You Can Understand The Nervous System: Part 3

Look at you, back for more! Alright so you’ve mastered the basics of the nervous system from lesson 1, and you understand nerves a little bit better thanks to lesson 2so what’s next? Now that you have a good foundation the fun part is getting to put it all together to understand how MS causes such a wide variety of symptoms.

As you learned, the brain and the nervous system are responsible for organizing and carrying out thousands of tasks. In order to tackle such an overwhelming responsibility the brain takes a “divide and conquer” approach. As you can see in the above picture each part of the brain is assigned a task. You can see there are areas for tasks such as speech, smell, hearing, memory, coordination, and body movement. There are also areas that control emotions, sleep, and bodily functions such as bowel and bladder control, breathing, and digestion.

That’s right, the nervous system controls all of these things!

So it would make sense that a disease that attacks the nervous system causes such a variety of problems. One doctor of mine called MS the wack-a-mole of diseases. WACK and you are now talking funny thanks to a lesion in your temporal lobe. BAM and there’s a lesion in your cerebellum that makes you walk like you’re drunk. BOOM and a cervical spine lesion makes your leg go numb. There is no way to know or predict where the lesions in a person with MS are going to occur. Some people have more spinal lesions then brain lesions and tend to have more issues with sensation, incontinence, and walking. Others have lesions that are worst in the areas that control cognition and they have trouble with concentration and memory. Many people have lesions that affect their optic nerve and give them vision problems. This is why we like to get an MRI when someone has a new symptom. The MRI allows us to see what is going on in the area of the brain that coordinates with the symptom. For instance if someone suddenly had blurry vision we would look closely at the optic nerve. The scan will tell if there is a lesion there and if it is old damage or an active attack happening right then. If the lesion enhances it is active, and we can give IV steroids to decrease the inflammation and speed up recovery. However, steroids do not reverse or stop any damage from happening. They merely speed up the recovery from a relapse by a couple of weeks.

During a relapse an area of the brain is under attack, and myelin around the nerves is damaged. This results in that “frayed wire” that you learned about in lesson 2. The nerves in that area of the brain effectively have their line of communication cut off, and as a result they either have a much more difficult time performing their normal duties, or they cannot perform them at all. Over time scar tissue forms and the nerves can even heal to some extent. The brain also finds ways to work around the damaged area so that all function is not lost. It’s like a bridge that has fallen after an earthquake. There’s no longer a way to get from one side of the shore to the other, but you can build another bridge! It takes time to build a bridge though, and before you can even begin to build you have to clear out the debris from the fallen bridge. The brain does the same thing, but in a lot less time! Bottom line, it takes time for your brain to heal and build alternative routes which is why it can take months to recover from a big relapse.

Back in my Neurosurgical ICU days the majority of my patients were in intensive care after having a stroke. A lot of the time the brain was so swollen that we kept them in medically induced comas. This took stress off of the brain by eliminating the need for it to do a lot of work which gave it an opportunity to rest and recover. Our patients stayed with us for a long time, months even, because you can’t rush the brain when it is healing. Imagine what happens when you get a bad bump or bruise. First the area swells and becomes dark purple over several days. Then slowly over time the color gets a little more yellow, and eventually it goes away completely. The same process has to happen when a stroke or a relapse occurs in the brain, but it takes longer then it does to clear just a simple bump or bruise.

Many patients have symptoms even in remission (you can read more about why that is here), and the best we can do for now is to try different medications and therapies to minimize how bad the symptoms are. Additionally most of us have symptoms that wax and wane, which give us those “bad days” that we so often talk about. Lots of things cause bad days for us including dehydration, lack of sleep, stress, extremes in temperatures, and even a simple cold can give us weeks of bad MS symptoms. All of those things makes it harder for nerves to conduct electrical signals, and for nerves already damaged by MS it’s like adding insult to injury.

I may not have the secret cure for MS, but I do have this crazy idea that knowledge is power. My wish for all of you is to at least have a better understanding of your body. Maybe you can even appreciate how miraculous the human body is a little better. I always say that my body does more things right then it does wrong. It’s easy to focus on numbness or pain, and forget that thousands of other things are still working as they should. So thanks body for putting up a good fight, and thanks to all of you for reading!