Brief Overview: Paget disease of bone (PDB), also known historically as osteitis deformans, is a focal disorder of bone metabolism that occurs in the aging skeleton; it is characterized by an accelerated rate of bone remodeling, resulting in overgrowth of bone at single (monostotic PDB) or multiple (polyostotic PDB) sites and impaired integrity of affected bone. Commonly affected areas include the skull, spine, pelvis, and long bones of the lower extremity.
Prevalence: Paget disease of bone (PDB) is a fairly common finding in aging bone, with estimates ranging from 2.3 to 9 percent in older patients within affected populations; it is often asymptomatic. Its onset is typically after age 55, with a slight predominance in men in some but not all studies. It is common in England, Scotland, Central Europe, and Greece, as well as in countries and cities settled by European immigrants, such as those in Australia, Canada, and the United States. Even within these countries, there are geographical clusters of disease. Paget disease is rarely reported in the Scandinavian countries and Asia.
Etiology: The cause of Paget disease is unknown. A person's genes may predispose them to developing Paget disease, while viruses and other environmental exposures may trigger its development.
Risk Factors:
- Genetic factors
- Family history
- Age > 55 years of age (rarely manifests prior to age 40)
- Male gender slightly more predominant
- European ancestry
- Potential environmental influences, like viral infection – information on this is limited
Commonly Associated Conditions:
- Osteoarthritis
- Hyperparathyroidism
- Hearing Loss – if Paget disease affects the skull
- Hyperuricemia
- Peyronie’s disease, and other fibrosing disorders
Common Medications:
- Bisphosphonates – inhibit the breakdown and removal of bone by inhibiting the osteoclast. Some common bisphosphonates are: alendronate, risedronate, pamidronate, and zoledronic acid. Sometimes other bisphosphonates may be used based on cost and availability. Your healthcare provider will likely make specific recommendations regarding calcium and Vitamin D supplementation when taking a bisphosphonate.
Common Labs, Imaging, and Tests:
- Blood test – serum alkaline phosphatase, serum calcium, serum Vitamin D
- Bone specific alkaline phosphatase
- Bone scan
- X-ray
- MRI/CT
Common Symptoms: The majority of patients with PDB are asymptomatic. The diagnosis in such patients is usually made incidentally following a routine chemistry screen showing an elevated serum concentration of alkaline phosphatase of bone origin or an imaging study obtained for some other reason that shows pagetic changes in bone.
The two main clinical manifestations of Paget disease are pain due to the pagetic lesion in bone itself or from secondary consequences of bone overgrowth and deformities in affected areas, such as osteoarthritis or nerve impingement. Fractures, bone tumors, neurologic disease, and abnormalities in calcium and phosphate balance can also occur. In addition, because of the vascularity of pagetic bone, excessive bleeding may occur during orthopaedic surgery.
When there are symptoms present, it can be related to Paget disease itself or to complications that occur because of abnormal bone growth. These symptoms can include, but are not limited to:
- Pain – typically mild to moderate and described as deep and aching, often reported to be worse at night
- Deformities
- Fractures
- Bone tumors – rare
- Hearing loss – if Paget disease affects the skull
Common Treatments:
- Medication to treat Paget disease
- Pain medication
- Surgery - sometimes the joints adjacent to affected bones become stiff and painful due to arthritis. Some patients with severe arthritis pain can benefit from joint replacement, if indicated.
Physical Findings:
- Skeletal deformity – may manifest as an increase in the size and/or abnormal shape of the bone
- Bowing of the femur or tibia can occur if these bones are involved
- Increased warmth of an affected bone – attributed to increased blood flow
- Skeletal growth or expansion occurs with Paget's disease of bone, becoming clinically obvious when the disease involves the skull, jaw, clavicle, femur, or tibia
Potential Complications and Contraindications, including, but not limited to:
- Because of the vascularity of pagetic bone, excessive bleeding may occur during surgery
- Fractures
- Hearing loss – if Paget disease affects the skull
- Osteoarthritis
- Bowing of the lower extremity
- Paralysis – often reversible
- Neoplasms – arise in less than 1% of patients with Paget’s disease of bone
- Benign giant cell tumors – rare
- Heart Failure
General Health and Lifestyle Guidance:
- Maintain mobility and bone strength through weight-bearing exercises. Discuss what kinds of exercises are safe for you with your healthcare provider
- Discuss the recommended amounts of calcium and vitamin D intake with your healthcare provider
- Avoid high-impact activities that may increase fracture risk, if directed to do so by your healthcare provider
- Use assistive devices or home modifications if indicated
- Monitor hearing and vision regularly
Suggested Questions to Ask Patients:
- Are you experiencing any new or worsening bone pain?
- Have you noticed any changes in your hearing?
- Do you have a family history of bone disorders?
- Are you having any difficulties with mobility or joint stiffness?
Suggested Talking Points:
- Explain that Paget disease is typically manageable with medication and monitoring
- Reassure that while complications can occur, a lot of people maintain a good quality of life
- Emphasize the importance of routine follow-up and lab testing, as directed by healthcare provider
- Educate on signs of complications (e.g., sudden pain, paralysis, hearing loss, etc.) that require prompt attention
Resources:
UpToDate
https://academic.oup.com/jcem/article/99/12/4408/2833929?login=false