Osteoporosis is a condition where bones become weak and porous and break more easily. The internal “honeycomb” structure of bone thins, and outer bone becomes brittle — increasing fracture risk, especially of the wrist, spine and hip.
Who is at risk?
- Older adults (risk increases with age)
- Postmenopausal women (loss of estrogen speeds bone loss)
- Long-term corticosteroid users (prednisone ≥ 5–7.5 mg/day)
- People with low body weight, poor nutrition, low calcium/vitamin D
- Smokers, heavy alcohol users, physically inactive individuals
- Certain diseases (hyperthyroidism, malabsorption, chronic inflammatory diseases) and some drugs (anticonvulsants, aromatase inhibitors)
Simple pathophysiology
Bone is constantly renewed by two cells: osteoclasts (break down bone) and osteoblasts (build bone). Osteoporosis happens when bone breakdown exceeds formation — due to hormones (low estrogen), aging, poor nutrition or drugs — so bone mineral density (BMD) falls and structure weakens.
Clinical features — what to watch for
- Often silent until a fracture occurs
- Fragility fractures after minor trauma (fall from standing height)
- Vertebral fractures: back pain, height loss, stooped posture (kyphosis)
- Wrist or hip fractures after low-energy injury
- Early subtle signs: weakened grip, receding gums, brittle nails
Diagnosis — practical steps
- Risk assessment: age, sex, fracture history, steroid use, smoking, alcohol, family history.
- Bone mineral density (BMD) test — DXA: gold standard. Reports T-score:
- T-score ≤ −2.5 = osteoporosis
- T-score between −1.0 and −2.5 = osteopenia (low bone mass)
- Basic labs: serum calcium, phosphate, vitamin D, renal and thyroid function, and testosterone in men if indicated.
- Use fracture-risk calculators (FRAX) to guide treatment decisions when needed.
Prevention & non-drug measures (first-line)
- Calcium: aim dietary intake; supplements if diet insufficient (max ~600 mg per dose).
- Vitamin D: maintain adequate levels (many adults need 800–1000 IU/day or as advised).
- Weight-bearing & muscle-strengthening exercise to build and preserve bone and reduce falls.
- Fall prevention: home safety, vision check, balance training.
- Lifestyle: stop smoking, limit alcohol, ensure adequate protein and nutrients.
Drug therapy — overview
Choice depends on fracture risk, BMD, cause (postmenopausal, glucocorticoid-induced, male osteoporosis), tolerance and cost. Two main strategies:
Antiresorptive agents (slow bone loss)
- Bisphosphonates (first-line): alendronate, risedronate, ibandronate, zoledronic acid. Reduce vertebral and hip fractures. Take oral tablets with plain water on empty stomach and stay upright (follow dosing instructions) to avoid esophageal irritation. IV options available for those who cannot tolerate oral forms.
- Raloxifene (SERM): reduces vertebral fractures and lowers breast cancer risk but may increase hot flashes and VTE risk.
- Calcitonin: limited role — may relieve acute vertebral fracture pain; less effective for fracture prevention.
- Estrogen/HRT: prevents bone loss but used for menopausal symptoms; long-term use limited by cardiovascular and cancer risks.
Anabolic agents (build bone)
- Teriparatide (PTH 1–34): daily subcutaneous injection (20 mcg). Increases bone formation and reduces fractures — reserved for very high-risk patients or those failing/ intolerant to bisphosphonates. Use limited duration (usually 18–24 months) and followed by antiresorptive therapy to maintain gains.
Special cases: glucocorticoid-induced osteoporosis
Steroid therapy causes rapid bone loss. Preventive measures include calcium, vitamin D, lifestyle and generally starting bisphosphonate therapy when prednisone ≥5 mg/day anticipated for ≥3 months.
Monitoring and safety
- Recheck BMD (DXA) about 1–2 years after starting therapy, then every 2 years or as needed.
- Monitor serum calcium and renal function when on bisphosphonates or teriparatide.
- Be aware of rare but serious adverse effects with long-term bisphosphonates: atypical femoral fractures and osteonecrosis of the jaw — dental checks and good oral hygiene recommended before therapy.
- Teriparatide contraindications: risk of osteosarcoma (rare) — avoid in patients with Paget’s disease or prior skeletal radiation.
Patient counselling — key points
- Take calcium and vitamin D as advised; food first is preferable for calcium.
- Follow bisphosphonate instructions exactly (morning, water only, sit upright 30–60 minutes) to reduce GI risks.
- Maintain weight-bearing exercise and fall-proof the home.
- Report new thigh or groin pain (rare atypical femur fracture sign) or dental problems.
- Adherence matters — stopping therapy without a plan increases fracture risk.
Detailed Notes:
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