Osteoporosis

Osteoporosis Definition Loss of bone mineral density and architectural loss of bone structure Epidemiology Lifetime risk is 56% for women and 29% for women Risk Factors Modifiable Non-Modifiable Alcohol Medications Steroids Inhibit osteoblastic formation, promotes apoptosis, stimulate osteoblastic, reduce Ca absorption and increased Ca excretion (the Ca things through PTH) Anti-epileptic agents Heparin Antidepressants Antipsychotics Antihypertensives Age Hormonal/nutritional/metabolic Genetics Sex hormone deprivation Previous fractures Breast or prostate cancer Early menopause Liver cirrhosis CKD Hyperparathyroidism T1DM -> low BMD T2DM -> increased BMD -> increased fracture risk Vitamin D deficiency Vitamin C deficiency Malabsorptive disorders Malnutrition Haematological Multiple myeloma Thalassemia Sickle cell Haemochromatosis Inflammatory RA Fragility Fractures Important Sustained after a fall from standing height or less in which a young healthy person would not be expected to fracture Common locations: Distal radius Humerus Neck of femur Pelvis Vertebra Most common Especially thoracic and lumbar spine Areas in which are not counted as fragility fractures: Facial bones Hand Foot Skull Cervical These do not predict future fractures Most happen in people with osteopenia Investigations Bone turnover markers Currently not useful for fracture risk prediction Bone formation Bone Reabsorption ALP CTX Total Serum/plasma Serum plasma NTX B-ALP Urine or serum Bone specific DPD Serum/plasma Urine P1NP PYD Serum/plasma Urine Osteocalcin serum DEXA T score: No. of SD away from a health young sex matched mean Adjusted for ethnicity DEXA BMD Values Definition T score more than -1.0 SD Normal T score of -1.0 and -2.5 SD Osteopenia T score equal to or less than -2.5 SD Osteoporosis T score of less than or equal to -2.5 SD or more fragility fractures Severe osteoporosis Z score: No. of SD away from a healthy age and sex matched mean Ethnicity adjusted Weight adjusted -> lunar only Normal range is between more than 2 and less than -2 Less than that indicates bone pathology Useful for predicting fracture risk qCT 3D imaging Measures BMD Trabecular bone score Derived from texture of the DEXA image Related to bone microarchitecture (weak, strong etc.) and fracture risk Provides an indirect measure of bone quality beyond BMD Helps predict future risk Predictors of Fracture Risk BMD Age Previous falls Low BMI Parental history of hip fracture Glucocorticoid therapy Secondary causes Sex hormone deficiency Hyperthyroidism Hyperparathyroidism Coeliac disease Renal failure Anorexia Haematological disease Use fracture risk calculators FRAX Garvan Lifestyle Calcium and vitamin D intake Exercise Smoking and alcohol cessation Healthy weight Pharmacological Influenced by: Gender Menopausal status Medical history If primary or secondary fracture prevention Patient preference Government subsidy Oral bisphosphates First line Once a week or once a month Poor oral absorption E.g. alendronate and risedronate IV bisphosphate Annual infusions More rapidly suppresses bone reabsorption E.g. zoledronic acid Subcutaneous denisumab RANK-L inhibitor Monoclonal antibody 6 monthly injection Raloxifene Serious adverse effects that happen in all anti-reabsorptves Hypocalcaemia esp. oral preps, in renal impairment and vitamin D deficiency Osteonecrosis of the jaw Atypical femoral fracture Anabolic agents Teriparatide Only one on PVS Romosozumab Abaloparatide Romosozumab Injected humanised monoclonal antibody against sclerostin Ablaloparatide Atypical femoral fracture Risk increases with use duration Femoral shaft fractures Little to no trauma associated May cause fall Non-comminated May be complete or incomplete Associated prodrome Dull thigh aches May see cortices thickening May see contralateral involvement Complications Debilitating bone fractures Severe pain Height loss Kyphosis Reduced mobility Disability