What is secondary progressive MS?

Secondary progressive multiple sclerosis (SPMS) relates to the phase of MS that comes after (or is secondary to) relapsing remitting MS. The majority of people diagnosed with relapsing remitting MS will go on to later develop secondary progressive MS.

There are two main ways in which disability can develop in people with MS. These are:

In relapsing remitting MS, disability results from the former, while in secondary progressive MS, disability comes from both.  In secondary progressive MS, you will either:

Approximately 65 percent of people diagnosed with relapsing remitting MS will develop secondary progressive MS within 15 years of the onset of initial symptoms. The longer you have the condition, the higher the likelihood becomes.

There are, however, those who never develop secondary progressive MS, even after decades.  These people are sometimes described as having benign MS as they have not developed major disability despite having MS for a long time.

To diagnose secondary progressive MS, there needs to be clear evidence that your level of disability has continued to worsen for at least six months, without being associated with a relapse. 

 This usually happens to people who already have some disability as a result of previous MS relapses, from which they have not completely recovered. For people who no longer have relapses, the diagnosis of secondary progressive MS can be quite straightforward, but for those who continue to have relapses, diagnosis can be quite difficult.

Another problem with diagnosis of secondary progressive MS is that your neurologist must confirm that the worsening relates directly to the MS and not some other cause.  Unrelated issues, such as a decrease in the level of fitness, menopausal symptoms, a fracture or muscular pain, may make evaluation difficult. 

Relapses are caused by the following changes within your central nervous system tissues:

When you have a relapse, the main process at work is inflammation, though in most relapses there is also some damage to the myelin and nerve fibres. The central nervous system can repair some or even all of the damage, but this does not always happen. If the nerve fibre dies, then repair cannot occur. Fortunately, we can afford to lose quite a lot of nerve fibres (possibly up to 40 per cent) without significant effect.

One theory suggests that the brain can compensate for a certain amount of damage to nerve fibres. Whilst this happens, people do not have any symptoms. But as more and more nerves are damaged, there is less and less capacity for adaptation. Once a certain threshold is reached, further loss of nerve fibres leads to an increase in disability known as progression.  If this theory is true, it could make a difference to how this stage is treated.  For example, steroids to treat relapses would no longer be appropriate. 

Some people with secondary progressive MS who experience relapses are eligible to use one of the MS Therapies.  The Association of British Neurologists Guidelines state that the therapies should only be offered if you are still having relapses and it is clear that your condition is worsening as a result of these. Unfortunately, it has not been shown to have a beneficial effect on reducing the rate of progression in SPMS.

Research has shown that Mitoxantrone, a potent drug that suppresses the immune system, may also be effective in treating secondary progressive MS, particularly for those who have relapses; it is much less effective for those who do not still have relapses.

A series of clinical studies conducted over the past 10 years in Europe showed that it can slow the progression of disability, reduce the frequency of relapses and reduce the number of new lesions in the brain. It is currently licensed in the US and Canada for secondary progressive MS and worsening relapsing remitting MS. Although it is not licensed in the UK, it can be prescribed on a named patient basis. Treatment with Mitoxantrone should be closely monitored as there is a very small risk of some potentially serious adverse effects, including heart problems and leukaemia. 

It is important to have access to a multi disciplinary healthcare team and to have a programme set up to treat the symptoms that you experience. This is because symptoms – such as spasticity, poor coordination and fatigue – can interact in a way that increases the impact on disability.

Also, studies have shown that physiotherapy can be of considerable benefit if you have secondary progressive MS.  Speak to your GP or MS nurse if you would like to find out about physiotherapy options.  

Last updated by MS Society Information Team, October 2004. Reviewed by Dr Alasdair Coles, MS Society Medical Advisor. 

Courtesy of:  MS Society in the UK