Definition and Diagnosis

DEXA (dual-energy X-ray absorptiometry) scan

•    T-score ≤ –2.5 → osteoporosis

•    T-score –1 to –2.5 → osteopenia

•    Z-score used in premenopausal women and younger men (age-matched)

Risk Assessment

FRAX score

•    Calculates 10-year probability of major osteoporotic fracture and hip fracture

•    Incorporates:

o    Age

o    Sex

o    BMI

o    Smoking, alcohol use

o    Prior fractures

o    Secondary causes

o    Glucocorticoid use

Secondary Causes of Osteoporosis

•    Endocrine

o    Hyperthyroidism

o    Hyperparathyroidism

o    Diabetes mellitus (type 1 > type 2)

o    Hypogonadism (e.g., anorexia nervosa, androgen deprivation therapy)

•    Hematologic

o    Multiple myeloma

o    Mastocytosis

•    Drugs

o    Glucocorticoids (≥5 mg prednisolone for >3 months)

o    Anticonvulsants (e.g., phenytoin, carbamazepine)

o    Proton pump inhibitors (long-term)

•    GI and liver

o    Malabsorption (e.g., coeliac disease, IBD)

o    Chronic liver disease

Treatment

Bisphosphonates

•    Alendronate, risedronate, zoledronic acid (IV)

•    Inhibit osteoclast-mediated bone resorption

•    Administration tips (oral agents):

o    Take on empty stomach with water

o    Stay upright ≥30 min

o    Avoid food/drinks during this period to reduce risk of oesophagitis

•    Side effects:

o    Atypical femoral fractures (rare)

o    Osteonecrosis of the jaw (rare, consider dental assessment before initiation)

Calcium and vitamin D supplementation

•    Indicated if dietary intake inadequate

•    Calcium ~1000–1200 mg/day, vitamin D ~800 IU/day

•    Alone usually insufficient but used adjunctively

Denosumab

•    RANKL inhibitor → inhibits osteoclast differentiation and activity

•    Indications:

o    Alternative if bisphosphonates contraindicated or not tolerated

•    Administered subcutaneously every 6 months

•    Risks: rebound vertebral fractures if stopped abruptly, hypocalcaemia

Other options

•    Selective estrogen receptor modulators (SERMs) (e.g., raloxifene): reduce vertebral fractures, may increase VTE risk

•    Teriparatide (recombinant PTH analog): reserved for severe osteoporosis or multiple fractures

Falls Prevention

•    Strength and balance training (e.g., physiotherapy)

•    Medication review → minimise sedatives, antihypertensives

•    Home hazard assessment → remove rugs, improve lighting

•    Vision and hearing correction

•    Footwear assessment

•    Vitamin D supplementation if deficient

Extra Revision Pearls

•    Glucocorticoid-induced osteoporosis: bisphosphonates recommended at initiation if long-term therapy planned

•    Vertebral fractures often asymptomatic — consider if unexplained back pain, height loss, kyphosis

•    "High-turnover osteoporosis": e.g., in hyperparathyroidism; alkaline phosphatase often raised

•    Re-evaluate need for bisphosphonates after 3–5 years (drug holiday considerations)