Running on Empty: Dealing with Fatigue



By Ben Thrower, M.D.
 
Fatigue is one of the most common and most bothersome symptoms experienced by people with MS; the word itself – fatigue – does not adequately express the magnitude of the problem.
 
We live in a busy, multitasking, “go, go, go” kind of world. Everyone gets tired, but the fatigue experienced by people with MS is different. By definition, it affects a person’s ability to carry out their daily activities. Fatigue can be a direct result of a person’s MS, or it may be because of other factors, such as disrupted sleep, deconditioning, mood disturbances, medications, or other medical problems. (Keep in mind that fatigue may be due to a combination of these factors.)
 
Fatigue that is a direct result of MS comes in two flavors: lassitude and nerve fiber fatigue. Lassitude is an overwhelming tiredness that comes on for no apparent reason. It has been described as, “swimming in a fur coat.” Others say it feels like someone has thrown a lead blanket over them. People with lassitude know they want to get up and go; their body, however, says otherwise.
 
Nerve fiber fatigue, on the other hand, does have an identifiable cause. This type of symptom is typically brought on by exertion or heat exposure. A typical example of this type of fatigue would be walking difficulties that worsen on a hot day or the farther you walk.
 
Talking about fatigue
 
When I discuss fatigue in the exam room, I frequently start the conversation by asking about sleep. Disrupted sleep is shockingly common in the MS community. If a person with MS says they are just as tired when they get up in the morning as they were when they went to bed, we may be dealing with
disrupted sleep. Obstructive sleep apnea is more common in people with MS. Many common MS symptoms may interfere with sleep, including muscle spasms, bladder issues, and pain. Depression and anxiety may result in difficulty getting to sleep or staying asleep.
 
Studies have shown that a only small percentage of adults in the U.S. get the amount of exercise needed. Add in some of the challenges posed by MS and it’s no surprise that many people with MS are deconditioned. For those with MS, regular exercise has been shown to improve energy levels and mood. The good news is that the exercise does not have to be anything fancy. The best exercise for a person with MS is the one they have access to and will stick with. In the words of the ancient Greek philosopher, Nike, “Just do it!”
 
Mood disturbances, such as depression, are more common in people with MS and may also disrupt sleep and affect energy levels. Many people with depression experience a symptom called anhedonia. This Greek word means you have a lack of desire to do things that you would normally enjoy. This could be eating, having sex, going out of the house, etc. So, how do we sort out fatigue from anhedonia (realizing you may have both)? If your spouse wants to go to the movies and you just cannot muster the energy to get off the couch, even though you really want to see this movie, you are likely dealing with fatigue. If this awesome movie and that great, hot popcorn just seem kind of “Meh!” you may be dealing with anhedonia from depression.
 
Also important to know, many of the medications used for managing MS may be associated with fatigue or drowsiness. Medications used for spasticity (baclofen, tizanidine, and clonazepam) may all cause fatigue. Anticholinergic medications (oxybutynin, tolteridine, etc.) used to treat overactive bladder symptoms may cause tiredness or drowsiness. Medications used for pain management and depression may also be associated with a drop in energy levels. The decision to treat various MS symptoms with a medication always includes a discussion of the risks and benefits. Finally, interferon beta injections (Betaseron, Rebif, Avonex, Plegridy, and Extavia) can be associated with post-injection flu-like side effects including fatigue and worsened depression. These drugs have been around a while and we have learned how to minimize these issues.
 
Finally, when thinking about fatigue, don’t forget that just because a person has MS, it does not mean they can’t have other health problems. Non-MS medications, low thyroid function, hormonal issues, and cardio-pulmonary disease can also contribute to fatigue. I strongly encourage people with MS to have a primary care provider and keep up with routine health screening.
 
There is a dangerous tendency to blame all symptoms in a person with MS on their MS, sometimes ignoring other health problems.
 
Identifying Causes of Fatigue
 
The underlying cause of primary MS fatigue, especially lassitude, remains unclear. Efforts to identify brain MRI abnormalities that correlate with fatigue have not provided an absolute answer. Some research suggests that problems with the immune system itself may result in an overabundance of inflammatory chemical messengers, called cytokines, that cause fatigue.
 
Nerve fiber fatigue, on the other hand, is a bit better understood. Electrical information in the brain and spinal cord is normally transmitted quickly and efficiently across myelinated nerve fibers. When nerve fibers are stripped of their myelin (demyelinated), these signals are no longer transmitted quickly. With exertion and/or heat exposure, the electrical transmission may stop altogether, a phenomenon called conduction block. Rest and cooling will put things back in order. It’s important to know that exertion and heat exposure are not causing any permanent damage.
 
Developing a Treatment Plan
 
So, as you can see, fatigue is common and somewhat complex in MS. Developing a treatment plan is a personal matter and depends upon what factors are contributing to fatigue in a given individual. Lassitude may improve with medications, including amantadine, modafanil, armodafanil, or stimulants, such as methylphenidate. An over-the-counter supplement, acetyl carnitine, was shown to help in some people.
 
Physical and occupational therapists offer training in energy conservation. This may help the person with MS work smarter and not harder. Nerve fiber fatigue can be minimized with cooling strategies, like using a cooling vest or cooling hat, as well as medications like dalfampridine and 4-aminopyridine. Sometimes, a combination of cooling accessories and medication is the most effective course. Regular exercise and sleep, healthy eating, and avoidance of smoking are all good health tips for everyone, but may be especially important for people with MS.
 
Talk to your healthcare team about fatigue. Help them out by describing how fatigue affects you, what it feels like, what makes it worse, and any new medications  you are taking. While fatigue in MS can have major effects on your quality of life, it is important to know that you do have treatment options.

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