[Clinically relevant breath tests in gastroenterological diagnostics--recommendations of the German Society for Neurogastroenterology and Motility as well as the German Society for Digestive and Metabolic Diseases]

Small Intestinal Bacterial Overgrowths and Intestinal Methanogen Overgrowths Breath Testing in a Real-Life French Cohort

INTRODUCTION

Breath testing has become a widely used tool to diagnose small intestinal bacterial overgrowths (SIBOs) and intestinal methanogen overgrowths (IMOs) in clinical settings. Owing to the heterogeneity in clinical manifestations and lack of standardization among centers performing breath testing, SIBO and IMO can be easily overlooked by the clinician. We studied the prevalence and symptoms of SIBO/IMO in French patients referred for breath testing after seeking medical advice.

METHODS

Breath test data and symptoms of 331 patients were assessed for SIBO/IMO using the H 2 /CH 4 lactulose breath test (LBT). Wilcoxon test or χ 2 test were used to compare patients with SIBO/IMO with patients without SIBO/IMO. LBT positive patients (H 2 +, CH 4 +, and CH 4 +/H 2 +) were compared using Kruskal-Wallis test for continuous data or χ 2 test for categorical data.

RESULTS

Among the 186 (68.1%) patients tested positive for an overgrowth with 40.3%, 47.3%, and 12.4% for H 2 +, CH 4 + and CH 4 +/H 2 +, respectively, the presence of diarrhea was significantly increased in hydrogen type overgrowths ( P < 0.001). No significant difference according to age, gender, and symptoms was associated with a positive test except for joint pain that was less prevalent among LBT positive patients ( P = 0.038). In 86.5% of IMOs, positivity with CH 4 values ≥10 ppm could be identified at baseline.

DISCUSSION

There are little discriminating symptoms that can help the clinician to identify patients likely to have a SIBO/IMO. However, SIBO/IMOs remain a common disorder widely underdiagnosed that need further studies to better apprehend functional bowel disorders.

Carbohydrate malabsorption in anorexia nervosa: a systematic review

OBJECTIVES

Anorexia nervosa (AN) is an eating disorder accompanied by a low body mass index and (self-) restricted food intake. Nutritional limitations can cause complaints of the digestive system, because of a disturbed absorption of food components. The absorption of carbohydrates may be seriously affected and reduced to a minimum. On this basis, a possible connection between AN, and the prevalence of gastrointestinal symptoms due to malabsorption was examined.

METHODS

For the systematic literature research with the aim of a better understanding of the topic the databases PubMed, Web of Science, Cochrane Library, Livivo and Google Scholar were used.

RESULTS

After the manual selection process of 2215 retrieved studies, 89 full texts were read and according to the predetermined eligibility criteria, finally 2 studies on the monosaccharide fructose and disaccharide lactose were included in this review.

CONCLUSION

Malabsorption is often observed in patients with AN. It may contribute to the gastrointestinal complaints reported by patients and hamper body weight regain. Among others, mucosal atrophy and duodenal transporter dysfunction are discussed as main reasons. In the future more studies on carbohydrate malabsorption related to low body weight as observed in AN are warranted and may be conducted rather in an outpatient setting.

European guideline on indications, performance, and clinical impact of hydrogen and methane breath tests in adult and pediatric patients: European Association for Gastroenterology, Endoscopy and Nutrition, European Society of Neurogastroenterology and Motility, and European Society for Paediatric Gastroenterology Hepatology and Nutrition consensus

INTRODUCTION

Measurement of breath hydrogen (H2 ) and methane (CH4 ) excretion after ingestion of test-carbohydrates is used for different diagnostic purposes. There is a lack of standardization among centers performing these tests and this, together with recent technical developments and evidence from clinical studies, highlight the need for a European guideline.

METHODS

This consensus-based clinical practice guideline defines the clinical indications, performance, and interpretation of H2 -CH4 -breath tests in adult and pediatric patients. A balance between scientific evidence and clinical experience was achieved by a Delphi consensus that involved 44 experts from 18 European countries. Eighty eight statements and recommendations were drafted based on a review of the literature. Consensus (≥80% agreement) was reached for 82. Quality of evidence was evaluated using validated criteria.

RESULTS

The guideline incorporates new insights into the role of symptom assessment to diagnose carbohydrate (e.g., lactose) intolerances and recommends that breath tests for carbohydrate malabsorption require additional validated concurrent symptom evaluation to establish carbohydrate intolerance. Regarding the use of breath tests for the evaluation of oro-cecal transit time and suspected small bowel bacterial overgrowth, this guideline highlights confounding factors associated with the interpretation of H2 -CH4 -breath tests in these indications and recommends approaches to mitigate these issues.

CONCLUSION

This clinical practice guideline should facilitate pan-European harmonization of diagnostic approaches to symptoms and disorders, which are very common in specialist and primary care gastroenterology practice, both in adult and pediatric patients. In addition, it identifies areas of future research needs to clarify diagnostic and therapeutic approaches.

Case report: Carbohydrate malabsorption in inpatients with anorexia nervosa

BACKGROUND

Gastrointestinal (GI) complaints are frequently observed in patients who suffer from anorexia nervosa (AN). These symptoms may hamper treatment and weight regain and are often perceived as the cause, not the consequence, of the disease. Since carbohydrate malabsorption also produces these symptoms, this might underly or contribute to these complaints. So far, the role of carbohydrate malabsorption (fructose malabsorption and lactose intolerance) in AN has not yet been investigated.

METHODS

For this case series, inpatients with AN of restrictive type (n = 3), purging type (n = 3), and atypical AN (n = 1) conducted hydrogen breath tests with 25 g of fructose and 50 g of lactose to investigate carbohydrate malabsorption. Results were then analyzed in association with body mass index (BMI) and patient-reported outcomes (disordered eating, body image disturbances, anxiety, depressive symptoms, perceived stress, and GI complaints).

RESULTS

Based on the hydrogen breath test results, three of the seven female patients were classified as lactose intolerant and one presented fructose malabsorption. Both hydrogen curves for fructose (r = -0.632, p < 0.001) and lactose (r = -0.704, p < 0.001) showed a negative correlation with BMI. No association was observed between hydrogen values and patient-reported outcomes.

CONCLUSION

In patients with AN, GI symptoms caused by intolerance of common monosaccharides and disaccharides may be an underestimated burden and should be considered in the diagnosis and therapy of patients with AN. Due to the observed correlation with BMI, GI complaints after ingestion of fructose or lactose likely develop with decreasing body weight and are potentially reversible with weight regain.

European guideline on indications, performance and clinical impact of 13 C-breath tests in adult and pediatric patients: An EAGEN, ESNM, and ESPGHAN consensus, supported by EPC

Introduction

¹³C‐breath tests are valuable, noninvasive diagnostic tests that can be widely applied for the assessment of gastroenterological symptoms and diseases. Currently, the potential of these tests is compromised by a lack of standardization regarding performance and interpretation among expert centers.

Methods

This consensus‐based clinical practice guideline defines the clinical indications, performance, and interpretation of ¹³C‐breath tests in adult and pediatric patients. A balance between scientific evidence and clinical experience was achieved by a Delphi consensus that involved 43 experts from 18 European countries. Consensus on individual statements and recommendations was established if ≥ 80% of reviewers agreed and <10% disagreed.

Results

The guideline gives an overview over general methodology of ¹³C‐breath testing and provides recommendations for the use of ¹³C‐breath tests to diagnose Helicobacter pylori infection, measure gastric emptying time, and monitor pancreatic exocrine and liver function in adult and pediatric patients. Other potential applications of ¹³C‐breath testing are summarized briefly. The recommendations specifically detail when and how individual ¹³C‐breath tests should be performed including examples for well‐established test protocols, patient preparation, and reporting of test results.

Conclusion

This clinical practice guideline should improve pan‐European harmonization of diagnostic approaches to symptoms and disorders, which are very common in specialist and primary care gastroenterology practice, both in adult and pediatric patients. In addition, this guideline identifies areas of future clinical research involving the use of ¹³C‐breath tests.

Methane breath tests and blood sugar tests in children with suspected carbohydrate malabsorption

Carbohydrate malabsorption and subsequent gastrointestinal symptoms are a common clinical problem in pediatrics. Hydrogen (H₂) and methane (CH₄) breath tests are a cheap and non-invasive procedure for diagnosing fructose and lactose malabsorption (FM/LM) but test accuracy and reliability as well as the impact of non-hydrogen producers (NHP) is unclear. CH₄ breath tests (MBT), blood sugar tests (BST) and clinical symptoms were compared with H₂ breath tests (HBT) for FM/LM. 187/82 tests were performed in children (2 to 18 years) with unclear chronic/recurrent abdominal pain and suspected FM/LM. In FM and LM, we found a significant correlation between HBT and MBT/BST. In LM, MBT differentiated most of the patients correctly and BST might be used as an exclusion test. However, additional MBT and BST had no diagnostic advantage in FM. NHP still remain a group of patients, which cannot be identified using the recommended CH₄ cut-off values in FM or LM. Reported symptoms during breath tests are not a reliable method to diagnose FM/LM. Overall a combined test approach might help in diagnosing children with suspected carbohydrate malabsorption.

Small Intestinal Bacterial Overgrowth: Clinical Features and Therapeutic Management

Small intestinal bacterial overgrowth (SIBO) is a common, yet underrecognized, problem. Its prevalence is unknown because SIBO requires diagnostic testing. Although abdominal bloating, gas, distension, and diarrhea are common symptoms, they do not predict positive diagnosis. Predisposing factors include proton-pump inhibitors, opioids, gastric bypass, colectomy, and dysmotility. Small bowel aspirate/culture with growth of 10-10 cfu/mL is generally accepted as the "best diagnostic method," but it is invasive. Glucose or lactulose breath testing is noninvasive but an indirect method that requires further standardization and validation for SIBO. Treatment, usually with antibiotics, aims to provide symptom relief through eradication of bacteria in the small intestine. Limited numbers of controlled studies have shown systemic antibiotics (norfloxacin and metronidazole) to be efficacious. However, 15 studies have shown rifaximin, a nonsystemic antibiotic, to be effective against SIBO and well tolerated. Through improved awareness and scientific rigor, the SIBO landscape is poised for transformation.

Development of a Multinational Clinical Practice Guideline: A Practical Structured Procedure

INTRODUCTION

The development of a clinical guideline is a challenging process. National and international organizations have established a variety of approaches, grading systems, evaluation scales, and voting modes; however, a practical description which illustrates all steps from starting the initiative to publication and dissemination of the guideline is usually not provided. We describe a structured guideline procedure that can be adjusted to the requirements of other multinational guidelines.

METHODS

A group of European specialist gastroenterological societies and national societies initiated a guideline for the use of breath tests in gastroenterology. A balance between scientific evidence and clinical experience was achieved by involving European specialist societies and physicians from 18 European countries. For persons contributing to the guideline process, different levels of involvement were defined. The tasks were assigned to different groups of persons, which formed scientific institutions.

RESULTS

We describe organizational structures and institutions, the stepwise approach, and illustrate the multistep guideline development procedure in a flowchart diagram that shows workflow and assigned responsibilities and provides details for the execution of each step, including timelines. The process is split into 4 phases: foundation, preparation, voting, and publication.

DISCUSSION

This structured procedure of a gastroenterological clinical practice guideline can serve as a blueprint for future multinational guideline initiatives and may aid future attempts to standardize and harmonize guideline development processes in gastroenterology and in other medical fields. Although the described procedure is for a diagnostic guideline, it may also be appropriate for therapeutic guidelines by adjusting the acceptance criteria for recommendations.

Hydrogen and Methane-Based Breath Testing in Gastrointestinal Disorders: The North American Consensus

OBJECTIVES

Breath tests (BTs) are important for the diagnosis of carbohydrate maldigestion syndromes and small intestinal bacterial overgrowth (SIBO). However, standardization is lacking regarding indications for testing, test methodology and interpretation of results. A consensus meeting of experts was convened to develop guidelines for clinicians and research.

METHODS

Pre-meeting survey questions encompassing five domains; indications, preparation, performance, interpretation of results, and knowledge gaps, were sent to 17 clinician-scientists, and 10 attended a live meeting. Using an evidence-based approach, 28 statements were finalized and voted on anonymously by a working group of specialists.

RESULTS

Consensus was reached on 26 statements encompassing all five domains. Consensus doses for lactulose, glucose, fructose and lactose BT were 10, 75, 25 and 25 g, respectively. Glucose and lactulose BTs remain the least invasive alternatives to diagnose SIBO. BT is useful in the diagnosis of carbohydrate maldigestion, methane-associated constipation, and evaluation of bloating/gas but not in the assessment of oro-cecal transit. A rise in hydrogen of ≥20 p.p.m. by 90 min during glucose or lactulose BT for SIBO was considered positive. Methane levels ≥10 p.p.m. was considered methane-positive. SIBO should be excluded prior to BT for carbohydrate malabsorption to avoid false positives. A rise in hydrogen of ≥20 p.p.m. from baseline during BT was considered positive for maldigestion.

CONCLUSIONS

BT is a useful, inexpensive, simple and safe diagnostic test in the evaluation of common gastroenterology problems. These consensus statements should help to standardize the indications, preparation, performance and interpretation of BT in clinical practice and research.

No differential effect of beverages sweetened with fructose, high-fructose corn syrup, or glucose on systemic or adipose tissue inflammation in normal-weight to obese adults: a randomized controlled trial

BACKGROUND

Sugar-sweetened beverage (SSB) consumption and low-grade chronic inflammation are both independently associated with type 2 diabetes and cardiovascular disease. Fructose, a major component of SSBs, may acutely trigger inflammation, which may be one link between SSB consumption and cardiometabolic disease.

OBJECTIVE

We sought to determine whether beverages sweetened with fructose, high-fructose corn syrup (HFCS), and glucose differentially influence systemic inflammation [fasting plasma C-reactive protein and interleukin-6 (IL-6) as primary endpoints] acutely and before major changes in body weight. Secondary endpoints included adipose tissue inflammation, intestinal permeability, and plasma fetuin-A as potential mechanistic links between fructose intake and low-grade inflammation.

DESIGN

We conducted a randomized, controlled, double-blind, crossover design dietary intervention (the Diet and Systemic Inflammation Study) in 24 normal-weight to obese adults without fructose malabsorption. Participants drank 4 servings/d of fructose-, glucose-, or HFCS-sweetened beverages accounting for 25% of estimated calorie requirements while consuming a standardized diet ad libitum for three 8-d periods.

RESULTS

Subjects consumed 116% of their estimated calorie requirement while drinking the beverages with no difference in total energy intake or body weight between groups as reported previously. Fasting plasma concentrations of C-reactive protein and IL-6 did not differ significantly at the end of the 3 diet periods. We did not detect a consistent differential effect of the diets on measures of adipose tissue inflammation except for adiponectin gene expression in adipose tissue (P = 0.005), which was lowest after the glucose phase. We also did not detect consistent evidence of a differential impact of these sugars on measures of intestinal permeability (lactulose:mannitol test, plasma zonulin, and plasma lipopolysaccharide-binding protein).

CONCLUSION

Excessive amounts of fructose, HFCS, and glucose from SSBs consumed over 8 d did not differentially affect low-grade chronic systemic inflammation in normal-weight to obese adults. This trial was registered at clinicaltrials.gov as NCT01424306.

No difference in ad libitum energy intake in healthy men and women consuming beverages sweetened with fructose, glucose, or high-fructose corn syrup: a randomized trial

BACKGROUND

Increased energy intake is consistently observed in individuals consuming sugar-sweetened beverages (SSBs), likely mainly because of an inadequate satiety response to liquid calories. However, SSBs have a high content of fructose, the consumption of which acutely fails to trigger responses in key signals involved in energy homeostasis. It is unclear whether the fructose content of SSBs contributes to the increased energy intake in individuals drinking SSBs.

OBJECTIVE

We investigated whether the relative amounts of fructose and glucose in SSBs modifies ad libitum energy intake over 8 d in healthy adults without fructose malabsorption.

DESIGN

We conducted 2 randomized, controlled, double-blind crossover studies to compare the effects of consuming 4 servings/d of a fructose-, glucose-, or aspartame-sweetened beverage (study A; n = 9) or a fructose-, glucose-, or high-fructose corn syrup (HFCS)-sweetened beverage (study B; n = 24) for 8 d on overall energy intake. SSBs were provided at 25% of estimated energy requirement, or an equivalent volume of the aspartame-sweetened beverage, and consumption was mandatory. All solid foods were provided at 125% of estimated energy requirements and were consumed ad libitum.

RESULTS

In study A, ad libitum energy intake was 120% ± 10%, 117% ± 12%, and 102% ± 15% of estimated energy requirements when subjects consumed the fructose-, glucose-, and aspartame-sweetened beverages. Energy intake was significantly higher in the fructose and glucose phases than in the aspartame phase (P < 0.003 for each), with no difference between the fructose and glucose phases (P = 0.462). In study B, total energy intake during the fructose, HFCS, and glucose phases was 116% ± 14%, 116% ± 16%, and 116% ± 16% of the subject's estimated total energy requirements (P = 0.880).

CONCLUSIONS

In healthy adults, total 8-d ad libitum energy intake was increased in individuals consuming SSBs compared with aspartame-sweetened beverages. The energy overconsumption observed in individuals consuming SSBs occurred independently of the relative amounts of fructose and glucose in the beverages. These trials were registered at clinicaltrials.gov as NCT00475475 and NCT01424306.

Starch Origin and Thermal Processing Affect Starch Digestion in a Minipig Model of Pancreatic Exocrine Insufficiency

Although steatorrhea is the most obvious symptom of pancreatic exocrine insufficiency (PEI), enzymatic digestion of protein and starch is also impaired. Low praecaecal digestibility of starch causes a forced microbial fermentation accounting for energy losses and meteorism. To optimise dietetic measures, knowledge of praecaecal digestibility of starch is needed but such information from PEI patients is rare. Minipigs fitted with an ileocaecal fistula with (n = 3) or without (n = 3) pancreatic duct ligation (PL) were used to estimate the rate of praecaecal disappearance (pcD) of starch. Different botanical sources of starch (rice, amaranth, potato, and pea) were fed either raw or cooked. In the controls (C), there was an almost complete pcD (>92%) except for potato starch (61.5%) which was significantly lower. In PL pcD of raw starch was significantly lower for all sources of starch except for amaranth (87.9%). Thermal processing increased pcD in PL, reaching values of C for starch from rice, potato, and pea. This study clearly underlines the need for precise specification of starch used for patients with specific dietetic needs like PEI. Data should be generated in suitable animal models or patients as tests in healthy individuals would not have given similar conclusions.

[Motility disorders of the small intestine]

Chronic intestinal pseudo-obstruction (CIPO) is the most severe form of intestinal motility disorder, which leads to chronic or intermittent symptoms and signs of (sub-)ileus despite the absence of an intestinal obstruction. Small bowel motility disturbances may occur as primary diseases or secondary to a large number of other diseases and disturbances including rheumatological diseases and neurotoxic drugs. Pathological alterations affect the nervous system, smooth muscles, and/or mesenchymal structures such as the interstitial cells of Cajal or glia cells. Clinical symptoms are unspecific so that the initially suspected diagnosis is almost always wrong. Thus, extensive and stepwise diagnostic procedures are required involving specialized centers in order to exclude intestinal obstruction, to search for complications and potential causes of the disease, to quantify the extension and severity of the motility disorder, and to clarify the pathomechanism if possible. General therapeutic goals include maintenance of adequate nutritional status, improvement of propulsive motility, amelioration of abdominal symptoms, and avoidance and/or therapy of complications. Some CIPO patients require permanent parenteral nutrition. If this causes intolerable complications, small bowel transplantation can be considered in suitable patients as ultima ratio.

The malabsorption of commonly occurring mono and disaccharides: levels of investigation and differential diagnoses

BACKGROUND

Adverse food reactions (AFR) have has recently attracted increased attention from the media and are now more commonly reported by patients. Its classification, diagnostic evaluation, and treatment are complex and present a considerable challenge in clinical practice. Non-immune-mediated types of food intolerance have a cumulative prevalence of 30% to 40%, while true (immune-mediated) food allergies affect only 2% to 5% of the German population.

METHOD

We selectively searched the literature for pertinent publications on carbohydrate malabsorption, with special attention to published guidelines and position papers.

RESULTS

Carbohydrate intolerance can be the result of a rare, systemic metabolic defect (e.g., fructose intolerance, with a prevalence of 1 in 25,000 persons) or of gastrointestinal carbohydrate malabsorption. The malabsorption of simple carbohydrates is the most common type of non-immune-mediated food intolerance, affecting 20% to 30% of the European population. This condition is caused either by deficient digestion of lactose or by malabsorption of fructose and/or sorbitol. Half of all cases of gastrointestinal carbohydrate intolerance have nonspecific manifestations, with a differential diagnosis including irritable bowel syndrome, intolerance reactions, chronic infections, bacterial overgrowth, drug side effects, and other diseases. The diagnostic evaluation includes a nutritional history, an H2 breath test, ultrasonography, endoscopy, and stool culture.

CONCLUSION

The goals of treatment for carbohydrate malabsorption are to eliminate the intake of the responsible carbohydrate substance or reduce it to a tolerable amount and to assure the physiological nutritional composition of the patient's diet. In parallel with these goals, the patient should receive extensive information about the condition, and any underlying disease should be adequately treated.

Simultaneous non-invasive measurement of liquid gastric emptying and small bowel transit by combined 13C-acetate and H2-lactulose breath test

The 13C-acetate breath test (13C-ABT) allows noninasive measurement of liquid gastric emptying time (LGET), the H2-lactulose breath (H2-LBT) measures orocecal transit time (OCTT). Because of different test principles, both tests can generally be combined. This would not only spare time and resources but may also deliver additional information on the integrated regulation of gastrointestinal motor functions. Our aim was to define an adequate test protocol and to generate normal values for the combined 13C-ABT/H2-LBT. Twenty two healthy volunteers participated (HV, 12 females, age: 26.5  ±  4.7 years, BMI: 22  ±  2.1 kgm(-2). Fasting subjects received 200 ml of an aequous solution containing 150 mg 13C-acetate and 10 g lactulose. Breath samples for H2 measurements were collected before ingestion of the test solution and afterwards at 5 min intervals for 180 min, for 13C measurements sampling intervals were prolonged to 15 min after the first hour. LGET was defined as time of maximal 13C-exhalation, OCTT as increase in H2 of ⩾ 20 ppm above basal. Small bowel transit time (SBTT) was calculated as the difference between OCTT and LGET. Mean [95% CI] values for LGET, OCTT and SBTT were 26 [23-30] min, 85 [68-102] min and 60 [44-76] min, respectively. Normal values for LGET and OCTT corresponded with published data. SBTT was not correlated with LGET (R2 = 0.019; p = 0.546). By contrast, there was a very tight and highly significant correlation between SBTT and OCTT (R2 = 0.933; p < 0.001). Multivariate linear regression analyses confirmed that age, sex and BMI had no significant effects on OCTT or SBTT while LGET was weakly correlated with BMI (R2 = 0.240; p = 0.021). In conclusion, the combined 13C-ABT/H2-LBT allows simultaneous measurement of LGET and OCTT as well as calculation of SBTT.

Unclear abdominal discomfort: pivotal role of carbohydrate malabsorption

Background/Aims

Carbohydrate malabsorption is frequent in patients with functional gastrointestinal disorders and in healthy volunteers and can cause gastrointestinal symptoms mimicking irritable bowel syndrome (IBS). The aim of this study was to investigate the prevalence of symptomatic lactose and fructose malabsorption in a large population of patients with IBS-like symptoms based on Rome II criteria.

Methods

Patients with unclear abdominal discomfort (n = 2,390) underwent lactose (50 g) and fructose (50 g) hydrogen (H₂) breath tests and depending on the results further testing with 25 g fructose or 50 g glucose, or upper endoscopy with duodenal biopsies. Additionally, this population was investigated regarding the prevalence of small intestinal bacterial overgrowth (SIBO) based on glucose breath test and celiac disease.

Results

Of the 2,390 patients with IBS-like symptoms, 848 (35%) were symptomatic lactose malabsorbers and 1,531 (64%) symptomatic fructose malabsorbers. A combined symptomatic carbohydrate malabsorption was found in 587 (25%) patients. Severe fructose malabsorbers (pathologic 25 g fructose test) exhaled significantly higher H₂ concentrations in the 50 g test than patients with negative 25 g fructose test (P < 0.001). Out of 460/659 patients with early significant H₂ increase in the lactose and fructose test who underwent a glucose breath test, 88 patients had positive results indicative of SIBO and they were significantly older than patients with negative test result (P < 0.01). Celiac disease was found in 1/161 patients by upper endoscopy.

Conclusions

Carbohydrate malabsorption is a frequent but underestimated condition in patients with IBS-like symptoms although diagnosis can be easily confirmed by H₂ breath testing.

[Functional gastrointestinal diseases]

Functional dyspepsia (FD) and irritable bowel syndrome (IBS) are the most important functional gastrointestinal diseases (FGID), and both affect about 5-15 % of the German population. The patients' symptoms are caused by disturbances of gastrointestinal (GI) motility, secretion and sensitivity. Central processing of visceral afferences is disturbed, and the course of the disease and individual symptom perception are influenced by psychosocial factors. Diagnosis of FD and IBS is based on a compatible symptom pattern, absence of alarm symptoms and exclusion of relevant differential diagnoses. The diagnosis of FD requires a normal upper GI endoscopy. Current German guidelines also demand a normal colonoscopy for diagnosis of IBS. Basic therapeutic measures include explanation of the nature of the disease and its harmlessness quo ad vitam . Individual trigger factors should be identified and eliminated if possible. Drug therapy of persisting complaints is guided by the dominant symptom.

A modified ¹³C-mixed triglyceride breath test detects moderate pancreatic exocrine insufficiency

OBJECTIVES

The noninvasive ¹³C-mixed triglyceride breath test (¹³C-MTG-T) has been shown to diagnose severe pancreatic exocrine insufficiency reliably. We hypothesized that sensitivity of the test could be increased by strict limitation of physical activity, correction for gastric emptying velocity, and/or increased lipid dose.

METHODS

In 10 healthy volunteers and 9 patients with suspected pancreatic disease, a secretin test, a modified ¹³C-MTG-T (250 mg ¹³C-MTG, 26 g fat, breath samples over 8 hours), and a ¹³C-octanoic acid gastric emptying test were performed. Subjects remained strictly seated during breath testing.

RESULTS

Intravenously administered secretin 1 U/kg·h stimulated outputs of all enzymes significantly. Mean basal and stimulated enzyme outputs were similar in patients and healthy controls; however, compared with normal values, 5 patients and 1 control had moderately decreased lipase output. Cumulative 4-, 6-, and 8-hour ¹³C exhalation was significantly lower in patients than in controls. Sensitivity of ¹³C-MTG-T (6-h cumulative ¹³C exhalation <27% of dose) for detection of decreased lipase output was 100%; specificity was 92%. Gastric emptying parameters were similar in patients and controls, and correction for these did not improve accuracy of ¹³C-MTG-T.

CONCLUSIONS

The modified ¹³C-MTG-T detects moderate pancreatic exocrine insufficiency.

No evidence of impaired gastric emptying in early Huntington's Disease

Background: Several factors, such as dysphagia, an increased motor activity, increased metabolic rate and a hypermetabolic state have been discussed as contributing to weight loss even at the early stages of Huntington’s Disease (HD). Aim of this pilot study was to investigate gastric emptying as a possible reason for weight loss in HD.

Methods: 11 HD participants at early stages of the disease and matched controls were investigated by using the well-established and non-invasive 13C-octanoate breath test. The “Gastroparesis Cardinal Symptom Index” and the “Short-Form Leeds Dyspepsia Questionnaire” were used for clinical evaluation of gastroparesis or dyspepsia.

Results: When compared to standard values ​​given in literature and controls all HD patients had normal breath test results. There was no evidence of gastroparesis or dyspepsia. There was a correlation of breath test results with the cognitive and functional performance of HD participants.

Conclusion: According to our data, there is no evidence of impaired gastric emptying in early HD. We can not exclude that gastric emptying contributes to weight loss at more advanced stages of the disease.

Application of the glucose hydrogen breath test for the detection of bacterial overgrowth in patients with cystic fibrosis--a reliable method?

Patients with cystic fibrosis (CF) have recently been deemed highly susceptible for bacterial intestinal overgrowth (BIO). We aimed to define the prevalence of BIO in children with CF by applying the H(2)-glucose breath test. Forty children with CF and ten healthy children received 1 g/kg D-glucose orally. Breath samples for H(2) content (ppm) were collected for 3 h. BIO was suspected if the breath hydrogen content increased by more than 20 ppm or if baseline concentrations topped 20 ppm. In 27 of 40 CF children (68%), breath hydrogen content exceeded 20 ppm. Whereas the breath hydrogen exhalation persisted above 20 ppm in almost all these children throughout the sampling period, none of the remaining children increased above this threshold. The high rate of CF children with elevated fasting hydrogen breath concentrations indicates that this phenomenon is less a sign of BIO rather than a consequence of global malabsorption and intestinal dysmotility.

Gliadin IgG antibodies and circulating immune complexes

OBJECTIVE

Circulating immune complexes (CICs) in blood are associated with autoimmune-diseases such as systemic lupus erythematosus, immune complex glomerulonephritis, rheumatoid arthritis and vasculitis. However, slightly increased serum concentrations of such CICs are sometimes also found in healthy individuals. The objective of the current study was to assess whether food antigens could play a role in the formation of CICs.

MATERIAL AND METHODS

A total of 352 (265 F, 87 M), so far, healthy individuals were tested for CICs containing C1q and immunoglobulin G (IgG) as well as for gliadin IgG antibodies using the ELISA technique. Additionally, fructose and lactose malabsorption was assessed using hydrogen breath tests.

RESULTS

In our study, 15.3% (54/352) of the patients presented with elevated CIC concentrations (above 50 microg/ml) and 6.5% (23/352) of the study population were positive for gliadin IgG antibodies (above 20 U/ml). CIC concentration levels were significantly higher in the group with elevated gliadin IgG antibodies (CIC median: 49.0 microg/ml) compared with the group with normal levels of gliadin IgG antibodies (CIC median: 30.0 microg/ml; Mann-Whitney U-test, U=1992; p <0.001). As expected, there was no difference in CIC concentrations (Mann-Whitney U-test, U=6106; p=0.783) and gliadin IgG (Mann-Whitney U-test, U=3761; p=0.411) between patients in the fructose or lactose malabsorber groups and the subjects without malabsorption.

CONCLUSIONS

The results of this study indicate that certain food antigens (e.g. gluten) could play a role in the formation of CICs. An association between CICs and fructose or lactose malabsorption seems to be improbable.

Methods and functions: Breath tests

Breath tests provide a valuable non-invasive diagnostic strategy to in vivo assess a variety of enzyme activities, organ functions or transport processes. Both the hydrogen breath tests and the (13)C-breath tests using the stable isotope (13)C as tracer are non-radioactive and safe, also in children and pregnancy. Hydrogen breath tests are widely used in clinical practice to explore gastrointestinal disorders. They are applied for diagnosing carbohydrate malassimilation, small intestinal bacterial overgrowth and for measuring the orocecal transit time. (13)C-breath tests non-invasively monitor the metabolisation of a (13)C-labelled substrate. Depending on the choice of the substrate they enable the assessment of gastric bacterial Helicobacter pylori infection, gastric emptying, liver and pancreatic function as well as measurements of many other enzyme activities. The knowledge of potential pitfalls and influencing factors are important for correct interpretation of breath test results before drawing clinical conclusions.

Intestinal and anorectal motility and functional disorders

Motility and functional disorders of the small intestine, the colon and the anorectum can induce or contribute to symptoms such as diarrhoea, constipation and abdominal pain and may impair nutrient absorption in severe cases. Acute affections of intestinal functions e.g. during gastrointestinal infections usually need no functional diagnostics but resolve spontaneously or with adequate therapy of the underlying disease. By contrast, chronic disturbances of small intestinal, colonic and anorectal motility and/or sensitivity are subject to gastrointestinal function tests. The role of these tests for diagnosis and therapeutic handling of severe intestinal dysmotility/chronic intestinal pseudo-obstruction, severe constipation, diarrhoea, fecal incontinence and irritable bowel syndrome will be discussed in this review that mainly focuses on adults.

Somatic comorbidities of irritable bowel syndrome: a systematic analysis

OBJECTIVE

A large number of irritable bowel syndrome (IBS) patients are additionally afflicted with other somatic intestinal and/or extraintestinal comorbidities. The occurrence of one or more comorbidities is correlated with enhanced medical help seeking, worse prognosis, and higher rates of anxiety and depression-all resulting in a reduced quality of life. The aims of this study were, firstly, to review the literature on comorbidities of IBS and to assess gastrointestinal and extraintestinal comorbidities, and, secondly, to evaluate explanatory hypotheses and possible common pathophysiological mechanisms.

METHODS

We systematically reviewed the scientific literature in the past 25 years, as cited in MEDLINE.

RESULTS

IBS patients present with a twofold increase in somatic comorbidities compared to controls, possibly caused by common pathophysiological mechanisms. Nevertheless, to date, there has been no convincing evidence for a consolidated underlying pathophysiology or somatization. Gastrointestinal disorders, such as functional dyspepsia, gastroesophageal reflux disease, functional constipation, and anal incontinence, occur in almost half of the patients. In a broad variety of extraintestinal comorbidities, fibromyalgia, chronic fatigue syndrome, and chronic pelvic pain are best documented and appear in up to 65%.

CONCLUSION

The knowledge and structured assessment of comorbid somatic symptoms might allow to identify subgroups of IBS patients with special characteristics and lead to adaptation of the therapeutic concept.

Efficacy of rifaximin, a nonabsorbed oral antibiotic, in the treatment of small intestinal bacterial overgrowth

INTRODUCTION

Rifamixin is an orally administrated, nonabsorbed antibiotic whose utility in eradication of small intestinal bacterial overgrowth (SIBO) is currently being evaluated.

PURPOSE

The aim of this study was to investigate efficacy and safety of rifaximin in relieving symptoms and normalizing the glucose breath test (GBT) in patients with SIBO.

METHODS

Symptom score assessment, consisting of frequency and severity of bloating, gas, abdominal pain, and bowel movements and the GBT were performed before and after treatment with rifaximin 800 mg/d for 4 weeks.

SUBJECTS

Twenty consecutive symptomatic patients (16 women and 4 men; mean age, 47.8 years; range, 19 to 85 years) who had a positive GBT were prospectively studied in an open-labeled fashion. Fourteen patients (70.0%) presented with diarrhea, 3 (15.0%) with bloating and gas, and 3 (15.0%) with constipation as the dominant symptom.

RESULTS

: Eleven patients were hydrogen producers, 8 exclusively methane, and 1 patient produced both gases by the GBT. Among patients with diarrhea, 12 of 14 (85.7%) reported improvement in symptom scores of more than 50%; 1 between 25% and 50%, 1 had no response after 4 weeks of rifamixin. Among patients with bloating and gas or constipation as the main symptom: 2 of 6 (33.3%) had improvement between 50% and 75%; 3 (50%) had 25% to 50% improvement, and 1 (16.7%) had no response. Repeat GBT at the end of the 4 weeks showed that 54.5% of hydrogen formers and 50.0% of methane producers were eradicated, and there was a significant reduction (P <0.05) in the area under the concentration-time curve and peak values. No adverse effects were observed.

CONCLUSIONS

Rifaximin in a dose of 800 mg per day for 4 weeks: 1) was safe and effective treatment in reducing symptoms in patients with SIBO of multiple etiologies, especially when diarrhea was the dominant symptom; and 2) normalized the GBT in approximately 50% of patients. Data support a future therapeutic role for rifaximin in SIBO.

The patient with slightly elevated pancreatic enzymes and abdominal complaints

Abdominal complaints in combination with slightly elevated serum pancreatic enzymes represent a classical clinical challenge. These symptoms may be due to coincidental unrelated harmless disorders, benign pancreatic alterations which are fairly easily treatable such as mild acute pancreatitis or uncomplicated chronic pancreatitis. However, serious, often insidious diseases such as pancreatic tumours may also present with this constellation as their first signs. Diagnostic procedures need to be stratified according to acuteness and severity of symptoms. While patients with acute onset of symptoms and severe complaints need immediate and combined laboratory and imaging investigations to allow adequate therapy, chronic and mild complaints usually justify a stepwise diagnostic approach consecutively using abdominal ultrasound, CT/MRI and endoscopic ultrasound as imaging procedures and reserving ERCP for cases which remain unclear or in which interventional therapy is needed. Diagnosis and follow-up are often particularly demanding in patients with cystic tumours of the pancreas. In chronic pancreatitis patients pain therapy and adequate control of pancreatic exocrine insufficiency may pose major problems. Patients with refractory pain may ultimately require surgical intervention. Another important indication for surgery in chronic pancreatitis is suspicion of cancer that cannot be ruled out by dedicated diagnostic procedures. This also applies to cystic tumours of the pancreas, which have a high risk of malignant transformation or may even already represent pancreatic cancer at the time of diagnosis.