Mechanism for Hyperoxaluria in Patients with Ileal Dysfunction

Hyperoxaluria was found in 66 per cent of 18 patients with disease or resection of the ileum. Previous theories to explain the mechanism for this secondary hyperoxaluria have implicated bacterial metabolism of bile-salt glycine in the colon or altered glyoxylate metabolism in the liver. The present studies show that, in this situation, bile-salt glycine is not a precursor of urinary oxalate and that glyoxylate metabolism is normal. However, patients with ileal resection and hyperoxaluria absorbed up to five times as much 14C oxalate as control subjects —mean ± S.E.M. of 31 ± 9.2 per cent, as compared with 6.6 ± 0.9 per cent — when the isotope was given with food, and treatment of these patients with low oxalate diets (<4 mg of oxalate per 24 hours) promptly abolished the hyperoxaluria. These results suggest that increased absorption of dietary oxalate is the cause of the hyperoxaluria seen in patients with ileal dysfunction. (N Engl J Med 289:172–176, 1973)