Osteoporosis

Question 1

Define osteoporosis

Answer 1

Disease characterised by low bone mass and structural deterioration of bone with damage to microstructure -> inc bone fragility inc susceptibility to fracture.
Progressive

Question 2

What are the different types of primary osteoporosis?

Answer 2

Type 1 - post-menopausal
Type 2 - age-related

Question 3

What are the common causes of secondary osteoporosis?

Answer 3

Hyperthyroidism
Hyperparathyroidism (High PTH, High Ca, Low P)
Alcohol abuse
Immobilisation
Rheumatoid arthitisis
Malabsorption disease (coeliac or anorexia nervosa)
Chronic Liver Disease

Question 4

What screening tool can be used to calculate the risk of a bony fracture in the elderly?

Answer 4

FRAX tool - risk of major hip or osteoporotic fracture in next ten years
Or QFracture (preferred by NICE) -

Question 5

What are the main risk factors for osteoporosis?

Answer 5

Age (between 40-90yrs) - leads to trabeculisation of cortical bone
Gender - female
Post menopausal
Prolonged untreated amenorrhea
Male hypogonadism
Low calcium or vitamin D intake
Previous fracture or Parent fractured hip
Smoking and alcohol
Glucorticoids (more than 3months)
RA, CKD, hyperthyroidism
Certain medications - SSRIs, PPIs, anti-epileptics and anti-oestrogens.

Question 6

Who does NICE recommend we assess for osteoporosis?

Answer 6

Anyone on long term corticosteroids
Previous fragility fracture
Anyone 50yrs+ with risk factors
All women over 65yrs
All men over 75yrs.

Question 7

What is the basic pathophysiology of osteoporosis?

Answer 7

Increased bone breakdown by osteoclasts
Decreased bone formation by osteoblasts
Causes a loss of bone mass
This can be influenced by collagen type 1A1, Vitamin D receptors and Oestrogen receptor genes/funcationality

Question 8

How does oestrogen deficiency lead to osteoporosis?

Answer 8

Increased number of remodelling units
Premature arrest of osteoblastic synthetic activity and perforation of trabeculae
Loss of resistance to fracture

Question 9

How do glucocorticoids lead to osteoporosis?

Answer 9

Induce a high-turnover state intially
Pronlonged used reduced turn-over rate with net loss of osteoblasts
Typically problematic when 10mg of pred once daily for 3 months or more

Question 10

What are the key clinical features of osteoporosis?

Answer 10

Long latent period before fragility occurs
Pathological or fragility fractures - mechanical method often first presentation

Question 11

What are the common frailty/pathological fractures?

Answer 11

Vertebral compression
Appendicular fractures (proximal femur or distal radius)

Question 12

How do vertebral compression fractures tend to present?

Answer 12

Sudden acute back pain at rest, bending or lifting
Restricted spinal flexion and intensified pain with prolonged standing
Anterior compression in T spine - Dowagers hump - thoracic kyphosis

Question 13

How do appendicular fractures tend to present?

Answer 13

Neck of femur - hip pain, unable to weight bear and shortened and externally rotated leg, pain in groin or hip, may radiate to knee.
Colles - FOOH, wrist pain and reduced range of movement

Question 14

What scan is used for osteoporosis to identify bone density?
How is this interpreted

Answer 14

DEXA scan or DXA scan
Generates a T score - patient bone health compared to SD from normal healthy
>-1.0 normal
<-1osteopenia
< -2.5 is osteoporosis
< -2.5 and fragility fracture = severe osteoporosis

Question 15

What investigations should be done for a patient with a fragility fracture?

Answer 15

Pain radiograph - reveal fractures including previously asymptomatic vertebral deformities

Question 16

What investigation should be done to rule out secondary osteoporosis?

Answer 16

History and physical exam
FBC
ESR - for RA.
U&Es - serum calcium, creatinine, phosphate
LFTs (ALP and transaminases)
TFTs
Vitamin D
Serum testosterone, LH and prolactin
PTH
Radiographs of lateral lumbar and thoracic spine
Protein immunoelectrophoresis and urinary Bence-Jones protein (for myeloma)

Question 17

What tool should be used to help guide treatment of osteoporosis?

Answer 17

FRAX tool

Question 18

How does the FRAX tool score influence treatment guidelines?

Answer 18

Use NOGG
Uses FRAX risk to calculate level of risk dependent on age and compare this to an intervention threshod
Low risk = lifestyle advice, reassess in 5 yrs max.
Intermediate risk = measure BMD and recalculate risk. If unable to get BMD use intervention threshold to determine if treatment is needed.
High risk = offer treatment to reduce fracture risk.Measure BMD to guide drug choice and provide a baseline for BMD monitoring.
Very high risk = Consider referral to osteoporosis specialist for assessment and consideration parenteral treatment. If a delay anticipated, start oral treatment in meantime as if high risk

Question 19

What are some common differentials for osteoporosis?

Answer 19

Osteomalacia - dec mineralisation, may be painful/tender and myopathy
Pagets disease of bone - bone/joint pain + deformities, neurological complications from immature woven bone
Myeloma
Primary and metastatic bone tumours
Lymphoma

Question 20

What conservative treatment is often given for osteoporosis?

Answer 20

Falls risk assessment
Weight-bearing and muscles strengthening
Optimum calciuim and VitD uptake from sun, diet or supplement/
Stop smoking, maintains healthy weight, maintain healthy alcohol intake
Reduced medications if needed (corticosteroids)

Question 21

What should bisphosphonates be offered to patients to help with osteoporosis?

Answer 21

Is FRAC risk of osteoporotic fragiity fracture >1%.
T-score <2.5 or less at the femoral neck.
T between -1.0 and -2.5 and a FRAX greater than 3%

Question 22

How shoudl bisphosphonates be used to treat osteoporosis?

Answer 22

First line
Adhere to hydroxyapatite and inhibit osteoclasts from resorbing bone.
Oral alendronate/risedronate should be given as 1w, zoledronic acid as 1yr infusion.
Should be taken whilst upright, remain upright for 30mins, on empty stomach.
Can cause upper GI problems - oesophagitis and needs monitoring in CKD4/5

Question 23

What is denosumab?
When should it be used in osteoporosis?

Answer 23

MAB - targeting RANKL for inhibition - prevents osteoclast activation
Used in extensive osteoporosis.
Sub cut 6/12
Anti-resorptive agent - increases BMD and reduces fracture risk at the spine.

Question 24

What is the key side effect of bisphosphonates?
How do we reduce the risk of these?

Answer 24

Osteonecrosis of the jaw - regular dental check ups.
Oesophagitis and GI ulceration - take upright, wash down with water, on an empty stomach
Pathological fracture - spiral fractures in the diaphysis of long bones

Question 25

When might HRT be used for osteoporosis treatment?

Answer 25

Early postmenopausal women Due to breast cancer and cardiovascular risk.

Question 26

What are the key complications of osteoporosis?

Answer 26

High fracture risk Limited mobility - weight gain, inc risk heart disease and diabetes Depression - due to loss of independence and isolation Pain - often persistent back pain High mortality - about 10% of patients with hip fracture die within 1 month

Question 27

Define fragility fracture

Answer 27

When a fracture occurs from a force that would not normally cause a fracture in a healthy bone NICE: force from standing or less to floor.

Question 28

What drugs are associated with a higher risk of osteoporosis?

Answer 28

Glucocorticoids Anticonvulsants Prolonged heparin therapy Cytotoxic therapy (chemotherapy)

Question 29

What score on a QFracture indicates that a DEXA scan is needed?

Answer 29

>10% Risk of osteoporotic fracture and hip fracture in the next 10yrs.

Question 30

How does a vitamin D deficiency affect the parathyroid gland?

Answer 30

Low Ca2+ triggers a secondary hyperparathyroidism -> can lead to osteoporosis

Question 31

What anatomy is important to know regarding neck of femur fractures and the blood supply?

Answer 31

NOF has a retrograde blood supply. The lateral and medial circumflex artery supply, just proximal to the intertrochanteric line. Branches from this anastomosis supply the neck and head of the femur by travelling through the intracapsular space. Therefore an intracapsular fracture can disrupt this blood supply leading to avascular necrosis of the femoral head.

Question 32

What is the key clinical point of an intra-capsular neck of femur fracture?

Answer 32

Risk of avascular necrosis of the neck of the femur. This must be graded using the Garden classification 1-4

Question 33

What are the different NOK fractures in the Gardener classification?

Answer 33

Type 1 - incomplete fracture or valgus impacted Type 2 - complete fracture without displacement Type 3 - complete with partial displacement Type 4 - complete with total displacement, femoral head may rotate back into anatomical position without the rest of the femur.

Question 34

What are the different types of extra-capsular neck of femur fractures?

Answer 34

Intertrochanteric - between greater and lesser trochanter Subtrochanteric - distal to lesser trochanter (within5cm)

Question 35

What are the different types of surgical management for a NOF fracture dependent on the fracture type?

Answer 35

Orthogeriatric input - ensure fit for surgery Surgery should be carried out <48hrs post-injury Hemi-arthoplasty- replace ball not socket - intracapsular low mobility patients Total hip replacement - intracapsular, baseline of walking in patient before fracture occured Internal fixation - capsular none displaced Dynamic hip screw - intertrochanteric fracture Intramedullary output - subtrochanteric fracture

Question 36

What is the key presentation of a hip fracture?

Answer 36

Shortened Externally rotated Abducted