Multiple Sclerosis and The Nervous System

Our best understanding of the most typical form of MS, which is relapsing/remitting MS, and how it evolves over time, especially when not treated, into more obviously progressive forms of the disease.

First off, usually by the time that a person has their first clinically obvious symptom of the disease, their MRI at that time will tend to show evidence of prior immunologic or inflammatory activity. Most people, even at the time of their very first symptom, actually will already have an abnormal MRI of their head, and that’s due to previous clinically silent inflammatory activity.

Each time there is a focus of inflammation, or a plaque, there is healing to a certain extent that occurs there. But over time, there is a gradual accumulation of plaque, or scar tissue, and as that accumulates over time, so does clinically obvious or evident disability. Even though there can be recoveries from attacks, and oftentimes early on in the disease there is even almost complete recovery after an attack, as time goes on, there tends to be less and less recovery. The previous activity of the disease – evidence of it – scar tissue mounts and a person is left with gradually accumulating problems associated with the disease. And so in a very real sense, the disease is progressing even though that person may not have gotten to that part of the disease that’s called secondary progressive.

Secondary/progressive MS is achieved when the time between attacks demonstrates worsening clinical abilities. Even though you’re not having attacks, you’re still getting slowly, steadily worse. That marks secondary progressive MS, and that’s a form of MS that we don’t have any great treatments for and a form of MS that we want to try to avoid our patients getting into with perhaps some treatment strategies that Dr. Galetta will discuss a little bit later.

The last thing I want to point out on this slide is a newer revelation. Almost from the very beginning of the disease – indeed, perhaps even beginning before the first clinical evidence of it – using sensitive enough techniques, one can detect, very minute initially, loss of brain tissue. It’s called atrophy. Clearly, this is not a good thing and if untreated, can continue on and gradually worsen as the disease progresses. As one might guess, as atrophy worsens, as brain tissue loss mounts, so does neurological disability. Again, this is the stage of the disease that we would like to avoid if at all possible through our treatment regimens.