CHRONIC INTOXICATION BY ETHANE-1-HYDROXY-1,1-DIPHOSPHONATE (EHDP) IN A CHILD WITH MYOSITIS-OSSIFICANS PROGRESSIVA

A child with myositis ossificans progressiva was treated for 8 years w ith ethane-1-hydroxy-1, 1-diphosphonate (EHDP) 30-40 mg/kg per day. La tterly he complained of severe, progressive bone and joint pain which made standing and walking almost impossible. A radiographic skeletal s urvey showed diffuse ricket-like lesions. Withdrawal of EHDP therapy p roduced substantial improvement in his general condition as well as in the radiographic appearance of the bones. Multiple exostoses were obs erved in this case and, particularly those around the knees, presented a peculiar morphology. This supports the theory that exostoses origin ate from a defect of metaphyseal modelling.