Paget's Disease and Osteomalacia

Question 1

What is the pathophysiology of Paget’s Disease?

Answer 1

Excessive bone remodelling, excessive bone resorption and growth.
Leads to multiple fractures and skeletal deformities

Question 2

What are the stages of Paget’s disease?

Answer 2

Lytic phase: osteoclasts resorb bone 20x more than normal
Mixed phase: lytic and blastic phase, loads of osteoblasts deposit bone in a haphazard way
Sclerotic phase: bone formation exceeds bone resorption, structurally disorganised and weaker bone
Dormant state

Question 3

What can trigger Paget’s disease to occur?

Answer 3

Triggered by infections e.g. the measles virus

Linked to genetic mutations e.g. SQSTM1

Question 4

What bones does Paget’s disease affect the most?

Answer 4

Skull
Lumbar Vertebrae
Pelvis
Femur

Question 5

What are the symptoms and signs of Paget’s disease?

Answer 5

Older male with bone pain and isolated ALP
Misshapen bone can impinge on nerves = pain
Lion like skull
Auditory loss and vision loss may occur
Kyphosis may occur
Lower limb muscle weakness/pelvic asymmetry/bow legs

Can result in osteosarcoma

Question 6

How do you diagnose Paget’s disease?

Answer 6

Increased levels of ALP
Decreased phosphate

X-Ray: lytic lesions (during lytic phase), thickened bone cortices
Bone biopsy to exclude malignancy

Question 7

How do you treat Paget’s disease?

Answer 7

Pain relievers
Antiresorptive medications (bisphosphonates- risedronate)
Surgery (corrects bone deformities, decompresses an impinged nerve)

Question 8

What are the risk factors of Paget’s disease?

Answer 8

Increasing age
Male sex
Northern latitude
Family history

Question 9

What happens in osteomalacia?

Answer 9

Normal bone tissue but decrease in mineral content of the bone
Presents as rickets if a child is still growing

Question 10

What are the causes of osteomalacia?

Answer 10

Vitamin D deficiency
Phosphate deficiency
ALP deficiency

Question 11

What are the features of osteomalacia?

Answer 11

Rickets: knock-kneed, bow leg, feature of hypocalcaemia
Osteomalacia: bone pain, fractures, muscle tenderness, proximal myopathy

Question 12

What do investigations show in osteomalacia?

Answer 12

low vitamin D in 100% of patients
low calcium and low phosphate
increased PTH
increased ALP

children: cupped, ragged metaphyseal surfaces
adults: translucent bands

Question 13

What is the treatment of osteomalacia?

Answer 13

calcium with vitamin D tablets