereas they were doubled during thirsting. Accordingly urine output was lower when AVP-levels were high. Parameters of colonic motility did not differ significantly (stool frequency 6.8 +/- 0.8/week for placebo vs. 6.8 +/- 0.5/week during AVP, stool weight 200.3 +/- 25.0 g/d vs. 210.6 +/- 21.1 gld, total colonic transit 22.9 +/- 7.0 hours vs. 25.7 +/- 5.8 hours).

CONCLUSION

1. AVP is well absorbed when applied subcutaneously. 2. AVP in the dosage given has no major influence on stool output and gastrointestinal transit time in healthy volunteers.

The effect of hormones and peptides involved in water balance on rat colonic motility in vitro

We have previously shown that restriction of water intake decreased stool frequency and stool weight in volunteers. The aim of this study was to investigate whether these effects of thirst could be mediated by an action of systematically released hormones on colonic smooth muscle. Using isolated colonic smooth muscle strips the effect of arginine-vasopressin (AVP), angiotensin II (ANG II) and aldosterone on rat colonic motility in vitro was investigated. AVP (10(-12)-10(-10) mol/l) and aldosterone (3 x 10(-10)-3 x 10(-8) mol/l) and physiological hormonal concentrations of ANG II (10(-13)-10(-10) mol/l) had no effect on either basal activity, direct stimulation of colonic smooth muscle or neurally stimulated contractions using carbachol 10(-7)-3 x 10(-5) mol/l or neurally stimulated contractions using electrical field stimulation at various stimulation frequencies (1-10 pps, 1 ms, 40 V). ANG II in higher concentrations (10(-7)-10(-6) mol/l) increased basal activity and neurally mediated contractions. Accordingly, ANG II (10(-6) mol/l) caused a prestimulation but did not increase the maximum contractile effect of carbachol. The response to ANG II was not affected by atropine (10(-6) mol/l). TTX (10(-6) mol/l) and N-nitro-L8-arginine (L-NNA) (3 x 10(-4) mol/l) stimulated basal muscular activity but did not affect the maximum contractile effect of ANG II. Systemic serum concentrations of AVP, aldosterone and ANG II are presumably not involved in thirst-induced colonic motility changes. The ANG II effect in higher concentrations is mediated by a direct stimulatory smooth muscle effect and/or by facilitating neuronal liberation of acetylcholine.(ABSTRACT TRUNCATED AT 250 WORDS)

Polyethylene glycol 4000 for slow transit constipation

Slow transit constipation is notoriously difficult to treat. We tested whether polyethylene glycole 4000 (PEG) improves slow transit constipation. Eight female outpatients with symptoms of constipation and a colonic marker transit of more than 60 h were included (age 46 +/- 4y, duration of complaints 17 +/- 3y) in a randomised controlled cross-over study. During a 6-week placebo and 6-week PEG-phase (60g PEG/d) the following parameters were measured: 1. subjective well-being with respect to defeacation on a visual analogue scale (-8 cm very bad, +8 cm very good), 2. in the first 5 weeks of each phase, average dose of sodium picosulfate (prescribed as only allowed laxans, dose adjusted and protocolled on a diary by patient) 3. stool frequency, 4. colonic transit of radiopague polythene pellets in the last week of each phase (the use of laxative was strictly prohibited in this last week). Both subjective and objective parameters of colonic function improved significantly. Visual analog scale ratings improved from -4.65, [-8; 0.5] to 4.65, [-8; 7.5]cm (median, range) (p = 0.028), the self-administered dose of sodium picosulfate decreased from 4, [0; 37] to 0, [0; 11] drops per day (p = 0.028), stool frequency increased from 3.1, [1; 30] to 11, [2; 33] defeacations per week (p = 0.017), and total colonic transit decreased from 91, [67; 116] to 43 h, [17; 76]h (p = 0.017). In conclusion, PEG improves colonic function in patients with slow transit constipation subjectively and objectively. PEG should be considered as an additional option in patients refractory to established forms of treatment.

Effects of long-term treatment with anthranoids and sodium picosulphate on the contents of vasoactive intestinal polypeptide, somatostatin and substance P in the rat colon

OBJECTIVE

To examine the effects of chronic treatment and a single high-dose application of anthranoids and sodium picosulphate on the neuropeptide content of the rat colon.

DESIGN AND METHODS

Over a 6-month period, eight groups of rats were each given one of the following: sennosides or sodium picosulphate in low daily doses (10 and 2.5 mg/kg/day, respectively), in high daily doses (40 and 10 mg/kg/day, respectively), and in high twice-weekly doses (30 and 7.5 mg/kg/day, respectively); high daily doses of danthron (500 mg/kg/day); and vehicle (tragacanth 0.5%) only. Four further groups of rats each received a single dose of vehicle or a high dose of one of the three laxatives. All rats were killed 48 h after the last dose. The ascending and descending colon were removed and separated into mucosa, submucosa, and muscularis externa. Vasoactive intestinal polypeptide (VIP), somatostatin, and substance P were extracted by boiling and homogenizing the tissue in acetic acid, and their levels were determined using validated radioimmunoassays.

RESULTS

After long-term treatment with high doses of sennosides and danthron, but not after a single high-dose administration, there was a significant reduction in mucosal levels of VIP and somatostatin and in submucosal levels of somatostatin of both colonic segments, as well as in the level of VIP in the muscularis externa of the descending colon. Substance P levels remained unaffected. Sodium picosulphate had no effect.

CONCLUSIONS

Chronic treatment with anthranoids in high doses, but not with sodium picosulphate, reduces VIP and somatostatin levels in the rat colon. This may represent damage to the enteric nervous tissue or a pharmacological effect of the anthranoids, causing decreased synthesis or increased breakdown of these peptides.

Cisapride in chronic idiopathic constipation: can the colon be re-educated? Bavarian Constipation Study Group

OBJECTIVE

To investigate whether dose tapering and, potentially, withdrawal of cisapride is possible without loss of therapeutic effect.

PATIENTS

A total of 119 patients with chronic constipation (less than three spontaneous, i.e., not laxative-induced, stools per week).

DESIGN

Randomized double-blind study.

METHODS

Group A (n = 56) was treated with cisapride 20 mg twice daily for 12 weeks. Treatment was continued for a further 12 weeks during which the patients were allowed to take a maximum of four tablets containing 5 mg cisapride each (maximum daily dose, 20 mg). Group B (n = 63) was treated with cisapride 20 mg twice daily for 6 weeks and then with cisapride 10 mg for 6 weeks. Treatment was then stopped and follow-up was continued for a further 12 weeks.

RESULTS

Stool frequency was increased in both groups during active treatment and was not reduced when the dose was decreased from 20 mg to 10 mg twice daily in group B but was maintained in group A. Laxative intake fell by 50% in both groups, but this effect was maintained during follow-up in group A only. Group A patients took nearly the maximum dosage of cisapride tablets allowed during follow-up (3.3 tablets per day +/- 0.2 SEM).

CONCLUSION

This study confirmed the efficacy of cisapride in chronic idiopathic constipation. Dose tapering below 15-20 mg per day, however, does not appear to be possible.

Interobserver agreement in defecography

PURPOSE

This study was designed to test the reproducibility of the diagnostic assessment of defecographies in patients with a suspected disorder of defecation.

METHODS

To evaluate interobserver agreement, 100 defecographic series of patients with complaints suggesting a disordered defecation were evaluated independently by three observers with a standardized questionnaire. After six weeks, a random sample of 35 of 100 defecographies was evaluated a second time with clinical data provided (history, proctologic examination). To evaluate whether the position of residual volume in the rectum would affect agreement, patients with substantial retention either in the upper or lower rectum were also evaluated separately.

RESULTS

Total agreement regarding rectocele and internal prolapse was 0.81 and 0.75, respectively (1.0 = complete agreement), and was significantly higher than chance agreement. Total agreement regarding residual volume in the rectum at the end of defecography and clinical relevance of findings was not different from chance agreement, providing clinical data did not significantly improve agreement. When residual volume was situated in the lower rectum, agreement regarding incompleteness of emptying and its clinical relevance was much better (0.93).

CONCLUSIONS

Interobserver agreement is good regarding the deformation of the rectum during defecography but not different from chance agreement regarding the completeness of evacuation.

How effective is nonlaxative treatment of constipation?

In almost any textbook of medicine so-called simple measures are proposed for treating constipation, such as increasing physical activity, drinking more fluid, triggering the gastrocolonic response by, e.g., drinking a glass of water or a cup of coffee, and bowel training. All of these have not been formally evaluated in constipated patients. Biofeedback training is useful for paradoxical puborectal contraction ('anismus'). Dietary fibre, e.g. in the form of wheat bran, increases stool weight and decreases colonic transit time. So every patient should have an empiric treatment with an adequate amount of fibre. Some patients, especially those with slow transit constipation and those with stasis in the right hemicolon, are not likely to respond to a therapy with bran, however.

Body acupuncture: effect on colonic function in chronic constipation

Acupuncture has been claimed to be an efficacious treatment for chronic constipation, though there are no studies to prove this. We therefore investigated the effect of body acupuncture on stool frequency and colonic transit time of radiopaque markers in 8 constipated patients (58 +/- 6 years, 3 female; vigorous straining necessary to open bowels without the use of laxatives for more than one year, total colonic marker transit > 60 h) in a control period and during a three weeks treatment period with six sessions. Acupuncture was performed as body acupuncture with electric needles (10 Hz, current titrated to individual threshold, 25 min each session) on acupuncture points Di4 [He Gu], Ma25 [Tian Shu], Le3 [Yuan], and B125 [Da Chang Yu]). Two patients dropped out during acupuncture because symptoms of constipation worsened. In the other 6 patients, stool frequencies and colonic transit times were not significantly different during control and acupuncture period (0.38 +/- 0.09 vs. 0.40 +/- 0.14 defecations per day +/- s.e.m., 95% confidence interval for the difference control minus acupuncture [-0.34; 0.30], and 97 +/- 17 vs. 108 +/- 24h, 95% Cl [-50; 27]). Segmental transit times for right and left hemicolon, and rectosigmoid colon did not differ significantly either. In conclusion, acupuncture as performed in this study does not influence objective parameters of colonic function to a clinically relevant degree.

Adverse effects of laxatives: fact and fiction

Laxatives are generally well tolerated and may be considered safe drugs. When taken at much higher than the recommended doses (laxative abuse) some side effects may occur (e.g. hypokalemia, metabolic alkalosis, renal tubular damage). It is controversial whether the laxatives currently used may lead to morphologic changes of the autonomous nervous system of the colon. Melanosis coli is due to pigment-laden macrophages within the submucosa. It occurs after long-term intake of anthraquinones and has no functional consequences. No case of 'cathartic colon' has been observed during the last few decades, and we can assume that it was probably caused by laxatives which are no longer in use.

[Smoking and gastrointestinal function]

Aspects of gastrointestinal function pathogenetically related to peptic ulcer have been studied extensively. Even as to secretion of gastric acid and pancreatic bicarbonate a definite statement concerning the impact of smoking is difficult. Most of the available studies found that smoking increases acid secretion and decreases pancreatic secretion. This may, at least in part, explain the untoward effect of smoking in ulcer disease. Gastric emptying is slightly decreased by smoking. Gastro-oesophageal and duodenogastric reflux are obviously not influenced to a clinically relevant extent. With regard to the colon, we did not retrieve any relevant publications. In summary, in patients with ulcer disease there is one good reason more to discourage from smoking.

What is behind dyspepsia?

The first aim of the present study was to determine the cause of dyspepsia after negative conventional diagnostic work-up. In such patients, an extended diagnostic work-up was performed including esophageal pH monitoring and manometry, gastric and hepatobiliary scintigraphy, and lactose tolerance test. In 88 of 220 dyspeptic patients (mean age 49 years, range 17-87; 114 women) presenting to our gastroenterological outpatient department, a cause for dyspepsia was found by conventional work-up. Thirty-one of the remaining patients did not enter extended work-up because of minor symptoms. In 47 of 101 patients entering extended work-up, a diagnosis was established (21 endoscopy-negative gastroesophageal reflux disease, 11 gastric stasis, 6 biliary dyskinesia, and 5 lactase deficiency among them). A second aim of the study was to determine whether clusters of symptoms such as "gastroesophageal reflux-like," "dysmotility-like," and "dyspepsia of unknown origin" reliably predict the groups of diseases suggested by these terms. This was not the case. In conclusion, in 40% of dyspeptic patients, a conventional diagnostic work-up led to a diagnosis that explained a patient's symptoms. After a negative conventional diagnostic work-up, an extended diagnostic work-up with functional tests yielded a possible explanation for their symptoms in 47% of patients. In such patients symptomatology was of little help for predicting the diagnosis.

Three year follow up of patients with gastrooesophageal reflux disease

Data on the natural course of gastrooesophageal reflux disease are sparse. One hundred and sixty six patients with typical reflux symptoms (heartburn and/or acid regurgitation) and pathologic pH monitoring (reflux time > 8.2% upright and/or > 3.0% supine) were studied. The patients were followed up by questionnaire and interview for a mean of 41 (seven to 86) months after diagnosis of reflux disease. Ten patients had died of diseases not reflux related. In 117 (75%) of the remaining 156 patients data on the course of gastrooesophageal reflux disease could be obtained. In 12 patients anti reflux surgery had been performed. Forty one (39%) of the remaining 105 patients have stopped taking medical therapy, in 13 of these patients symptoms had completely disappeared. Sixty four patients continued on medication (40 on demand, 24 regularly). When asked how their symptoms would be if they completely stopped medication, 71 patients considered their symptoms to be equal or worse and 21 patients to be improved as compared with the initial investigation. Patients with persisting symptoms at follow up had significantly more supine reflux (p < 0.05) at the initial pH monitoring as compared with patients with improved symptoms. The presence and grade of oesophageal erosions at initial endoscopy, duration of symptoms, age, sex, and smoking habits had no influence on the course of gastrooesophageal reflux disease. In conclusion, reflux symptoms disappear only in a minority of patients with proven gastrooesophageal reflux disease. More than half of all patients continue medication, either on demand or regularly. Severe supine reflux is an unfavourable prognostic factor.

Is the volume retained after defecation a valuable parameter at defecography?

The intention of this study was to correlate the retained volume at the end of defecography to certain defecographic findings and to the sense of incomplete emptying. In 170 defecographic series, the retained barium was estimated planimetrically. No particular defecographic finding determined a higher or lower amount of remaining volume, and the sense of incomplete evacuation did not depend on the amount of retained volume. Thresholds of urge and perception on anorectal manometry did not differ between patients with and without the feeling of incomplete evacuation. A rectocele, isolated or combined with an internal prolapse, caused the retained volume to be in the lowermost part of the rectum, whereas, in the case of an isolated intussusception, the remaining volume was located in the middle or higher part of the rectum. It is concluded that defecographic findings do not in general explain incomplete emptying or the sense of incomplete emptying, but they may determine the localization of the retained volume.

Abdominal wall massage: effect on colonic function in healthy volunteers and in patients with chronic constipation

Colonic massage has been claimed to be an efficacious treatment for chronic constipation, though there are no studies to prove this. We therefore investigated the effect of abdominal wall massage on stool frequency and colonic transit time of radiopaque markers in 9 constipated patients (68 +/- 5 years, 5 female, colonic transit greater than 60 h) and in 7 healthy male volunteers (27 +/- 1.2 years) in a control phase and during a three week treatment phase with 9 sessions. Massage was performed as propulsive abdominal wall massage along the presumed course of the colon in an aboral direction (each session 20 min). Stool frequency did not change significantly from control to massage, neither in patients [0.59 +/- 0.08 to 0.68 +/- 0.09 defaecations per day, 95% CI control-massage (-0.23; 0.04)] nor in healthy volunteers 1.11 +/- 0.11 to 0.86 +/- 0.13, 95% CI (-0.01; 0.53)]. Total colonic transit times remained similar during the control and massage phase in patients (126 +/- 19 and 111 +/- 17 h, 95% CI (-11; 41)] and in healthy volunteers (40 +/- 7 and 38 +/- 6 h, 95% CI (-8; 13)]. Even when patients and healthy volunteers were statistically evaluated together, control and massage did not differ significantly. In patients, scores of well-being and stool consistency did not differ significantly during control and massage periods. So colonic massage does not change parameters of colonic function to a clinically relevant degree in healthy volunteers and constipated patients of the investigated age-groups.

Which pH threshold is best in esophageal pH monitoring?

Two questions were examined, namely, 1) whether pH 4 is really the optimal threshold for the definition of acid gastroesophageal reflux, and 2) to what extent shifting of the upper limits of normal affects sensitivity and specificity of 24-h pH monitoring. To answer these questions, we studied 74 patients with proven reflux disease and 37 asymptomatic volunteers, using ambulatory 24-h esophageal pH monitoring. Gastroesophageal reflux was defined as episodes with esophageal pH of less than the threshold values 3.0, 3.5, 4.0, 4.5, or 5.0, respectively. For each of these pH thresholds, the percentage time with esophageal pH below the threshold was calculated separately for periods of upright and supine body position. Two-dimensional receiver-operating-characteristic (ROC) analysis was used to define upper limits of normal. A maximum of sensitivity, specificity, and rate of correct decisions (all 89%) was obtained using pH 4 for the definition of gastroesophageal reflux, although other pH thresholds were not much worse. On the basis of pH 4, the upper limits of normal could be shifted around the "optimal upper limit of normal" within a certain limit without considerable loss of accuracy of pH monitoring. This may explain the divergences between upper limits of normal obtained by different laboratories. In conclusion, 1) the threshold pH 4 should further be used for the definition of acid gastroesophageal reflux, and, 2) within certain limits, shifting of the upper limits of normal has little effect on the accuracy of pH monitoring in gastroesophageal reflux disease.

Esophageal 24-h pH monitoring: is prior manometry necessary for correct positioning of the electrode?

In 24-h esophageal pH monitoring, the electrode is usually positioned 5 cm above the manometrically localized esophagogastric junction. In order to replace esophageal manometry for this purpose, we tested whether the esophagogastric junction can be identified correctly by fluoroscopy or the determination of the pH-step between stomach and esophagus, compared with esophageal manometry. The distance from the nares to the esophagogastric junction was determined three times with each of the three methods in 46 patients and 14 volunteers. Fluoroscopy assumed the esophagogastric junction 1.23 +/- 0.23 cm (mean +/- SE) lower than the peak pressure point determined at manometry, pH-step only 0.45 +/- 0.16 cm. With pH-step, only one subject had a difference of more than 3 cm to the manometrically defined esophagogastric junction, whether gastroesophageal reflux disease (as proven by pH monitoring) was present or not. We conclude that the esophagogastric junction can usually be identified with sufficient accuracy by the measurement of the pH-step between stomach and esophagus. Fluoroscopy is far less accurate than pH-step, and should not be used.

Low fluid intake lowers stool output in healthy male volunteers

Inadequate fluid intake is though to be one frequent cause of chronic constipation, although this has never been shown. In order to test whether fluid deprivation has an influence on colonic function, we studied eight healthy male volunteers (median age 23 y, range 21-28 y) with respect to stool frequency, stool weight and mean oroanal transit of radiopaque markers in a control week with a fluid intake of more than 2500 ml beverages per day and in a week with a fluid intake of less than 500 ml beverages per day. The two weeks followed each other in randomised order (with a wash out week in-between) and were standardised as to nutrition and physical activity. Stool frequency diminished from 6.9 +/- 0.9 to 4.9 +/- 0.3 (mean +/- SEM) defaecations per week (p = 0.041) and stool weight from 1.29 +/- 0.20 to 0.94 +/- 0.17 kg per week (p = 0.048) during fluid restriction. Mean oroanal transit times were similar in the two weeks. In conclusion, our study shows that a relatively short period of fluid deprivation decreases stool frequency and stool weight in healthy volunteers. Therefore, a low fluid intake may well be an aetiologic factor for chronic constipation in some patients and too low a fluid intake should be corrected. There is no evidence, however, that an increase of fluid intake within feasible limits has a beneficial effect on chronic constipation.

Behavioral modification of colonic function. Can constipation be learned?

We challenged the two hypotheses: first, that defecation can be suppressed for an extended time, and second, if so, that this has an effect on upper colonic motility. Thus we studied 12 male volunteers with conditions of identical nutrition and patterns of physical activity over a two-week period, where one week with normal defecation and one week with voluntary prolonged suppression of defecation followed each other in randomized order. Frequencies of defecation, stool weights, total and segmental colonic transit times (using radiopaque markers) were compared. Frequency of defecations and stool weights were lower during suppressed defecation [8.9 +/- 0.66 vs 3.7 +/- 0.41 (mean +/- SE) bowel movements per week, P = 0.003, and 1.30 +/- 0.09 vs 0.98 +/- 0.13 kg/week, P = 0.01]. Total transit times were increased from 28.8 +/- 4.4 to 53.1 +/- 4.3 hr, P = 0.004. Segmental transit times were increased in the rectosigmoid (from 8.83 +/- 3.6 to 32.1 +/- 5.6 hr, P = 0.04) and right hemicolon (from 14.5 +/- 0.9 hr to 19.7 +/- 1.5 hr, P = 0.02) by suppression of defecation. We conclude that defecation habits may induce changes in colonic function such as those seen in constipation and that functional anorectal outlet obstruction may, probably by reflex mediation, affect the right colon.

[Measurement of colon transit time]

Several methods have been described to measure colonic transit times. The physical properties of all types of markers used allow to analyze and quantify them in stool samples or in the colon. The selective measurement of colonic (ceco-anal) transit time requires complicated intubation techniques. For most purposes it is sufficient to approximate the colonic transit by the whole gut transit, since oro-cecal transit time usually is only about a tenth of whole gut transit time. For this purpose the marker can be administered orally. In order to measure segmental colonic transit times it is necessary to monitor the distribution of the markers within the colon. For that purpose scintigraphic techniques are suited, but they require special equipment and are time consuming. Radio-opaque pellets, in contrast, are cheap, easy to handle, and have no known side effects. The following procedure is recommended: the patient swallows a gelatin capsule which contains 20 radio-opaque pellets on each of 6 consecutive days at the same time when on day seven a single abdominal x-ray is obtained. Then, segmental and total colonic transit times can be calculated from the number of retained pellets.

Symptoms in gastro-oesophageal reflux disease

Symptomatology was evaluated in 304 patients referred for 24 h oesophageal pH monitoring. Of several symptoms thought to be related to gastrooesophageal reflux disease (GORD), only heartburn (68% vs 48%) and acid regurgitation (60% vs 48%) occurred in more of the patients with GORD (as determined by pH monitoring) than of those with normal pH monitoring. When heartburn or acid regurgitation clearly dominated the patient's complaints, they had very high specificity (89% and 95%, respectively) but low sensitivity (38% and 6%) for GORD. A third of the patients reported such inconclusive symptomatology at history-taking that no preliminary diagnosis about the presence or absence of GORD could be made. In the remaining 200 patients, a clinical diagnosis by history had a sensitivity of 78% and specificity of 60%. A discriminant analysis of symptoms was inferior to a history taken by an experienced gastroenterologist.

Relation between fasting antroduodenal motility and transpyloric fluid movements

The effect of fasting antroduodenal motility on duodenogastric fluid movements was studied in 12 healthy volunteers. Antroduodenal motility was recorded using a multilumen manometry tube. Gastric emptying and secretion and the duodenogastric reflux of bile acids and marker were measured simultaneously by means of a marker dilution technique. Gastric emptying and acid secretion were higher in phase II than in phase I of the fasting motor activity cycle [median (range) 1.74 (1.2-4.2) ml/min vs. 0.90 (0.0-2.4) ml/min and 63.5 (6.4-115.0) vs. 37.9 (5.8-86.4) mumol/min, P less than 0.01]. The duodenogastric reflux rates of bile acids and marker were similar in all phases and showed large intra- and interindividual variations. There was no correlation between antroduodenal coordination during phase II motility and gastric emptying and duodenogastric reflux. It is concluded that the interdigestive motility pattern has moderate effects on fasting emptying of liquid gastric contents and on gastric secretion but no effects on duodenogastric reflux.

Intragastric bile acid concentrations in critically ill, artificially ventilated patients

Bile acids have experimentally been found to damage the gastric mucosa and, thus, may be involved in stress lesion pathogenesis. We therefore measured intragastric bile acid concentrations in 26 critically ill, artificially ventilated patients. The control group consisted of eight healthy volunteers, whose treatment was similar to that of the patients with respect to bed rest, enteral feeding, and administration of H2-blockers. Gastric contents were aspirated via a gastric tube every hour for 24 h. Patients had higher intragastric bile acid concentrations than healthy controls, whether fasting [median 1.3 mmol/L (range 0.7-2.5) versus 0.3 (0.2-0.5) (p less than 0.05)] or fed via a gastric tube [1.3 (0.4-4.0) versus 0.4 (0.2-0.7) (p less than 0.05)]. Physiotherapy, nursing, and drugs (opiates, benzodiazepines, dopamine, pirenzepine, and metoclopramide) had no detectable influence on intragastric bile acid concentrations and pH in patients. We conclude that patients at risk to develop stress lesions have largely increased gastric bile acid concentrations that probably are due to increased duodenogastric reflux. This might be relevant for stress lesion pathogenesis.

Is long-term esophageal pH monitoring of clinical value?

Two hundred eighty-nine patients with various chest symptoms were studied by interview for the presence and type of symptoms, and by long-term esophageal pH monitoring for acid reflux. One hundred eighty of the patients also had upper gastrointestinal endoscopy. There was significant correlation between the results of all three methods. pH monitoring was more sensitive (92.9% vs. 81.0%) and specific (41.3% vs. 23.9%), and classified more patients correctly (55.6% vs. 37.2%), than an interview by an experienced gastroenterologist when esophageal erosions were regarded as "gold standard" for pathologic reflux. Of all patients, 31.5% had unclear symptoms and therefore could not be diagnosed by interview alone. Forty nine percent of these had pathologic reflux on pH monitoring. Among the patients, 72.3% who had symptoms typical of reflux disease also had a pathologic result at pH monitoring. It is concluded that most patients with unambiguous symptoms of esophageal reflux can correctly be diagnosed by interview, but that esophageal pH monitoring has a role in the management of patients with less characteristic chest symptoms.

Effects of albuterol (salbutamol) on esophageal motility and gastroesophageal reflux in healthy volunteers

Orally or intravenously administered beta 2-adrenergic drugs have been found to inhibit esophageal motor function. Since inhalation of these drugs results in less systemic side effects, the present double-blind study was designed to investigate the influence of inhalation of the beta 2-adrenergic agonist albuterol (salbutamol) on esophageal motor function and gastroesophageal reflux in ten healthy volunteers. Esophageal motor function was recorded using a pneumohydraulically perfused multilumen manometry tube. Twenty-four-hour pH profiles were measured while the volunteers were ambulatory using a combined glass electrode connected to a portable recorder. Inhalation decreased neither lower esophageal sphincter pressure nor esophageal peristaltic amplitudes. Gastroesophageal reflux was similar on both occasions during inhalation of albuterol (3.1% [range, 1.0% to 25.5%] median upright time, with esophageal pH less than 4; and 0.1% [range, 0.0% to 10.7%] supine time) and during placebo treatment (3.6% [range, 1.6% to 19.8%] upright and 0.0% [range, 0.0% to 2.5%] supine time). Our data support the study of inhalation of beta 2-adrenergic drugs in asthmatic patients with accompanying gastroesophageal reflux.

[Is a duodenogastric reflux of pathogenic significance?]

Experimentally, the gastric and the duodenal mucosa can both be damaged by acute exposure to small intestinal juice. Though chronic exposure to bile causes mucosal erythema and hyperplasia, the gastric mucosal barrier is not damaged. Duodenogastric reflux is relevant in the pathogenesis of postoperative bilious vomiting and probably of "alkaline" reflux esophagitis. The exact mechanism of mucosal damage has not been established. Duodenogastric reflux is likely to be irrelevant in the pathogenesis of (microscopic) gastritis, of gastric ulcer, and of reflux esophagitis without previous gastric surgery.

Effect of wheat bran on weight of stool and gastrointestinal transit time: a meta analysis

Twenty original papers that reported on the effect of wheat bran on large bowel function were analysed. Bran increased the stool weight and decreased the transit time in each study in healthy controls and in patients with the irritable bowel syndrome, with diverticula, and with chronic constipation. Statistical evaluation of the data showed, however, that constipated patients had lower stool output and slower transit whether or not they had taken bran, and they responded less well to bran treatment than controls. From these data it is concluded that bran can be expected to be only partially effective in restoring normal stool weight and transit time in patients who are constipated.

Effect of wheat bran on weight of stool and gastrointestinal transit time: a meta analysis

Twenty original papers that reported on the effect of wheat bran on large bowel function were analysed. Bran increased the stool weight and decreased the transit time in each study in healthy controls and in patients with the irritable bowel syndrome, with diverticula, and with chronic constipation. Statistical evaluation of the data showed, however, that constipated patients had lower stool output and slower transit whether or not they had taken bran, and they responded less well to bran treatment than controls. From these data it is concluded that bran can be expected to be only partially effective in restoring normal stool weight and transit time in patients who are constipated.