Prevalence and Causes of Abdominal Pain Following Fully Divided Roux-En-Y Gastric Bypass Surgery

Abstract

Abdominal pain is the most frequent presenting symptom in a gastroenterology clinic. In the United States, Roux-en-Y gastric bypass (RYGB) is the most commonly performed procedure for surgical treatment of medically-complicated obesity. The purpose of this study is to determine the prevalence of abdominal pain following RYGB, determine its causes and conceptualize a diagnostic algorithm for efficient management of abdominal pain in these patients. This is a prospective, cohort study performed in an urban community hospital. Consecutive RYGB patients (n = 147) seen at a new joint Medical/Surgical Bariatric Clinic from February 1, 2008, to January 31, 2009, were included in this study. Chief complaint and the location of abdominal pain were recorded. Information collected included date of surgery, duration of symptom, weight loss after surgery, smoking status, and the use of an NSAID/aspirin. Baseline demographics (ie, age, sex, and body mass index) were also recorded. In diagnostic evaluation, 25 patients underwent glucose hydrogen breath testing (GHBT), 19 completed upper endoscopy, 8 received empiric trials of metronidazole, and 4 underwent CT scan of the abdomen. Whole blood thiamine levels were measured in all patients. Re-examination of patients who were evaluated for abdominal pain was performed 1 year after completion of the patients' initial evaluation (up to May 2010). Of the 147 patients, 49 reported a chief complaint of abdominal pain. Duration of abdominal pain ranged from 1 week to 7 years (median: 6 months). Following an initial evaluation, a diagnosis was established in 38 of 49 patients (77%). These diagnoses included: small intestinal bacterial overgrowth (SIBO; n = 25), thiamine deficiency (n = 5), marginal ulceration at the site of the gastrojejunal anastomosis (n = 3), cholecystitis (n = 2), and partial small intestinal obstruction (n = 1). One patient obtained prolonged pain relief after a nerve block for abdominal wall pain. Appropriate treatment was initiated based upon the initial diagnosis. During a 1 year follow-up period, 1 additional patient (2%) received relief of abdominal pain following cholecystectomy, 42 (85%) reported improvement in their abdominal pain, while 2 patients did not follow-up. This study demonstrates that abdominal pain is common after RYGB with a prevalence of 33%. SIBO (diagnosed by abnormal GHBT) was the commonest cause for chronic abdominal pain with thiamine deficiency, marginal ulcer and chronic cholecystitis being the other important causes. Diagnostic algorithm for chronic abdominal pain following RYGB should be initiated with a glucose-hydrogen breath test to diagnose SIBO. In patients with a normal GHBT, further evaluation should include upper endoscopy and consideration of abdominal imaging. Diagnosis may not be established in up to 25% of patients. However, the majority of RYGB patients will have sustained improvement in their abdominal pain after appropriate diagnosis and treatment.