Summary

Paget´s disease of bone is a focal disorder of the skeleton, which may affect one single bone or several bones. It is characterized by increased bone turnover and by overgrowth. The bones affected by Paget´s disease exhibit diminished bone quality and increased fragility. Only a small fraction (about 5%) of patients with Paget´s disease suffer from clinical symptoms. These are overgrowth and deformation of bones, which are visible. The skin in the vicinity of affected bones can exhibit inflammatory signs like red colour and increased temperature. Bones affected by Paget´s disease may cause pain. However, pain may also result from adjacent joints and muscles, which are stressed. The biomechanic function of the skeleton is disturbed. The associated curvature of the pagetic femur or tibia causes instability of gait, leg length discrepancy and malalignment of the joints. When pagetic bone is proximal to a joint, pain and early osteoarthritis may occur. Adjacant organs may also be affected resulting from bone deformation, and compression of nerve channels may result in neurologic symptoms (nerve injury, chronic back pain). Further symptoms are hearing loss, dental problems, and depression. Cardiac symptoms are rare. During the last decades, not only the prevalence but also the severity of clinical symptoms appear to decrease. Because of the increase in bone turnover, Paget´s disease of bone results in an increase in biochemical markers of bone turnover. Typical is the marked increase in alkaline phosphatase, which correlates with disease activity and may serve for treatment monitoring.