Hyperoxaluric nephrolithiasis is a complication of Roux-en-Y gastric bypass surgery.
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.
Sinha
M K
MK
Department of Internal Medicine, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA.
Collazo-Clavell
M L
ML
Rule
A
A
Milliner
D S
DS
Nelson
W
W
Sarr
M G
MG
Kumar
R
R
Lieske
J C
JC
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
D002129:Calcium Oxalate