People suffering Complex Regional Pain Syndrome (CRPS) sometimes believe that as a result of their CRPS they have either developed, or are at an increased risk of developing, osteoporosis. But is that correct?
What is osteoporosis?
Osteoporosis is a disease which results in a loss of bone density; quite literally ‘porous bone’. With that loss of density, bones become more fragile and easier to fracture. In advanced osteoporosis even basic activities of daily living can sometimes result in fractures.
About 80% of people suffering osteoporosis are women; usually older women, but the condition can also affect younger people.
What causes osteoporosis?
Loss of bone density is part of the natural ageing process and affects everyone. On average the process begins when we are in our mid-30s. There are several reasons why more women are affected than men. These include:
- the fact that women tend to have bones that are smaller, thinner and less dense than men;
- the fact that high levels of oestrogen help protect bone density and as levels of oestrogen fall following the menopause, bone density declines.
Can CRPS increase the risk of developing osteoporosis?
Newer medical imaging technology means that it is now possible to very accurately measure bone density. This technology, which is known as dual energy x-ray absorptiometry (DEXA) has been used in studies on people with CRPS. The imaging of a CRPS affected limb, particularly where the CRPS is long established, will often show a loss of bone density which can be quite substantial.
However, the loss of bone density is inevitably shown to be limited to the affected limb, rather than demonstrating that the person has more generalised osteoporosis. It is not thought that the presence of this localised osteoporosis creates an increased risk of developing more generalised osteoporosis.
What is the cause of this localised osteoporosis?
It is thought that the most likely reason for the development of this localised osteoporosis is lack of use of the limb due to immobility. This ‘disuse osteoporosis’, which is also suffered by astronauts during a prolonged period in space, results from a reduction in the mechanical stress on the bones. Such a reduction in mechanical stress induces an acceleration of bone resorption and a reduction in bone formation, leading to a loss of bone density.
Can localised osteoporosis be prevented or slowed down?
Doctors may prescribe Bisphosphonates, which are a type of drug that can slow done the loss of bone density. Whether or not drugs are prescribed, taking supplements such as Calcium and Vitamin D is strongly recommended.
Working with a physical therapist, if it is possible to engage the affected limb or limbs in some form of regular physical activity, that may in itself help to slow down the rate of loss of bone density. However, for many, the extent of their CRPS symptoms means that will not be possible.
Of course, immobility can also have a detrimental effect on areas of the body not directly affected by CRPS. It is therefore important to work with a physical therapist on developing an exercise routine to maintain, as far as possible, both overall levels of fitness and more general bone density.