Osteoporosis Flashcards

1
Q

What is osteoporosis?

A

Skeletal condition characterised by low bone mass/reduced bone density, deterioration of bone tissue and disruption of bone architecture; all of the above leaves to decreased bone strength and increased fracture risk.

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2
Q

Discuss the pathophysiology of osteoporosis

A

Bone resorption > bone deposition

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3
Q

State some risk factors for osteoporosis- think about modifiable and non-modifiable risk factors

A

Non-modifiable

  • Age(>65yrs)
  • Female (particularly being post-menopausal)
  • Caucasian or south asian
  • Family history
  • History of low trauma fracture
  • Rheumatoid arthritis

Modifiable

  • Low body weight
  • Premature menopause
  • Calcium/vit D deficiency
  • Inadequate physical activity/reduced mobility and activity
  • Cigarette smokiing
  • Excessive alcohol intake
  • Iatrogenic e.g. corticosteroids, aromatase inhibitors, SSRIs, PPIs
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4
Q

Which categories of pts should you consider assessing for osteoporosis? (3)

A
  • Women >65yrs
  • Men >75yrs
  • Younger pts with risk factors
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5
Q

What tool is used to assess someones risk of osteoporosis?

A

FRAX tool

  • Prediction of risk of fragility fracture in next 10yrs
  • Uses information such as:
    • Age
    • BMI
    • Co-morbidities
    • Smoking
    • Alcohol
    • Family history
    • Result from DEXA scan (don’t have to enter this so can use tool without DEXA scan)
  • Gives result as % 10 year probability of a:
    • Major osteoporotic fracture
    • Hip fracture
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6
Q

What would be the next step following if you do a FRAX assessment without DEX and the result is:

  • Low risk
  • Intermediate risk
  • High risk
A
  • Low= reassure
  • Intermediate= offer DEXA and recalculate with results
  • High= offer treatment
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7
Q

What is the main investigation you want to do for a pt with suspected osteoporosis?

A

DEXA scan (dual energy x-ray absorptiometry) which measures bone mineral density

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8
Q

Describe how a DEXA scan works

Results from which part of skeleton are most important in the classification and hence management of osteoporosis?

A
  • Brief x-ray scan that measures how much radiation is absorbed by bone to indicate density of bone. Uses two low energy x-rays (one is absorbed by bone and one is absorbed by soft tissues)
  • Better than normal x-ray because:
    • More accurate for measuring bone density
    • Lower radiation dose
  • Can measure bone density at any location in skeleton but the reading at the hip is key
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9
Q

Bone density, obtained from a DEXA scan, can be represented as two scores. State the two scores and state what each score is

Which score is most clinically important?

A
  • Z score: number of standard deviations below the mean bone density for their age and gender
  • T score: number of standard deviations below the mean bone density of a person who is the same gender at age of peak density (25yrs)

T score is most clinically important as it is used in WHO classification of osteoporosis

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10
Q

Interpret the following T scores according to the WHO classification:

  • > -1
  • -1 to -2.5
  • < -2.5
  • < -2.5 + fracture
A
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11
Q

If a pt has a Z score of > -2, what should you be thinking?

*Remember, T score looks at number of standard deviations below mean density of bones of a healthy adult. Z score is numbe of standard deviations below mean density of bones of someone that age and gender.

A

Prompt evaluation of causes of secondary osteoporosis

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12
Q

A FRAX assessment with a DEXA scan will suggest two options; what are these options?

A

FRAX assessment with DEXA will either tell you to:

  • Treat
  • Give lifestylae advice and reassure
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13
Q

Discuss the management of osteoporosis, include conservative and pharmacological management

A

Conservative

  • Weight bearing exercise
  • Weight reduction
  • Adequate calcium intake
  • Adequate vitamin D
  • Avoiding falls
  • Smoking cessation
  • Reduce alcohol

Pharmacological

  • Supplementation (always- even if levels adequete)
    • Calcium
    • Vit D
  • 1st line= bisphosphonates (oral or IV if oral not tolerated)
  • 2nd line= denosumab or teriparatide
  • May also consider strontium ranelate
  • If a woman is going through early menopause consider HRT or raloxifene
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14
Q

Describe the mechanism of action of bisphosphonates

A

Reduce osteoclast activity preventing reabsorption of bone

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15
Q

State some examples of bisphosphonates

A
  • Alendronate (weekly, oral)
  • Risedronate (weekly, oral)
  • Zoledronic acid (yearly, IV)
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16
Q

State some side effects of bisphosphonates

A
  • Reflux & oesophageal erosions
  • Atypical fractures
  • Osteonecrosis of the jaw
  • Osteonecrosis of external auditory canal
17
Q

Describe the mechanism of action of denosumab

A

Monoclonal antibody that blocks osteoclast activity

18
Q

Describe the mechanism of action of strontium ranelate

State some side effects

A
  • Similar element to calcium that stimulates osteoblasts and inhibits osteoclasts
  • Increases risk of DVT, PE, MI
19
Q

Describe the mechanism of action of teriparatide

A

(parathyroid hormone analogue)

20
Q

State some potential complications of osteoporosis

A
  • Fractures
  • Treatment related ADRs as discussed
21
Q

What’s the difference between osteoporosis and osteopenia?

A

Osteopenia= less severe reduction in bone density compared to osteoporosis

22
Q

Bisphosphonates can cause reflux and oesophageal erosion; what instructions are given to pts to minimise this?

A
  • Take on empty stomach
  • Sitting upright for 30 mins before moving or eating
23
Q

Compliance with bisphosphonates is poor; true or false?

A

True

24
Q

Bisphosphonates are absorbed very well; true or false?

A

False, bisphosphonates are poorly absorbed

25
Q

Discuss the follow up required for:

  • Pts at low risk not given treatment
  • Pts on bisphosphonates
A
  • Low risk & not on treatment: lifestyle advice and follow up within 5yrs for repeat assessment
  • Pts on bisphosphonates: repeat FRAX and DEXA after 3-5yrs and a treatment holiday should be considered if BMD has improved and they have not suffered any fragility fractures. Treatment break is 18months-3years before repeating assessment
26
Q

Explain the difference between the different types of osteoporosis, include:

  • Primary osteoporosis: type 1 and type 2
  • Secondary osteoporosis
A

Primary Osteoporosis

  • Type 1: post menopausal women (generally women aged 50-70yrs)
  • Type 2: age-associated “senile osteoporosis” (>70yrs)

Secondary Osteoporosis: due to underlying disease process, medications or lifestyle behaviours.

27
Q

State some causes of secondary osteoporosis

A

Diseases/medical conditions

  • Coeliac disease
  • Eating disorders
  • Cystic fibrosis
  • Hyperparathyroidism
  • Hyperthryoidism
  • Multiple myeloma

Drugs

  • Corticosteroids
28
Q

What is osteomyelitis?

A

Inflammation of bone & bone marrow usually caused by bacterial infection

Can be acute or chronic

29
Q

What is most common causative organism of osteomyelitis?

A

Staphylococcus aureus

30
Q

State some risk factors for osteomyelitis

A
  • Open fractures
  • Orthopaedic operations, particularly with prosthetic joints
  • Diabetes, particularly with diabetic foot ulcers
  • Peripheral arterial disease
  • IV drug use
  • Immunosuppression
31
Q

Describe typical presentation of osteomyelitis

A
  • Fever
  • Pain and tenderness
  • Erythema
  • Swelling

The presentation of osteomyelitis can be quite non-specific, with generalised symptoms of infection such as fever, lethargy, nausea and muscle aches.

32
Q

What investigations may be done is suspected osteomyelitis?

A
  • Bloods
    • FBC: increased WCC
    • ESR/CRP: increased
    • Blood cultures: may be +ve for causative organism
  • Imaging:
    • X-ray: often don’t show changes
    • MRI: GOLD STANDARD- best way to exclude
  • Other:
    • Bone cultures: determine causative organism & sensitivities
33
Q

X-rays do not often show any changes- particularly in early disease hence cannot be used to exclude osteomyelitis. State some potential signs of osteomyelitis on x-ray

A
  • Periosteal reaction (changes to the surface of the bone)
  • Localised osteopenia (thinning of the bone)
  • Destruction of areas of the bone
34
Q

Discuss the management of osteomyelitis

A

Management involves a combination of surgical debridement of the infected bone and tissues and antibiotic therapy

Antibiotic Choice

  • Flucloxacillin for 6 weeks (possibly with rifampicin or fusidic acid also in first 2/52)
  • Alternatives:
    • Penicillin allergy: clindamycin
    • MRSA: vancomycin or teicoplanin
  • Chronic osteomyelitis usually requires 3 months or more of antibiotics

Osteomyelitis associated with prosthetic joints (e.g., a hip replacement) may require complete revision surgery to replace the prosthesis.

35
Q

At what steroid dosage & duration should we consider prescribing bone protection for a patient?

A

The risk of osteoporosis is thought to rise significantly once a patient is taking the equivalent of prednisolone 7.5mg a day for 3 or more months. It is important to note that we should manage patients in an anticipatory, i.e. if it likely that the patient will have to take steroids for at least 3 months then we should start bone protection straight away, rather than waiting until 3 months has elapsed. A good example is a patient with newly diagnosed polymyalgia rheumatica. As it is very likely they will be on a significant dose of prednisolone for greater than 3 months bone protection should be commenced immediately.

*From passmed

36
Q

Discuss how we can prevent osteoporosis secondary to prolonged steroid use

A
  • If at risk, all should be given calcium & vit D supplementation
  • Can also consider giving bisphosphonates (see image from passmed)
37
Q

Patients over 75yrs who have had a fragility fracture may not need a DEXA scan prior to starting bisphosphonates; true or false?

A

True; “Patients who’ve had a fragility fracture and are >= 75 years of age are presumed to have underlying osteoporosis and should be started on first-line therapy (an oral bisphosphonate), without the need for a DEXA scan.” Passmed

38
Q

Define a fragilty fracture

A

A fragility fracture is defined as a fracture following a fall from standing height or less.