A case of oxalate nephrocalcinosis and primary hyperoxaluria

Nephropathy in dietary hyperoxaluria: A potentially preventable acute or chronic kidney disease

Hyperoxaluria can cause not only nephrolithiasis and nephrocalcinosis, but also renal parenchymal disease histologically characterized by deposition of calcium oxalate crystals throughout the renal parenchyma, profound tubular damage and interstitial inflammation and fibrosis. Hyperoxaluric nephropathy presents clinically as acute or chronic renal failure that may progress to end-stage renal disease (ESRD). This sequence of events, well recognized in the past in primary and enteric hyperoxalurias, has also been documented in a few cases of dietary hyperoxaluria. Estimates of oxalate intake in patients with chronic dietary hyperoxaluria who developed chronic kidney disease or ESRD were comparable to the reported average oxalate content of the diets of certain populations worldwide, thus raising the question whether dietary hyperoxaluria is a primary cause of ESRD in these regions. Studies addressing this question have the potential of improving population health and should be undertaken, alongside ongoing studies which are yielding fresh insights into the mechanisms of intestinal absorption and renal excretion of oxalate, and into the mechanisms of development of oxalate-induced renal parenchymal disease. Novel preventive and therapeutic strategies for treating all types of hyperoxaluria are expected to develop from these studies.

Oxalate in the human thyroid gland

Ninety-seven fixed surgical thyroid specimens and 63 unfixed and 40 fixed thyroid specimens from autopsies were examined for their oxalate content. Proteases were used to process the tissue, and the oxalate was determined with an enzymatic assay. The fixed samples were grouped into seven diagnostic categories (diffuse colloid goitre; partially diffuse, partially nodular colloid goitre; nodular colloid goitre; goitre with multifocal functional autonomy; non-functioning adenoma; unifocal functional autonomy; Graves' disease). The oxalate concentrations of the samples were mainly dependent on age and gender, which were distributed unequally among the seven diagnostic groups. In thyroid tissue from cases of Graves' disease, however, the concentration of oxalate was remarkably low and statistically different from those of four of the six other groups.

Control of hyperoxaluria with large doses of pyridoxine in patients with kidney stones

Pyridoxine in doses of 250-500 mg daily by mouth was administered to 12 patients suffering from recurrent calcium oxalate renal calculi and idiopathic hyperoxaluria. This therapy decreased urinary oxalate excretion significantly (p less than 0.025) during up to 18 months of treatment. In that period eight patients showed no evidence of active stone disease; three showed slight increase in the size of their old stone(s) and one patient formed one new stone. None of these patients developed any significant complications of the therapy. These findings support the view that pyridoxine in pharmacological doses is useful in the control of elevated urinary oxalate excretion in patients with recurrent renal oxalate calculi.