Bone status in primary hyperparathyroidism

Traditional bone involvement, such as osteoitis fibrosa, has become very ra re (< 1%) in primary hyperparathyroidism (PHPT); nevertheless, fractures se em more frequent than in controls, with a predilection for fractures of the distal extremity of the radius, pelvis, ribs and vertebrae, and a relative modest incidence of fractures of the upper extremity of the femur. Histo-m orphometric studies have stressed a discrepancy between cortical and trabec ular bone with an increase of bone remodeling. The cortical width is consta ntly diminished and the cortical porosity is increased whereas trabecular v olume is normal and micro-architecture preserved. Bone mineral density (BMD ) allows an early diagnosis of bone disease and takes a growing place in th e management of patients. Since the consensus conference in 1991, the measu rement of BMD has been incorporated in the surgical decision with a thresho ld: Z-score < -2. The demineralisation predominates on sites rich in cortic al bone (1/3 proximal of the distal radius); the radius, which was the firs t site evaluated for technical reasons, is also the most discriminating one . Spine demineralisation is met in more severe forms and BMD measurement of the whole body is promising but requires more studies. In the absence of a radical processing, moderate forms remain stable, whereas more severe form s have a tendency to deteriorate. The evaluation of spine and femoral BMD i s useful for the follow-up because the bone gain after parathyroidectomy is significant early on at these sites (rich in trabecular bone with high bon e turnover), whereas the BMD of radius is relatively stable. Joint Bone Spi ne 2001 ; 68 : 112-9. (C) 2001 Editions scientifiques et medicales Elsevier SAS.