Abstract 31

Trying to increase bone mineral density (BMD) in patients with Osteogenesis imperfecta (OI), and so to decrease the incidence of fractures that results in ages between 2 and 15 years, received pamidronate by slow intravenous infusion (3 hs), in a dose of 0.3 - 1 mg/kg/day, during 3 days, every 3 or 4 months. During each infusion, oral calcium was added: 500-1000mg/day. Serum calcium and total alkaline phosphatase and urinary calcium excretion were measured before and at the end of 3 days infusion. BMD was measured in lumbar spine by dual energy X-ray absorptiometry (DEXA) and results were compared with those obtained in 3 children with OI that were without treatment. Results: Median (range) BMD increased at 6 months was 18.8% (-1.5 to 31%). Different to the 2% (0.3 - 3%) observed in the children with OI without treatment. No changes in serum calcium levels were observed before and after pamidronate infusion. A reduction of 5% and 24% in levels of serum total alkaline phosphatase and urinary calcium excretion respectively, were found. One child presented fever during infusion, and another one referred parestesias after it. During 6 months treatment 2 children diminished the fracture incidence in relation to a similar period prior to treatment. All children showed a better exercise tolerance. These preliminary results suggest that pamidronate intravenous infusion can increase BMD in children with OI. To confirm this, a longer time of follow up is necessary.