Hypercalciuria: some diagnostic, pathogenetic and therapeutic aspects

Hypocalciuria in stone formers has been object of intensive investigation, owing to the evidence that calcium is the main component of most renal stones and increased calcium excretion is the most common metabolic finding, Pak et nl., in the attempt to give a classification criterion of the hypercalciuric syndromes, proposed a simple test which substantially identified two main subsets: hypercalciuria sustained by increased intestinal calcium input and hypercalciuria mainly dependent on renal calcium leak, However, following studies challenged the validity of this classification. Nowadays, an alternative classification is widely accepted, mainly based on the evaluation of the daily and fasting urinary calcium excretion on both free and low calcium diets, This classification splits the hypercalciuric syndromes into two main groups, the diet-dependent and diet-independent hypercalciurias, In agreement with this classification, we propose a S-step diagnostic approach, which, in addition to the above concepts, takes into account the potential bone involvement in this clinical set. Some final considerations on the dietary and pharmacological prescriptions in the hypocalciuric syndromes are given.