Paget’s Disease


  • Common; incidence rises with age; estimated up to 8% of people 85 or over
  • Characterised by focal areas of disorganised bone remodelling


  • Genetic component- ~15% have a family history; mutations of the sequestosome 1 gene (SQSTM1) have been shown to be important
  • Paramyxovirus infections (e.g. measles; RSV) are potentially triggers (although the exact association is debated)


  • Lytic Phase
    • Rapid increase in bone resorption by osteoclasts, followed by an increase in osteoblastic activity in response
      • The new bone produced by the osteoblasts is poorly organised, structurally weak and highly vascular (osteoblast activity is excessive in an attempt to keep up with osteoclast activity)
        • increased vascularity and formation of arteriovenous shunts can cause an increase in cardiac output to compensate
        • can also cause a degenerative arthritis
  • Intermediate phase
    • As osteoclastic activity decreases, there becomes a point where osteoclast and osteoblast activity equalise and bone remains fairly stable
  • Sclerotic/Blastic phase
    • Eventually, osteoclastic activity burns out and osteoblastic activity persists, and woven (unorganised) bone is replaced by lamellar bone.  After this, disease becomes quiescent.
  • Although it can affect any bone in the body, Paget’s tends to affect the axial skeletal, long bones and the skull


  • Classically, bone pain, deformity (particularly of the long bones e.g. femur; and the skull), deafness (not due to compression of the auditory nerve but conduction impairment due to otosclerosis), osteo-(degenerative) arthritis and pathological fractures
    • Many patients won’t present with all (or any) features and can be diagnosed by incidental x-ray
    • Other features include other cranial nerve palsies, radiculopathy, spinal cord compression/spinal stenosis
    • Patients have a small risk of developing osteosarcoma


  • Bone biochemistry
    • Raised Alk Phos
    • May have normal calcium and normal-low phosphate
    • Vitamin D may be normal
  • X-ray
    • Bone expansion, with alternating areas of radiolucency and osteosclerosis (woven bone)
  • Radionuclide scanning
    • Highlights areas of active disease
    • Identify the extent of disease


  • Bisphosphonate treatment (for active disease)
    • Make sure to correct any vit D and calcium deficiency prior to treatment to avoid hypocalcaemia
    • If pain does not improve with bisphosphonates, it is likely that pain is actually due to a complication e.g. osteoarthritis, fracture etc
  • Calcitonin can also be used
  • NSAIDs may be useful for pain

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