Osteoporosis — Pathophysiology and Management

Definition (WHO): low bone mass with microarchitectural deterioration → fragility fractures; T‑score ≤ −2.5 on DEXA. Common sites: vertebral compression, hip (femoral neck/intertrochanteric), distal radius. Risk factors: age, female sex, postmenopausal status, low BMI, glucocorticoids, smoking/alcohol, endocrine/renal disease. Workup: DEXA (hip/spine), FRAX (10‑yr risk), labs to exclude secondary causes (Ca, PO4, ALP, 25‑OH Vit D, TSH, PTH, renal/liver). Treatment: lifestyle (Ca 1000–1200 mg; Vit D 800–1000 IU; resistance/balance exercise; fall prevention); pharmacotherapy for T ≤ −2.5 or prior fragility fracture or high FRAX. Pharmacology: bisphosphonates (alendronate, risedronate, zoledronate), denosumab, anabolic agents (teriparatide/abaloparatide; romosozumab), SERMs (raloxifene) in selected women. Monitoring: repeat DEXA 1–2 years; drug holidays after 3–5 yrs oral/3 yrs IV bisphosphonate in low‑risk; continue in high‑risk. Complications & prevention: vertebral kyphosis, hip fracture morbidity/mortality; hip protectors, home safety, vision correction.