Elsevier

Seminars in Nephrology

Volume 28, Issue 2, March 2008, Pages 163-173
Seminars in Nephrology

Nephrolithiasis After Bariatric Surgery for Obesity

https://doi.org/10.1016/j.semnephrol.2008.01.009Get rights and content

Summary

Surgical intervention has become an accepted therapeutic alternative for the patient with medically complicated obesity. Multiple investigators have reported significant and sustained weight loss after bariatric surgery that is associated with improvement of many weight-related medical comorbidities, and statistically significant decreased overall mortality for surgically treated as compared with medically treated subjects. Although the Roux-en-Y gastric bypass (RYGB) is considered an acceptably safe treatment, an increasing number of patients are being recognized with nephrolithiasis after this, the most common bariatric surgery currently performed. The main risk factor appears to be hyperoxaluria, although low urine volume and citrate concentrations may contribute. The incidence of these urinary risk factors among the total post-RYGB population is unknown, but may be more than previously suspected based on small pilot studies. The etiology of the hyperoxaluria is unknown, but may be related to subtle and seemingly subclinical fat malabsorption. Clearly, further study is needed, especially to define better treatment options than the standard advice for a low-fat, low-oxalate diet, and use of calcium as an oxalate binder.

Section snippets

Surgical Options for Obesity Treatment

The bariatric procedures currently used promote weight loss via varied mechanisms (Fig. 1). Restrictive procedures such as vertical banded gastroplasty (VBG) and laparoscopic adjustable gastric band (LAGB) each limit caloric intake by the physical restriction imposed by the band on dietary intake. The VBG consists of a stapled proximal gastric pouch with a fixed and nonadjustable outlet created by a mesh band or Silastic (Dow Corning, Midland, MI) ring. Although still performed, poor long-term

Complications of Obesity Surgery

The current bariatric procedures have been deemed relatively safe and effective, even though both short-term and long-term complications have been recognized, including osteopenia, osteomalacia, and, more rarely, neurologic disorders.22, 23, 24, 25, 26, 27, 28 Overall morbidity rates vary from 10% to 23% depending on the surgical procedure performed, although these have been declining as a result of increased attention being paid to potential metabolic consequences (eg, calcium and other

Hyperoxaluria After Jejunoileal Bypass: Lessons From the Past

Historically, nephrolithiasis was a well-recognized complication of bariatric surgery. In particular the development of calcium oxalate stones was a serious complication of jejunoileal (JI) bypass surgery performed in the 1970s for the management of obesity and hypercholesterolemia. This risk for nephrolithiasis, renal failure, and other life-threatening complications such as liver disease led to the abandonment of this surgery more than 20 years ago.32

The best evidence regarding the true risk

Renal Stones After RYGB

Little is known about the impact of most currently offered bariatric surgeries on the risk for nephrolithiasis. Because obesity and insulin resistance have been implicated as risk factors for nephrolithiasis, especially uric acid stones, one might reasonably hypothesize that RYGB could ameliorate kidney stone risk.8, 29 Further, the RYGB surgery with a Roux limb less than 150 cm in length generally has been believed not to cause fat malabsorption, thought to be a critical factor in the

Hyperoxaluria After RYGB

To get a better sense regarding how common hyperoxaluria might be in the total group of patients who undergo RYGB, we next completed a small pilot study of patients randomly selected before (n = 20), 6 months after (n = 8), and 12 months after (n = 13) proximal RYGB. At baseline hyperoxaluria was rare (mean oxalate, 0.35 mmol/d), and urinary calcium oxalate supersaturation was not increased above the reference mean (Fig. 3). Urinary composition was not changed significantly in the 6-month

Treatment of Nephrolithiasis after RYGB

Typical treatment strategies for enteric hyperoxaluria, as described earlier, are prescription of a low-fat, low-oxalate diet, generous fluid intake, use of oral oxalate binders such as calcium, and potassium citrate as a crystallization inhibitor. In practice, these dietary modifications may be quite difficult to implement. For example, many patients have learned to alter their eating patterns after RYGB and consume many small meals and/or snacks to avoid dumping symptoms. The use of oxalate

Conclusions and Future Directions

As a first step, it will be vital to define the scope of the problem. How common is hyperoxaluria after RYGB or other forms of bariatric surgery? How many of these patients develop stones and/or renal damage? Based on the preliminary data described earlier, it seems likely that the prevalence of hyperoxaluria and nephrolithiasis will be significant. Therefore, studies that can identify improved strategies to decrease urinary oxalate levels among the ever-expanding pool of patients undergoing

References (54)

  • C. De Prisco et al.

    Metabolic bone disease after gastric bypass surgery for obesity

    Am J Med Sci

    (2005)
  • M.L. Collazo-Clavell et al.

    Osteomalacia after Roux-en-Y gastric bypass

    Endocr Pract

    (2004)
  • W.K. Nelson et al.

    Enteric hyperoxaluria, nephrolithiasis, and oxalate nephropathy: potentially serious and unappreciated complications of Roux-en-Y gastric bypass

    Surg Obes Rel Dis

    (2005)
  • J.H. Parks et al.

    Urine stone risk factors in nephrolithiasis patients with and without bowel disease

    Kidney Int

    (2003)
  • N.B. Dhar et al.

    Jejunoileal bypass reversal: effect on renal function, metabolic parameters and stone formation

    J Urol

    (2005)
  • M.K. Sinha et al.

    Hyperoxaluric nephrolithiasis is a complication of Roux-en-Y gastric bypass surgery

    Kidney Int

    (2007)
  • J.R. Asplin et al.

    Hyperoxaluria in kidney stone formers treated with modern bariatric surgery

    J Urol

    (2007)
  • R.A. Argenzio et al.

    Intestinal oxalate-degrading bacteria reduce oxalate absorption and toxicity in guinea pigs

    J Nutr

    (1988)
  • M.J. Allison et al.

    Oxalate degradation by gastrointestinal bacteria from humans

    J Nutr

    (1986)
  • J.C. Lieske et al.

    Use of a probiotic to decrease enteric hyperoxaluria

    Kidney Int

    (2005)
  • M. Hatch et al.

    Oxalobacter sp. reduces urinary oxalate excretion by promoting enteric oxalate secretion

    Kidney Int

    (2006)
  • B. Hoppe et al.

    Oxalobacter formigenes: a potential tool for the treatment of primary hyperoxaluria type 1

    Kidney Int

    (2006)
  • M.G. Sarr et al.

    Technical and practical considerations involved in operations on patients weighing more than 270 kg

    Arch Surg

    (1995)
  • T.H. Kim et al.

    Early U.S. outcomes of laparoscopic gastric bypass versus laparoscopic adjustable silicone gastric banding for morbid obesity

    Surg Endosc

    (2006)
  • C. Mehrotra et al.

    Population-based study of trends, costs, and complications of weight loss surgeries from 1990 to 2002

    Obes Res

    (2005)
  • S. Sauerland et al.

    Obesity surgery: evidence-based guidelines of the European Association for Endoscopic Surgery (EAES)

    Surg Endosc

    (2005)
  • T. Olbers et al.

    Randomized clinical trial of laparoscopic Roux-en-Y gastric bypass versus laparoscopic vertical banded gastroplasty for obesity

    Br J Surg

    (2005)
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    Supported by grants from the National Institutes of Health (DK 73354, AR 30582, DK 77669, AT 002534, and DK 39337), the Oxalosis and Hyperoxaluria Foundation, and Mayo Foundation.

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