Osteoporosis

Causes

Appropriate Tests

 

Clinical assessment, including age, gender, presence of systemic disease.

See also Bone fracture (pathological).

Generalised

Investigation may be appropriate to demonstrate increased bone loss prior to the development of clinical disease in high risk patients; to establish the diagnosis of osteoporosis; to monitor efficacy of treatment. Osteoporosis is diagnosed based on bone density (BMD) measurement and is defined as a BMD T score of £-2.5. Absolute fracture risk calculation is used to inform treatment decision http://garvan.org.au/promotions/bone-fracture-risk/calculator/

 http://www.shef.ac.uk/FRAX/

Other investigation may include diagnostic imaging to demonstrate fractures. Laboratory investigations may include Calcium, Phosphate, Albumin, Vitamin D, Alkaline phosphatase; fasting spot urine Calcium and, Creatinine , and bone turnover markers (BTM).

The recommended BTM are serum procollagen type I N propeptide (PINP) for bone formation and serum C-terminal cross-linking telopeptide of type I collagen (CTX) for bone resorption, which may be especially useful in monitoring treatment for which baseline and serial measurements are required. Urine deoxypyridinoline (DPD) or urine N-terminal cross-linking telopeptide of type I collagen (NTX) may be used as alternative bone resorption markers.

Post-menopausal

Bone loss commences prior to the menopause.

Cushing's syndrome

 

Hyperthyroidism

 

Plasma cell myeloma

 

Gonadal hypofunction 

See Amenorrhoea, Testicular failure.

Alcoholism

 

Malabsorption

 

Chronic metabolic acidosis, especially

  • Chronic renal failure
  • Renal tubular acidosis
  • Organic acidaemias

Bone may also show osteomalacia/rickets and effects of hyperparathyroidism. Bone specific alkaline phosphatase (B-ALP) or intact PINP assays are least affected by renal impairment.

Juvenile osteoporosis

 

Localised

 

Disuse atrophy

 

Sudeck's atrophy

 

Paget's disease of the bone

 

Reference:

Vasikaran S, et al. Osteoporos Int 2011;22(2):391-420