CLINICAL, HUMORAL AND CENTELLOGRAPHIC ASSESSMENT OF PAMIDRONATE AS POTENTIAL TREATMENT OF DIAPHYSEAL DYSPLASIA - RIBBING AND CAMMURATI-ENGELMANN-DISEASES

Cammurati-Engelmann's Disease or Progressive Diaphyseal Dysplasia (PDD ), is a rare autosomal dominant disorder, sometimes non hereditable, w hich begins in childhood, and is characterized by symmetrical excess o f osseous apposition in diaphysis and metaphysis of long bones. In sev ere cases skull and vertebrae could be involved. Clinically, patients refer limb pain, muscular weakness and atrophy, easy fatigability and waddling gait. Later on, S. Ribbing described an illness that he thoug ht was a separate entity with sclerosis and enlargement of diaphysis o f femora and tibiae, which begins after puberty, is less extensive, no t always symmetric and without gait or neurological involvement. Some authors think it may be an adult form of the PDD. As no specific treat ments are available we report one case of each entity, treated with th e bisphosphonate pamidronate, by the oral route. A white female, 69 ye ars old, with clinic and radiology of Ribbing's Disease, had positive scintigraphy in the affected areas and elevated bone biochemical marke rs: Serum alkaline phosphatase (SAP): 57 UKA. Total urinary hydroxypro line (THP): 60 mg/24 h. Bone Gla protein (BGP): 40 ng/ml. Considering the high bone turnover treatment with oral pamidronate, 400 mg/day plu s Calcium 1g/day was started, dose was then progressively reduced. Aft er two months pain almost disappeared, and THP became normal: 14 mg/24 h; with normalization of BGP values: 8 ng/ml, and a decrease of SAP: 21 UKA. Tc-99m MDP uptake by affected bones decreased after 1 year of treatment. Because of these results we decided to begin treatment in a white female 17 years old, 32 kg weight, 1.47 m height with PDD chara cteristics and also a high bone turnover (THP: 95 mg/24 h, SAP: 32 UKA ). After six months of Calcium 1 g/day, given with meals, and oral pam idronate 100 mg/day, she became painless with normal strength and gait , almost normalization of THP (48 mg/24 h). Although a small decrease of SAP, and no changes in scintigraphy. These results obtained with pa midronate suggest that it mat be useful to treat dysplasias with high bone turnover.