Last updated:
March 22, 2026
Osteoporosis is a skeletal disease characterised by low bone mineral density and microarchitectural defects. This leads to increased fragility and susceptibility to fracture. It is commonly asymptomatic until fractures happen. It is diagnosed objectively using a DEXA Scan with a T-score ≤ – 2.5. The T-score is a measurement of standard deviations relative to the average healthy adult in their 20s.
Osteoporosis is a common disease process. It primarily occurs in women > 50 years old.
Definition of terms
| Term | Definition |
|---|---|
| Osteoporosis | Low bone mineral density and microarchitectural defects. T-score ≤ -2.5 |
| Osteopaenia | Low bone mineral density and microarchitectural defects. T-score -1.5 to -2.5 |
| Osteomalacia | Disorder of bone mineralization with intact bone matrix. This is unrelated to osteoporosis or osteopaenia |
Differentials of pathologic fractures
| Category | Differentials |
|---|---|
| Metabolic disease | Osteoporosis, osteopaenia, Paget disease of bone, renal osteodystrophy, osteomalacia, primary hyperparathyroidism, hyperthyroidism |
| Malignancy | Multiple myeloma, bony metastases |
- Risk factors for osteoporosis (SHATTERED)
- Steroid use of > 5 mg per day – glucocorticoids induce a high turnover rate
- Hyperthyroidism, hyperparathyroidism, hypercalciuria
- Alcohol and tobacco use
- Thin (BMI < 18.5)
- Testosterone decrease, e.g. antiandrogen treatment for prostate cancer, hypogonadism
- Early menopause
- Renal or hepatic failure
- Erosive or inflammatory bone disease, e.g. myeloma or rheumatoid arthritis
- Dietary causes, e.g. malabsorption, calcium and vitamin D deficiency; Diabetes mellitus type 1
- Other risk factors
- Age > 50 years: bone density naturally decreases
- Sedentary lifestyle: weight-bearing activities strengthen bone
- Low estrogen – increases remodelling units and arrests osteoblastic synthesis
- Postmenopausal
- Nulliparity
- White race
- Medications
- Antiepileptics e.g. phenytoin
- Patient history
- Pathophysiology
- Oestrogen deficiency
- Increased bone resorption by osteoclasts and decreased bone formation by osteoblasts → Loss of bone mass
- Signs and symptoms
- Physical examination
- Thoracic hyperkyphosis
- Dowager’s hump (humpback)
- Decrease in height
- Point tenderness
- Gait instability
- Investigations
- DEXA scan: screening for all women over the age of 65 years. Women aged 60 – 64 may be screened based on clinical suspicion. The T-score is the number of standard deviations the bone mineral density is from the youthful average.
- T-score > 1.0 is normal
- T-score -1.0 to -2.5 is osteopaenia
- T-score ≤ -2.5 is osteoporosis
- X-ray: for fracture (sudden, localised bony tenderness)
- Complete blood count: rule out multiple myeloma
- Normal in osteoporosis
- Pancytopaenia in multiple myeloma
- Serum calcium: rule out hypocalcaemia
- Normal in primary osteoporosis
- Hypocalcemia may cause secondary osteoporosis
- UEC: rule out renal osteodystrophy
- Abnormal in renal osteodystrophy (FOLLOW UP WITH ptf, mG AND 25-vIT d)
- Alkaline phosphatase: to rule out Paget’s disease of bone
- Thyroid panel: rule out hyperthyroidism
- Low TSH and elevated T4 indicate hyperthyroidism
- UPEP and SPEP: rule out multiple myeloma in patients with multiple vertebral fractures
- DEXA scan: screening for all women over the age of 65 years. Women aged 60 – 64 may be screened based on clinical suspicion. The T-score is the number of standard deviations the bone mineral density is from the youthful average.
- Treatment
- Smoking cessation
- Reduce alcohol consumption
- Weight-bearing exercises to increase bone mineral density
- Balance exercises to reduce the risk of falls
- Calcium and vitamin D supplements, if they are insufficient in the diet
- Hormone replacement therapy to prevent osteoporosis
- Increased cardiovascular risk
- Increased risk of breast cancer
- Bisphosphonates (alendronate, risedronate, ibandronate, zoledronic acid) – first-line
- Also used for prevention in long-term steroid use
- Pills are swallowed with plenty of water, 30 minutes before eating, and while remaining upright for > 30 minutes
- Denosumab (monoclonal antibody to RANK ligand) is first-line
- SERMs (raloxifene) are second-line for women
- Has a lower risk of breast cancer
- PTH analogues (teriparatide) are second-line for both men and women
- Useful for patients who still get fractures despite other treatment
- Calcitonin is third-line
- Reduces pain after a vertebral fracture
- Testosterone for hypogonadal men to promote trabecular connectivity
- Complications
- Limited mobility
- Depression
- Complications of bisphosphonates
- Oesophagitis
- Phosphosensitivity
- Gastrointestinal upset
- Jaw osteonecrosis
- Complications of teriparatide
- Osteonecrosis of the jaw
- Atypical femoral fractures
- Increased risk of renal malignancy