Bone Diseases

Question 1

What is arthritis?

Answer 1

inflammation of joints

Question 2

What is arthrosis?

Answer 2

non-inflammatory joint disease

Question 3

What is arthralgia?

Answer 3

joint pain

Question 4

Bone is a mineralised connective tissue with 3 main features. What are they?

Answer 4

• load bearing
• dynamic
• self-repairing

Question 5

What does it mean by saying bone is dynamic?

Answer 5

• It is continuously changing – always being formed, resorbed and adapting due to changing stresses in the environment

Question 6

The cycle of remodelling of bone takes place over a 3-6 month period and requires the correct amount of what? (3)

Answer 6

• calcium
• Vit D
• phosohate

Question 7

Bone is a store for what?

Answer 7

Calcium

Question 8

What are the 2 types of calcium you can find in the bone?

Answer 8

Exchangeable and non-exchangeable

Question 9

What happens to the exchangeable calcium found in the bone?

Answer 9

It can move into the ECF if more calcium is required there

Question 10

Why does exchangeable calcium move into the ECF?

Answer 10

because the ca level in the ECF needs to be maintained at a prcise level as it is responsible for things such as nerve and muscle function

Question 11

Apart from via bone, how is calcium absorped into the ECF and how is it lost?

Answer 11

absorption = through gut

loss = gut and urine

Question 12

Calcium levels in the ECF are rugulated by what?

Describe the process.

Answer 12

The parathyroid hormone

If the serum calcium level falls, there is an increase in production of parathyroid hormone (from parathyroid glands) which increases calcium release from bone and redices renal calcium excretion.

Question 14

Hypoparathyroidism leads to what?

Answer 14

Low serum calcium

Question 15

Hyperparathyroidism can be primary or secondary. Describe both.

Answer 15

• Primary = gland dysfunction (tumour)
  
  • High serum calcium results
  • Inappropritate action of osteoclasts
• Secondary = caused by low serum calcium
  
  • Oestoclasts activated appropriately to increase calcium levels
• Both result in increased bone reabsorption – will show up as radiolucencies in radiogrpahs

Question 16

How is Vit D absorped into the body?

Answer 16

Via skin from sunlight or from diet

Question 17

What can cause problems with Vit D absorption?

Answer 17

• Low sunlight exposure
  
  • Housebound
  • Dark skinned in a Northern Country (pigmentation = less absorption of sunlight)
• Poor GI absorption
  
  • Poor nutrition
  • Small intestine disease – malabsorption
• Drug interactions
  
  • Some antiepilepic drugs (Carbamazepine, phenytoin)
  • Vit D deficiency is normally a combination of factors

Question 18

What is osteomalacia?

Answer 18

• osteoid matrix is formed properly and in the correct amount but is poorly mineralised
• leads to a soft tissue

Question 19

Osteomalacia is called what during bone formation?

Answer 19

Rickets

Question 20

Both osteomalacia and rickets are related to what?

Answer 20

A calcium deficiency - the serum calcium levels are preserved at the expense of the bone

Question 21

The effects of osteomalacia/rickets on the bone are what?

Answer 21

• Bones bend under pressure ‘bow legs’
• Vertebral compression in adults
• Bones ‘ache’ to touch

Question 22

What are some effects of hypocalcaemia?

Answer 22

• Muscle weakness
• Trousseau and Chvostek signs positive
• Carpal muscle spasm
• Facial twitching from VII tapping

Question 23

How is osteomalacia/rickets managed?

Answer 23

• Correction of the cause
  
  • Malnutrition
  • Control GI disease
• Sunlight exposure
  
  • 30mins x 5 weekly
• Dietary Vit D

Question 24

What is osteoporosis?

Answer 24

• reduced quantitiy of normal mineralised bone
• the osteoid matrix is lay down properly and mineralised properly, there is just less of it
• is an age-related change and is inevitable.

Question 25

What are risk factors for osteoporosis?

Answer 25

• Age
• Female sex
• Endocrine problems
  
  • Oestrogen and testosterone deficiency
  • Cushings syndrome
• Genetic
  
  • Family hx
  • Race – caucasian and asian women
  • Early menopause
• Patient factors
  
  • Inactivity
  • Smoking
  • Excess alcohol use
  • Poor dietary calcium
• Medical drugs use
  
  • Steroids
  • Antiepileptics
  • These drugs affect calcium metabolism

Question 26

At what age is peak bone mass?

Answer 26

24-35 years old

Question 27

Whats the difference beween peak bone mass and the decline in males and females?

Answer 27

• Men tend to have a higher peak bone mass than females
• oestrogen withdrawl (menopause) increases the bone mass loss rate in women

Question 28

What are the effects of osteoporosis?

Answer 28

• Increased risk of bone fractures
  
  • Especially long bones like the femur
  • The bone loss is no longer adequate to support stresses and sudden forces
• Effects on the vertebrae
  
  • Height loss
  • Kyphosis & Scoliosis
  • Nerve root compression – back pain

Question 29

What steps can be taken to help prevent osteoporosis?

Answer 29

• Build maximum Peak Bone Mass
  
  • Exercise
  • High dietary calcium intake
• Reduce rate of bone mass loss
  
  • Continue exercise and calcium intake
  • Reduce hormone related effects
    
    • Oestrogen hormone replacement therapy
• Reduce drug related effects
  
  • Consider ‘osteoporosis prevention’ drugs – biphosphonates
• Hormone replacement therapy after menopause

Question 30

How do biphosphonates work?

Answer 30

Reduce osteoclast action

Question 31

Why are biphosphonates relavent in dentistry?

Answer 31

concerned about medication related/induced osteonecrosis of the jaw (MONJ)

Poorer wound healing and bone repair

extractions