Osteoporosis Flashcards
What is osteoporosis?
A skeletal disease characterised by low bone density and micro-architectural defects in bone tissue resulting in increased bone fragility and susceptibility to fracture.
What group of people is mostly affected by osteoporosis?
Post-menopausal white women
What is the pathophysiology of osteoporosis?
In osteoporosis the balance between bone resorption and formation is disrupted. In post-menopausal women this is often due to a decrease in oestrogen which normally inhibits resorption and so resorption can occur in an uncontrolled manner
What are the clinical features if osteoporosis?
Asymptomatic until a fracture occurs Low bone mass Low BMI Spinal kyphosis Back pain
What is a DXA scan and how is it used to diagnose osteoporosis?
It is similar to an XRay. Two rays of different wavelength are directed at the bone. The difference is absorption between the two gives an indication of the density of the bone and from this a T score can be calculated.
What is a T score and how is it used to diagnose osteoporosis?
A T score is the number of standard deviations above or below the mean for a healthy adult population of the same sex and ethnicity as the patient for BMD. A T score of -2.5 or less is indicative of osteoporosis
What is the goal of treatment in osteoporosis?
To increase bone strength and prevent fractures
What are the non pharmacological treatments of osteoporosis?
Prevention of falls by eliminating trip hazards, regular weight-bearing exercise to increase bone strength
What are the pharmacological treatments of osteoporosis?
The most commonly used drugs are bisphosphonates. Raloxifene or denosumab can also be used. Calcium and vitamin D supplementation are also used.
How does raloxifene work in regards to treatment of osteoporosis?
It binds to the oestrogen receptor, leading to DNA transcription of many proteins such as OPG
What is the mechanism of action of nitrogen containing bisphosphonates with regards to osteoporosis treatment?
They inhibit enzyme sin the 3-hydroxyl-3-methulguanyly coenzyma A pathway to reduce recruitment of osteoclasts and reduce osteoclastic activity
What is the mechanism of action of non-nitrogen containing bisphosphonates with regards to osteoporosis treatment?
These produce cytotoxic analogues of ATP which increase osteoclastic death to decrease bone resorption
Zoledronci acid is a bisphosphonate used in the treatment of osteoporosis. How must it be administered?
IV
Alendronic acid is a bisphosphonate used in the treatment of osteoporosis. How is it administered?
Orally
