CASE REPORT: PAMIDRONATE INFUSION IN A 3-MONTH OLD INFANT WITH OSTEOGENESIS IMPERFECTA

Abstract

INTRODUCTION
Bisphosphate is a well-recognised treatment for children with osteogenesis imperfecta (OI). However, for neonatalonset or young infants, there are no large groups reported and no clear guideline on the safest dosing regimen.

CASE
Our patient presented with a left femur fracture at the age of 1.5 months. A week later, she was diagnosed with severe OI when she suffered four more fractures despite minimal handling; bilateral humerus, left clavicle and right femur. Her sclerae had a tinge of blue at first review. She was started on pamidronate two-monthly cycle (regimen as below) at 3 months old after the fractures had healed. Prior to pamidronate, she was started on cholecalciferol with optimisation of vitamin D level>75 nmol/L. 1st cycle 0.25 mg/kg for 1 day, 2nd cycle 0.25 mg/kg for 3 days, Subsequent cycles 0.5 mg/kg for 3 days every 2 months (total dose 9 mg/kg/year). For the 1st cycle of pamidronate, she had transient hypophosphatemia and mild hypocalcemia 2.02 mmol/L post-infusion, easily corrected with oral calcium carbonate and calcitriol. For the 2nd cycle, she was also given a short course of oral calcium carbonate and calcitriol as post-infusion her calcium level was borderline at 2.1 mmol/L. Subsequently for her 3rd and 4th cycle, her calcium levels were stable post-infusion with no need for additional supplements. In total, she received 4 cycles 2 monthly apart (total cumulative dose 3.8 mg/kg) and did not had any recurrent fractures since treatment. There had also been a marked improvement in her gross motor development and mobilisation.

CONCLUSION
We report a young infant with OI who showed a good short-term outcome with pamidronate treatment and tolerated well our dosing regimen.