The Combined Use of Intravenous and Oral Calcium for the Treatment of Vitamin D Dependent Rickets Type II

The study assessed the effectiveness of intravenous high-dose calcium infusions followed by high-dose oral calcium in treating vitamin D dependent rickets type II (VDDRII) in two siblings. The treatment normalized calcium and phosphate levels within 3-5 days and alkaline phosphatase and PTH levels within 15-20 months, with radiological healing observed in 42 days. The elder sister received daily infusions for 3-5 months, and the younger brother for 2 months, both followed by weekly infusions and maintenance on oral calcium. The treatment led to complete biochemical and radiological healing, improved height, and no evidence of nephrocalcinosis or kidney function deterioration. Early treatment was crucial for better growth and prevention of bone deformities, and it may also improve alopecia, though the mechanism requires further investigation.