Normal bone turnover markers in a patient with active Paget's disease of bone: response to treatment with zoledronic acid.

The treatment of Paget's disease of bone (PDB) aims at the suppression of abnormal bone turnover; bisphosphonates are currently the treatment of choice. Indications for antiresorptive treatment in symptomatic patients with PDB include bone or joint pain, neurological complications, surgery planned at an active pagetic site and hypercalcaemia from immobilisation. The goals of antiresorptive treatment are clinical improvement and biochemical remission, as assessed by the normalisation of bone turnover markers. Clinical deterioration, especially bone pain, should be considered before deciding to treat patients with late sclerotic (burned-out) PDB. Bone scintigraphy may be of importance in these patients, because it depicts increased osteoblastic activity, when bone markers may not. We present a case of late sclerotic PDB with clinical deterioration but normal bone turnover markers, who experienced significant clinical improvement after treatment with zoledronic acid.