Osteitis Deformans (Paget Disease of Bone)
- Focal disorder of hyperactive bone resorption followed by excessive bone formation (remodeling) that is stimulated by abnormal osteoclasts
- Results in enlarged, disorganized, weakened, and highly vascularized mosaic of bone
- Painful condition, with easily deformed bone that is subject to fractures from minimal trauma
- Most commonly affected sites:
- Pelvis, spine, skull, extremities
- Cranial and vertebral involvement can lead to neurologic deficits.
- Synonym(s): Paget disease of bone; osteodystrophia deformans
- Predominant age: >50 years
- Less common in patients from ages 20 to 50 years
- Does not occur in children (Juvenile Paget disease is unrelated to the adult disease.)
- Predominant sex: males > females (1.8:1)
- Prevalence increases with increasing age.
- More common if Caucasian, especially in United Kingdom, France, Germany, Italy, United States, Australia, or New Zealand
- 3% of Caucasians >50 years have at least one gene focus.
- Rare in African Americans and Asians
- Incidence and prevalence have decreased in recent years; likely due to genetic and environmental factors
Etiology and Pathophysiology
- Unknown, although several theories proposed:
- Slow viral infection (controversial): due to paramyxovirus, respiratory syncytial virus, canine distemper virus and measles; causing expression to develop over many years
- Zoonotic infections
- Toxin occupational exposure
- Childhood malnutrition—vitamin D deficiency or low dietary calcium
- Three pathologic phases:
- Lytic phase: Osteoclasts are large, contain 10 to 100 nuclei, and have abnormal configuration.
- Mixed phase: Excessive osteoblastic bone formation predominates from increase in number of osteoblasts; nonlinear collagen deposition results.
- Sclerotic phase: Sclerotic bone–containing cement lines form a mosaic pattern (woven bone), with vasculature infiltration and fibrous connective tissue deposition.
- At least seven genetic loci have been identified that are associated with Paget disease of bone.
- Mutations in SQSTM1, predominately ubiquitin-binding associated (UBA) domain and P392L, are associated. Product of SQSTM1 affects osteoclast differentiation and activation.
- First-degree relative with osteitis deformans (OD)
- 15–30% of patients note a family history of OD.
- Caucasian and European ethnicity
Fracture reduction: Avoid excessive mechanical stress on afflicted bones.
Commonly Associated Conditions
- Secondary osteoarthritis
- Peyronie disease
- Accelerated atherosclerosis
- Osteoporosis circumscripta
- Frontotemporal dementia (rare)
- Hereditary inclusion body myopathy (rare)
- Bone sarcoma (rare)
There's more to see -- the rest of this topic is available only to subscribers.