MS The Disease
How Does Multiple Sclerosis Progress?
The first signs of MS often appear between the ages of 20 and 40 years. Sometimes MS can start in children or in elderly people, too. The course of the disease and the development of any disability vary depending on the severity or location of inflammation or how quickly the myelin breaks down.
Inflammation of areas of the CNS’s white matter may cause a person to have symptoms of MS. After an initial event, each subsequent episode of symptoms is called a relapse. Sometimes these attacks may be called exacerbations. When the inflammation is resolved, the symptoms may subside: this is known as remission or ‘recovery'. The recovery may not mean a return to the way things were before the relapse. Some symptoms may be left behind (residual symptoms). And sometimes the symptoms persist for several weeks.
Symptoms are one way to mark the progression of disease in MS. However, MS can also progress silently through axonal loss. The brain can adapt to and compensate for some level of damage, and symptoms are highly dependent on where the damage takes place (since different parts of the brain are responsible for different activities). So a person with MS can look and feel fine, yet his or her disease may be active.
There can also be a more gradual progression of the disease. If this is the case, you will notice a gradual loss of physical and cognitive functions, often over a period of years.
Given this potential for silent or invisible progression, treatment is important for people diagnosed with MS, even when symptoms may not be apparent.
Forms of MS
The overall course the disease takes in any one individual enables us to make a rough distinction between different types of MS.
Figure: Forms of MS
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1. Relapsing-remitting MS (RR-MS):
This type shows clearly defined relapses with some amount of recovery. It is the most common form of MS; around 80-90% (RefM2) of people have RR-MS when they are diagnosed. However, on average around 50% of them will have developed secondary progressive MS (RefM2) within 10 years (see below). For this reason, treatment at diagnosis with MS therapies to slow the development or progression of disability may be important in combating the disease in the long term.
2. Secondary progressive MS:
Initially this type follows a relapsing-remitting course with relapses and remissions being common. Over time a variable but continued loss of physical and cognitive functions starts to take over and relapses become less common.
3. Primary progressive MS:
This type shows no relapses, but over a period of years there is continual loss of physical and
cognitive functions. This form of MS affects about 10-15% of all people with MS at the onset of
their illness (RefM2).
Dividing MS into groups according to the progress of the disease is often a question of
looking back at its course over a longer period. However, because MS varies so much between
individuals, it is nearly impossible to predict how MS might affect a person in the future. Thus,
if you are diagnosed with a particular form of the disease, there’s no way to predict when, or if,
you will progress to another form.