Paget's disease of bone

Question 1

What is thought to be the cause of Paget’s disease of the bone?

Answer 1

There is thought to be a genetic element, with 5-10% having mutations that increase activity of Nfkß, and RANKL, which is an osteockast receptor activator Nfkß ligand

Question 2

What is Paget’s disease of the bone?

Answer 2

Paget’ disease of the bone is a chronic condition involving cellular remodelling and deformity of one or more bones (Osteitis deformans)

Question 3

Who is most at risk Paget’s disease of the bone?

Answer 3

Late adulthood
Males

Question 4

What are some viral infections that can predispose to Paget’s disease of the bone?

Answer 4

Paramyxovirus
Measles
RSV

Question 5

How can measles predispose to Paget’s disease of bone?

Answer 5

Measles virus nucleocapsid protein MVNP is found in Paget’s and seems to stimulate osteoclast activity

Question 6

What bones are most commonly affected by Paget’s disease of bone?

Answer 6

Long bones
Pelvis
Lumbar spine
Skull

Question 7

Describe the pathophysiology of Paget’s disease of bone

Answer 7

Abnormal osteoclastic activity, followed by increased osteoblastic activity results in abnormal bone structure with reduced strength and increased fracture risk

The net result is thick excess bone with abnormal reversal lines with a mosaic pattern

So bone will mature, but is soft and porous

Question 8

What are the 3 stages of Paget’s disease?

Answer 8

• Osteolytic (Resorption pits with large osteoclasts)
• Mixed (Osteoclasis and osteoblastic activity)
• Osteosclerotic

Question 9

How will Paget’s disease of the bone present?

Answer 9

This is often asymptomatic, however, micro-fractures or nerve compression will cause pain

Question 10

What are some example of bone deformities in Paget’s disease of bone?

Answer 10

• Leontiasis ossea - New hats
• Platybasia - Skull base deformity
• Sabre tibia

Question 11

What are some complications of Paget’s disease of bone?

Answer 11

Increased metabolism will lead to heat, warm skin, AV shunt and effectivey high output heart failure

This can lead to secondary malignancy - Osteosarcoma or fibrosarcoma

Question 12

What are the main tests used in Paget’s disease of bone?

Answer 12

X-ray
Isotope bone scanning
Bloods

Question 13

What will X-ray show in Paget’s disease of bone?

Answer 13

• Well defined lucency in initial lytic phase
• Enlarged bone, increased density and coarse trabecular pattern in later sclerotic phase

Question 14

What will blood testing show in Paget’s disease of bone?

Answer 14

Raised ALP (Possibly)

Question 15

How should Paget’s disease of bone be managed?

Answer 15

1st line - Analgesics only
2nd line - Bisphosphonates

Surveillance if risk of malignancy