Osteoporosis Flashcards
What is osteoporosis?
Osteoporosis is a systemic skeletal disorder characterized by ** low bone mass** and microarchitectural deterioration of bone tissue, leading to increased bone fragility (susceptibility to fractures, particularly in the hip, spine, and wrist.)
What causes primary osteoporosis?
Primary osteoporosis results from aging (leading to loss of bone mass) and the reduction in estrogen levels, especially post-menopause in women.
What are some causes of secondary osteoporosis? What are some specific lifestyle factors?
PMH, DH, SH
- Chronic diseases (e.g., rheumatoid arthritis - chronic inflammation, IBD - reduced absorption, liver/renal disease, hyperthyroidism - increasing rate of bone metabolism, hyperparathyroidism),
- Multiple myeloma, metastatic bone cancer
- medications (e.g., glucocorticoids, anticonvulsants),
- lifestyle factors (e.g., alcohol abuse, smoking)
How does osteoporosis affect bone anatomy?
Osteoporosis weakens bone structure by affecting the microarchitecture of bone.
Normal bone consists of a matrix of collagen fibers and hydroxyapatite, maintained by a balance between osteoblasts (bone-forming cells) and osteoclasts (bone-resorbing cells).
What is the pathophysiology of osteoporosis?
An imbalance between bone resorption and bone formation.
Increased osteoclast activity and/or decreased osteoblast activity lead to a loss of bone density and strength.
What are some non-modifiable risk factors for osteoporosis? List 5 factors.
Non-modifiable risk factors include age (older age), gender (female), family history of osteoporosis, early menopause, and ethnicity (Caucasian or Asian descent).
What are some modifiable risk factors for osteoporosis?
Modifiable risk factors include
* low calcium and vitamin D intake,
* sedentary lifestyle, immobilisation
* smoking,
* excessive alcohol consumption,
* low body weight,
* poor nutrition,
* use of certain medications,
* chronic diseases,
* eating disorders,
What are the clinical features of osteoporosis?
Osteoporosis is often asymptomatic until a fracture occurs.
Major complications include fractures (particularly hip, vertebral, and wrist fractures), chronic pain, height loss, spinal deformities, and reduced quality of life due to pain, disability, and loss of independence
It is estimated that around one in three women and one in five men aged 50 and over will suffer from an osteoporotic fracture.
What are the most common sites of osteoporotic fragility fractures?
Spine/vertebrae, wrist, hip, and other long bones, after low-energy trauma.
Spine — causes vertebral fractures, height loss, spinal deformities, chronic pain.
What are the key investigations and diagnostic tools for osteoporosis? Which blood tests are ordered to rule out secondary causes — which should be normal?
- Dual-energy X-ray Absorptiometry (DEXA) Scan for measuring Bone Mineral Density (BMD),
- blood tests to rule out secondary causes e.g. (calcium, vitamin D, thyroid function tests, renal function, and testosterone in men. In primary osteoporosis due to aging, these are typically normal.),
- vertebral imaging (X-rays, MRI, CT scans)
What are the T-score ranges and their descriptions for bone density?
Which score is diagnostic?
- Normal Bone Density: -1.0 or above
- Osteopenia (Low Bone Mass): Between -1.0 and -2.5
- Osteoporosis: -2.5 or below
- Severe (Established) Osteoporosis: -2.5 or below with one or more fragility fractures
Which tool is used to assess the 10-year probability of osteoporotic fractures?
FRAX Tool
https://frax.shef.ac.uk/FRAX/tool.aspx?country=9
Measures a sum comprised of risk factors.
What are some non-pharmacological management strategies for osteoporosis?
Lifestyle modifications (regular weight-bearing and muscle-strengthening exercises, smoking cessation, moderation of alcohol intake, fall prevention strategies) and dietary changes (adequate intake of calcium and vitamin D).
What are some pharmacological treatments for osteoporosis? Which two options are specific to women?
- Bisphosphonates (e.g., alendronate, risedronate), calcium and vitamin D supplements,
- Injections e.g. denosumab if bisphosphonates unsuitable,
For women:
* selective estrogen receptor modulators (SERMs) e.g. raloxifene which mimics oestrogen action on bone, and hormone replacement therapy (HRT).
What are bisphosphonates and how do they work in treating osteoporosis?
They work by inhibiting osteoclast-mediated bone resorption, which helps to maintain or increase bone density.
Common bisphosphonates include alendronate, risedronate, and ibandronate.
