Hypercalciuria in chronically institutionalized bedridden children: frequency, predictive factors and response to treatment with thiazides.

Calcium and creatinine concentrations were analyzed in urine samples of 42 chronically institutionalized bedridden children, with neurologic disorders. Their ages ranged from 2 to 16 (mean 8.7) years. Hypercalciuria, defined as UCa/UCr ratio greater than 0.21, was recognized in 18 children (42.8%), the mean UCa/UCr ratio of this group was 0.40 +/- 0.18. Twenty-four children were normocalciuric, with a mean UCa/UCr ratio of 0.08 +/- 0.03. There were no significant differences between the two groups with regard to age, sex, length of institutionalization, the basic neurologic disorder, diet, anticonvulsive medications, exposure to sunlight and weekly hours of physiotherapy. Age- and sex-matched percentiles for fat and muscle areas were similar in both groups. Seven limb fractures had occurred in the hypercalciuric group during the last three years, but only in one of the normocalciuric patients (p less than 0.02). The hypercalciuric children were treated with a hydrochlorothiazide-amiloride preparation for three weeks, which resulted in reduction of their mean UCa/UCr ratio by 57.7%, to 0.17 +/- 0.13 (p less than 0.005); only four children remained hypercalciuric. We conclude that resorptive hypercalciuria is common among chronically immobilized bedridden children. Hypercalciuria in such children should be specifically looked for, because of its association with deranged bone metabolism and increased frequency of limb fractures. Treatment with thiazides was found to be efficient in reducing urinary calcium excretion in our hypercalciuric patients. This therapeutic modality for the reduction of morbidity in bedridden chronically immobilized children should be further explored.