More on mild (but clinically significant) metabolic hyperoxaluria and its response to pyridoxine

Abstract

The condition mild metabolic hyperoxaluria has been previously described in Vienna in 1985 (1). It is called “metabolic” hyperoxaluria because urinary glycollate is raised, as well as urinary oxalate, so distinguishing it from hyperoxaluria due to high oxalate intake or increased absorption of dietary oxalate due to steatorrhoea or other causes. The adjective “mild” signifies that the degree of hyperoxaluria is not as great as in primary hyperoxaluria and usually 0.6–0.8 mmol/24 h in an adult. However, it is stressed that the clinical condition is certainly not mild and can be quite severe with frequent generation and passage of virtually pure calcium oxalate stones. As mentioned elsewhere (2), the condition can be accompanied by renal tubular acidosis (RTA), but this report is limited to those without RTA, except that one of the original cases (NY) is included.