title: Hyperoxaluric nephrolithiasis is a complication of Roux-en-Y gastric bypass surgery.
abstract: Roux-en-Y bypass surgery is the most common bariatric procedure currently performed in the United States for medically complicated obesity. Although this leads to a marked and sustained weight loss, we have identified an increasing number of patients with episodes of nephrolithiasis afterwards. We describe a case series of 60 patients seen at Mayo Clinic-Rochester that developed nephrolithiasis after Roux-en-Y gastric bypass (RYGB), including a subset of 31 patients who had undergone metabolic evaluation in the Mayo Stone Clinic. The mean body mass index of the patients before procedure was 57 kg/m(2) with a mean decrease of 20 kg/m(2) at the time of the stone event, which averaged 2.2 years post-procedure. When analyzed, calcium oxalate stones were found in 19 and mixed calcium oxalate/uric acid stones in two patients. Hyperoxaluria was a prevalent factor even in patients without a prior history of nephrolithiasis, and usually presented more than 6 months after the procedure. Calcium oxalate supersaturation, however, was equally high in patients less than 6 months post-procedure due to lower urine volumes. In a small random sampling of patients undergoing this bypass procedure, hyperoxaluria was rare preoperatively but common 12 months after surgery. We conclude that hyperoxaluria is a potential complicating factor of RYGB surgery manifested as a risk for calcium oxalate stones.
authors: Department of Internal Medicine, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA.
authors: M K
authors: MK
authors: Sinha
authors: M L
authors: ML
authors: Collazo-Clavell
authors: A
authors: A
authors: Rule
authors: D S
authors: DS
authors: Milliner
authors: W
authors: W
authors: Nelson
authors: M G
authors: MG
authors: Sarr
authors: R
authors: R
authors: Kumar
authors: J C
authors: JC
authors: Lieske
mesh_terms: D000328:Adult; D015992:Body Mass Index; D002129:Calcium Oxalate / Q000652:urine; D003430:Cross-Sectional Studies; D005260:Female; D015390:Gastric Bypass / Q000009:adverse effects*; D006801:Humans; D006959:Hyperoxaluria / Q000150:complications / Q000209:etiology* / Q000652:urine; D008297:Male; D008875:Middle Aged; D053040:Nephrolithiasis / Q000209:etiology* / Q000652:urine; D011184:Postoperative Period; D012307:Risk Factors
chemical_list: D002129:Calcium Oxalate