To those who do not have MS, it may come as a surprise that fatigue is the most disabling symptom of MS. For those who have MS, this is not at all surprising. Part of the reason that fatigue is so common and potentially disabling relates to the fact that many different kinds of fatigue are experienced by people with MS, and it is possible to have none or all of the forms at the same time.
Obviously, MS does not protect you from the normal fatigue that anyone else may experience. However, a person with MS sometimes may have a "short-circuiting" type of fatigue. This occurs when a limb has weakness due to demyelination. if it is fatigued, the limb exhibits increased weakness due to demyelination. The limb will recover when the arm or leg is rested, but it may be bothersome when activities require its ongoing use. Repeatedly asking the demyelinated nerve to perform when it is repeatedly short-circuiting causes fatigue. The judicious use of aerobic exercise (see Chapter 20) may help build endurance, if not strength, and thus may decease this form of fatigue. However overexercising with weights increases both fatigue and weakness, so a careful balance must be sought.
Management strategies include the appropriate use of exercise and rest, with the understanding that "no pain, no gain" is simply wrong and that rest should come before short-circuiting fatigue becomes significant.
If a person does not remain active, muscles atrophy and decon-ditioning occurs. This is another source of fatigue. Maintaining mobility is essential! The appropriate management strategy for this type of fatigue is exercise and maintaining of mobility. Depression (see also Chapter 22) may be associated with MS and may cause significant fatigue. This may result from not eating or sleeping well, or it may be associated with a general feeling of depression. It is essential to recognize that this fatigue is related to depression. It should be managed by aggressively treating the depression with medication and counseling.
The most common fatigue seen in MS is called lassitude. It is sometimes referred to as "MS fatigue." Lassitude is characterized by an overwhelming sleepiness that may come on abruptly and severely at any time of day. This form of fatigue likely is biochemical in origin, and medications that modify brain chemistry may be helpful. Amantidine (Symmetrel®) is an example of a medication that affects the nervous system and also has antiviral effects. The antidepressants, including fluoxetine (Prozac®), paroxetine (Paxil®), and sertraline (Zoloft®), may be useful for this type of fatigue, even in those who are not depressed. These medications may not be interchangeable, with one working better for one person and a different one for another. Lassitude is a bothersome form of fatigue because a person may look well and yet not be able to function. A new, novel medication, modafinil (Provigil®) has been shown to decrease MS fatigue and has become a commonly used treatment for this problem. Its mode of action is not clear but it does work by altering the brain's neurochemistry. This is becoming the most popular anti-fatigue drug In MS. It has a potential side effect of agitation, which should be reported to your physician immediately.
Stimulant medications sometimes may be necessary. These include pemoline (Cylert®), methylphenidate (Ritalin®), and occasionally dextroamphetamine (Dexedrine®). These medications should be used with caution because they may be habit-forming and may lead to agitation. A well-timed nap sometimes is most helpful in managing lassitude. The management strategy for this form of fatigue includes rest and the use of antidepressant and stimulant medications.
Even though fatigue is common and potentially disabling, it is clear that people who have MS are not fragile. Although rest may be helpful, the idea that fatigue leads to increased demyelination has not been proven. The idea that MS progression occurs if a person does not rest a great deal is also without merit. You need to listen to your body, but there always are times when a little extra push is necessary, and this is not a cause for fear.
In summary, the approach to fatigue in MS involves identifying the type of fatigue and treating it specifically. Removing any contributing causes is essential. These include infections, stress, and overutilization of some medications. While medications can help, rehabilitative techniques can also be valuable.
Occupational therapists may be helpful in teaching the concept of energy conservation to those who have moderate or severe fatigue of differing varieties. Efficiency in performing activities of daily living, which include dressing, grooming, toileting, eating, and so forth, may increase the energy available for other activities.
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