Role of the Gastroenterologist in Managing Obesity

John K DiBaise; Amy E Foxx-Orenstein

Disclosures

Expert Rev Gastroenterol Hepatol. 2013;7(5):439-451. 

In This Article

Role of Endoscopy and Motility Procedures in the Bariatric Surgery Patient

Preoperative endoscopy

GI endoscopists play an integral role in the management of the bariatric surgery patient, particularly in the prevention and treatment of postoperative complications. Guidelines from the American Society for Gastrointestinal Endoscopy recommend that preoperative upper endoscopy should be considered in all bariatric patients, whether symptomatic or not, particularly those undergoing RYGB and BPD/DS as it will be difficult to evaluate the excluded distal stomach and/or duodenum postoperatively using routine endoscopy.[53] Similarly, European guidelines also recommend preoperative upper endoscopy in all bariatric surgery patients, although admittedly based on low- to medium-quality evidence.[81] The rationale for performing an esophagogastroduodenoscopy in this setting is to detect abnormalities that may impact the preoperative management, the surgery performed or the development of postoperative symptoms or complications. Several studies have demonstrated that preoperative endoscopy can identify a variety of clinically significant pathologies including esophagitis, large hiatal hernia, Barrett's esophagus, gastritis and ulcers, even in asymptomatic individuals.[82,83] Furthermore, preoperative endoscopy has been shown to have a low cost per clinically significant lesion identified.[84] Nevertheless, due to the relatively low yield of preoperative endoscopy, a nonendoscopic approach (e.g., upper GI barium contrast study and/or Helicobacter pylori testing) has been suggested in asymptomatic patients to provide preoperative risk stratification. H. pylori may be present in up to 40% of patients undergoing bariatric surgery and appears to increase the risk of postoperative anastomotic ulceration.[85]

Intraoperative Endoscopy

Intraoperative endoscopy to test for anastomotic leakage, assess the size of the gastric pouch and stoma and evaluate for immediate staple line hemorrhage is typically performed by the surgeon. Despite a lack of high-quality studies to support the practice, the currently available data suggest that intraoperative leak testing is associated with a low incidence of postoperative leaks.[86]

Postoperative Endoscopy

When faced with a symptomatic patient after bariatric surgery, particularly one of the bypass operations, the time interval since surgery should be considered as an important factor in the differential diagnosis and evaluation strategy. Although the gastroenterologist plays a key role in the evaluation of upper GI symptoms (Box 2) and the management of complications (Box 3 & Box 4) postoperatively, complications that arise during the immediate postoperative period (e.g., anastomotic leak or bleeding, small bowel obstruction) are generally managed surgically due to concerns about the immature anastomosis. Of critical importance is for the gastroenterologist to be familiar with the postoperative anatomy and work in close collaboration with their bariatric surgery colleagues to maximize the outcome and safety of endoscopy in this setting. The choice of endoscope will depend on the need for intubation of the biliary limb and excluded portion of the stomach.

Common symptoms occurring typically >6 weeks after bariatric surgery prompting endoscopy include upper abdominal pain, nausea, vomiting, pyrosis, dysphagia and diarrhea. The etiology of these symptoms is often multifactorial; however, noncompliance with postoperative dietary restrictions, particularly in the setting of persistent nausea and vomiting, should always be considered. Importantly, persistent vomiting after bariatric surgery may lead to protein energy malnutrition and thiamine deficiency with resultant Wernicke's encephalopathy.[87] If unrecognized or inadequately treated, irreversible neurologic damage may result. Among patients with symptoms after RYGB presenting for endoscopy, one study found that a normal postsurgical anatomy was found, most commonly followed by anastomotic ulceration. Presentation with abdominal pain and performance of endoscopy at least 6 months postoperatively were predictive of a normal examination, while lack of nausea, vomiting and dysphagia predicted the absence of an anastomotic stricture.[88]

Small intestinal bacterial overgrowth appears to occur relatively commonly after RYGB[89] and may result in a variety of signs and symptoms including abdominal bloating, nausea, abdominal discomfort, steatorrhea, flatulence, anemia and weight loss. Bariatric operations may also result in dumping syndrome when high-density carbohydrates are consumed. Early dumping symptoms comprise both GI and vasomotor symptoms, whereas late dumping symptoms are the result of reactive hypoglycemia.[90] Diarrhea may also occur after the malabsorptive operations because of dietary fat ingestion. In this situation, reduced fat consumption or supplementation with pancreatic enzymes may reduce symptoms. More commonly, particularly after RYGB, constipation occurs because of decreased food and water intake and/or use of certain medications including iron, narcotics, or antidepressants. Finally, as previously mentioned, with rapid weight loss there is an increased risk for developing gallstones requiring endoscopic intervention and/or cholecystectomy.[91]

Endoscopy is useful to diagnose an anastomotic stricture, marginal ulcer, staple-line dehiscence, gastrogastric fistula, esophagitis, band slippage and erosion and small intestinal bacterial overgrowth. An anastomotic stricture occurs in about 5–7% of patients following RYGB and appears to be more common with stapled anastomoses. Endoscopic balloon dilation to a goal of about 15 mm appears to be safe and effective in most cases without resultant weight gain.[92] Marginal ulcers develop in up to 16% of RYGB patients, with abdominal pain and bleeding being common clinical presentations; however, nearly one-third may be asymptomatic.[93] Recurrent marginal ulcers may require surgical revision of the anastomosis.[94] GI bleeding, either acute or chronic, occurs in about 1–4% of patients after RYGB and most commonly occurs as a result of ulceration at the gastrojejunal anastomosis. Bleeding from other staple lines or anastomoses may also occur. Band erosion and band slippage are complications typically associated with the AGB; however, a variant of the RYGB that utilizes a band (albeit, not adjustable) to reinforce the gastrojejunal anastomosis may also develop these complications.[95] Band erosion is best diagnosed endoscopically but, in the case of the AGB, will require surgical removal given the presence of tubing that connects the band to a subcutaneous port. After RYGB, an endoscopic procedure is also occasionally necessary to treat choledocholithiasis and, rarely, to place a percutaneous gastrostomy tube in the excluded stomach for decompression or feeding. A balloon-assisted enteroscope may be needed for successful completion of both procedures. Endoscopic repair of small (<10 mm) gastrogastric fistulae is also feasible; although in most cases, the closure is only temporary.[96] Failure to lose weight or eventual weight regain are other potential indications for endoscopy.[97] A full description of these postoperative symptoms and complications is beyond the scope of this review. The interested reader is directed to other recent reviews for a more complete discussion of the endoscopic evaluation and management of postoperative bariatric surgery symptoms and complications.[53,98]

GI Motility Procedures

The role of GI motility procedures in the bariatric surgery patient remains poorly defined. Preoperatively, esophageal manometry and ambulatory pH (with or without impedance testing) is occasionally performed in the patient with GERD and may impact operation selection, as GERD symptoms occur more commonly after AGB and gastrectomy, while RYGB often leads to a resolution of reflux symptoms. Dysphagia may also occur following AGB, and an unusual achalasia-like condition has been described following this operation that may resolve with removal of the band.[99] Esophageal manometry is necessary to identify this condition; however, a dilated esophagus is sometimes present on imaging studies and should raise the suspicion of this complication. Intestinal manometry is rarely needed but may help to identify Roux limb dysmotility or the rare instance of accidental antiperistaltic positioning of the Roux limb during RYGB.[100] Although small intestinal bacterial overgrowth appears to be relatively common after certain bariatric operations, particularly the bypass operations, diagnosis by hydrogen breath testing is of uncertain utility given the altered anatomy, and small bowel aspirate is generally recommended instead. Finally, fecal incontinence is an underappreciated problem both in obesity and after bariatric surgery. A recent report showed that fecal incontinence was common after bariatric surgery, and risk factors for fecal incontinence in women after bariatric surgery included diarrhea and worsening of diarrhea postoperatively, suggesting that such surgery may uncover prior weaknesses in the continence mechanism.[101] Therefore, anorectal manometry and endoanal ultrasonography may play a role in the evaluation of some patients with defecatory complaints after bariatric surgery.

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