Irritable bowel syndrome: relationship of disorders in the transit of a single solid meal to symptom patterns

Gastrointestinal motility in patients with ulcerative colitis

In the first study 62 patients with ulcerative colitis and 20 healthy controls were fed a test meal of mashed potatoes and baked beans containing transit markers. Mouth-to-caecum transit was significantly slower in the patients than in controls; gastric emptying, however, was similar. Patients with active colitis had proximal colonic stasis, with rapid transit through the rectosigmoid region. In the patients with quiescent colitis the colonic distribution of markers was normal. Stool weight and frequency were significantly higher in the patients with active colitis. In the second study anorectal function was assessed in 29 patients with ulcerative colitis and in 12 healthy controls by measuring interluminal pressures at multiple sites in the anus and rectum before and during serial distention of a rectal balloon. Overall, resting and maximum squeeze sphincter pressures did not differ in patients with active or quiescent colitis and controls; however, in six patients with moderately severe colitis and incontinence, maximum squeeze pressure was significantly lower than in controls. The rectal volumes required to induce sensations of wind, a desire to defaecate, and pain were significantly lower in the patients with active colitis than patients with quiescent colitis and controls. Rectal pressures in response to rectal distention were higher in patients with active colitis. During disease remission rectal sensitivity decreased and rectal compliance increased. In the third study integrated pressure activity of the sigmoid colon, rectum, and anus was studied in patients with ulcerative colitis and healthy controls before and during provocation by rectal infusion of 1500 ml of warm saline.(ABSTRACT TRUNCATED AT 250 WORDS)

Na+-dependent bile acid transport in the ileum: the balance between diarrhea and constipation

Ileal Na+-dependent bile acid transport was quantified in vitro as the uptake of 3H-taurocholate into brush-border membrane vesicles. Vesicles were prepared from ileal biopsies of 158 patients placed in 10 diagnostic categories. Active bile acid transport (expressed as picomoles taurocholate uptake per milligram brush-border membrane protein per 15 s, median and interquartile ranges indicated) did not differ significantly in 6 categories: irritable bowel syndrome (71, 35-97; n = 21), colon polyps (42, 30-89; n = 29), colitis (62, 33-91; n = 31), postvagotomy or postcholecystectomy (69, 37-97; n = 11), diarrhea without increased bile acid loss (58, 48-85; n = 12), and lack of gastrointestinal pathology (74, 45-103; n = 22). A decreased active bile acid transport was found in 3 categories: ileal disease (4, 1-36; n = 11), partial ileal resection (5, 1-35; n = 5), and constipation (41, 22-50; n = 8). Bile acid transport was increased in patients with bile acid-losing diarrhea with endoscopically and histologically normal ilea (111, 94-135; n = 8). These findings indicate that a low fecal bile acid loss, presumed to be present in constipated patients, is associated with a low Na+-dependent ileal bile acid transport and a high bile acid loss is associated with a high active bile acid transport. Ileal bile acid transport might be regulated by the availability of bile acids to the ileal enterocytes.

Psychophysiologic responses to a realistic laboratory abdominal pain stimulus

Small doses of the carbohydrate lactulose are widely used in the clinical setting to assess small bowel transit time because lactulose is not absorbed by the small intestine and its arrival in the intestine can be detected non-invasively by breath hydrogen testing. In this study, doses of this safe, widely used substance higher than those typically administered for transit tests were given to 12 healthy young adult men to produce symptoms of gas and intestinal distention similar to those commonly experienced by patients with irritable bowel syndrome and recurrent abdominal pain. Comparison of subjective and physiological responses to the administration of 0 and 30 g of lactulose in a double-blind placebo-controlled trial demonstrated that the 30 g lactulose dose produced significant increases in a number of measures reflecting the intra-intestinal pain stimulus. The results of the present study indicate that lactulose is a realistic and ethically acceptable stimulus for the production of transient mild abdominal pain in the laboratory.

Symptomatic, radionuclide and therapeutic assessment of chronic idiopathic dyspepsia. A double-blind placebo-controlled evaluation of cisapride

Twenty-eight patients with chronic idiopathic dyspepsia defined by the presence of chronic unexplained symptoms suggestive of gastric stasis and directly related to food ingestion were included in this prospective study. Gastric emptying of the liquid and solid phases of a meal was quantified by a dual-isotope method, and symptoms were evaluated by a diary and a visual analog scale. Delay in gastric emptying was evidenced in 59% of the dyspeptic patients; it occurred with liquids in more cases than solids. Quantitative and qualitative evaluation of symptoms was of no practical value in predicting the presence of objective stasis. The dyspeptic patients were included in a double-blind randomized controlled trial of cisapride, a new gastrokinetic drug devoid of central antiemetic effects. After six weeks of cisapride treatment, all patients with initially abnormal gastric emptying rates for liquids, and all but one for solids returned to normal ranges, and significant differences between cisapride and placebo groups were observed for half emptying times of both solids (136 +/- 16 min vs 227 +/- 32 min; P less than 0.02) and liquids (61 +/- 4 min vs 132 +/- 37 min; P less than 0.01). Cisapride also significantly improved dyspeptic symptom scores at weeks 3 and 6 of treatment as compared to those measured before treatment. Nevertheless, the decrease in global diary score was significantly higher than that seen with placebo at week 3 (-16 +/- 6 vs -1 +/- 9; P less than 0.05), but not at week 6 (-18 +/- 5 vs -10 +/- 8).(ABSTRACT TRUNCATED AT 250 WORDS)

Gastrointestinal transit after proctocolectomy with ileal pouch-anal anastomosis or ileostomy

Proctocolectomy with ileal pouch-anal anastomosis increases the frequency of stooling, perhaps due in part to the loss of an ileocecal or colonic braking effect on gastrointestinal transit. To assess whether colectomy with ileal pouch-anal anastomosis (IPAA) or with ileostomy accelerates gastrointestinal transit, we studied 16 IPAA patients (mean +/- SEM stool frequency, 8 +/- 1 stools/day), 5 patients after colectomy and Brooke ileostomy, and 8 healthy, unoperated controls (1 +/- 1 stools/day). Gastric emptying of liquids and small bowel transit of chyme were measured concurrently with a dual isotope technique. Gastric emptying was similar among all groups. In contrast, postprandial small bowel transit of the head of a duodenal marker was slowed, not accelerated, in IPAA patients (178 +/- 26 min) compared to Brooke subjects (80 +/- 32 min, P less than 0.05) and controls (75 +/- 15 min, P less than 0.01). Maximal filling of both the ileal pouch (341 +/- 19 min) and the ileostomy bag (348 +/- 12 min) occurred later than filling of the colon in controls (243 +/- 32 min, P less than 0.01). Overall stool frequency did not correlate with small bowel transit in the ileoanal patients, but the two ileoanal subjects with greatest stool frequency (11 and 18 stools/day) had the earliest arrival of marker at the pouch. In conclusion, removal of the colon markedly slowed small bowel transit in most patients, although it did not alter gastric emptying of liquids. Creation of an ileal pouch and ileoanal anastomosis further slowed transit of the head of the meal.(ABSTRACT TRUNCATED AT 250 WORDS)

Relationships between symptoms, menstrual cycle and orocaecal transit in normal and constipated women

Because severe constipation is a disorder largely confined to young women, the possibility that menstrually related factors contribute to disturbed gastrointestinal motor function has been raised. It has also been reported that normal menstruating women show changes in upper gut transit between the follicular and luteal phases of the menstrual cycle and that patients with constipation show prolonged transit. We therefore studied relationships between symptom severity and orocaecal transit during the menstrual cycle in a group of 14 constipated women and a series of control groups comprising seven normal menstruating women, five postmenopausal women, and eight normal men, to determine whether phases of the menstrual cycle were associated with alteration in symptoms or transit. A regular menstrual cycle was reported by 13 of the 14 patients (range 26-30 days) and by all the menstruating female volunteers. Seven patients noted variation in constipation during the menstrual cycle, in all cases this comprised an improvement in symptoms just before or during menstruation. No consistent relationship between symptom severity and follicular or luteal phase was noted. Repeated orocaecal transit measurements in the four study groups showed no consistent differences (greater than 0.05) between groups or during the menstrual cycle (mean change weeks 1-4, -10 +/- 20 min). These findings are inconsistent with the hypothesis of a progesterone related effect upon orocaecal transit in either normal or constipated women.

Treatment of chronic diarrhoea: loperamide versus ispaghula husk and calcium

Twenty-five patients with chronic diarrhoea were included in an open, randomized crossover trial comparing the effect of loperamide with ispaghula and calcium. Nineteen patients completed both treatments. Before treatment the median number of daily stools was 7 (range, 4-13), stool consistency was loose in all, and urgency was present in 16 out of 19 patients. Both treatments halved stool frequency, but with regard to urgency and stool consistency ispaghula and calcium was significantly better. A combination of ispaghula and calcium seems to be a cheap and effective alternative to conventional treatment of chronic diarrhoea. Moreover, side effects were minimized.

Repeatability of lactulose hydrogen breath test in subjects with normal or prolonged orocecal transit

The within-subject repeatability of orocecal transit assessed with lactulose hydrogen breath test was evaluated in 15 healthy volunteers and 16 constipated or obese patients. The test was repeated twice in each subject. Mean (SD) transit time was 105 (63) and 103 (60) min in the first and second series of tests, respectively, showing that the first measurement did not affect the second. The within-subject repeatability of the test was related to the length of transit, the scatter of the differences between the first and second test being greater with the increase of the mean gastrointestinal transit time. The 95% coefficient of repeatability was 84 min for all measurements and 30 and 118 min, respectively, for transit times under and over 100 min. The lowest reproducibility of the test was found in constipated patients with prolonged orocecal transit.

Dysmotility of the small intestine in irritable bowel syndrome

Though the pathophysiology of the irritable bowel syndrome (IBS) is commonly attributed to dysfunction of the large intestine, evidence exists to incriminate the small bowel. In order to further explore the role of the small bowel in IBS several stimuli were applied, in an attempt to unmask the dysmotility of the jejunum and ileum. These included infusions of cholecystokinin-octapeptide (CCK-OP), a high fat meal, neostigmine and balloon distension of the ileum. Three groups (n = 8) each of age and sex matched healthy volunteers were studied; patients with IBS complained of predominant constipation (n = 8) or diarrhoea (n = 8). Patients with IBS responded excessively to stimulation by CCK-OP, fatty meal, and ileal distension. In general patients with diarrhoea were more sensitive to stimuli than those with constipation. The ileum responded more to stimulation than the jejunum. As in the large bowel, stimuli appear to unmask intestinal dysmotility in patients with IBS. Motor abnormalities were often accompanied by abdominal symptoms, raising the possibility that dysfunction of the small bowel contributes to the symptoms of IBS.

Starch malabsorption and breath gas excretion in healthy humans consuming low- and high-starch diets

Dietary starch delivery to the colon and excretion in stools and the ability of unabsorbed carbohydrates to promote hydrogen and methane release in breath were evaluated in 6 volunteers during two 8-day periods on starch diets of 100 and 300 g, respectively. Significantly less starch was recovered from the terminal ileum by aspiration per 24 h during the low-starch period (4.1 +/- 0.3 vs. 9.5 +/- 1.1 g, mean +/- SEM, p less than 0.01). Unabsorbed glucose tended to rise during the high-starch period (2.7 +/- 0.8 vs. 1.1 +/- 0.3 g). Fecal outputs of starch, glucose, volatile fatty acids, and lactic acid were not significantly different during the two periods. Daily breath hydrogen excretion was unchanged (181.2 +/- 22.7 vs. 193.7 +/- 19.8 ml for the low- and high-starch periods, respectively), whereas breath methane excretion increased markedly in the three methane producers during the high-starch period (217.2 +/- 80.9 vs. 32.4 +/- 7.3 ml). Starch malabsorption in the healthy small intestine was moderate even with a high-starch diet and less than that previously estimated by indirect methods. Unabsorbed starch catabolism by the colonic flora does not seem to explain most of the breath hydrogen excretion.

Orocoecal transit time in healthy and constipated children

Orocoecal transit time (OCTT), assessed by means of H2 breath test after lactulose and/or after a semisolid standard meal, was studied in normal and constipated children. Both control subjects and patients with constipation showed a significantly longer OCTT after a standard meal than after lactulose ingestion (p less than 0.01). Whereas the OCTT after lactulose did not differ in the two groups, the constipated patients had a significantly longer transit time after a standard meal when compared to controls (p less than 0.05). No correlation was observed within each group between the OCTT after a standard meal or after lactulose ingestion (r = -0.077; p greater than 0.01). These findings suggest that 1) measurement of the transit of a standard meal instead of a lactulose solution may offer more direct insight into the role of small intestinal transit of food, both in physiological and pathological conditions, 2) gastrointestinal segments other than colon may play a role in chronic non organic constipation of childhood.

Faecal chymotrypsin: a reliable index of exocrine pancreatic function

Simultaneous measurements of duodenal and faecal chymotrypsin were made in 30 children aged 3 weeks to 14 years. Apparent chymotrypsin secretion rates measured after stimulation with pancreozymin were compared with the mean faecal chymotrypsin concentration derived from three stool specimens collected at random within 72 hours of the intraduodenal test. In the 25 children who responded to pancreozymin stimulation the mean faecal chymotrypsin concentration was significantly positively correlated with the apparent chymotrypsin secretion rate. Correlation using single specimen stools collected at random was appreciably poorer. In the five children with undetectable or only traces of chymotrypsin in the duodenum after stimulation, the mean faecal chymotrypsin concentrations were only 3-10% of the lower limit of the reference interval. In a second group of 46 children with cystic fibrosis proved by sweat tests and clinical evidence of malabsorption, the chymotrypsin concentration measured in a single stool specimen collected at random was unequivocally subnormal in each case. Faecal chymotrypsin measurement is a rapid, simple, cheap, readily repeated, non-invasive test of high specificity and sensitivity. Faecal chymotrypsin should be measured before contemplating intraduodenal tests of pancreatic function.

Impact of age, sex, race, and functional complaints on hydrogen (H2) production

In order to evaluate factors that may influence H2 generation, the effects of age, sex, race, and functional complaints on breath H2 were studied in 62 subjects. These included 34 young hospital employees, 17 healthy ambulatory elderly subjects, and 11 patients with functional bowel disease. The ability to produce H2 was defined by an increase in breath H2 to greater than 20 parts per million within 4 hr of ingesting 10 g of the nonabsorbable sugar lactulose. Overall, 21% of subjects were nonproducers, and the incidence of nonproduction did not vary among the groups. The elderly subjects had significantly greater breath H2 concentrations than the younger subjects at 150 minutes (P less than 0.05). Sex, race, and functional complaints did not influence H2 production. These findings indicate that patient's age and potential inability to make H2 need to be considered in the routine interpretation of H2 breath tests.

The irritable bowel syndrome

The irritable bowel syndrome (IBS) is an extremely common disorder. It is believed to occur usually after emotional stress and perhaps because of behavioural and dietary factors. There is definite evidence of disturbed gastrointestinal function associated with IBS; however, a diagnostic marker remains elusive. The current trend is to diagnose IBS on the basis of the patient's history and the findings at physical examination and after minimal investigation. The physician-patient relationship remains the most important factor in the management of IBS. Long-term benefit may be achieved with the use of dietary fibre supplements or stool-bulking agents. The evaluation of currently available drugs is difficult because of the placebo effect. Drug therapy should be aimed at specific symptoms and used mainly during the initial phase of treatment.

Gastrointestinal and colonic segmental transit time evaluated by a single abdominal x-ray in healthy subjects and constipated patients

Gastrointestinal transit time (GITT) and segmental colonic transit times were studied in 56 healthy subjects by repeated daily ingestion of 10 radiopaque markers followed by abdominal x-ray. A seven-day procedure including marker intake for 6 days and a single radiograph on day 7 was found to be a simple method to differentiate between rapid, normal and prolonged transit. Addition of 20 distinguishable markers on day 6 helped to describe transit profiles. Healthy women had longer GITT than men (median 2.4 and 1.9 days, respectively) measured as mean 50% excretion time for the ingested doses of markers. For comparisons with patients percentiles for transit were calculated. In constipated patients the 7-day method demonstrated prolonged GITT as well as transit dysfunction in separate colonic segments. The method seems convenient for clinical use in diagnostic as well as therapeutic studies of colonic transit.

Colonic myoelectrical activity in IBS painless diarrhoea

Colonic myoelectrical activity was recorded during 24 hours in 23 patients with painless diarrhoea and compared with a control group of 10 healthy subjects without digestive functional disorders. Diurnal fasting activity showed no significant difference in the total long spike bursts activity (LSB lasting greater than 7 seconds), but short spike bursts activity (SSB, lasting less than 7 seconds) was significantly lower (p less than 0.05) in diarrhoeal patients. A striking difference was observed in colonic response to eating, with an increased number of migrating long spike bursts (MLSB: mass movements) during the first postprandial hour in diarrhoeal patients (p less than 0.001), while short spike bursts (segmental activity) were almost absent in the rectosigmoid area. A marked decrease in the retrograde LSB activity was also observed in eight patients. During the night (from 2200 h to 0600 h) the number of migrating long spike bursts was increased in the diarrhoea group, but almost absent in controls (p less than 0.001). This study shows that colonic motor activity was altered in painless diarrhoea. These disturbances were not limited to the decreased SSB activity in the sigmoid, but involved the whole colon, with lower SSB activity and abnormal increase of migrating long spike bursts activity (MLSB) in postprandial and nocturnal periods.

Laboratory assessment of inflammatory bowel disease

Presently there are no specific laboratory tests to diagnose inflammatory bowel disease (IBD). Nonspecific tests to differentiate diarrhea due to mucosal injury from that occurring in patients with normal bowel mucosa (eg, fecal occult blood, leukocytes, etc) are not helpful. Tests to exclude infections agents are very important, since the clinical and radiological appearance of these may mimic IBD, and patients with IBD may suffer from superinfection. There are no laboratory tests which can differentiate Crohn's colitis from ulcerative colitis (UC). The tests used in the assessment and management of severely ill patients (Hgb, WBC, electrolytes, etc) are important, since abnormalities need to be corrected on an ongoing basis. The tests used to assess nutritional status are of little clinical value, since "clinical assessment" is as good as the laboratory assessment. Estimation of disease activity by tests is rarely better than the judgment of the clinician. Workup for malabsorption in Crohn's disease and the assessment of absorptive capacity of the terminal ileum are important for proper planning of management. Laboratory tests are also useful in clarifying the nature of some complications (eg, anemias and joint diseases).

Studies on the mechanism of bowel disturbance in ulcerative colitis

The transit of a radiolabeled meal through the gastrointestinal tract and stool output were measured in 62 patients with ulcerative colitis, subdivided according to the activity and extent of their disease. The results were compared with those from 20 sex-matched normal subjects. Mouth-to-cecum transit was significantly slower than normal in all patient groups although gastric emptying was normal. Whole gut transit was not accelerated in any group of patients. An abdominal x-ray taken 48 h after ingesting the meal showed that patients with active colitis had proximal colonic stasis, whereas transit through the rectosigmoid region was rapid. Stool weights and frequencies were higher in patients with active colitis than in patients with quiescent disease. Patients with active colitis also passed smaller amounts of stool during each bowel movement, suggesting that they experienced a desire to defecate at lower rectal volumes. These results indicate that (a) diarrhea in ulcerative colitis is associated with rectosigmoid irritability rather than rapid transit and (b) caution should be used when treating active colitis with antidiarrheal drugs that could further retard proximal colonic transit.

Influence of olsalazine on gastrointestinal transit in ulcerative colitis

The effect of olsalazine on stool output and the transit of a solid radiolabelled meal through the stomach, small intestine and colon was studied in six patients with ulcerative colitis intolerant of sulphasalazine. Olsalazine 250 mg four times daily significantly accelerated gastric emptying (mean +/- SD; 45.3 +/- 24.2 min v 67.3 +/- 33.1 min, p less than 0.05), mouth to caecum transit time (242 +/- 41 min v 325 +/- 33 min, p less than 0.02) and whole gut transit time (60.5 +/- 26 h v 37.8 +/- 17.8 h, p less than 0.05). No significant changes were seen in mean daily stool weight (215 +/- 41 g v 162 +/- 62 g) and mean daily stool frequency (2.2 +/- 0.6 v 2.4 +/- 1.8). None of these patients developed diarrhoea, but acceleration of gastric and intestinal transit may be responsible for the diarrhoea reported in some patients taking this drug.

Altered small bowel motility in irritable bowel syndrome is correlated with symptoms

The pathogenesis of irritable bowel syndrome (IBS) has been related more to dysmotility of the colon than to abnormalities of the small intestine. To look for small bowel abnormalities, we recorded ultraluminal pressures in 16 patients with IBS. All patients complained of abdominal pain, and diarrhea (n = 8) or constipation (n = 8) were also prominent symptoms. Comparable studies were performed on 16 age-matched controls. The observations include diurnal and nocturnal fasting recordings and the response to a fatty meal. Periodicities of the interdigestive migrating myoelectric complexes were shorter in IBS (p less than 0.05); this was due to much shorter diurnal cycles in patients with diarrhea (77 +/- 10 min) than those with constipation (118 +/- 15 min) or controls (113 +/- 10 min, both p less than 0.05). All groups exhibited circadian changes, with nocturnal cycles being more frequent. Two specific patterns of small bowel motor activity were more common in IBS--ileal propulsive waves and clusters of jejunal pressure activity (both p less than 0.05 compared to controls). Moreover, cramping abdominal pain was usually noted in IBS when ileal motility was propulsive; jejunal bursts were also sometimes associated with abdominal symptoms. We conclude that motility of the small intestine is modified in some patients with IBS and that certain motor patterns are related to their symptoms.

Is there a relationship between symptoms of the irritable bowel syndrome and objective measurements of large bowel function? A longitudinal study

Four patients with the irritable bowel syndrome completed 28 day continuous stool collections and concurrent symptom diaries. The diaries revealed that three patients had multiple pains. When the diaries were compared with objective measurements, no relationship could be detected between the occurrence of pain or any other symptom on the one hand and stool weight, stool form or consistency, mean whole gut transit time, or interdefecatory transit on the other. Patients' descriptions of urgency, looseness and frequency of defecation give little guide to intestinal events, at least using currently available techniques.

Gastrointestinal motility in patients with the irritable bowel syndrome

Patients with the irritable bowel syndrome (IBS) often have symptoms from both proximal and distal parts of the gut. Motility disturbances have been reported to occur from the esophagus to the distal colon in IBS patients. The patients often have a decreased lower esophageal sphincter pressure and various abnormalities of esophageal peristalsis. Mean transit time in the small intestine after a meal is short in patients with diarrhoea, and long in patients with constipation and pain compared with normals. IBS patients also show abnormalities of the interdigestive MMC, particularly when exposed to stressful stimuli. Previous studies of the colonic oscillating control potential suggested an increased prevalence of 3/min. slow waves in IBS patients compared with normals, but later studies could not confirm this. Long time measurements with multiple electrodes along the colon show a high prevalence of short-lasting segmental contractions in constipated patients, while both short and long-lasting contractions are decreased in painless diarrhoea. Rectal recordings in IBS patients have shown an increased contractile response up to 3 hrs after a meal. --The disturbed gut motility in IBS patients seems to be due no neural influences rather than strictly myogenic factors.

Irritable bowel syndrome (IBS)--definition and pathophysiology

The article presents some individual perceptions of the nature of the disease we call the Irritable Bowel Syndrome (IBS), and attempts to rationalise the variable presenting features, the influence of the psyche and the lack of pathological or biochemical markers. Among the topics discussed include the existence of recognisable subsets of the disease, the influence of mental stress, and the pathophysiology of the presenting symptoms. My impression is that IBS is a condition, in which the gut is hypersensitive and hyper-reactive to mechanical and chemical stimuli and as such, can be compared with asthma in the respiratory system. This hyper-reactivity could be caused by increased mucosal permeability, increased numbers and/or responses of effector cells such as mast cells or enterochromaffin cells, and enhancement of intrinsic nerve reflexes by increased activity of efferent vagal fibres.

An approach to the design of therapeutic trials in IBS

The lack of easily definable end points and the variable clinical presentation make it difficult to design appropriate therapeutic trials for the Irritable Bowel Syndrome. In this article. I have described the approach that our unit have taken. Aspects of trial design that are important include the selection of those who present with frequent (greater than 3 times a week), and long standing symptoms (greater than 6 months), the inclusion of a baseline as well as a placebo period so that placebo response can be assessed, a flexible dose regime, concomitant measurement of relevant physiological changes and assessment of the response of individual symptoms as well as global response so that the indications for a particular type of treatment can be determined.

Gastric emptying rate and small bowel transit time in patients with irritable bowel syndrome determined with 99mTc-labeled pellets and scintigraphy

A new method employing 99mTc-labeled pellets for determination of the gastric emptying rate and small bowel transit time is described. The participants were six normal subjects and 16 patients with irritable bowel syndrome (eight with diarrhea and eight with obstipation as the primary complaint). The gastric emptying rate was the same in the three groups. The patients in the obstipation group had a significantly longer small bowel transit time than the normals (P less than 0.02) and the patients in the diarrhea group (P less than 0.01). There was no demonstrable difference between the small bowel transit time in the normals and in the patients in the diarrhea group.

Bloated irritable bowel syndrome defined by dynamic 99mTc bran scan

The motility of the ileocaecal region of the gut was studied in 10 women with irritable bowel syndrome (IBS) and bloating and in 8 normal women. Bran labelled with 37 MBq 99mTc was administered after fasting, and a dynamic scan was done after a standard meal 3 h later. Time-activity curves were plotted for the ileum and caecum. In controls, ileal emptying was faster, peak % counts in the caecum were higher, and ileocaecal clearance was greater than in those with IBS. The profound motor dysfunction seen in those with IBS may account for their symptoms, and the "bran scan" could become an important diagnostic aid.

Transit of pharmaceutical dosage forms through the small intestine

The gastrointestinal transit of pharmaceutical dosage forms has been measured in 201 studies in normal subjects using gamma scintigraphy. Solutions, small pellets, and single units (matrix tablets and osmotic pumps) were administered with different amounts of food in the stomach, ranging from fasted state to heavy breakfast. Gastric emptying was affected by the nature of the dosage form and the presence of food in the stomach. Solutions and pellets were emptied even when the stomach was in the digestive mode, while single units were retained for long periods of time, depending on the size of the meal. In contrast, measured intestinal transit times were independent of the dosage form and fed state. The small intestinal transit time of about three hours (mean +/- 1 h SEM) has implications for the design of dosage forms for the sustained release of drugs in specific positions in the gastrointestinal tract.

Assessment of orocoecal transit time by means of a hydrogen (H2) breath test as compared with a radiologic control method

The definition of the orocoecal transit time by means of the hydrogen (H2) breath test is not unequivocal. In this study the orocoecal transit time as measured with an H2 breath test was compared with that obtained with a radiologic method. Two definitions of orocoecal transit time by the H2 breath test were evaluated: the time from eating to the first of three consecutively rising H2 values, and the interval to H2 values 50% above 'small-bowel level'. Transit times measured in accordance with both definitions were closely correlated to that obtained with the radiologic method (A, r = 0.84; B, r = 0.90; for both, p less than 0.001), but transit time measured by definition A gave shorter values than the radiologic method (p less than 0.05). The mean transit time in patients with constipation was significantly longer than that in normal subjects and patients with functional diarrhoea (p less than 0.05). There was a significant correlation between the difference in transit time measured with the H2 breath test and the radiologic method and the transit time measured by the control method. This may indicate that rapid transit is associated with a delayed 'colonic' rise in H2 levels and slow transit with an early H2 rise.

Physiological studies in young women with chronic constipation

Manometric, radiological and neurophysiological investigations were performed on 34 women, aged between 14 and 53, who suffered with chronic constipation refractory to treatment, and on 27 age-matched normal female control subjects. The constipated patients had more difficulty in evacuating simulated stools than control subjects and 13 out of 19 patients tested obstructed defaecation by contracting the external sphincter during straining. The constipated group required a greater degree of rectal distension than control subjects to induce rectal contractions, anal relaxation and a desire to defaecate. Other modalities of rectal sensation were normal in the constipated subjects. Compared with controls, constipated patients had significantly lower anal pressures, an abnormal degree of perineal descent on straining and an obtuse anorectal angulation at rest. These results were compatible with weakness of the pelvic floor and neuropathic damage to the external sphincter. Mouth to anus transit time was abnormally prolonged in 60% of constipated patients, but was within the normal range in the remainder. Anorectal function in patients with slow transit was not significantly different from that in patients with a normal transit time. The mouth to caecum transit time of a standard meal was prolonged in constipated patients irrespective of the duration of the whole gut transit. Gastric emptying was not significantly prolonged.

A comparative study of the mouth to caecum transit time in children and adults using a weight adapted lactulose dose

Mouth to caecum transit time (M.C.T.T.) was assessed in 41 subjects divided into 3 age groups (0-1 year, 1-4 years and 22-27 years) with the hydrogen breath test (H.B.T.) using lactulose as the hydrogen source (250 mg/kg; minimal dose 1.5 g in a 10% aqueous solution). The M.C.T.T. remained constant from the second month of age. In children under 1 year of age a high percentage of non-responders was found compared to the older age-groups. In 8 adults two test-substrates, pure lactulose (Legendal, L) and a mixture of lactulose, lactose and galactose (Duphalac, D) were compared. There was no significant difference in M.C.T.T., mean hydrogen production and clinical symptoms using D or L as substrate. We conclude that the H.B.T. using a relative dosage is a suitable test for children, but under the age of 1 year it is less useful because of the high percentage of non-responders. Because of the relation between body height and small bowel length the results suggest an increase in the velocity of the intestinal content with age.

Adaptation of cholesterol and bile acid metabolism and vitamin B12 absorption in the long-term follow-up after partial ileal bypass

Cholesterol and bile acid metabolism and vitamin B12 were studied in 19 patients with heterozygous familial hypercholesterolemia in an 8-yr follow-up (3-12 yr after ileal bypass operation), and in 11 unoperated controls. Absorption of cholesterol and vitamin B12 were decreased by the operation, but improved slowly, and at 8 yr cholesterol absorption was normal. Cholesterol excretion as fecal neutral steroids was not increased by the operation, and at 8 yr the flux of endogenous cholesterol to the gut was similar in the operated and control patients. Cholesterol absorption was positively correlated with mouth to anus transit time in the unoperated patients. Fecal bile acid excretion was increased immediately after the operation and continued to increase even after the second postoperative year. In the operated patients fecal excretion of fat, water, and dry matter were positively correlated with fecal bile acid excretion. Our study suggests that adaptive changes occur slowly after ileal bypass, resulting in gradual normalization of cholesterol absorption, despite continuing bile acid malabsorption, and that the intestinal transit time is related to steroid absorption even under physiologic conditions.

Simultaneous measurement of gastric emptying, small bowel residence and colonic filling of a solid meal by the use of the gamma camera

A method for determining the profiles of gastric emptying, small intestinal residence, and colonic filling of a solid test meal, labelled with 250 microCi 99mTechnetium sulphur colloid has been evaluated in nine healthy volunteers and six patients with a disturbance in bowel habit. Mean small bowel transit time was determined by deconvolving the rate of colonic filling with the rate of gastric emptying. In normal subjects, the stomach appeared to empty exponentially with a half time of 1.2 +/- 0.3 hours (mean +/- SD). Food reached the colon by 2.8 +/- 1.5 hours. The mean small bowel transit time was 4.0 +/- 1.4 hours. In most normal subjects, the colon appeared to fill in a linear fashion with approximately 16% food residues entering every hour, and the profile of colonic filling in normal subjects was similar to the profile of ileal emptying observed after feeding a similar radiolabelled solid meal to 14 patients equipped with terminal ileostomies. There was a highly significant correlation between the onset of breath hydrogen excretion and the appearance of radioactivity over the caecum (r = 0.88, p less than 0.01), though in one third of subjects the increase in caecal radioactivity preceded the rise in breath hydrogen concentration by more than 20 minutes. There was also a highly significant correlation between the mean transit time and values for colonic filling but not values for gastric emptying. Patients with irritable bowel syndrome who had diarrhoea tended towards short small bowel transit and early colonic filling, whereas patients who have constipation tended towards long small bowel transit and delayed colonic filling. This method offers a novel means of assessing small bowel transit time, small bowel residence and the profile of colonic filling in man.

Whole-bowel transit in patients with the irritable bowel syndrome

The transit of radiolabelled preparations through the stomach, small intestine and colon was monitored in ten patients with the irritable bowel syndrome. Five patients complained of diarrhoea, and five complained of constipation. The preparations comprised a non-disintegrating capsule and a multiparticulate system. Both preparations emptied from the stomach together and at the same rates in both groups of patients. In the patients complaining of constipation, the transit times through the small intestine were the same for both preparations. In the patients complaining of diarrhoea, the capsule passed through the small intestine slightly faster than the particles, but there were no significant differences in the small-intestinal transit rates of the two patient groups. Within the colon, the transit of the capsule was faster than that of the small particles. Although movement through the colon was, on average, faster in the group of patients complaining of diarrhoea, there was considerable intersubject variability, and the differences in transit rates between the two patient groups were not statistically significant.

Impairment of defecation in young women with severe constipation

Anorectal manometry, radiology, and tests of simulated defecation were carried out in 14 severely constipated young women and 29 age-matched controls. The resting anal sphincter pressures were reduced in the patients, but the squeeze pressures, rectoanal inhibitory reflex, and rectal pressures upon balloon distention were all normal. At rest, the anorectal angle was more obtuse in the constipated group, but there was no overall increase in perineal descent in constipated patients compared with controls. The presence of a balloon in the rectum and the onset of pain were perceived in constipated patients at volumes that were not significantly different from those in normal volunteers. Constipated patients, however, required higher rectal volumes to induce the desire to defecate and to stimulate regular rectal contractions. Constipated patients also found it more difficult to pass simulated stools from the rectum than the normal controls and, unlike most normal controls, failed to inhibit their external anal sphincter on attempted defecation. These findings suggest that young women with severe constipation have great difficulty initiating the coordinated set of events that constitute a normal defecation response.

Functional diarrhoea

Functional diarrhoea remains an elusive and a difficult condition to diagnose and treat; however, with careful history-taking a logical approach to management can be made. Each patient must be considered individually and sub-classification should be attempted. It is very important to rule out organic disease. Unfortunately treatment remains empirical in the majority of cases, but more is now known about functional disorders and there is hope for the future.

Colonic metabolism of wheat starch in healthy humans. Effects on fecal outputs and clinical symptoms

To study the intracolonic digestion of starch, 5 healthy volunteers were maintained on a constant diet for 7 days. On the fourth day, the cecum was intubated and a suspension of raw wheat starch (50 g, in 500 ml of 154 mM NaCl and containing 10 g of polyethylene glycol 4000) was infused into the distal ileum at 2 ml/min. Hydrogen excretion in breath was measured, cecal contents were sampled, and symptoms were recorded. For the 2-3 days before and after starch infusions, fecal weight, pH, and percentage of dry matter were monitored; fecal outputs of starch, volatile fatty acids, lactic acid, ethanol, polyethylene glycol, alpha-amylase, nitrogen, and ammonia were also measured. A lactulose (10 g) hydrogen breath test was performed 5-7 days after the starch infusions. After the infusion of starch, concentrations of lactic and volatile fatty acids increased and pH decreased markedly in cecal contents. None of the fecal values changed significantly after starch, however, indicating that carbohydrate catabolism was nearly complete and that the colon absorbed the catabolic products efficiently. Abdominal symptoms, especially bloating, were noted by all subjects, and 2 subjects complained of cramping pain. No subject experienced diarrhea. The amounts of starch metabolized in the colon (47.3 +/- 2.9 g), as calculated from the excretion of H2 in breath compared to the hydrogen breath test after lactulose, were close to the actual load (50 g).

Extra intestinal influences on exhaled breath hydrogen measurements during the investigation of gastrointestinal disease

During the clinical investigation of patients with gastrointestinal disease by exhaled breath hydrogen measurement, the occurrence of inexplicable variations in recorded hydrogen values led to a search for extra intestinal factors which were capable of adversely influencing breath hydrogen concentration and impairing the diagnostic accuracy of the test. Serial breath samples were collected from normal subjects under a variety of conditions which might occur during routine clinical study, including, hyperventilation, exercise, cigarette smoking, and carbohydrate ingestion. Breath hydrogen concentrations were consistently reduced by hyperventilation (p less than 0.01) and exercise (p less than 0.05). Cigarette smoking, in contrast, caused a marked rise in measured breath hydrogen (p less than 0.01), as did oral carbohydrate (p less than 0.05). Prior bactericidal mouthwash abolished this carbohydrate associated rise, suggesting that the hydrogen was the result of fermentation by oropharyngeal bacteria. Because, in all instances, the changes in breath hydrogen were of sufficient magnitude to interfere with data interpretation, it is recommended that these factors are eliminated, whenever possible, from conditions of study.

Increased serum pancreatic polypeptide and serum gastrin secretion in patients with functional dyspepsia: correlation to the shape of the duodenal loop

Simultaneous measurement of food-stimulated serum pancreatic polypeptide and serum gastrin was carried out in 18 patients with functional dyspepsia and correlated to the shape of the duodenal loop. Significantly higher serum concentrations of pancreatic polypeptide and gastrin were encountered in patients with an abnormal shape of the duodenal loop compared to patients with a normal shape. Although no cause could be given to the phenomenon it may be taken into account when evaluating hormone profiles in patients with functional dyspepsia.

Interpretation of the breath hydrogen profile obtained after ingesting a solid meal containing unabsorbable carbohydrate

The extent to which monitoring breath hydrogen excretion provides information concerning the entry of the residues of a solid test meal into the colon was investigated in 89 normal subjects, and 11 patients with the irritable bowel syndrome. The profile of breath hydrogen concentration showed an early peak, that occurred soon after ingesting the test meal in 89% subjects. This was followed by a later more prolonged rise in breath hydrogen concentration. The early peak occurred well before a radioactive marker, incorporated in the test meal, reached the caecum and the data suggest it was predominantly caused by the emptying of the remnants of the previous meal from the ileum into the colon. This hypothesis was supported by direct measurements of the rate of delivery of ileostomy effluent in 12 subjects with terminal ileostomies. Fermentation of carbohydrate in the mouth may, however, contribute to the initial peak, but this contribution may be avoided by collecting gas samples from the nares. The secondary rise in breath hydrogen excretion was closely correlated with the arrival of the radioactive marker in the caecum (r = 0.91), p less than 0.001), though the time, at which the secondary peak of breath hydrogen excretion occurred was poorly correlated with the time that all the radioactive test meal had entered the colon. When lactulose was infused directly into the colon, as little as 0.5 g produced a discernible hydrogen response, which occurred within two minutes of the infusion. Increasing the rate of colonic infusion of a 50 ml solution of 10% lactulose from 0.02 to 0.15 g/min in five subjects significantly increased the breath hydrogen concentration. At infusion rates below 0.075 g lactulose/minute, the peak breath hydrogen response preceded the end ot the infusion, while at higher rates of infusion, the peak hydrogen response occurred after the end of the infusion. Although these results confirmed that monitoring breath hydrogen concentration usefully signalled the time taken for a meal containing unabsorbed carbohydrate to reach the colon, it did not reliably indicate the time when all of the meal had entered the colon. Finally, the use of the maximum increase in breath hydrogen concentration as an index of the degree of carbohydrate malabsorption assumes uniform rates of entry into the colon.

Upper gastrointestinal and mental symptoms in the irritable bowel syndrome

Gastrointestinal and mental symptoms were assessed in 101 outpatients with the irritable bowel syndrome (IBS). A normal female population was used for comparison of mental symptoms. By definition all patients had abdominal pains and/or change of bowel habits (constipation or diarrhoea, or both) but no demonstrable organic disease. Upper gastrointestinal symptoms without peptic ulcer disease were reported by 87% of the patients. Mental symptoms were reported by almost all patients. Symptoms of anxiety, fatiguability, hostile feelings, sadness, and sleep disturbances were seen significantly more often among IBS women than in the controls. We conclude that patients with IBS frequently have upper gastrointestinal and mental symptoms that should be taken into account in the therapeutic management and evaluation of new modes of treatment.

Role of loperamide and placebo in management of irritable bowel syndrome (IBS)

Symptom scores, stool data, and the transit of a standard, solid meal were measured in 28 patients with irritable bowel syndrome (IBS) during baseline conditions and after five weeks of treatment with placebo and loperamide, given as a flexible dosage regime in the form of a double-blind, cross-over trial. All patients had undergone a comprehensive series of diagnostic investigations and had failed to respond to dietary supplementation with coarse wheat bran (10-30 g daily). Loperamide treatment accelerated gastric emptying, compared with placebo (1.2 +/- 0.1 vs 1.5 +/- 0.1 hr; P less than 0.001) and delayed both small bowel (6.2 +/- 0.3 vs 4.3 +/- 0.3 hr; P less than 0.001) and whole gut transit (56 +/- 5 vs 42 +/- 4 hr; P less than 0.01). Eighteen patients said they felt better taking loperamide compared with placebo and, at follow up, 15 of these patients remained satisfied with the effects of the drug. Most symptoms improved significantly on placebo compared with the baseline period, but three of these [diarrhea (P less than 0.01), urgency (P less than 0.01) and borborygmi (P less than 0.05)] showed a further significant improvement on loperamide. Improvement in diarrhea was not associated with any change in stool weight but was associated with reductions in stool frequency (P less than 0.001), passage of unformed stools (P less than 0.01), and incidence of urgency (P less than 0.001). Urgency was the only symptom that was significantly more common in the success group, compared with the group who did not feel better on loperamide.

Oral domperidone: double blind comparison with placebo in irritable bowel syndrome

Symptom scores, stool data, and the transit of a standard, solid meal were measured in 25 patients with irritable bowel syndrome during baseline conditions and after four weeks treatment with placebo and domperidone in the form of a double-blind cross-over trial. All patients had previously undergone a comprehensive series of diagnostic investigations and had failed to respond to dietary supplementation with coarse wheat bran (10-30 g daily). Compared with placebo treatment, domperidone had no significant effect on gastric emptying, small bowel or whole gut transit times, stool weight, frequency, or consistency. Most symptoms improved significantly with both placebo and domperidone treatments, compared with the baseline period, but there was no significant difference between placebo and domperidone for any of the symptoms. Abdominal distension, however, was reported on more days per week during domperidone treatment (p = 0.02). The findings in this study do not support the use of domperidone in the management of irritable bowel syndrome.