Week 7- Fractures + Osteoporosis Flashcards
What are some functions of bone?
Attachment for muscles & tendons
Protection of vital organs
Red blood cell factory
Reservoir of calcium & phosphate
Involved in energy regulation
How can the structure of bone be described?
Extra-cellular matrix
What 4 types of cell make up bone?
Osteocyte
Osteoblast
Osteoclast
Osteogenic cell
What is the function of an osteocyte?
(Coordinators)
Maintains bone tissue
>90% of bone cells
Mechanoreceptors
Coordinate bone turnover and the response to injury
What is the function of an osteoblast?
(Builders)
Forms bone matrix
Live at the bone surface
Deposit new bone
What is the function of an osteoclast?
(Eaters)
Resorbs bone
Highly specialised macrophages
Degrade bone matrix
What is the function. of an osteogenic cell?
(osteoprogenitor)
(Pre-cursers)
Stem cell
Pre-cursors to osteocytes and osteoblasts
What is the organic component of the extra-cellular matrix?
Collagen (predominantly Type 1)
What is the inorganic component of the extra-cellular matrix?
Hydroxyapatite
What’s the definition of a fracture?
Discontinuity of bone, resulting from a mechanical force which exceeds the bone’s ability to withstand them
What are some common fractures in older adults?
Hip
Spine
Wrist
Humerus
What are the statistics for patient’s survival after a hip fracture?
After a hip fracture, 1/10 cases will die within one month and 1/3 are dead at one year
Why are fractures more likely in older adults?
Poorer bone quality and increased risk of falls
What causes the increased risk of falls in older adults?
Neurological impairment- stroke, visual impairment, balance, dementia
Loss of muscle muss
Environment
Medications
Arthritis
What is the diagnostic criteria for osteoporosis?
Individuals with bone mineral density (BMD) > -2.5 SD below the young normal mean (T-Score)
What is osteoporosis?
A disease characterised by low bone mass and micro-architectural deterioration of bone tissue, leading to enhanced bone fragility and increased fracture risk
How does bone mass change with age?
Excessive bone resorption without compensatory bone formation
What are some risk factors for osteoporosis?
Smoking
Excess alcohol consumption
Genetics- responsible for 70-80% of your peak bone mass, parental history of hip fracture
Ethnicity- risk greater in Caucasians>Asian>African
Lack of exercise
Sex hormone deficiency (menopause)
Chronic inflammatory disease e.g. Rheumatoid Arthritis
Medications- corticosteroids, oestrogen inhibitors
How is osteoporosis diagnosed?
DEXA scan
Bone density compared to 30-year-old of the same sex
Used for Dx of OP in the elderly
Results-
-1 to -2.5 = osteopaenia
>-2.5 = osteoporosis
Who would be given a DEXA scan?
Fragility fracture aged >50 years
Suspected vertebral fracture
Taking oral glucocorticoids
Ten-year fracture risk >10%
What are some ways to prevent osteoporotic fractures?
Lifestyle
Muscle strengthening
Balance exercises
Avoid bone thinning drugs
What things can be used to treat osteoporosis?
Vit D and calcium
Exercise
Anabolic drugs
Bisphosphonates
How do bisphosphonates work in the treatment of osteoporosis?
They result in osteoclast apoptosis
What are some common names of bisphosphonates?
Risedronate (Actonel)
Alendronate (Fosamax)
Zoledronic Acid (Reclast)
Pamidronate (Aredia)
How do anabolic drugs work in the treatment of osteoporosis?
They are an antibody to sclerostin
Sclerostin inhibits bone formation
If you inhibit an inhibitor of bone formation you will increase BMD
What are some common names of anabolic drugs?
Romosozumab
Teriparatide
What are some negatives of bisphosphonates?
Indigestion sometimes occurs with oral bisphosphonates
Some patients do not like fasting before taking oral bisphosphonates
Intravenous bisphosphonates may cause flu-like illness for a few days after treatment (issue in Covid19-era)
Rare side effects- osteonecrosis of the jaw, increased risk of atypical femoral fractures if taken for many years
What are some negatives of anabolic drugs (specifically Romosozumab)?
May increase the risk of CV events
What do the treatments for osteoporosis focus on?
Preventing bone loss and/or promoting gain of bone that has been lost
