Intestinal gas in plain abdominal radiographs does not correlate with symptoms after lactulose challenge

Evaluation of abdominal gas by plain abdominal radiographs

BACKGROUND

Our aim was to determine the reliability of plain abdominal radiographs for the evaluation of abdominal gas content in patients with functional digestive symptoms.

METHODS

Abdominal CT scan scout views, mimicking a conventional plain abdominal radiograph, were obtained from 30 patients both during episodes of abdominal distension and basal conditions. Physicians (n = 50) were instructed to rate the estimated volume of gas in the 60 images presented in random sequence using a scale graded from 0 to ≥600 ml.

KEY RESULTS

The gas volumes estimated in the scout views differed from those measured by CT by a median of 90 (95% CI 70-102) ml, and the misestimation was not related to the absolute volume in the image. The accuracy of the observers, measured by their mean misestimation, was not related to their specialty or the training status (misestimation by 96 (95% CI 85-104) ml in staff vs 78 (70-106) ml in residents; p = 0.297). The accuracy was independent of the order of presentation of the images. Gas volume measured by CT in the images obtained during episodes of abdominal distension differed by a median of 39 (95% CI 29-66) ml from those during basal conditions, and this difference was misestimated by a median of 107 (95% CI 94-119) ml. The accuracy of these estimations was not related to the absolute gas volumes (R = -0.352; p < 0.001) or the magnitude of the differences.

CONCLUSIONS & INFERENCES

Plain abdominal radiographs have limited value for the evaluation of abdominal gas volume in patients with functional gut disorders.

Menstrual Cycle Variation in MRI-Based Quantification of Intraluminal Gas in Women With and Without Dysmenorrhea

Women frequently report increased bloating, flatulence, and pain during the perimenstrual period. However, it is unknown whether women have more intraluminal gas during menses. To evaluate whether pain-free women or women with dysmenorrhea have different amounts of intraluminal bowel gas during the menses, we utilized magnetic resonance imaging (MRI) to determine colonic gas volumes throughout the menstrual cycle. To avoid dietary influence, the participants were instructed to avoid gas-producing foods before their scheduled MRI. We verified the measurement repeatability across the reviewers and obtained an intraclass correlation coefficient of 0.92. There were no significant differences in intraluminal gas volume between menses and non-menses scans (p = 0.679). Even among the women with dysmenorrhea, there was no significant difference in the intraluminal gas volume between menses and non-menses (p = 0.753). During menstruation, the participants with dysmenorrhea had less intraluminal gas than participants without dysmenorrhea (p = 0.044). However, the correlation between the bowel gas volume and the pain symptoms were not significant (p > 0.05). Although increased bowel symptoms and bloating are reported in the women with dysmenorrhea during menses, our results do not support the hypothesis that increased intraluminal gas is a contributing factor. Although dietary treatment has been shown in other studies to improve menstrual pain, the mechanism responsible for abdominal symptoms requires further investigation. Our findings demonstrate that the intraluminal bowel gas volume measurements are feasible and are unaffected by menses under a controlled diet. The method described might prove helpful in future mechanistic studies in clarifying the role of intraluminal bowel gas in other conditions.

Clinical Response of Rifaximin Treatment in Patients with Abdominal Bloating

BACKGROUND/AIMS

Abdominal bloating is a troublesome complaint due to insufficient understanding of the pathophysiology. The aim of this study was to evaluate the efficacy of rifaximin in reducing bloating associated with functional gastrointestinal disorders (FGIDs).

METHODS

A total of 63 patients were treated with rifaximin for FGIDs with bloating or gas-related symptoms between 2007 and 2013 at Seoul National University Bundang Hospital. Rifaximin was administered at a dose between 800 mg/day and 1,200 mg/day for 5 to 14 days. The proportion of patients who had adequate relief of global FGID symptoms and FGID-related bloating was retrospectively assessed. The response was recorded when the symptoms were reduced by at least 50% at the follow-up after treatment cessation.

RESULTS

The mean age was 56.8±14.2 years; 49.2% were females. According to Rome III criteria, 20.6% (13/63) had irritable bowel syndrome (IBS) with constipation, 9.5% (6/63) had IBS with diarrhea, 4.8% (3/63) had mixed IBS, 23.8% (15/63) had functional dyspepsia, and 12.7% (8/63) had functional bloating. Of the 51 subjects who were followed-up, 30 (58.8%) had adequate relief of global FGID symptoms and 26 (51.0%) experienced improvement of abdominal bloating after rifaximin treatment. The proportion of female was slightly higher in non-response group than in the response group (60.0% vs. 34.6%, p=0.069). Otherwise, there was no difference between the two groups.

CONCLUSIONS

Despite the limitations of this retrospective study, our data confirms that rifaximin may be beneficial for abdominal bloating. Further prospective clinical trial with a larger cohort is needed.

Relevance of Colonic Gas Analysis and Transit Study in Patients With Chronic Constipation

Background/Aims

Colon transit time (CTT) is a useful diagnostic tool in chronic constipation, but requires good patient compliance. We analyzed the correlation between the gas volume score (GVS) and CTT in patients with chronic constipation.

Methods

The study included 145 consecutive patients (65 men) with chronic constipation. The primary outcome was the correlation between the colon GVS and CTT. Secondary outcomes were the differences in colon GVS according to CTT and subtypes of chronic constipation.

Results

There were 81 patients with “CTT < 45 hours” and 64 patients with “CTT ≥ 45 hours.” In addition, 88 patients were classified as having functional constipation and 57 were classified as having constipation predominant irritable bowel syndrome (IBS-C). There was no significant correlation between CTT and colon GVS. However, the right colon GVS showed a positive correlation with right CTT (r = 0.255, P = 0.007). The median total colon GVS was significantly higher in patients with “CTT ≥ 45 hours” than in those with “CTT < 45 hours” (5.65% vs 4.15%, P = 0.010). There were no significant differences in colon GVS between the functional constipation and IBS-C.

Conclusions

We were unable to detect a correlation between GVS and CTT in patients with chronic constipation. However, total colon GVS may be a method of predicting slow transit in patients with chronic constipation.

Differential effects of FODMAPs (fermentable oligo-, di-, mono-saccharides and polyols) on small and large intestinal contents in healthy subjects shown by MRI

OBJECTIVES

The objective of this study was to investigate whether ingestion of fructose and fructans (such as inulin) can exacerbate irritable bowel syndrome (IBS) symptoms. The aim was to better understand the origin of these symptoms by magnetic resonance imaging (MRI) of the gut.

METHODS

A total of 16 healthy volunteers participated in a four-way, randomized, single-blind, crossover study in which they consumed 500 ml of water containing 40 g of either glucose, fructose, inulin, or a 1:1 mixture of 40 g glucose and 40 g fructose. MRI scans were performed hourly for 5 h, assessing the volume of gastric contents, small bowel water content (SBWC), and colonic gas. Breath hydrogen (H2) was measured and symptoms recorded after each scan.

RESULTS

Data are reported as mean (s.d.) (95% CI) when normally distributed and median (range) when not. Fructose increased area under the curve (AUC) from 0-5 h of SBWC to 71 (23) l/min, significantly greater than for glucose at 36 (11-132) l/min (P<0.001), whereas AUC SBWC after inulin, 33 (17-106) l/min, was no different from that after glucose. Adding glucose to fructose decreased AUC SBWC to 55 (28) l/min (P=0.08) vs. fructose. Inulin substantially increased AUC colonic gas to 33 (20) l/min, significantly greater than glucose and glucose+fructose (both P<0.05). Breath H2 rose more with inulin than with fructose. Glucose when combined with fructose significantly reduced breath H2 by 7,700 (3,121-12,300) p.p.m./min relative to fructose alone (P<0.01, n=13).

CONCLUSIONS

Fructose but not inulin distends the small bowel with water. Adding glucose to fructose reduces the effect of fructose on SBWC and breath hydrogen. Inulin distends the colon with gas more than fructose, but causes few symptoms in healthy volunteers.

Methanogens, methane and gastrointestinal motility

Anaerobic fermentation of the undigested polysaccharide fraction of carbohydrates produces hydrogen in the intestine which is the substrate for methane production by intestinal methanogens. Hydrogen and methane are excreted in the flatus and in breath giving the opportunity to indirectly measure their production using breath testing. Although methane is detected in 30%-50% of the healthy adult population worldwide, its production has been epidemiologically and clinically associated with constipation related diseases, like constipation predominant irritable bowel syndrome and chronic constipation. While a causative relation is not proven yet, there is strong evidence from animal studies that methane delays intestinal transit, possibly acting as a neuromuscular transmitter. This evidence is further supported by the universal finding that methane production (measured by breath test) is associated with delayed transit time in clinical studies. There is also preliminary evidence that antibiotic reduction of methanogens (as evidenced by reduced methane production) predicts the clinical response in terms of symptomatic improvement in patients with constipation predominant irritable bowel syndrome. However, we have not identified yet the mechanism of action of methane on intestinal motility, and since methane production does not account for all constipation associated cases, there is need for high quality clinical trials to examine methane as a biomarker for the diagnosis or as a biomarker that predicts antibiotic treatment response in patients with constipation related disorders.

Colonic methane production modifies gastrointestinal toxicity associated with adjuvant 5-fluorouracil chemotherapy for colorectal cancer

GOALS

To investigate the association of colonic methane, formed by methanogenic achaea, and pH with gastrointestinal symptoms during colorectal cancer chemotherapy.

BACKGROUND

Adjuvant 5-fluorouracil chemotherapy reduces recurrences in colorectal cancer, but causes severe gastrointestinal toxicity, partly related to disturbed intestinal microbiota.

STUDY

Resected colorectal cancer patients (n=143) were analyzed for colonic methanogenesis and pH before and during the 24 weeks of 5-fluorouracil chemotherapy and for gastrointestinal symptoms during chemotherapy. This study was performed within the setting of an intervention study on the effects of Lactobacillus on chemotherapy-related gastrointestinal toxicity. The site of resected cancer, resection type, stoma, chemotherapy regimen, hypolactasia, and Lactobacillus intervention were considered as possible confounding factors, and multivariate models were constructed.

RESULTS

Baseline methane producers had less frequent diarrhea (more than or equal to moderate) during chemotherapy than nonproducers [odds ratio (OR), 0.42; 95% confidence interval (CI), 0.20 to 0.88; P=0.022] and more frequent constipation (OR, 4.56; 95% CI, 2.01 to 10.32; P<0.001). Baseline fecal pH was also associated with symptoms during chemotherapy; higher the pH, the lower the risk of diarrhea (OR, 0.56; 95% CI, 0.31 to 1.02; P=0.058) and higher the risk of constipation (OR, 2.23; 95% CI, 1.35 to 3.68; P=0.002). In multivariate stepwise models, methanogenesis was a significant explaining factor with inverse association with diarrhea and positive association with constipation. Fecal pH, which was significantly associated with methane production, was no longer a significant explaining factor when methanogensis was included in the model.

CONCLUSIONS

Methane producer status has a role in determining whether patient experiences diarrhea or constipation during 5-fluorouracil therapy. This underscores the importance of intestinal microbiota in the development of intestinal toxicity during 5-fluorouracil therapy.

Computed tomography assessment of intestinal gas volumes in functional gastrointestinal disorders

BACKGROUND/AIMS

Many patients with functional gastrointestinal disorders (FGIDs) rank sensations of bloating and distension among their most debilitating symptoms. Previous studies that have examined intestinal gas volume (IGV) in patients with FGIDs have employed a variety of invasive and imaging techniques. These studies are limited by small numbers and have shown conflicting results. The aim of our study was to estimate, using CT of the abdomen and pelvis (CTAP), IGV in patients attending FGID clinic and to compare IGV in patients with and without FGID.

METHODS

All CTAP (n = 312) performed on patients (n = 207) attending a specialized FGID clinic over 10-year period were included in this study. Patients were classified into one of 3 groups according to the established clinical grading system, as organic gastrointestinal disorder (OGID, ie, patients with an organic non-functional disorder, n = 84), FGID (n = 36) or organic and functional gastrointestinal disorder (OFGID, ie, patients with an organic and a functional disorder, n = 87). Two independent readers blinded to the diagnostic group calculated IGV using threshold based 3D region growing with OsiriX.

RESULTS

Median IGVs for the FGID, OGID, and OFGID groups were 197.6, 220.6 and 155.0 mL, respectively. Stepwise linear regression revealed age at study, gender, and calculated body mass index to predict the log IGV with an r(2) of 0.116, and P < 0.001. There was a significant positive correlation between age and IGV in OGID (Spearman's = 0.253, P = 0.02) but this correlation was non-significant in the other groups.

CONCLUSIONS

Although bloating is a classic symptom in FGID patients, IGV may not be increased compared with OGID and OFGID patients.

Quantitative analysis of intestinal gas in patients with acute pancreatitis

BACKGROUND

Disturbance of gastrointestinal function is a common complication in the early phase of acute pancreatitis (AP). Intestinal gas may reflect the function of the gut. Using plain abdominal radiographs, we investigated whether intestinal gas volume is related to AP.

METHODS

Plain abdominal radiographs of 68 patients with AP within 24 hours after admission and 21 normal controls were digitized and transmitted to a computer. The region of intestinal gas was identified by an image manipulation software and the gas volume score (GVS) was calculated. The relationships between the GVS values and various clinical factors of AP were analyzed.

RESULTS

The GVS in the AP group was 0.084+/-0.016, in the mild AP (MAP) group 0.070+/-0.005, and in the severe AP (SAP) group 0.094+/-0.013; all values were higher than that in the control group (P<0.01). The GVS in the SAP group was higher than that in the MAP group. The GVSs were correlated to the Ranson's scores (r=0.762, P<0.01) and the acute physiology and chronic health evaluation II (APACHE II) scores (r=0.801, P<0.01). In addition, the GVS in patients with secondary pancreatic and/or peripancreatic infection was 0.107+/-0.014, higher than that in patients without secondary infection (P<0.01). GVS was not related to gender, age, etiology or clinical outcome of AP.

CONCLUSIONS

Intestinal gas volume is significantly elevated in patients with AP. It is closely related to Ranson's and APACHE II score and secondary pancreatic and/or peripancreatic infection. GVS may be a new prognostic tool for assessing the severity of AP in the early course of the disease.

Colonic hypersensitivity is a major determinant of the efficacy of bloating treatment in constipation-predominant irritable bowel syndrome

The pathophysiology of bloating is largely unknown, and many mechanisms have been proposed. An alteration of intestinal gas production may have a role in a subgroup of patients, but available data are conflicting. We have previously shown that hypersensitivity to colonic fermentation is associated with severe bloating in a subgroup of patients with low intestinal gas production. Accordingly, we evaluated whether modification of intestinal gas production improves bloating severity according to the presence of visceral hypersensitivity to colonic fermentation. Twenty-four IBS-C patients with severe bloating underwent intestinal gas production measurement by hydrogen breath test after lactulose, and a recto-sigmoid barostat test in order to evaluate sensitivity thresholds in a basal condition and after induction of colonic fermentation. The subjects were then randomly assigned to receive either rifaximin or placebo according to a double-blind, randomized, cross-over trial. Rifaximin induced an improvement of symptom severity. A post hoc analysis according to the presence of hypersensitivity to colonic fermentation shows that rifaximin induces a significant improvement in symptom severity only in normosensitive, hyperproducer patients. Modulation of colonic flora, in order to reduce fermentation, does not interfere with bloating severity in patients with visceral hypersensitivity, thus suggesting that in this subgroup of subjects gas production is not crucial for the onset of bloating.

Relationships among the lactulose breath test, intestinal gas volume, and gastrointestinal symptoms in patients with irritable bowel syndrome

BACKGROUND AND AIMS

Irritable bowel syndrome (IBS) patients frequently complain of gas-related symptoms, and the lactulose breath test (LBT) is a test that assesses the amount of fermented gas generated by bacteria in the bowel. We aimed to assess the relationship among intestinal gas volume, LBT result, and gastrointestinal symptom score in healthy control and functional bowel disorder (FBD) subjects.

METHOD

In 84 IBS subjects, 24 FBD subjects other than IBS, and 25 healthy controls, a symptom questionnaire that enquired about seven main symptoms, plain abdominal radiography and a LBT were checked on the same day. The intestinal gas volume was calculated as the gas volume score (GVS) with a digitalized image of plain supine abdominal radiographs.

RESULTS

The GVS was greater in the LBT (+) group compared to the LBT (-) group (P = 0.02). The GVS was greater in the FBD and IBS groups than in the control group (P < 0.01). The GVS showed low but positive correlations with the severity and frequency of bloating, flatulence, abdominal pain, constipation, and tenesmus (P < 0.05). The severity of flatulence (P = 0.02) and the frequency of bloating (P = 0.02) in the LBT (+) group were significantly higher than those in the LBT (-) group.

CONCLUSIONS

Subjects with positive LBT had more gas-related symptoms and greater gas volume scores. Gas-related symptoms, positive LBT and increased GVS were significantly associated to each other. These findings can broaden the understanding of the pathophysiologic mechanisms of gas-related symptoms in IBS.

Methane on breath testing is associated with constipation: a systematic review and meta-analysis

BACKGROUND

A growing body of literature suggests an association between methane and constipation. Studies also link degree of methane production to severity of constipation and have shown constipation is improved following antibiotics.

AIMS

We aim to conduct a systematic review and meta-analysis to examine the cumulative evidence regarding the association between methane and constipation.

METHODS

A literature search was performed using MEDLINE and Embase to identify studies where the presence (or absence) of methane was assessed in constipated subjects. Search terms included "methane," "breath test," "constipation," "motility," "transit," "irritable bowel syndrome" and/or "IBS." Pooled odds ratios were generated using a random effects model. In a separate analysis, studies that measured intestinal transit in methane and non-methane subjects were systematically reviewed.

RESULTS

Nine studies met inclusion criteria for the meta-analysis. Among these, 1,277 subjects were examined by breath testing (N = 319 methane producers and N = 958 methane non-producers). Pooling all studies, a significant association was found between methane on breath test and constipation (OR = 3.51, CI = 2.00-6.16). Among adults only, methane was significantly associated with constipation (OR = 3.47, CI = 1.84-6.54). Similar results were seen when only examining subjects with IBS (OR = 3.60, CI = 1.61-8.06). The systematic review identified eight additional papers which all demonstrated an association between methane and delayed transit.

CONCLUSIONS

We demonstrate that methane present on breath testing is significantly associated with constipation in both IBS and functional constipation. These results suggest there may be merit in using breath testing in constipation. Moreover, methane may be used to identify candidates for antibiotic treatment of constipation.

Carbohydrate intolerance in patients with self-reported food hypersensitivity: comparison of lactulose and glucose

OBJECTIVE

Malabsorption of low-digestible carbohydrates is physiological, but poorly tolerated in some patients. We investigated symptom anticipation and microbial fermentation as possible mechanisms of carbohydrate intolerance in patients with self-reported food hypersensitivity.

MATERIAL AND METHODS

In a randomized, double-blind, cross-over study, 27 consecutive patients with unexplained, self-reported food hypersensitivity were given 10 g lactulose and 10 g glucose (placebo). Symptoms and pulmonary excretion of hydrogen and methane were assessed. Short-chain fatty acids (SCFAs), lactate and prostaglandin E(2) (PGE(2)) were analyzed in rectal dialysis fluid, and compared to dialysates from nine healthy volunteers.

RESULTS

Post-lactulose symptom scores were correlated with habitual symptom scores (r = 0.6, p = 0.001), significantly higher than post-glucose symptom scores (p = 0.01) and significantly higher in patients than controls (p = 0.0007). Levels of SCFAs, lactate and PGE(2) in rectal dialysates were not significantly different after lactulose and glucose, or between patients and controls. Hydrogen excretion was not correlated with symptom scores.

CONCLUSIONS

The findings suggest that self-reported food hypersensitivity is related to microbial fermentation of malabsorbed carbohydrates and not to symptom anticipation solely. Levels of SCFAs, lactate and PGE(2) in rectal dialysates could not explain the fermentation-associated hypersensitivity.

Constipation is relieved more by rye bread than wheat bread or laxatives without increased adverse gastrointestinal effects

Rye bread and lactobacilli modify the colonic environment and have the potential to relieve constipation and could be a safe and convenient alternative to laxatives. The effects of rye bread and cultured buttermilk with Lactobacillus rhamnosus GG (LGG) on bowel function and colon metabolism were investigated and compared with laxatives in 51 constipated adults. They were randomized to receive whole-grain rye bread (minimum 240 g/d), LGG (2 x 10(10) colony-forming units/d), whole-grain rye bread (minimum 240 g/d) + LGG (2 x 10(10) colony-forming units/d), white wheat bread (maximum 192 g/d), or laxatives (as usual for a participant) for 3 wk. Participants recorded their dietary habits, bowel function, and gastrointestinal symptoms. Fecal weight, pH, SCFA and bacterial enzyme activities, total intestinal transit time (TITT), and breath hydrogen were determined. Rye bread, compared with white wheat bread, shortened TITT by 23% (P = 0.040), increased weekly defecations by 1.4 (P = 0.014), softened feces [odds ratio (OR) 3.98; P = 0.037], eased defecation (OR 5.08; P = 0.018), increased fecal acetic acid and butyric acid contents by 24% (P = 0.044) and 63% (P <0.001), respectively, and reduced fecal beta-glucuronidase activity by 23% (P = 0.014). Compared with laxatives, rye bread reduced TITT by 41% (P = 0.006), fecal beta-glucuronidase activity by 38% (P = 0.033), and fecal pH by 0.31 units (P = 0.006). LGG did not relieve constipation or significantly affect colonic metabolism. Gastrointestinal adverse effects did not significantly differ among the study groups. In conclusion, rye bread relieves mild constipation and improves colonic metabolism compared with white wheat bread and commonly used laxatives without increasing gastrointestinal adverse effects.

Antibiotic or bacterial therapy in post-giardiasis irritable bowel syndrome

OBJECTIVE. Intestinal infection with Giardia lamblia may lead to therapy-resistant, long-lasting post-giardiasis irritable bowel syndrome (IBS). We report two open pilot studies aiming to treat this condition, using either antibiotics or bacterio-therapy. MATERIAL AND METHODS. Twenty-eight patients with persistent abdominal symptoms, following clearance of G. lamblia infection, were investigated. Eighteen received treatment with rifaximin plus metronidazole (8-10 days) whereas 10 received a suspension of live faecal flora, installed into the duodenum during gastro-duodenoscopy. Customary abdominal symptoms and symptoms following a lactulose breath test were quantified by questionnaires. Hydrogen and methane production after lactulose were analysed in expired air and excretion of fat and short-chain fatty acids (SCFAs) was examined in faeces. RESULTS. As compared with pre-treatment values, total customary symptom scores were barely significantly reduced (p = 0.07) after antibiotics, but were highly significantly reduced (p = 0.0009) after bacterio-therapy. However, symptom improvement following bacterio-therapy did not persist 1 year later. Hydrogen breath excretion was slightly reduced after antibiotics, but not after bacterio-therapy. Compared with healthy persons, faecal excretion of fat was significantly increased in Giardia-cured patients. SCFAs were increased in the bacterio-therapy group, and were not influenced by therapy. CONCLUSIONS. Both antibiotics and bacterio-therapy were ineffective with respect to cure of post-giardiasis IBS. High faecal excretion of fat and SCFAs suggests that intestinal malabsorption of fat and carbohydrates may play a role in the IBS-like complaints of these patients.

Plasma glucagon-like peptide 1 and peptide YY levels are not altered in symptomatic fructose-sorbitol malabsorption

OBJECTIVE

Carbohydrate malabsorption causes more symptoms in patients with functional gastrointestinal disorders than in healthy individuals. The purpose of this study was to investigate whether this could be explained by differences in ileal brake hormone secretion.

MATERIAL AND METHODS

Eighteen consecutive patients with functional abdominal complaints, referred to our clinic for investigation of self-reported food hypersensitivity, were included in the study and compared with 15 healthy volunteers. All subjects ingested a mixture of 25 g fructose and 5 g sorbitol. Pulmonary hydrogen and methane excretion and plasma glucagon-like peptide 1 (GLP-1) and peptide YY (PYY) levels were measured during the next 3 h. Both habitual and post-test symptoms were assessed.

RESULTS

Malabsorption of fructose and sorbitol was present in 61% of the patients and 73% of the controls. Nevertheless, the patients experienced significantly more symptoms following carbohydrate challenge, and 78% of the patients claimed that the challenge replicated their habitual gastrointestinal complaints. No significant differences in gas excretion or GLP-1 and PYY levels were found between patients and controls or between symptomatic and asymptomatic carbohydrate malabsorbers. A weak correlation between hydrogen excretion and PYY levels was demonstrated in non-producers of methane.

CONCLUSIONS

Neither intestinal gas production nor ileal brake hormone secretion seems to play a role in the symptomatology of carbohydrate intolerance in patients with self-reported food hypersensitivity. Other mechanisms related to bacterial fermentation may be involved and should be investigated further.

Breath Hydrogen Gas Concentration Linked to Intestinal Gas Distribution and Malabsorption in Patients with Small-bowel Pseudo-obstruction

BACKGROUND

The patient with colonic obstruction may frequently have bacterial overgrowth and increased breath hydrogen (H2) levels because the bacterium can contact with food residues for longer time. We experienced two cases with intestinal obstruction whose breath H2 concentrations were measured continuously. CASE 1: A 70-year-old woman with small bowel obstruction was treated with a gastric tube. When small bowel gas decreased and colonic gas was demonstrated on the plain abdominal radiograph, the breath H2 concentration increased to 6 ppm and reduced again shortly. CASE 2: A 41-year-old man with functional small bowel obstruction after surgical treatment was treated with intravenous administration of erythromycin. Although the plain abdominal radiograph demonstrated a decrease of small-bowel gas, the breath H2 gas kept the low level. After a clear-liquid meal was supplied, fasting breath H2 concentration increased rapidly to 22 ppm and gradually decreased to 9 ppm despite the fact that the intestinal gas was unchanged on X-ray. A rapid increase of breath H2 concentration may reflect the movement of small bowel contents to the colon in patients with small-bowel pseudo-obstruction or malabsorption following diet progression.

CONCLUSIONS

Change in breath H2 concentration had a close association with distribution and movement of intestinal gas.

Effects of Seal Oil on Meal-Induced Symptoms and Gastric Accommodation in Patients with Subjective Food Hypersensitivity: A Pilot Study

Background

Food hypersensitivity is a prevalent condition with poorly characterized underlying mechanisms. In the present pilot study we investigated effects of seal oil and soy oil on meal-induced symptoms and gastric accommodation in patients with subjective food hypersensitivity (FH). Single dose experiment: On three consecutive days, 10 mL of seal oil, soy oil, or saline were randomly administered into the duodenum of 10 patients with subjective FH and 10 healthy volunteers through a nasoduodenal feeding tube 10-20 minutes before the ingestion of a test meal. Short-term treatment study: 24 patients with subjective FH were randomly allocated to 10 days’ treatment with either 10 mL of seal or soy oil, self-administrated through an indwelling nasoduodenal feeding tube, 3 times daily. In both experiments meal-induced abdominal symptoms and gastric accommodation were measured by visual analogue scales and external ultrasound respectively.

Results

Symptoms and gastric accommodation were not significantly influenced by single doses of seal or soy oil. When given daily for 10 days, seal oil, but not soy oil, reduced total symptom scores significantly ( P = 0.03). The symptomatic improvement was not associated with improvements in gastric accommodation.

Conclusion

Daily administration of seal oil may benefit patients with subjective FH. The beneficial effect of seal oil in patients with subjective FH can not be ascribed to improved gastric accommodation.

Lactulose breath test results in patients with persistent abdominal symptoms following Giardia lamblia infection

OBJECTIVE

Bacterial overgrowth has been implicated in the pathogenesis of irritable bowel syndrome (IBS). The objective of this study was to investigate whether post-infectious IBS following Giardia lamblia infection is related to intestinal bacterial overgrowth, as diagnosed by the lactulose breath test (LBT).

MATERIAL AND METHODS

Seventy-seven patients with persistent gastrointestinal complaints related to a recent outbreak of G. lamblia infection were included in the study. Despite one or several courses of treatment with metronidazole during the previous months, 23 of the patients were still stool positive for G. lamblia, whereas the remaining 54 patients had cleared the infection. All patients and 42 healthy volunteers underwent a LBT with 10 g lactulose, and their customary and post-LBT abdominal symptoms were scored.

RESULTS

Ninety-five percent of the patients had IBS. Lactulose-induced hydrogen breath excretion was not significantly different in patients and controls. Customary and post-LBT symptoms were abnormally high in the patients, irrespective of both G. lamblia infection status and LBT results. Furthermore, lactulose challenge replicated the patients' customary complaints in 70% of the patients.

CONCLUSIONS

Gastrointestinal complaints in patients with persistent or cleared giardiasis were unrelated to hydrogen breath excretion after lactulose challenge. Post-giardiasis IBS cannot be ascribed to intestinal bacterial overgrowth, as diagnosed by LBT.