Osteoporosis: Diagnosis and Management for PLAB 1
Osteoporosis is a systemic skeletal disease characterized by low bone mass and microarchitectural deterioration of bone tissue, leading to increased bone fragility and susceptibility to fracture. This module covers its diagnosis and management, crucial for PLAB 1 preparation.
Understanding Osteoporosis
Bone is a dynamic tissue constantly undergoing remodeling. Osteoporosis occurs when the rate of bone resorption exceeds the rate of bone formation, leading to a net loss of bone density and structural integrity. This makes bones brittle and prone to fractures, particularly in the spine, hip, and wrist.
Diagnosis of Osteoporosis
Diagnosis relies on a combination of clinical assessment, bone mineral density (BMD) measurement, and exclusion of secondary causes.
Dual-energy X-ray absorptiometry (DXA) scan.
DXA scans are the gold standard for measuring BMD. The results are reported as T-scores and Z-scores.
| Score | Definition | Implication |
|---|---|---|
| T-score | Comparison to the mean BMD of a healthy young adult of the same sex. | Used for postmenopausal women and men aged 50 and older. |
| Z-score | Comparison to the mean BMD of individuals of the same age, sex, and ethnicity. | Used for premenopausal women, men younger than 50, and children. |
Diagnostic categories based on T-scores (for postmenopausal women and men aged 50+):
Normal: T-score of -1.0 or greater. Low Bone Mass (Osteopenia): T-score between -1.0 and -2.5. Osteoporosis: T-score of -2.5 or less. Severe Osteoporosis: T-score of -2.5 or less with one or more fragility fractures.
Risk Assessment and Secondary Causes
A thorough medical history is crucial to identify risk factors for osteoporosis and to rule out secondary causes. These include:
Lifestyle Factors: Low calcium and vitamin D intake, smoking, excessive alcohol consumption, sedentary lifestyle. Medical Conditions: Hyperthyroidism, hyperparathyroidism, rheumatoid arthritis, malabsorption syndromes (e.g., celiac disease, inflammatory bowel disease), chronic kidney disease, type 1 diabetes. Medications: Long-term corticosteroid use (prednisolone > 5mg/day for >3 months), certain anticonvulsants, aromatase inhibitors, androgen deprivation therapy.
Corticosteroids (e.g., prednisolone).
Management of Osteoporosis
Management aims to reduce fracture risk through lifestyle modifications, pharmacological interventions, and fall prevention.
Lifestyle Modifications
Adequate intake of calcium and vitamin D is fundamental. Regular weight-bearing and muscle-strengthening exercises are recommended. Smoking cessation and moderation of alcohol intake are also important.
Pharmacological Interventions
Several classes of medications are available to treat osteoporosis:
The primary pharmacological agents for osteoporosis are bisphosphonates. They work by inhibiting osteoclast activity, thereby reducing bone resorption. Examples include alendronate, risedronate, and zoledronic acid. They are typically taken orally or intravenously. Other important drug classes include Denosumab (a monoclonal antibody that inhibits osteoclast formation and activity), Teriparatide (a parathyroid hormone analogue that stimulates bone formation), and Hormone Replacement Therapy (HRT) for postmenopausal women, though its use is more restricted due to potential risks.
Text-based content
Library pages focus on text content
Key drug classes and their mechanisms:
Loading diagram...
Fall Prevention
Strategies to prevent falls are critical, especially for individuals with established osteoporosis. This includes home safety assessments, vision correction, medication review to avoid sedating drugs, and balance-enhancing exercises.
Remember, the goal of osteoporosis management is to prevent fractures. This involves a multi-faceted approach combining lifestyle, medication, and fall prevention.
Learning Resources
Provides comprehensive guidance on the assessment of fracture risk and the diagnosis of osteoporosis in adults.
An overview of osteoporosis, its causes, symptoms, diagnosis, and treatment from the UK's National Health Service.
A wealth of patient-focused information, including factsheets, guides, and advice on living with osteoporosis.
A clinical decision support tool offering evidence-based information on the diagnosis and management of osteoporosis.
A detailed, evidence-based overview of osteoporosis diagnosis and management, suitable for healthcare professionals.
Provides in-depth information on the pathophysiology, diagnosis, and treatment of osteoporosis.
Information on the importance of calcium and vitamin D for bone health and dietary sources.
Focuses on osteoporosis in women, including risk factors, screening, and prevention strategies.
The WHO Fracture Risk Assessment Tool (FRAX) helps estimate the 10-year probability of fracture.
An overview of the various treatment options available for osteoporosis, including medications and lifestyle changes.