Oxalate Metabolism after Intestinal Bypass Operations

Abstract

Hyperoxaluria and kidney stones are frequent following intestinal bypass operations. The urinary oxalate excretion was studied for 10-13 days during enteral and parenteral nutrition in 6 patients operated on because of massive obesity with a jejunoileostomy. The oxalate excretion in urine was higher than normal in all patients on normal diet. The excretion decreased on low-oxalate diet. Further decrease was observed during total parenteral nutrition (TPN). The oxalate excretion was stabilized at a low level within 48 h after the start of TPN and was unchanged during the rest of the study. This included a period of 2 days when a load of the oxalate precursor glycine (10 and 20 g) was given parenterally to 5 patients, resulting in increased serum glycine concentration. A slight decrease in oxalate excretion was found when the amino acid part (Vamin with 10% glucose) of the TPN solution was given enterally instead of parenterally in 2 patients. The main reason for hyperoxaluria in patients with intestinal bypass operations is evidently hyperabsorption of dietary oxalate. These patients probably have a normal endogenous oxalate production.