Definition:
- Osteoporosis is a skeletal disorder characterized by compromised bone strength, predisposing individuals to an increased risk of fractures.
Epidemiology:
- Common, especially in postmenopausal women and older men.
- Risk increases with age.
Pathophysiology:
- Bone remodeling imbalance: Bone resorption outpaces bone formation, leading to decreased bone mass and deterioration of bone microarchitecture.
- Key cells involved: Osteoclasts (bone resorption), osteoblasts (bone formation).
Risk Factors:
- Non-modifiable: Age, female gender, family history, postmenopause, history of fractures.
- Modifiable: Smoking, excessive alcohol intake, low body weight, poor nutrition, physical inactivity, certain medications (e.g., glucocorticoids).
Clinical Features:
- Often asymptomatic until a fracture occurs.
- Fractures typically occur in the hip, spine, and wrist.
- May present with height loss, back pain, or a stooped posture.
Diagnosis:
- Bone Mineral Density (BMD) testing using dual-energy X-ray absorptiometry (DEXA) scan.
- Diagnosis based on T-score:
- Normal: T-score above -1.0
- Osteopenia: T-score between -1.0 and -2.5
- Osteoporosis: T-score at or below -2.5
- Laboratory tests to exclude secondary causes.
Management:
- Lifestyle modifications: Diet rich in calcium and vitamin D, regular weight-bearing and muscle-strengthening exercises, fall prevention.
- Pharmacological treatment: Bisphosphonates are first-line. Other options include denosumab, selective estrogen receptor modulators (SERMs), teriparatide.
- Treatment of underlying conditions contributing to bone loss.
Prevention:
- Early lifestyle modifications.
- Screening at-risk populations.
Key Points for Medical Students:
- Understand the pathophysiology of bone remodeling and the factors leading to osteoporosis.
- Recognize the importance of early identification and prevention, especially in at-risk groups.
- Be familiar with the use of DEXA scan for diagnosis and monitoring.
- Know the various treatment options and their indications.