What is Paget’s disease of the bone?
Paget’s disease of the bone is a chronic disorder in which the normal cycle of bone renewal is disrupted. Osteoclasts break down old bone faster than usual and osteoblasts form new bone in a disorganized way. The resulting bone is larger, weaker, and more prone to deformity and fractures. Commonly affected sites include the skull, spine, pelvis, and long bones of the arms and legs.
What causes Paget’s disease of the bone?
The exact cause is unknown, but several factors appear to increase risk:
- Genetic factors: Family history of the disease increases likelihood.
- Viral infections: Certain slow-acting viruses have been proposed as triggers.
- Age: Rare before age 40; risk increases with advancing age.
- Geography: More common in Europe (especially the UK), North America, Australia, and New Zealand.
- Gender: Slightly more frequent in men than women.
What happens in Paget’s disease of the bone?
Normally, bone is constantly remodeled by paired actions of osteoclasts (resorption) and osteoblasts (formation). In Paget’s disease:
- Osteoclasts become overactive and resorb bone excessively.
- Osteoblasts respond by creating new bone rapidly but in a chaotic, disorganized pattern.
- The new bone is structurally unsound and prone to enlargement, deformity, and fracture.
What are the symptoms of Paget’s disease of the bone?
Many people have no symptoms and are diagnosed incidentally. When symptoms occur, they may include:
- Deep, aching bone pain
- Joint pain and stiffness
- Enlarged or misshapen bones
- Increased fracture risk
Symptoms by location:
- Pelvis: Hip pain
- Spine: Back pain, possible nerve compression causing leg numbness or tingling
- Skull: Headache, hearing loss
- Legs: Bowing of the femur or tibia, knee pain
What are the complications of Paget’s disease?
- Osteoarthritis from altered bone shape and joint alignment
- Pathologic fractures
- Rare development of bone cancer (osteosarcoma)
- High-output heart failure if extensive bone involvement increases blood flow demands
- Hypercalcemia if bone breakdown releases excess calcium
How is Paget’s disease of the bone diagnosed?
Clinical evaluation
- Medical history and family history
- Physical exam for bone tenderness, deformities, and neurologic signs
Imaging
- X-rays to identify characteristic bone changes
- Bone scan (scintigraphy) to locate all affected sites
Laboratory tests
- Serum alkaline phosphatase (ALP) often elevated
- Calcium and vitamin D levels to rule out other disorders
In rare cases, bone biopsy may be needed to exclude malignancy.
How is Paget’s disease of the bone treated?
Medications
- Bisphosphonates (alendronate, risedronate, zoledronic acid) to inhibit bone resorption
- Calcitonin (salmon calcitonin) if bisphosphonates are not tolerated
Pain management
- Nonsteroidal anti-inflammatory drugs (ibuprofen, naproxen)
- Acetaminophen for pain relief
Surgery
- Fracture repair
- Joint replacement for severe arthritis
- Osteotomy to correct bone deformities
- Decompression to relieve nerve pressure
Lifestyle and supportive care
- Adequate calcium and vitamin D intake
- Exercise to maintain mobility and strength
- Assistive devices (canes, walkers) to reduce fall risk
Regular monitoring with blood tests and imaging helps assess treatment response and detect complications early.
Sources
- MedlinePlus. Paget’s disease of the bone. Accessed May 15, 2024.
- Cleveland Clinic Journal of Medicine. Seton M. Paget disease of bone: Diagnosis and drug therapy. 2013;80(7):452–462.
- NIH Osteoporosis and Related Bone Diseases National Resource Center. How is Paget’s disease of the bone diagnosed? Accessed May 15, 2024.
- National Organization for Rare Disorders. Paget’s Disease. Accessed May 15, 2024.
- National Institute of Arthritis and Musculoskeletal and Skin Diseases. Paget’s Disease of Bone. Accessed May 15, 2024.