Bone disease

Question 1

What is osteoporosis?

Answer 1

a condition of skeletal fragility characterised by reduced bone mass and micro architectural deterioration predisposing to an increased risk of fractures

bone density >2.5 standard deviations below the young adult mean

Question 2

What are the secondary causes of osteoporosis?

Answer 2

drugs - steroid, sex hormone antagonist, lithium
endocrine - cushings, acromegaly, hypopituitarism
inflammatory - RA, AS, IBD
Nutritional - Vitamin D, calcium malabsorption
Genetic - marfan’s, turners

Question 3

What are the main RFs for developing osteoporosis?

Answer 3

old age (particularly post-menopausal women) 
disuse 
perimenopausal state (HRT use minimises this)
prolonged corticosteroid therapy (RA) 
endocrine disorders 
liver disease (alcoholic liver disease)

Question 4

Describe the pathology of osteoporosis?

Answer 4

bone remodelling involves resorption by osteoclasts and replacement by osteoblasts. This is normally in equilibrium. Osteoporosis when this process is unbalanced resulting in the loss of bone mineral density

Question 5

What is the clinical presentation of osteoporosis?

Answer 5

fracture is the only cause of symptoms - asymptomatic until fracture

Question 6

How does a vertebral crush fracture present?

Answer 6

sudden onset of severe pain in the spine
localised at the affected level and radiating around to the front
only 1/3 vertebral fracture is symptomatic
increasing kyphosis, height loss and abdominal protuberance followed by a crushed vertebra

Question 7

Which fractures are very suggestive of osteoporosis?

Answer 7

vertebrae
hip
wrist

Question 8

What investigations should be used to investigate osteoporosis?

Answer 8

X-ray
DEXA bone scan
Biopsy can be used if diagnosis is in doubt

other tests:
renal function 
bone profile (calcium, vitamin D, phosphate, alkaline phosphate, PTH) 
thyroid function test 
bone turnover markers 
multiple myeloma screen

Question 9

What are the signs of osteoporosis on x-ray?

Answer 9

multiple fractures
looser zones
pencil thin cortices
increased alkaline phosphatase

Question 10

What is the gold standard test for osteoporosis?

Answer 10

DEXA scan

Question 11

What are lifestyle advice can be given to patients with osteoporosis?

Answer 11

improve calcium intake
weight bearing exercise
smoking cessation

Question 12

What medical management is used in osteoporosis?

Answer 12

• vitamin D and calcium supplements
• bisphosphonates
• denosamab S/C ever 6/12 (monoclonal antibody)
  Other: HRT, testosterone treatment, parathyroid hormone

Question 13

What is the definition of osteomalacia?

Answer 13

normal deposition of bone osteoid by osteoblasts and normal bone architecture with inadequate mineralization of bone matrix

Question 14

Which bisphosphonates are used to treat osteoporosis?

Answer 14

allerdronic acid - 70mg weekly
risedronate sodium
zolendronic acid IV

Question 15

What prevention and lifestyle advice is given to women at risk of developing osteoporosis?

Answer 15

oestrogen hormone replacement therapy is the most effective way of maintaining bone density and reducing fracture risk.
don’t use is risk of breast cancer
continue for no longer than 5 years

Question 16

What are the causes of osteomalacia?

Answer 16

usually as a result of abnormalities in vitamin D metabolism

• inadequate intake
• inadequate body synthesis of vitamin D
• malabsorption due to intestinal disease
• renal disease
• rare: liver diseas, drug therapy

Question 17

How does osteomalacia present in adults?

Answer 17

• vague bone or muscle pain with tenderness usually in the lower limbs
• pathological fractures/microfractures of the lower limb
• generalised weakness

Question 18

How does osteomalacia present in children (=rickets) ?

Answer 18

• neonatal rickets may present with a thin deformed skull
• thickening of the wrists
• bow legs
• coxa vera
• tetany and convulsions are seen occasionally

Question 19

What investigations should be used when suspecting osteopenia?

Answer 19

Bloods: serum ALP, plasma calcium, serum phosphat, serum-25-hydroxyvitamin D
X-ray
Iliac crest biopsy (used if tests don’t confirm diagnosis)
Tetracycline-labelled bone biopsy (used in research)

Question 20

What is the difference between osteoporosis and osteomalacia?

Answer 20

osteoporosis = decreased bone mass and normal ratio of mineral to matrix 
osteomalacia = ratio of mineral to matrix is decreased

Question 21

What is Pagets disease of the bone?

Answer 21

common disease of unknown cause affecting the bone in the elderly
chronic disorder that typically results in enlarged deformed bones due to excessive breakdown and formation of bone tissue that causes bones to weaken resulting in bone pain, arthritis, deformities or fractures

Question 22

Describe the pathology of Paget’s disease

Answer 22

abnormally large multinucleated osteoclasts are markedly increased in number and activity causing bone resorption. Osteoblasts then respond in turn, producing weak disorganised woven bone. This sequence of events is repeated several times producing abnormally large deformed bones with increased vascularity

Question 23

How does Paget’s disease present?

3 options

Answer 23

1 - symptomatic patients complain of pain, warmth and tenderness over the affected limb

2 - with a complication such as a fracture or deformity

3 - as an incidental finding

Question 24

What are the symptoms of a symptomatic patient?

Answer 24

bone pain - commonly waxing and waning
joint pain - if involved bone is close to the joint, leading to damaged cartilage and OA
deformities - bowed tibia, skull changes

Question 25

What are the complications of paget's disease?

Answer 25

nerve decompression - deafness from CN VIII involvement. increased bone blood flow - myocardial hypertrophy, high output cardiac failure pathological fractures

Question 26

What investigations are used in pages disease?

Answer 26

X-ray - sketch survey is required Bone scans - demonstrates extent of involvement Serum ALP - increased Mild hypercalcaemia in very extensive disease Urine - raised urine hydroxyproline due to increased bone turnover

Question 27

What is shown in the blood results of someone with Paget's?

Answer 27

Serum ALP increased with normal calcium and phosphate due to increased bone turnover. Can be used as a marker for treatment and relapse

Question 28

What is the treatment for Paget's disease?

Answer 28

1) Simple analgesics for bone pain 2) Bisphosphonates (MAIN STAY) 3) Monitor serum ALP regularly with urinary hydroxyproline excretion 4) Treatment of asymptomatic patients is appropriate as risk of complications like fractures 5) Surgery

Question 29

How are bisphosphonates given to patients with Paget's disease?

Answer 29

IV is very effective - give for 6 weeks and repeat after 6 months if required Oral is effective - give for 12 weeks and repeat after 6 months if needed

Question 30

What surgery is used in Paget's disease?

Answer 30

Osteotomy may be needed for secondary joint disease Intra-articular lidocaine to differentiate between bone and joint disease Neurosurgery for spinal disease Osteosarcoma may need amputation

Question 31

What is primary osteonecrosis?

Answer 31

Avascular necrosis | Bone death resulting from poor blood supply to an area of bone

Question 32

What is the natural history of osteonecrosis?

Answer 32

1) bone death without structural change 2) repair and early structural repair 3) major structural repair 4) articular destruction

Question 33

What are the risk factors for primary osteonecrosis?

Answer 33

``` bone fracture idiopathic syndromes exogenous corticosteroid therapy alcohol abuse infection (septic arthritis) marrow infiltration (malignant disease and gaucheries' disease) ```

Question 34

What are the target sites for primary osteonecrosis?

Answer 34

``` femoral head femoral condyles head of humerus proximal pole of the scaphoid proximal pole of the talus ``` all lie on the outskirts of the bones main vascular supple and are enclosed by articular cartilage which itself is avascular

Question 35

How would a patient with osteonecrosis present?

Answer 35

``` often well advanced at presentation pain near joint stiffness in the joint local tenderness and swelling of a nearby joint restricted movement ```

Question 36

What are the investigations needed in suspected osteonecrosis?

Answer 36

``` x-ray (changes only present after several months) MRI (to pick up early osteonecrosis) Radionuclear scanning (diminished activity in the avascular segment but more often increased activity due to vascular reaction) ```

Question 37

How is osteonecrosis treated?

Answer 37

no treatment needed for the upper limb eliminate the cause stage 1 or 2: bone collapse may be eliminated by weight relief, splinting and surgical decompression stage 3: realignment osteotomy can be done to transfer stress to an undamaged area and relieve pain if articular cartilage destruction, treat as OA