Fractures & Osteoporosis Flashcards
What is osteoporosis?
Defining feature – bone disease characterized by a reduced bone density - results in micro-architectural deterioration of bone tissue (insufficient quantity) - increased risk of fracture in response to normal stressors/pressure
Most common bone disease
Common fracture sites – forearm, spine and hip
Increased risk of fractures with age - Increased risk of falling and decline in bone mass, mainly in women (oestrogen)
Decrease in bone mass – osteoblasts can’t keep up with the rate of removal by osteoclasts – thought to be partly due to the differentiation of bone marrow stem cells into adipocytes
Osteoporosis sometimes occurs due to the failure to attain adequate peak bone mass, but it is mainly due to age-related bone loss
What are the risk factors for OP?
- Genetic factors – account for up to 80% of variation in bone density – RANK and Wnt signalling pathways have been implicated.
- Environmental factors – exercise and calcium intake during growth and adolescence - important for maximising peak bone density
- Environmental factors/lifestyle - smoking has a detrimental impact on BMD (partly due to earlier menopause onset) and heavy alcohol intake
What is idiopathic and secondary osteoporosis?
Idiopathic - Term used to describe patients that have osteoporosis for no known cause - misleading as patients in this category have inheritance of genetic variants that influence bone density
Secondary Osteoporosis - OP that arises due to a primary cause - diseases and/or drug treatments
Secondary causes of osteoporosis are particularly common in men – accounting for 50% of patients – hypogonadism, glucocorticoid use and excess alcohol consumption
What are the clinical features of OP?
Osteoporosis is usually not diagnosed until a fracture occurs
Normally suffer from a fragility fracture - fracture that occurs as the result of a fall from standing height or less - note this does not mean that they have OP, as they could have osteopenia.
Fractures
* Clinical signs - pain, local tenderness and deformity.
* Hip fracture - unable to bear weight + a shortened externally rotated limb
* Vertebral fracture - variable symptoms – acute severe back pain, radiating pain, height loss, kyphosis
What investigations can confirm OP?
Most important – DXA scan of the lumbar spine and hip - should be considered in patients over 50 who have suffered a fragility fracture and those with clinical risk factors
Other people that should receive a DXA - patients under 50 with strong risk factors – e.g. premature menopause and high-dose glucocorticoids
What non-pharmacological and pharmacological treatments are usually used for OP?
Non-pharmacological interventions
* Mitigating the risk created by life-style factors - smoking cessation, reduction in alcohol intake, adequate calcium intake and exercise
Pharmacological
Bisphosphonates
- First line treatment for osteoporosis – reduce risk but not completely eliminate it - basic principle – cause osteoclast apoptosis
- Following administration…
i. Bisphosphonates target bone surfaces
ii. Ingested by osteoclasts during bone resorption
iii. Bisphosphonates is released inside osteoclasts and impairs bone resorption
iv. Results in increase bone density due to increase in bone density
What are some adverse effects associated with bisphosphonates?
- Oral - Upper GI distress caused in 5% of patients - take with plently of water, on an empty stomach and stay upright for more than 30min.
- Intravenous – main side effects - transient influenza-like illness typified by fever, malaise, anorexia and generalised aches – occurs in 24-48 hours
Less common - Osteonecrosis, atypical fractures, hypocalcaemia, atrial fibrillation.
What are some other pharmological treatments that can be used for OP?
- Denosumab - Monoclonal antibody that inhibits bone resorption – neutralizing the effects of RANKL
- Calcium and Vitamin D - used as an adjunct
- Teriparatide - Teriparatide (TPTD) is the 1-34 fragment of human parathyroid hormone (PTH) - works by stimulating new bone formation.
- Raloxifene - a selective oestrogen receptor modulator (SERM) that acts as a partial agonist at oestrogen receptors
What types of surgery are performed on OP patients?
Surgery
* Orthopaedic surgery with internal fixation is frequently required to reduce and stabilise osteoporotic fractures.
* Other forms of surgeries include… hip replacements and vertebroplasty (stabilizing compression fractures in the spine
When using a DXA scan, at point do we consider an inididual to have osteopenia and osteoporosis?
Osteopenia (transition to osteoporosis) - BMD that is -1 to -2.5 standard deviations from the mean.
Osteoporosis - BMD that greater than -2.5 standard deviations from the mean.
When using a DXA scan, at point do we consider an inididual to have osteopenia and osteoporosis?
Osteopenia (transition to osteoporosis) - BMD that is -1 to 2.5 standard deviations from the mean.
Osteoporosis - BMD that greater than 2.5 standard deviations from the mean.
Important to note that although BMD is important - age is the most important risk factor
When is a T-score and a Z-score used in BMD DXA result comparisons?
Who should receive a DEXA scan?
- Fragility fracture aged >50 years
- Suspected vertebral fracture
- Taking oral glucocorticoids
- Ten-year fracture risk >10%
What are the common line of treatments for OP?
Note - Anabolic drugs have been shown to be very effective
Romosozumab is an antibody to sclerostin. Sclerostin inhibits bone formation so Romosozumab inhibits an inhibitor of bone formation, thereby increasing BMD - better for vertebral bone
