Hyperoxaluria associated with intestinal bypass surgery for morbid obesity: occurrence, pathogenesis and approaches to treatment.

Hyperoxaluria occurs in most patients after the conventional jejunoileal bypass procedure for obesity. The mechanism of hyperoxaluria is complex, involving persistence of dietary oxalate in solution as well as increased colonic permeability to oxalate. Endogenous oxalate formation also contributes to hyperoxaluria. Treatment is unsatisfactory and involves a low-oxalate diet and simultaneous administration of agents which bind oxalate and bile acids, such as aluminum hydroxide. Hyperoxaluria was not present in 21 of 22 patients who had undergone the pancreato-biliary bypass procedure.