DECREASED CORTICAL AND INCREASED CANCELLOUS BONE IN 2 CHILDREN WITH PRIMARY HYPERPARATHYROIDISM

The basis for this study is two children with primary hyperparathyroid ism (PHPT) who radiagraphically manifested both marked subperiosteal r esorption and prominent osteosclerosis. We hypothesize that the parath yroid hormone (PTH) elevation not only increased osteoclastic resorpti on of cortical bone but also simultaneously enhanced cancellous bone f ormation, giving rise to osteosclerosis. In this report, we describe t he changes in trabecular and cortical bone density, as measured by qua ntitative computed tomography (QCT), in these two young patients with severe PHPT, before and after removal of a parathyroid adenoma. Before surgery, the radiographic findings of subperiosteal resorption and os teosclerosis were associated with low cortical and high cancellous bon e density values in both children. Within 1 week of surgery, both cort ical and cancellous bone density values increased and serum concentrat ions of calcium and, to a lesser degree, phosphorus decreased due to t he ''hungry bone syndrome.'' Twelve weeks after parathyroidectomy, QCT bone density values and skeletal radiographs were normal in both pati ents. The findings suggest that in patients with severe PHPT, the cata bolic effect of PTH on cortical bone may be associated with a simultan eous anabolic effect on cancellous bone, and PTH may cause a significa nt redistribution of bone mineral from cortical to cancellous bone. Co pyright (C) 1996 by W.B. Saunders Company