Disorders of bone health Flashcards

1
Q

What is osteoporosis?

A

Progressive systemic skeletal disease characterised by low bone mass and micro-architectural deterioration of bone tissue with a consequent increase in bony fragility and susceptibility to fracture

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2
Q

What cell is overactive in osteoporosis?

A

Osteoclastic activity is higher than osteoblast activity leading to net bone loss

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3
Q

What regulates bone loss?

A
Sex hormone deficiency
Body weight
Genetics
Diet
Immobility
Diseases
Glucocorticoids and aromatase inhibitors
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4
Q

What are common osteoporotic fracture sites?

A

NOF
Vertebral bodies
Distal radius
Humeral neck

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5
Q

How is bone density assessed?

A

DEXA scan

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6
Q

Which areas are assessed in a DEXA scan?

A

Hip

L1-4

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7
Q

What is the T score?

A

A T-score shows how much your bone density is higher or lower than the bone density of a healthy 30-year old adult

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8
Q

What is the Z score?

A

Current bone density with those of your age, gender and weight

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9
Q

What is osteopenia?

A

BMD more than 1 DS below the young adult mean but less than 2.5 SD below

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10
Q

What is osteoporosis?

A

BMD more than 1.5 DS below the young adult mean

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11
Q

Who should be referred for a DEXA scan?

A

Patients over 50 with low trauma fracture

Increased risk of fracture based on risk factors using Qfracture or FRAX

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12
Q

What are modifiable risks for fragility fractures?

A
BMD
Alcohol
Weight
Smoking
Physical activity 
Pharma risk factors
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13
Q

What should be in the work up of suspected osteoporosis?

A
U+Es, LFTs, bone biochem, FBC, PB, TSH 
Coeliac antibodies
Testosterone
25OH vit D
PTH
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14
Q

What are secondary causes of osteoporosis?

A

Endocrine: hyperthyroidis, hyperparathyroidism, cushings
GI: coeliac, IBD, chronic liver disease, chronic pancreatitis
Resp: CF, COPD
CKD

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15
Q

What drug treatments are available in the treatment of osteoporosis?

A
Calcium and vit D supplements
Bisphosphonates
Denosumab
Teriparatide
HRT
SERMS 
Testosterone
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16
Q

How much calcium should be in the diet?

A

700mg

Post menopausal women should aim for 1000mg to reduce fracture risk

17
Q

What is the most of action of bisphosphonates?

A

Osteoclast cell death to prevent resorption of bone
Prevents bone loss
Reduces the risk of hip and spine fractures

18
Q

How long should bisphosphonates be given for?

A
5 years (10y if vertebral fracture)
Long term concerns: osteonecrosis of the jaw, oesophageal Ca, atypical fractures
19
Q

What should be given in the case of unacceptable GI reactions to bisphosphonates orally?

A

Once yearly IV infusion of zoledronic acid

5mg in 100ml NaCl over 15 mins

20
Q

What is denosumab?

A

Monoclonal antibody that targets and binds with high affinity and specificity to RANKL - prevents activation of its receptor, RANK, inhibiting development and activation of osteoclasts

21
Q

What are the adverse effects of denosumab?

A

Hypocalcaemia
Eczema
Cellulitis

22
Q

How is denosumab given?

A

Subcut injections 6 monthly

23
Q

What is teriparatide?

A

Recombinant parathyroid hormone which stimulates bone growth

24
Q

What is the direct action of corticosteroids on bone health?

A

Reduction of osteoblast activity and lifespan
Suppression of replication of osteoblast precursors
Reduction in calcium absorption

25
Q

What are the indirect effects of corticosteroids on bone?

A

Inhibition of gonadal and adrenal steroid production

26
Q

What is paget’s disease?

A

Abnormal osteoclastic activity followed by increased osteoblastic activity leading to abnormal bone structure with reduced strength and increased fracture risk

27
Q

What bones will paget’s disease affect?

A

Long bones
Pelvis
Lumbar spine
Skull - hearing loss

28
Q

What will pagets disease present as?

A
Bone pain
Deformity
Deafness
Compressive neuropathies 
Osteosarcoma is a rare complication
29
Q

How is paget’s disease diagnosed?

A

Isotope bone scan

Biochem: isolated raised alk phos (sign of osteoblastic activity)

30
Q

How is pagets disease treated?

A

Bisphosphonates

Analgesia

31
Q

What causes osteogenesis imperfecta?

A

Secondary to mutations of type 1 collagen genes

32
Q

What is the mode of inheritance of OI?

A

Autosomal dominant inheritance

33
Q

What other signs bar bones does OI show?

A

Blue sclera

Dentinogenesis imperfecta

34
Q

How can OI present?

A

Fractures in childhood - important differential for NAI

35
Q

How is OI managed?

A

Fracture fixation
Surgery to correct
Bisphosphonates