Diagnosis and treatment of Paget's disease of bone.

Paget's disease of bone (PDB) is a metabolic bone disease characterized by increased bone resorption followed by excessive unregulated bone formation. This results in weakened, deformed bones of increased mass in which the collagen fibres assume a haphazard irregular mosaic pattern instead of the normal parallel symmetry. PDB rarely occurs before middle age and its prevalence increases steadily with age. The overall prevalence in Caucasians is approximately 3%; although it appears to be declining. There is a geographic variation in prevalence, with highest rates found in the UK. PDB affects both men and women, with a slight predominance in men. PDB may be asymptomatic or symptomatic, depending on the bones involved; the most common symptom is pain in the affected bone. While its aetiology remains elusive, genetic factors and environmental influences are implicated. In 2002, guidelines for PDB management were developed in Great Britain and have gained worldwide acceptance. In this position paper, an Expert Panel of Canadian endocrinologists and rheumatologists examines current evidence on the diagnosis and treatment of PDB to provide Canadian recommendations. In general, diagnosis may be confirmed both by X-ray and by the biochemical marker serum alkaline phosphatase, which is elevated in 85% of individuals with untreated active PDB. Treatment is indicated for all patients with symptoms and for asymptomatic patients with active PDB in areas of the skeleton with the potential to produce complications of clinical importance. The Panel recommends treating PDB with bisphosphonates that have demonstrated superior efficacy and remission rates.