Osteoporosis¶

Claire Lo

Background¶

Definition: decreased bone mass leading to increased risk of fracture
Differential: malignancy (e.g., multiple myeloma), elder abuse (e.g., spiral fractures of long bones), hyperparathyroidism, Paget’s disease

	Post-Menopausal Women	Pre-Menopausal Women
Risk Factors	current smoker, >3 alcoholic drinks/day, chronic glucocorticoids (>4 weeks), previous fracture, parental history of fracture, RA, low-weight bearing status	Female Athlete Triad (disordered eating, amenorrhea, bone loss)
Presentation	height loss, fragility fracture (GLF, minor trauma)	repetitive long bone stress fractures, atypical fractures (pubic ramus, femoral neck, non-metatarsal foot bones)
Screening	all women 65yo+ (Grade B USPSTF)	women <65yo w/ clinical risk factors via FRAX score (Grade B USPSTF)
Tests	Gold Standard: DEXA hip and lumbar spine Labs: 25[OH]D, calcium, phosphorus, albumin, total protein, LFTs (ALP), PTH
Diagnosis	T score ≦ -2.5 at femoral neck or spine OR fragility fracture of vertebra, pelvis, wrist, humerus, rib
Management	vitamin D supplementation, calcium if necessary, smoking cessation, weight bearing activity, Rx
Monitoring	DEXA q 2 years (for osteoporosis), q 4 years (for osteopenia), q15 years (for normal BMD).

Interpretation of DEXA Score
- Osteoporosis: T score ≦ -2.5
- Osteopenia: -1.0 > T score > -2.5
- Normal bone mineral density: T score  -1.0
Interpretation of FRAX (Fracture Risk Assessment Tool):
- 10-year risk of major osteoporotic fracture (Google “FRAX tool.”)

Indications: T score ≦ -2.5 (osteoporosis) OR -1.0 > T score > -2.5 with FRAX>3% for hip fracture
First line: oral bisphosphonates (alendronate 10mg qd, at least 30min before food)
If eGFR<30: refer to endocrinology for IV zoledronic acid or IV denosumab
If severe (T score< -3.0): consider anabolic (e.g., teriparatide) as first line agent