How Does MS Progress?
Unlike many medical conditions, multiple sclerosis is often unpredictable. The way it progressed in one person can be different from how it progresses in another. So let's go through the progression of MS.
From the first episode with so-called “clinically isolated symptoms,” about 50% of individuals will develop the disease within 2 years, while roughly 10% will no longer show any MS-related symptoms.
The initial episode can manifest with a variety of symptoms, ranging from non-specific numbness, tingling, and balance issues with double vision to severe muscle weakness and fatigue. Some people will have mild symptoms over their lifetime, while others will end up in a wheelchair.
Generally speaking, doctors classify the progression of MS based on four types (or patterns):
- Relapsing-remitting MS (RR MS) – As its name implies, this form of MS is characterized by acute attacks followed by remissions, and is usually seen during the early stages of the disease. This is the most common form of MS, seen in 80% of MS sufferers. During acute attacks, the symptoms worsen and they last anywhere from several days to weeks. After an acute attack, an individual may recover partially, or fully, or in some cases, no recovery of some functions at all will be seen. The recovery time may take anywhere from a few weeks to months. Overall, the disease does not progress (worsen) between two acute attacks.
- Primary progressive MS (PP MS) – In this form of the disease, there is a gradual worsening of symptoms and disability, and we don’t see the relapse remission pattern anymore. Statistics show that roughly 15% of those affected by MS will display this form.
- Secondary progressive MS (SP MS) – Patients initially present with a relapsing-remitting form that over time (anywhere from a few months to years or even decades) evolves into a progressive MS.
- Progressive relapsing MS (PR MS) – This form of MS can be easily confused with primary progressive MS as there is a gradual progression (worsening) of the symptoms; however, the patient may also have acute attacks followed by various degrees of recovery. It is the least common form of MS (5%).
Changes in Symptoms
It is next to impossible to predict how a person's MS symptoms will progress, because everyone is different, and MS symptoms are sometimes connected with the areas of the brain or spinal cord not affected by the disease.
For example, if the area of the brain or the optical nerve responsible for vision is affected, an individual will usually present with vision problems. If the spinal cord in the lower back is affected, there may be weakness and numbness in the legs that is experienced. However, sometimes the location of lesions appears to not correlate with the symptoms the person has.
In addition, the number of lesions seen on an MRI does not always correlate with symptoms. Some individuals may have a few plaques and many symptoms while others may have several lesions and very few symptoms.
To make things even more complicated, there is no way to predict where a new lesion will form – they occur randomly – or if that lesion will cause symptoms. What is known, however, is that our body can heal itself and repair – thus, over time some plaques may shrink or disappear, while new ones may occur.