Paget's Disease of Bone Flashcards
Define
Characterized by excessive bone remodelling at one (monostotic) or more (polyostotic) sites resulting in bone that is structurally disorganized
Aka. osteitis deformans
Increased bone turnover associated with increased numbers of osteoblasts and osteoclasts
→ With resultant remodelling, bone enlargement, deformity, and weakness
Causes
Causes → aetiology unknown
Genetic factors and viral infection may play a role
Excessive bone resorption by abnormally large osteoclasts is followed by increased bone formation by osteoblasts in a disorganized fashion
This results in an abnormal (mosaic) pattern of lamellar bone
The marrow spaces are filled by an excess of fibrous tissue
with a marked increase in blood vessels.
Epidemiology
Rare in the under-40s
Incidence rises with age (3% over 55yrs old, 10% of all 80yrs old) Commoner in temperate climates, and in Anglo-Saxons
Symptoms
Asymptomatic in ~70%
May be ASYMPTOMATIC
May present with insidious onset pain, which is aggravated by weight bearing and movement
Headaches
Deafness
Increasing skull size
Signs
Bitemporal skull enlargement with frontal bossing (prominent, protruding forehead)
Spinal kyphosis
Anterolateral bowing of femur, tibia or forearm
Skin over the affected bone may be warm (due to increased vascularity)
Sensorineural deafness (due to compression of vestibulocochlear nerve)
Investigations
Bloods
- High ALP
- Ca2+ and phosphate = NORMAL
Bone Radiographs
- Enlarged, deformed bones
- Lytic and sclerotic appearance
- Lack of distinction between cortex and medulla
Skull changes:
- Osteoporosis circumscripta
- Enlargement of frontal and occipital areas
- Cotton wool appearance
Bone Scan
- Assesses extent of skeletal involvement
- Pagetic bone lesions are seen as areas with markedly increased uptake
Resorption Markers
- Monitors disease activity
- Check urinary hydroxyproline
