DocWire News: What causes fatigue in patients with MS?
Dr. Kantor: When you’re thinking about fatigue and multiple sclerosis, it’s important to think about what type of fatigue are we talking about? Are we talking about fatigue that’s from the MS or not from the MS? If it’s from the MS, are we talking about primary MS fatigue or secondary MS fatigue? Let’s look a little bit more deeper at that. You can have fatigue and have multiple sclerosis, and it could be not related. The most common reason in the United States for people being fatigued has nothing to do with a chronic illness. It has to do with poor sleep hygiene, meaning that the bedroom should be used for two things, and one of them is sleep. And the other one isn’t eating or watching TV. The other thing is, as all of our necks enlarge, more and more of us actually get obstructive sleep apnea, which means that you don’t have a restful night. And that means that you’re fatigued during the day.
But that’s different than MS fatigue. MS fatigue can be a lot worse than regular fatigue, and it can be hard sometimes for the care partners or even for us physicians to understand what our patients are describing. MS fatigue can come on suddenly. It can be very, very severe and it cannot be resolved or relieved by sleep. And so, when you think about primary MS fatigue, this is fatigue that happens because of the pathophysiology of multiple sclerosis itself. And so, if we think of MS as being a lifetime auto-immune diagnosis, then what can happen is there’s inflammation within the central nervous system. So inside the white and gray matter in the brain, there can be a low lying inflammation that can go on. This inflammation can cause symptoms of fatigue.
There are other ways of understanding primary MS fatigue. One of them can be that there can be compensatory mechanisms that work or don’t work in somebody with multiple sclerosis. And there’s been some very interesting advanced imaging studies that look at how the front of the brain versus the back of the brain works in somebody with MS who has fatigue versus somebody with MS without fatigue or versus healthy controls. And what we find a lot of the times is that parts of the brain just can’t keep up with what’s going on in somebody with multiple sclerosis. Oftentimes, we think about MS, we think about brain atrophy and the volume loss that can happen over time. Studies haven’t really shown that overall brain atrophy, either of the white or gray matter, is connected or correlated to fatigue, but specific locations, if you have atrophy of those locations, there can be more MS fatigue. That’s primary MS Fatigue.
Secondary MS fatigue is fatigue that happens because of your multiple sclerosis, but not directly because of the pathophysiology of MS itself. For example, if you’re on a medication to relieve spasticity in multiple sclerosis, then that medicine can make you sleepy. It can make you somnolent, and you can be fatigued. That’s a secondary cause of MS fatigue. If you’re not walking right because of your MS, then what can happen to a patient is they have to expend more energy to do regular daily activities, and this can make them feel fatigued. And so, when you’re evaluating a patient with multiple sclerosis, it’s important to think, “Is this related to the MS? Is it not?” If it’s related to the MS, is it primarily from the MS pathophysiology itself? Or is it secondary to something else in their MS?
DocWire News: How does MS fatigue differ from normal fatigue?
Dr. Kantor: The word fatigue is used commonly in our language. Every day, people use the word fatigue. They say, “Oh, I feel fatigued today.” That’s not exactly the same kind of fatigue that you can see in MS. In MS, it can really be life altering. It can be a reason for people to stop doing activities of daily living. It can be a reason for people to have problems with work, either not working or being there, but not really being there. And we call that presenteeism. There can also be absenteeism where people don’t actually show up to work because of the MS fatigue. MS fatigue can come on suddenly, and it cannot be relieved by sleep. And these are some of the features that are sometimes different from MS fatigue and from everyday fatigue.
DocWire News: How does fatigue affect quality of life for these patients?
Dr. Kantor: Quality of life of people with MS can be impacted by a lot of things, but fatigue can be one of the major drivers of a lower quality of life. People oftentimes think of MS as being a disease that has to do with walking. It has to do with being a wheelchair. The truth is people who are in wheelchairs, they’re not the ones with the lower quality of life. It’s people who have things like fatigue or cognitive problems, and those symptoms can really impact a person’s life and they can reduce their quality of life. For example, if somebody with MS has fatigue, then they are less likely to be working. And in fact, in some studies, including in the NARCOMS database and in the largest US-based registry for multiple sclerosis, the largest national registry is called Corona, different than the virus.
And in Corona MS, what we found, is that about half the people are not working. Fatigue can be a major driver of that. It can mean that people might not show up to work, or if people do show up to work, they’re just not really there. We call that presenteeism. It can impact someone’s ability to drive. If you’re too fatigued to drive, well, then you need someone else to drive you around, and that can obviously impact your quality of life. If you’re not able to go to your son or daughter’s a football game or basketball game, well, that’s going to impact your quality of life. All of these things are intertwined, but fatigue can be a main driver of reducing quality of life in people with multiple sclerosis.