PAGET"S DISEASE

Question 1

What is PD?

Answer 1

• Also known as osteitis deformans.

- A focal disorder of bone remodeling

Question 2

What is the aetiology of PD?

Answer 2

• unknown
• may result from latent viral infection (canine distemper virus, measles or respiratory syncytial virus) in osteoclasts in genetically susceptible individuals.

Question 3

Describe the pathophysiology of PD

Answer 3

• There is increased osteoclastic bone resorption followed by formation of WEAKER NEW BONE, increased local bone blood flow and fibrous tissue
• Ultimately, formation exceeds resorption but the new woven bone is WEAKER than normal bone - this leads to deformity and increased fracture risk
• Disease doesn’t spread but can become symptomatic at previously silent sites

Question 4

What are the risk factors of PD?

Answer 4

Family History

Question 5

What is the epidemiology of PD?

Answer 5

• Incidence increases with age - rare under 40 yrs
• Affects up to 10% of individuals by the age of 90
• More common in Europe and Northern England
• UK has highest prevalence in the world
• More common in FEMALES then males

Question 6

What are the common sites affected by PD?

Answer 6

• pelvis
• lumbar spine
• femur
• thoracic spine
• skull
• tibia

although any bone can be involved but small bones rare.

Question 7

What are the signs and symptoms of PD?

Answer 7

Signs:
-Deformities, in particular bowed tibia and skull changes

Symptoms:
-Bone pain
-Joint pain - when an involved bone is close to a joint
-Neurological complications due to nerve compression:
>Deafness from 8th cranial nerve involvement
>Paraparesis - partial paralysis of lower limbs
>Hydrocephalus due to blockage of the aqueduct of Sylvius
-High-output cardiac failure and myocardial hypertrophy due to increased bone blood flow - rare

Question 8

What are the investigations of PD?

Answer 8

• Bloods; raised ALP, normal Ca and Pho
• Urinary hydroxyproline excretion is raised - marker of disease activity
• X-ray
• Isotope bone scans - Useful to determine the extent of skeletal involvemen

Question 9

What might be seen on an X-ray for PD?

Answer 9

• Localised bony enlargement and distortion
• Sclerotic changes (increased density)
• Osteolytic areas (loss of bone and reduced density)

Question 10

What is the treatment and management of PD?

Answer 10

• Bisphosphonates e.g. IV/Oral Zolendronate or Oral Alendronate which inhibit bone resorption by decreasing osteoclast activity - 1st line treatment
• NSAIDs e.g. Ibuprofen for pain

-Disease activity monitored by symptoms and measurement of serum ALP or urinary hydroxyproline