ESPE Abstracts

Hereditary vitamin D-resistant rickets (HVDRR) is an autosomal recessive disorder characterized by end organ resistance to 1α,25-dihydroxyvitamin D3 (1,25D3). The syndrome is recognized by severe early onset rickets with bowing of the lower extremities, short stature, often alopecia and severe hypocalcemia.

Objectives: To study the effectiveness of our designed protocol of continuous high dose intracaval calcium infusion for the treatment of HVDRR.

Patients and Methods: We studied 12 patients with HVDRR, four of them had alopecia. Age of starting treatment protocol ranged from 2 -12 years. Daily infusions ranging from 1-2.2 g elemental calcium with oral phosphate from 1-2 g and oral calcium from 3.2–4.2 g elemental calcium were given for a period of 8-18 months. Followed by maintenance on oral calcium equivalent to 6.2 - 8g elemental calcium per day with oral phosphate 1-2 g. Measurements of serum calcium, phosphate and serum alkaline phosphatase were obtained before, during and after the calcium infusions. Urea and electrolytes, serum parathyroid hormone and vitamin D metabolites were measured prior to calcium infusion, then repeated monthly. Kidney ultrasound was done every 6-months. Skeletal X-ray was done before, 6 and 12 months of treatment.

Results: The daily intra-caval infusions of calcium with oral phosphate and calcium resulted in marvelous clinical, biochemical and radiological responses with normalization of calcium, phosphate, alkaline phosphatase and parathyroid hormone in 8-24 months with improvement in height slandered deviation. The patients showed no radiological evidence of nephrocalcinosis on follow up.

Conclusion: The use of intra-caval calcium infusions followed by high dose oral calcium with oral phosphate is an effective method for treatment of HVDR.