AKT · Endocrine/Calcium, bone & parathyroid

Osteoporosis

Reduced bone mineral density → fragility fracture risk

Overview

Reduced bone mass and microarchitectural deterioration causing fragility fractures (low-trauma fractures of hip, vertebrae, wrist). Often silent until a fracture. Risk is quantified with FRAX/QFracture and DXA (T-score ≤ -2.5 = osteoporosis). Treated with calcium/vitamin D and a bisphosphonate; exclude secondary causes.

Recognise

Fragility fracture (fall from standing height): hip, vertebral (height loss, kyphosis, back pain), Colles' (wrist)
Asymptomatic until fracture; risk factors: age, female/postmenopausal, steroids, smoking, alcohol, low BMI, family history, early menopause
Secondary causes: hyperthyroidism, hyperparathyroidism, Cushing's, hypogonadism, coeliac, myeloma, chronic steroids ('SHATTERED')

Red flags

New vertebral fracture / hip fracture → high imminent re-fracture risk; consider underlying malignancy in atypical fractures
Bilateral atypical femoral fractures / osteonecrosis of the jaw with long-term bisphosphonates

Differentials & how to tell them apart

Osteomalaciadefective mineralisation — bone PAIN, proximal myopathy, low calcium/phosphate, HIGH ALP, low vitamin D

Metastatic bone disease / myelomapathological fracture, lytic lesions, raised calcium/ESR/paraprotein

Paget's disease of boneisolated raised ALP, bone deformity/pain, normal calcium

Investigations

FRAX/QFracture risk assessment → DXA (T-score; osteoporosis ≤ -2.5). Bloods to exclude secondary causes (calcium, phosphate, ALP, PTH, vitamin D, TFTs, testosterone, coeliac, myeloma screen).

Management

Calcium/vitamin D + oral bisphosphonate (alendronate/risedronate)

1Assess fracture risk (FRAX/QFracture) → DXA. If T-score ≤ -2.5 (or after a fragility fracture), ensure calcium/vitamin D replete and offer an oral bisphosphonate (alendronate or risedronate weekly).Gate: Counsel bisphosphonate administration (upright, fasting, with water — oesophagitis) and rare risks (osteonecrosis of the jaw, atypical femoral fracture); exclude/treat SECONDARY causes (steroids, hyperthyroid, myeloma, coeliac) before assuming primary osteoporosis
2Oral not tolerated/contraindicated → IV zoledronate or denosumab; very high risk/teriparatide for severe disease; review treatment duration (drug holiday).

Calcium + vitamin D (ensure replete) — foundation, especially if deficient/housebound

Oral bisphosphonate (alendronate/risedronate) — first-line; take upright fasting with water, remain upright; oesophagitis, rare ONJ/atypical fractures

IV zoledronate / denosumab / teriparatide / romosozumab — specialist alternatives if oral not tolerated/contraindicated or very high risk

Key points

Fragility fracture or T-score ≤ -2.5 = osteoporosis (usually painless until it breaks). Bisphosphonate first-line with the upright/fasting counselling. Bone PAIN + high ALP + low calcium points to osteomalacia instead; isolated high ALP to Paget's.

Monitor & prognosis

Fracture incidence; DXA; treatment review.

Fractures preventable with treatment.

Source: NICE CKS Osteoporosis; NOGG