Paget's Disease of Bone

Question 1

Define Paget’s disease

Answer 1

Excessive bone remodelling at one or more sites -> structurally
disorganised bone
Commonly affects the femur, pelvis, skull and tibia

Question 2

What are the causes/risk factors of Paget’s disease?

Answer 2

Excessive bone resorption followed by increased bone formation
in a disorganised fashion -> abnormal mosaic lamellar bone
• Genetic
• Viral infection e.g. paramyxovirus (measles)

Question 3

What are the symptoms of Paget’s disease?

Answer 3

• Asymptomatic
• Insidious onset pain worse on weight-bearing and
movement
• Headaches
• Deafness
• Fractures

Question 4

What are the signs of Paget’s disease?

Answer 4

• Bitemporal skull enlargement with frontal bossing
• Kyphosis
• Anterolateral bowing of femur, tibia, forearm
• Warm skin over bones involved
• Sensorineural deafness
• High output cardiac murmur

Question 5

What investigations are carried out for Paget’s disease?

Answer 5

• ALP - elevated
• Ca2+ - normal, except if immobilised.
• PO43- - normal, except if immobilised.
• X-Rays - enlarged, deformed bones with mixed lytic/sclerotic appearance.
- Lack of distinction between cortex and medulla.
- Skull: Osteoporosis Circumscripta, enlargement of frontal and occipital areas, associated with a ‘cotton wool’ appearance.
• Radioisotope Bone Scan - 99mTC MDP: To assess the extent of skeletal involvement, but is not specific for diagnosis. Lesions are seen as focal areas of markedly increased uptake (hotspots).
• Urinary Hydroxyproline - excretion is increased and may also be used as a marker of disease activity.