Renal bone disorders in children: therapy with vitamin D3 or 1,25-dihydroxycholecalciferol.

Twelve children with chronic renal failure (CRF) and sixteen children receiving regular dialysis therapy (RDT) were treated with between 10,000 and 50,000 IU of vitamin D daily. This was associated with an increase in serum calcium levels and reduction in PTH levels. In the children with CRF, secondary hyperparathyroidism was improved with treatment but its development was not completely prevented nor was healing complete. In the patients receiving RDT, treatment with vitamin D improved the changes associated with secondary hyperparathyroidism in 50% of cases but these features sometimes reappeared despite continuing treatment. Hypercalcaemia or metastatic calcification was not seen. Subsequently, 1,25(OH)2D3 was administered to 14 children receiving RDT. This was associated with the return of serum calcium levels to normal, inhibition of PTH synthesis and an improvement in intestinal calcium absorption. Fibro-osteoclasia was cured and there was improvement in actual bone resorption. There was also improvement in osteoidosis in those children who showed disturbances of mineralisation. Calcification in the limbus area of the eyes may occur and hypercalcaemia was seen commonly. Treatment with 1,25(OH)2D3 should only be offered to children with severe renal bone disease. Neither vitamin D3 nor 1,25(OH)2D3 can guarantee complete recovery of osteodystrophy and of growth arrest in uraemic children.