Metabolic Bone Disease 1

Question 1

What is Paget’s Disease of bone

Answer 1

Paget’s disease of bone refers to a disorder of bone turnover. There is excessive bone turnover (formation and reabsorption) due to excessive activity of both osteoblasts and osteoclasts.

Question 2

What does the bone look like due to pagets disease

Answer 2

This excessive turnover is not coordinated, leading to patchy areas of high density (sclerosis) and low density (lysis). This results in enlarged and misshapen bones with structural problems

Question 3

What does the misshapen bone is pagers increase the risk of

Answer 3

Pathological fractures

Question 4

What bones are pagets more common

Answer 4

It particularly affects the axial skeleton (the bones of the head and spine)

Also affects

Femur Fibia, tibia and humerus

Forearms bones
Pelvis .

Question 5

What biochemically causes Paget’s disease

Answer 5

Elevated serum phosphatase

Question 6

What is the epidemiology to Paget’s disease

Answer 6

Strong genetic component

15-30% are familial

Restricted geographic distribution: those of Anglo-Saxon origins

UK, Easy coast amercia, autrailia, NZ

Question 7

How does pages disease present

Answer 7

Bone pain (all the time) 
Bone deformity
Fractures
Hearing loss can occur if it affects the bones of the ear
Heat of the affected bone

Question 8

What is the aetiology of pagets

Answer 8

} Environmental trigger: Possibility of chronic viral infection within Osteoclast. Thought that the virus had an effect in the patient youth

Question 9

What are investigations for Paget’s disease

Answer 9

X-ray

Bloods (biochemistry)

Question 10

What could the Xray findings be of someone with Paget’s

Answer 10

Bone enlargement and deformity

Osteoporosis circumscripta

Cotton wool appearance of the skull

V-shaped defects in the long bones

Question 11

What is Osteoporosis circumscripta

Answer 11

Describes well defined osteolytic lesions that appear less dense compared with normal bone

Question 12

What is expected biochemically in bloods from someone with pagets

Answer 12

Raised alkaline phosphatase (and other
LFTs are normal)

Normal calcium

Normal phosphate

Question 13

What is the treatment for Paget’s disease

Answer 13

Bisphosphatase

NSAIDs for bone pain

Calcium and vitamin D supplementation, particularly whilst on bisphosphonates

Surgery is rarely required for fractures, severe deformity or arthritis

Question 14

How do Bisphosphatases work in the treatment for Paget’s disease

Answer 14

They are generally very effective. They interfere with osteoclast activity and seem to restore normal bone metabolism. They improve symptoms and prevent further abnormal bone changes.

Question 15

When do you not treat Paget’s disease

Answer 15

No evidence to treat asymptomatic Paget’s unless in skull or in area requiring surgical intervention.

Question 16

What are the complications of Paget’s disease

Answer 16

Osteogenic sarcoma (osteosarcoma)

Spinal Stenosis and Spinal cord compression

Question 17

What is rickets

Answer 17

Rickets is a condition affecting children where there is defective bone mineralisation causing “soft” and deformed bones

Question 18

What is Osteomalacia

Answer 18

Osteomalacia is a condition where there is defective bone mineralisation causing “soft” bones in adults

Question 19

What causes the defective bone mineralisation in osteomalacia

Answer 19

Severe nutritional vitamin D or Calcium deficiency

Question 20

What are the symptoms of osteomalacia

Answer 20

Bone pain
Muscle weakness
Increased falls risk

Large forehead – also called frontal bossing

Question 21

What population is Osteomalacia more commonly seen in

Answer 21

Seen more common in the Asian population (darker skin and dress habits)

Question 22

What conditions is chronic Vit D deficiency seen

Answer 22

Inflammatory Bowel disease

Chronic kidney disease

Question 23

When does inflammatory bowel disease cause Vit D deficiency

Answer 23

It causes malabsorption of vit D

Question 24

When does kidney failure disease cause Vit D deficiency

Answer 24

The kidneys are essential in metabolising vitamin D to its active form.

Question 25

What are investigations for Osteomalacia

Answer 25

Serum 25-hydroxyvitamin D is the laboratory investigation for vitamin D

Question 26

What range of vit D suggests vitamin D deficiency

Answer 26

<25 nmol/L

Question 27

What range of vit D suggests vitamin D insufficiency

Answer 27

25 – 50 nmol/L

Question 28

What range of vit D is optimal

Answer 28

75 nmol/L

Question 29

What level might PTH be in Osteomalacia

Answer 29

Elevated (secondary hyperparathyroidism)

Question 30

What is treatment for Osteomalacia

Answer 30

Treatment is with supplementary vitamin D (colecalciferol).

Question 31

What is Osteogenesis imperfecta

Answer 31

Genetic disorder of connective tissue (collagen) characterised by fragile bones

Question 32

What types of Osteogenesis imperfecta exist

Answer 32

Type 1
Type 2
Type 3
Type 4

Question 33

What is type 1

Answer 33

Milder form-when child starts to walk and can present in adults

Question 34

What is type 2

Answer 34

Lethal by age 1 (most severe)

Question 35

What is type 3

Answer 35

Progressive deforming with severe bone dysplasia and poor growth

Question 36

What is type 4

Answer 36

Similar to type 1 but more severe

Question 37

What are features of osteogenesis imperfecta

Answer 37

Growth deficiency
Defective tooth formation (dentigenesis imperfecta)
Hearing loss
Blue sclera
Scoliosis / Barrel Chest
Ligamentous laxity
Easy bruising