Osteoporosis

This is a useful indicator of general health and underlying disease, for example normocytic normochromic anaemia may be seen in rheumatoid arthritis and pituitary failure.

Hypokalaemia may occur in glucocorticoid excess.

Chronic liver disease is a risk factor for osteoporosis.

Primary hyperparathyroidism is a recognised risk factor for osteoporosis. Hypercalcaemia may also occur with malignancy.

Hypocalcaemia may indicate vitamin D deficiency.

Vitamin D deficiency is common and should be treated with pharmacological replacement doses, rather than standard supplementation.

Long term suppression of TSH increases the risk of osteoporosis, though does not necessarily imply overt thyrotoxicosis.

Elevation of thyroxine with a low TSH demands treatment for thyrotoxicosis.

In men presenting with osteoporosis, testosterone should be assessed early morning on at least two occasions, and in conjunction with sex hormone binding globulin, in order to calculate free androgen index.

If this is low, further investigation into the cause of hypogonadism are mandatory, before optimum treatment is determined.

If hypercalcaemia is documented, the first step in determining the cause is checking PTH level.

Hyperparathyroidism is a recognised risk factor for osteoporosis.

It is worth documenting luteinising hormone and follicle stimulating hormone in male patients with a reduced testosterone level, and in women below 50 years with oligomenorrhoea. 

In hypogonadal patients, and those with possible pituitary disease, full baseline pituitary function should be assessed and further investigation of hypopituitarism considered.

If Cushing’s syndrome is suspected clinically, UFCs are a sensitive but not specific initial screen.

Dexamethasone suppression testing should also be performed in all patients with suspected Cushing's.

This is not required in all cases, as many patients will have a confirmed diagnosis of osteoporosis on clinical grounds.

Bone densitometry scanning is very useful in the risk stratification of those suspected to have, or with multiple risk factors for osteoporosis but who have not sustained any low impact fractures.

Plain radiography can be useful to determine the likely cause for example of back pain and to aid interpretation of denitometry scans. For example, if vertebral bone density is surprisingly high, this may be due to vertebral collapse which should be evident on plain films.