Paget's Disease of Bone – Top USMLE Diseases

Bisphosphonates are pyrophosphate analogs most well-known for treating osteoporosis by preventing bone loss. Bisphosphonates end in the suffix “-dronate” or “-dronic acid" (e.g., alendronate, risedronate, pamidronate) and bind to hydroxyapatite crystals in bone, inhibiting osteoclast-induced bone resorption. Bisphosphonates are indicated for postmenopausal osteoporosis, glucocorticoid-induced osteopenia/osteoporosis, and Paget disease of the bone. Adverse effects include hypocalcemia, hypophosphatemia, avascular necrosis of the femur, and osteonecrosis of the jaw. Contraindications include hypersensitivity reactions and esophageal disorders. Bisphosphonates may interact with aminoglycosides, aspirin, and proton pump inhibitors.

Paget's disease of bone (PDB), also known historically as osteitis deformans, is a focal disorder of bone metabolism that affects about 2%–9% of people. Commonly affected areas include the skull, spine, pelvis, and long bones of the lower extremity. The 2 main clinical manifestations of Paget's disease are bone pain and the consequences of bone deformities, such as fractures, osteoarthritis, or nerve impingement. The management includes bisphosphonates, calcitonin, and surgery for the management of fractures, deformities, and complications. The prognosis for PDB is good, especially if treatment is started before major changes have occurred in the bones.