Breath Hydrogen as a Biomarker for Glucose Malabsorption after Roux-en-Y Gastric Bypass Surgery.

OBJECTIVE: Abdominal symptoms are common after bariatric surgery, and these individuals commonly have upper gut bacterial overgrowth, a known cause of malabsorption. Breath hydrogen determination after oral glucose is a safe and inexpensive test for malabsorption. This study is designed to investigate breath hydrogen levels after oral glucose in symptomatic individuals who had undergone Roux-en-Y gastric bypass surgery. METHODS: This is a retrospective study of individuals (n = 63; 60 females; 3 males; mean age 49 years) who had gastric bypass surgery and then glucose breath testing to evaluate abdominal symptoms. RESULTS: Among 63 postoperative individuals, 51 (81%) had a late rise (≥45 minutes) in breath hydrogen or methane, supporting glucose malabsorption; 46 (90%) of these 51 subjects also had an early rise (≤30 minutes) in breath hydrogen or methane supporting upper gut bacterial overgrowth. Glucose malabsorption was more frequent in subjects with upper gut bacterial overgrowth compared to subjects with no evidence for bacterial overgrowth (P < 0.001). CONCLUSION: These data support the presence of intestinal glucose malabsorption associated with upper gut bacterial overgrowth in individuals with abdominal symptoms after gastric bypass surgery. Breath hydrogen testing after oral glucose should be considered to evaluate potential malabsorption in symptomatic, postoperative individuals.

Constipation in patients with thiamine deficiency after Roux-en-Y gastric bypass surgery.

BACKGROUND/AIMS: Roux-en-Y gastric bypass surgery is the most common bariatric surgery worldwide. We have described thiamine deficiency in patients with small intestinal bacterial overgrowth after gastric bypass. We hypothesized that symptoms of thiamine deficiency are common after gastric bypass. The aims of this study were to examine the prevalence of and treatment of symptoms of thiamine deficiency after gastric bypass. METHODS: This is a prospective study performed in a large urban, community hospital. Consecutive gastric bypass patients seen from February 1, 2008 to May 1, 2009 are included. Thiamine deficiency in this study included both: consistent clinical symptoms and either (1) low blood thiamine level or (2) resolution of clinical symptoms after receiving thiamine. RESULTS: Of 151 patients, 25 females and 2 males met the criteria for thiamine deficiency (prevalence of 18%). In these 27 patients, 12 had one symptom of thiamine deficiency, while 15 had symptoms consistent with multiple subtypes. Eleven patients reported constipation at 0.33-12 years (mean 4.8) after gastric bypass. Elevated serum folate levels were seen in 6 of 10 tested patients and there was an abnormal glucose-hydrogen breath test in 9 of 10 tested patients, supporting the presence of small intestinal bacterial overgrowth. Frequency of defecation improved after thiamine treatment. CONCLUSION: Thiamine deficiency resulting from small intestinal bacterial overgrowth should be considered in patients being seen for constipation after gastric bypass surgery.

What factors are associated with the difficult-to-sedate endoscopy patient?

BACKGROUND: Difficult sedation during endoscopy results in inadequate examinations and aborted procedures. We hypothesized that gender, alcohol abuse, physical/sexual abuse, and anxiety are predictors of difficult-to-sedate endoscopy patients. METHODS: This is a prospective cohort study. At the time of enrollment, subjects completed the following three validated questionnaires: state-trait anxiety inventory, self-report version of alcohol use disorder inventory, and Drossman questionnaire for physical/sexual abuse. Conscious sedation was administered for the endoscopic procedures at the discretion of the endoscopist and was graded in accordance with the Richmond agitation sedation scale (RASS). Subjects' perceptions of sedation were documented on a four-point Likert scale 24 h after their procedure. RESULTS: One-hundred and forty-three (79 %) of the 180 subjects enrolled completed the study. On the basis of the RASS score, 56 (39 %) subjects were found to be difficult to sedate of which only five were dissatisfied with their sedation experience. State (n = 39; p = 0.003) and trait (n = 41; p = 0.008) anxiety and chronic psychotropic use (p = 0.040) were associated with difficult sedation. No association was found between difficult sedation and gender (p = 0.77), alcohol abuse (p = 0.11), sexual abuse (p = 0.15), physical abuse (p = 0.72), chronic opioid use (p = 0.16), or benzodiazepines (BDZ) use (p = 0.10). CONCLUSION: Pre-procedural state or trait anxiety is associated with difficult sedation during endoscopy. In this study neither alcohol abuse nor chronic opiate/BDZ use was associated with difficult sedation.

Nutritional deficiencies after bariatric surgery.

Lifestyle intervention programmes often produce insufficient weight loss and poor weight loss maintenance. As a result, an increasing number of patients with obesity and related comorbidities undergo bariatric surgery, which includes approaches such as the adjustable gastric band or the 'divided' Roux-en-Y gastric bypass (RYGB). This Review summarizes the current knowledge on nutrient deficiencies that can develop after bariatric surgery and highlights follow-up and treatment options for bariatric surgery patients who develop a micronutrient deficiency. The major macronutrient deficiency after bariatric surgery is protein malnutrition. Deficiencies in micronutrients, which include trace elements, essential minerals, and water-soluble and fat-soluble vitamins, are common before bariatric surgery and often persist postoperatively, despite universal recommendations on multivitamin and mineral supplements. Other disorders, including small intestinal bacterial overgrowth, can promote micronutrient deficiencies, especially in patients with diabetes mellitus. Recognition of the clinical presentations of micronutrient deficiencies is important, both to enable early intervention and to minimize long-term adverse effects. A major clinical concern is the relationship between vitamin D deficiency and the development of metabolic bone diseases, such as osteoporosis or osteomalacia; metabolic bone diseases may explain the increased risk of hip fracture in patients after RYGB. Further studies are required to determine the optimal levels of nutrient supplementation and whether postoperative laboratory monitoring effectively detects nutrient deficiencies. In the absence of such data, clinicians should inquire about and treat symptoms that suggest nutrient deficiencies.

Origins of and recognition of micronutrient deficiencies after gastric bypass surgery.

Roux-en-Y gastric bypass surgery remains the major surgical option for individuals with medically complicated obesity. The importance of preoperative evaluation to permit identification of micronutrient deficiencies is being re-evaluated. The risk of complications related to pregnancy after gastric bypass supports careful follow-up. Micronutrient deficiencies are common in postoperative gastric bypass patients, despite the suggested use of routine vitamin and mineral supplements after surgery. Copper deficiency must be considered as an origin for visual disorders after gastric bypass. Vitamin D deficiency with metabolic bone disease remains common after gastric bypass and the results suggest that the present postoperative supplements of calcium and vitamin D are inadequate. Major nutritional complications of bariatric surgery are occurring more than 20 years after surgery. There is no evidence for intestinal adaptation as there remains decreased intestinal absorption of iron up to 18 months after gastric bypass surgery. This article supports ongoing examination of nutritional complications after gastric bypass surgery and supports the notion that the daily doses of micronutrient supplements, such as vitamin D, may need to be revised.