Low prevalence of positive hydrogen breath tests in patients with functional gastrointestinal conditions and hypermobile Ehlers-Danlos syndrome

BACKGROUND

Using hydrogen breath testing (HBT) to diagnose small intestinal bacterial overgrowth (SIBO) remains controversial in patients with functional gastrointestinal (GI) disorders, and unknown in those with hypermobility Ehlers-Danlos syndrome (hEDS). We assessed prevalence of positive HBTs in these groups, evaluated the predictive value of GI symptoms and the potential role of proton pump inhibitors (PPIs) on test results.

METHODS

Sequential patients referred for HBT to a tertiary unit were classified into the following groups: GI maldigestion/malabsorption, GI sensorimotor disorders, hEDS, and functional GI disorders. All underwent standardized HBT, and the yield was assessed against symptoms and PPI use.

KEY RESULTS

A total of 1062 HBTs were performed over 3 years (70% female, mean age 48 ± 16 years). Overall, 7.5% (80/1062) patients had a positive HBT. Prevalence of positive HBT was highest in patients with GI maldigestion/malabsorption (17.9%; DOR 16.16, p < 0.001), GI sensorimotor disorders (15.9%; DOR 8.84, p < 0.001), compared to functional GI disorders (1.6%; DOR 1.0) (p < 0.0001). None of the hEDS patients tested positive for HBT. A positive HBT was independently associated with increased age (DOR 1.03; p < 0.001) and symptoms of diarrhea (DOR 3.95; p < 0.0001). Patients on PPIs tended towards a positive HBT than patients off PPIs (16.1% vs 6.9%; DOR 2.47; p < 0.0001).

CONCLUSIONS & INFERENCES

Less than 2% of patients with functional GI disorders, and none of the patients with hEDS had a positive HBT. Pre-test probability was higher in patients with: GI structural or neurological disorders; use of long-term PPIs and symptoms of diarrhea. These criteria may be helpful in making appropriate therapeutic decisions and avoiding unnecessary hydrogen breath testing.

Hydrogen Breath Tests: Are They Really Useful in the Nutritional Management of Digestive Disease?

Background: Carbohydrate malabsorption is a frequent digestive problem associated with abdominal pain, bloating and diarrhea. Hydrogen breath testing (BT) represents the most reliable and validated diagnostic technique. The aim of this manuscript was to clarify the usefulness of BTs in the nutritional management of these disorders. Methods: A literature search for BT related to carbohydrate malabsorption was carried out using the online databases of Pubmed, Medline and Cochrane. Results: Lactose BT showed good sensitivity and optimal specificity for lactose malabsorption. However, an accurate diagnosis of lactose intolerance should require blind lactose challenge although this method is difficult to utilize in clinical practice. Regarding dose-depending fructose and sorbitol malabsorption, BTs could not add diagnostic advantage compared with a direct dietary intervention. In addition, carbohydrates are fundamental components of fermentable oligo-, di- and monosaccharides and polyols (FODMAPs). Before starting a low FODMAP diet, lactose BT should be suggested in a population with low prevalence of hypolactasia. Conclusions: BTs represent a valid and noninvasive technique in many digestive conditions. Regarding the management of carbohydrate intolerance, lactose BT can be recommended with some limitations. No sufficient evidence is available about the usefulness of BTs for other sugars in clinical practice.

Small Intestinal Bacterial Overgrowth: Comprehensive Review of Diagnosis, Prevention, and Treatment Methods

Small intestinal bacterial overgrowth (SIBO) is a commonly diagnosed gastrointestinal disorder affecting millions of individuals throughout the United States. It refers to a condition in which there is an excess and imbalance of small intestinal bacteria. Despite its prevalence, it remains underdiagnosed due to the invasive nature of diagnostic testing. Symptoms observed in SIBO, including abdominal distension, bloating, diarrhea, and gas formation, are nonspecific and can overlap with other gastrointestinal disorders. Frequently cited predisposing factors include gastric acid suppression, dysmotility, gastric bypass, and opioids. The diagnostic gold standard remains small bowel aspirate and culture. However, due to its invasive nature, it remains an unpopular method among patients and clinicians alike. Glucose and lactulose breath testing have become the go-to diagnostic method in clinical practice due to its noninvasive nature and low cost. Treatment is guided towards the eradication of bacteria in the small bowel and usually consists of a prolonged course of oral antibiotics. Due to recent advances in our understanding of the human microbiome, we are surely poised for a transformation in our approach to diagnosing and treating this condition.

Increased Fecal Lactobacillus Is Associated With a Positive Glucose Hydrogen Breath Test in Bangladeshi Children

Background

Glucose hydrogen breath testing is a noninvasive test for small intestine bacterial overgrowth (SIBO). A positive glucose hydrogen breath test is common in children from low-income countries and has been found to be associated with malnutrition as measured by stunted growth. The microbiome associated with positive breath testing is relatively unstudied.

Methods

We performed 16 S V4 rDNA microbiome analysis on the stool of 90 Bangladeshi children aged 2 years from an impoverished neighborhood who were tested at the same time for SIBO by glucose hydrogen breath testing. Data were analyzed by linear discriminant analysis effect size with SIBO as the outcome. Any selected genera were tested individually by Wilcoxon’s rank-sum test to ensure that linear discriminant analysis effect size results were not outlier-skewed.

Results

Linear discriminant analysis effect size analysis identified Lactobacillus (linear discriminate analysis score, 4.59; P = .03) as over-represented in 15 out of the 90 children who were SIBO positive.

Conclusions

These results suggest that glucose hydrogen breath test positivity in children from low-income settings may be due to an upper intestinal Lactobacillus bloom, potentially explaining the association of SIBO with the gut damage and inflammation that leads to malnutrition.

Low-FODMAP Diet for Treatment of Irritable Bowel Syndrome

Functional bowel disorders, including irritable bowel syndrome (IBS), are common disorders that have a significant impact on patients' quality of life. These disorders present major challenges to healthcare providers, as few effective medical therapies are currently available. Recently, there has been increasing interest in dietary therapies for IBS, particularly a diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs). Since ingestion of FODMAPs increases the delivery of readily fermentable substrates and water to the distal small intestine and colon-which results in luminal distention and gas-the reduction of FODMAPs in a patient's diet may improve functional gastrointestinal symptoms. This paper will review the pathophysiology of IBS and the role of FODMAPs for the treatment of this condition.