Relationship of hypercalciuria to diet and bladder stone formation in spinal cord injury patients.

We have investigated the effectiveness of a low calcium diet, low sodium diet, and hydrochlorthiazide to reduce urinary calcium excretion in ten spinal cord injured patients during the early phase of their rehabilitation. Five patients were given the regular hospital diet and low calcium diet (300 mg calcium/day diet) on a randomized cross-over design. The other five patients were given four treatment modalities: a. regular diet, b. low calcium diet, c. low sodium diet (2 gm sodium/day diet), d. low calcium diet plus hydrochlorthiazide 25 mg twice a day according to a cross-over randomized block design. Each treatment regimen lasted two weeks and 24-hour urinary calcium concentrations were determined weekly. The result indicated that low calcium diet, low sodium diet or low calcium diet plus hydrochlorthiazide reduced hypercalciuria significantly (P less than 0.01). Low calcium diet combined with hydrochlorthiazide was the most effective treatment for hypercalciuria. In retrospective studies, we found that recently injured patients developed hypercalciuria, however, there was no significant difference in the incidence of bladder stone formation in patients with hypercalciuria compared with those with normal urinary calcium excretion.