Osteoporosis is the most important
metabolic bone disease and places an increasing burden on the healthcare system. The condition can be prevented by the early introduction of
hormone replacement therapy. The role of
bisphosphonates in achieving the same result is being actively explored. The attraction of preventing bone loss is that it preserves the micro-architecture of bone, and therefore its mechanical integrity. The great problem of treating the established condition is that substantial bone loss is accompanied by architectural disintegration. Replacing lost bone may not necessarily restore mechanical integrity and protect against fractures. The management of Paget's disease has been quite revolutionised by the introduction of the
bisphosphonates. The condition is a result of a primary increase in osteoclastic
bone resorption which can be corrected by
bisphosphonates, with considerable symptomatic improvement. The increasing potency and safety margin of the newer agents has meant that the threshold for treatment has fallen. There is now potential for long term control of bone turnover with the hope of preventing late complications. Hypercalcaemia of
malignancy is usually the result of both increased bone destruction and decreased urinary
calcium excretion. These two components of hypercalcaemia demand different approaches to management. The general availability of an ever-expanding range of increasingly potent
bisphosphonates has resulted in a dramatic improvement in the treatment of increased
bone resorption associated with
malignancy. Many types of tumour, either directly or indirectly, compromise the ability of the kidney to eliminate a
calcium load derived from increased bone destruction.
Calcitonin is the only agent which is currently available to counter this process.