Comparative Assessment of Radioisotope Glucose and Breath Test

Study Overview
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Brief Summary
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This is a research study about improving our diagnostic method for small intestinal bacterial overgrowth (SIBO). Patients undergoing Standard of Care (SOC) Endoscopically assisted glucose breath test (EAGBT) will undergo upper endoscopy and glucose breath tests. In this study, investigators wish to utilize Nuclear Medicine techniques to locate where the glucose solution that is administered during EAGBT is being consumed by bacteria is in the small bowel when it detects SIBO.

Detailed Description
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Small intestinal bacterial overgrowth (SIBO) is characterized by bloating, gas, distention, and diarrhea due to colonization and an excessive amount of bacteria in the small bowel. Distal SIBO is the presence of excessive amounts of bacteria in the distal jejunum and/or ileum. Diagnosis of SIBO requires either duodenal aspirate with culture analysis or more commonly with breath hydrogen/methane testing. Hydrogen breath testing often uses either oral glucose or lactulose solutions. If bacteria are present in the small bowel they will ferment glucose or lactulose, producing hydrogen or methane as a byproduct. These gases are absorbed into the bowel, and then eliminated via pulmonary expiration. By detecting a rise in breath H2 and CH4 values compared to baseline, SIBO can be diagnosed. However, after oral ingestion, the majority of the glucose substrate is absorbed in the duodenum and proximal jejunum. Therefore, Glucose breath test (GBT) is good for the detection of proximal SIBO, but misses distal SIBO. Investigators have recently shown that glucose administration into the distal duodenum through upper endoscopy has a higher positive yield for SIBO in patients with negative oral GBT. However, it is unclear if the rise in breath H2 or CH4 is because of glucose fermentation by bacteria in the distal small bowel or from fermentation by bacteria in the colon, i.e. false-positive test. Study objective here is to administer a radio-labeled glucose solution into the duodenum via an endoscopically placed nasoduodenal tube, and then determine if the rise in breath hydrogen and/or methane correlates with the location of the isotopic glucose solution in the bowel by simultaneous nuclear imaging. Results of breath testing will also be compared with duodenal aspirate/cultures taken at the time of endoscopy. Clinical response to treatment will be assessed on follow up.

Official Title
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Does Rise in Breath Hydrogen During Endoscopically Assisted Glucose Breath Test (EAGBT) Correlate With Radio-Isotope Location in Small Bowel: Improving Detection of Distal SIBO

Conditions
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Small Intestinal Bacterial Overgrowth

Intervention / Treatment
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* Radiation: Using Isotope (Tc99m-Sulfur Colloid) to label glucose and administer this directly into duodenum.


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients with recent gas, bloating, distension, and suspected SIBO Negative oral GBT 18 years and older Exclusion Criteria: Pregnancy Diabetes Previous abdominal surgery except cholecystectomy, appendectomy Diet prep non-adherence Smoking or exercise causing hyperventilation prior to exam

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Intervention/Treatment |
| --- |
|Radiation: Using Isotope (Tc99m-Sulfur Colloid) to label glucose and administer this directly into duodenum.|Patients will be undergoing Standard of Care procedure EAGBT for collection of duodenal fluid (aspirate and culture) and placement of a catheter into the duodenum. This catheter will be used for infusion of glucose isotope into the small bowel. Subsequently Standard of Care nuclear medicine imaging will be used to track the location of the isotope in the gut.|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Correlation between GBT result and isotope detection in small bowel | Overall correlation (positive and negative) between the location of glucose isotope in small bowel (imaging) and changes in in hydrogen and methane values obtained during the breath test. | February 6, 2019 (anticipated) - December 14, 2021 (anticipated) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Diagnostic yield of EAGBT compared to oral GBT | We will compare the yield (positive, negative and overall) of endoscopic assisted GBT versus orally administered GBT | February 6, 2019 (anticipated) - December 14, 2021 (anticipated) | 
| Diagnostic yield of EAGBT compared to duodenal aspirate and culture | We will compare the positive and negative yield of EAGBT with the positive (>1000 CFU/ml) or negative yield of aerobic and anaerobic cultures. | February 6, 2019 (anticipated) - December 14, 2021 (anticipated) | 
| Symptom patterns and demographics | Compare the gas and bloating symptom patterns, clinical characteristics predisposing factors including underlying dysmotility and other demographic features between patients with positive and negative EAGBT and cultures. | February 6, 2019 (anticipated) - December 14, 2021 (anticipated) |