[Bone and phosphoro-calcium metabolism in reflex sympathetic dystrophy]

A combined study organised by the French Society of Rheumatology was devoted to the investigation of bone and phosphoro-calcium metabolism in cases of reflex sympathetic dystrophy. The following observations were made: the usual phosphoro-calcium parameters are not altered, apart from a slight elevation of the urinary calcium in multifocal forms of the disease, during the 3rd and 4th months; the level of PTH, studied in 11 patients, was normal in each case; the examination of 8 bone biopsies, one performed in the 7th week and six others performed during the 3rd and 4th months of the disease, showed, initially, invasion of the spongy tissue by oedema, signs of marrow stress and bone stress, with a reduction in the number of osteoblasts, without any marked alteration of bone remodelling. At a later stage, the biopsy shows intense bone remodelling with hyperosteoclastosis and hyperosteoblastosis and the formation of irregular bone tissue which later becomes lamellar. Electron microscopic study of two biopsies revealed signs of acellular demineralisation with normal appearance of the osteoblasts and osteoclasts.