• Primary prevention
• Untreated early menopause (<45)
• Low BMI (<19, anorexia)
• Untreated hypogonadism in men
• Aromatase inhibitor treatment
• Vitamin D deficiency/osteomalacia
• Primary hyperparathyroidism/Cushing's syndrome
• Thyrotoxicosis
• Growth hormone treatment
• High alcohol intake
• Liver disease (e.g. PBC)
• Malabsorption (e.g. celiac)
  
• Oral steroids (daily for >3 months)
• Inflammatory arthropathies
• Kidney dialysis
• Transplant assessment
• Prolonged immobility (>6 months bed ridden)
• Family history (1st degree relative with osteoporosis)
• Secondary prevention
• Follow up scan (usually no sooner than 2-5 years)
• Height loss/kyphosis (>3 cm)
• Vertebral fracture
• Low trauma fracture (e.g. fall from standing position, excluding fingers and toes)
• Radiological evidence of osteopenia

Parathyroid hormone effects

• Bone
• Indirectly stimulates osteoclasts
• PTH stimulates osteoblasts to increase their expression of RANKL and inhibits their expression of osteoprotegerin (OPG)
  
• OPG binds to RANKL and blocks it from interacting with RANK, a receptor for RANKL
• The binding of RANKL to RANK (facilitated by the decreased amount of OPG) stimulates these osteoclast precursors to fuse, forming new osteoclasts
• Kidney
• Enhances active reabsorption of calcium and magnesium from distal tubules and the thick ascending limb
• Decreases the reabsorption of phosphate, with a net loss in plasma phosphate concentration
• When the calcium:phosphate ratio increases, more calcium is free in the circulation
• Intestine
  
• Enhances the absorption of calcium in the intestine by increasing the production of activated vitamin D by up-regulating 25-hydroxyvitamin D3 1-alpha-hydroxylase in the kidney
  
• 1,25-dihydroxy vitamin D increases the absorption of calcium (as Ca2+ ions) by the intestine via calbindin

FRAX

• Gives the 10 year probability of a fracture
  
• Hip fracture
  
• Major osteoporotic fracture (clinical spine, forearm, hip or shoulder fracture)
  
• Factors:
• Current age
• Gender
• Prior osteoporotic fracture
  
• Morphometric vertebral fracture, prior clinical vertebral fracture or a hip fracture is an especially strong risk factor
• Femoral neck BMD
• Low body mass index
• Oral glucocorticoids for more than 3 months
  
• At a dose of prednisolone of 5mg daily or more (or equivalent doses of other glucocorticoids)
• Current smoking
• Parental history of hip fracture
• Alcohol intake (3 or more units a day)
• Rheumatoid arthritis
• Secondary osteoporosis
  
• e.g. - type I diabetes, untreated long-standing hyperthyroidism, hypogonadism or premature menopause (<45 years), chronic malnutrition, or malabsorption etc.

• Fully human monoclonal antibody
  
• Indications:
• Osteoporosis, treatment-induced bone loss, bone metastases, rheumatoid arthritis, multiple myeloma, giant cell tumor of bone
• Designed to inhibit RANKL
• Contraindicated in patients with hypocalcemia
• Sufficient calcium and vitamin D levels must be reached before starting on denosumab therapy

Raloxifene

• Oral selective estrogen receptor modulator (SERM)
• Has estrogenic actions on bone and anti-estrogenic actions on the uterus and breast
• Used in the prevention of osteoporosis in postmenopausal women

Calcium ranges

• Total calcium
  
• 2.2-2.6 mmol/L
• Ionised calcium
  
• 1.1-1.4 mmol/L 
• Biologic effect of calcium is determined by the amount of ionized calcium, rather than the total calcium
• Ionized calcium does not vary with the albumin level
• Useful to measure the ionized calcium level when the serum albumin is not within normal ranges, or when a calcium disorder is suspected despite a normal total calcium level
• Corrected calcium
• A fall in albumin DECREASES the measured total calcium level
  
• Each 1 g/dL decrease of albumin will decrease 0.8 mg/dL in measured serum Ca and thus 0.8 must be added to the measured Calcium to get a corrected Calcium value

Notes

• Zoledronate is given yearly (5 mg infusion)
• Flu-like symptoms from bisphosphonates
• Activate gamma/delta T cells
• DEXA scan doesn't measure structure, only density
• Steroids preferentially attack certain trabeculae, potentially weakening bone without reducing density
• Z score is used for:
• Very young patients (not yet at peak bone density)
• Very old patients (to check if their low T score is "normal" or not)