Osteoporosis is a Disease of the Bone

Osteoporosis is a disease of the bone that is characterized by loss of bone mass and mineral content, resulting in them become a lot thinner and brittle making them susceptible to fractures from minimal trauma.

It is a common problem amongst elderly patients, though it can occur as a result of long term illnesses and medication use. According to the National Osteoporosis Foundations 2013 updated report, one in 2 Caucasian women and 1 in 5 men over age 50 will suffer from an osteoporotic fracture at some point in their lives.1

This article will cover some aspects of clinical diagnosis and management and prevention of osteoporosis.

Causes of Osteoporosis

Osteoporosis is divided into 2 main types depending on the cause –

1. Primary Osteoporosis

Here there is no cause identifiable. It is usually physiological such as being age related or post menopausal.

2. Secondary Osteoporosis

This occurs due an underlying disease or due to medications.

  • Endocrine causes –  Acromegaly, Cushings syndrome,
    hyperthyroidism, hyperparathyroidism, adrenal insufficiency
  • Malabsorption syndromes
  • Mineral and vitamin
    deficiencies – Calcium deficiency, Vitamin D deficiency
  • Inflammatory disorders –
    Systemic lupus erythematosus, Rheumatoid arthritis, Ankylosing spondylitis,
    inflammatory bowel disease
  • Genetic causes – Glycogen
    storage disorders, Marfans syndrome, hemochromatosis, hypogonadism.

These are just some of the secondary causes of osteoporosis.

Clinical features

Patients with osteoporosis usually have it diagnosed when they sustain a fracture of some sort. Otherwise there do not appear to be any specific symptoms of osteoporosis. However, there may sometimes be subtle signs that osteoporosis is setting in. These can include a loss of height, a change in spine curvature and sign suggestive of a secondary cause of osteoporosis.

Diagnosis

As has been previously mentioned, many times osteoporosis is diagnosed following a fall and sustaining a fracture of the hip or the vertebra. However, there are certain simple tests that can be performed diagnose osteoporosis-

1. Blood tests – the presence of anaemia may indicate an underlying bone marrow pathology or blood disorder that could be there secondary cause of osteoporosis. In patients with primary osteoporosis, the serum levels of calcium and phosphate are usually normal.

However they may be altered in the presence of an underlying endocrine disease. Other commonly performed tests include a serum ferritin (for haemochromatosis), liver function tests and thyroid function tests. These days vitamin D levels are being estimated in the blood as it has been shown that many women who do suffer from osteoporosis are vitamin D deficient.

2. Plain x-ray-plain x-ray of the bones will usually show thinning of the cortex with associated loss of bone alignment and integrity if there is an underlying fracture.

Fractures in Osteoporosis

3. Dual energy x-ray absorptiometry – Also called a DXA scan, this test is currently considered the gold standard for the diagnosis of osteoporosis. It is useful in calculating the bone mineral density which is considered to be a good marker to estimate the risk of fractures from underlying osteoporosis.

The bone mineral density is estimated using a T- score and a Z-score. The table below illustrates the values of the T score that will coincide with the degree of reduction of bone mineral density. A normal T score is one that lies within one standard deviation of the normal value for a particular age.

T Score For Estimating Bone Mineral Density

  • -1 to -2.5 = Osteopenia
  • Less than -2.5 = Osteoporosis
  • Less than -2.5 + fractures =
    Severe Osteoporosis

4. CT scan

This test also allows for measuring bone mineral density. It is useful to visualise fractures and is a very sensitive method to diagnose osteoporosis involving the spine.

5. Other tests

When in most cases osteoporosis, the DXA scan is used, other tests also exist which are not used very often. These include a magnetic resonance imaging (MRI), Ultrasound and even a bone biopsy if required.

Treatment

There are a number of treatment options available to manage patients with osteoporosis. These range from lifestyle modifications to drug treatments and physical therapy.

1. Lifestyle modifications

These usually apply to words the prevention of osteoporosis rather than treatment. The advice normally provided would be to increase calcium intake and vitamin D intake. Calcium is present in dairy products and meat while vitamin D is present in eggs, milk and orange juice.

Low intensity exercise also seems to play an important part in the management of patients with osteoporosis. Weight-bearing exercises allow for increased bone thickness and this can in turn prevent fractures. Exercises that can be performed include simple walking, jogging, swimming and even cycling. Structured aerobic exercise programs also extremely helpful.

2. Drug treatment

Patients who have suffered a fracture due to osteoporosis or who have a very low bone mineral density on scan benefit from drug therapy. It is recommended by the National osteoporosis foundation that drug therapy restarted in postmenopausal women and men over the age of 50 years in case any complications due to osteoporosis may have occurred.

Calcium and vitamin D supplements are easily available and now commonly prescribed for patients with osteoporosis.

However, in addition to these, patients are also given a group of drugs called bisphosphonates. These include drugs such as Alendronate, Risedronate and Zoledronic acid. These drugs combined calcium and help increase the bone mineral density.

Other treatments for managing osteoporosis include calcitonin and Denosumab, which is a humanised monoclonal antibody.

3. Physical therapy

Physical therapy forms an integral part of management of patients in osteoporosis, particularly in the elderly patient group. Following sustaining a fracture, the mobility of patients is compromised significantly and physical therapists will help patients get back on their feet and train them using weight bearing exercises. This in turn increases bone mineral density and can help prevent future fractures.

Prevention of osteoporosis

Osteoporosis can be prevented by calcium and vitamins B supplementation and by avoiding risk factors such as smoking, lack of exercise and excessive consumption of alcohol.

Conclusion

Osteoporosis is a common health problem in elderly patients. Management should be aimed at preventing its onset and thus preventing fractures. Treatments are available which will help improve bone mineral density and prevent the complications of osteoporosis.

References

1. National Osteoporosis Foundation. Clinician’s Guide to Prevention and Treatment of Osteoporosis. Available at http://www.nof.org/professionals/clinical-guidelines. Accessed March 23, 2013.