FATIGUE

Fatigue is a common, troubling symptom for people with MS.  There are many possible causes for fatigue, and, before being able to treat it effectively, those causes must be identified.  It is helpful to work with a healthcare provider to identify the factors that may be contributing to fatigue.

FATIGUE AND MS

Fatigue occurs in 75-90% of people with MS.  For about two-thirds of people with MS, fatigue is one of their worst symptoms.  It is a major symptom that interferes with quality of life, and it is one of the two main reasons for unemployment among people with MS (1-4). 

Fatigue is sometimes referred to as an “invisible” symptom because, unlike conditions such as weakness or walking problems, fatigue may not be apparent to others.  Since it is “invisible,” it is sometimes difficult for friends and family to understand how severely a person with MS may be affected by fatigue.  Fatigue may occur in those who are at any stage of MS; there is not a clear relationship between fatigue and the severity of MS or the activity of the disease (3-6).

WHAT IS FATIGUE?

Various definitions for fatigue have been proposed.  For people with MS, fatigue has been described as a lack of physical or mental energy that interferes with regular activities (1).  Intermittent fatigue occurs in many people with MS or without MS; the more notable, chronic fatigue that is seen in MS is characterized by being present for at least half the time for more than six weeks (1). 

MS fatigue has specific features (1,2,4).  The characteristics that distinguish MS fatigue are:

Ø      ·        Comes on easily.

Ø      ·        Interferes with or prevents physical functioning.

Ø      ·        Interferes with daily activities.

Ø      ·        Worsens with heat.

WHAT CAUSES FATIGUE?

MS itself causes a characteristic form of fatigue.  However, many other factors that are not directly related to MS may produce fatigue in a person with MS (1,7,8).  When evaluating fatigue, it is important to keep these other possible causes in mind:

·        Depression:  Depression, which occurs relatively frequently in people with MS, causes sadness as well fatigue.  Other features of depression include loss of interest in activities and changes in sleeping and eating habits.  Diagnosing depression and treating it with medications and psychotherapy can relieve fatigue and other depression symptoms.

·        Heat:  Heat is notorious for worsening MS symptoms, especially fatigue.  Fatigue may be provoked by very small increases in body temperature, which may be brought on by hot weather, warm baths or showers, and exercise.  Avoiding heat and using cooling strategies (such as cold drinks, air conditioning, and cooling garments) may be helpful.

·        Sleep:  Inadequate sleep may cause fatigue.  In people with MS, sleep may be interrupted by muscle stiffness (spasticity), bladder problems, pain, depression, and irregular breathing (sleep apnea).  Sleep apnea can be diagnosed with a sleep study.  A variety of treatments are used for these sleep-related conditions.

·        Other medical problems:  Fatigue may be caused by a variety of other medical problems, including thyroid problems, infections, anemia, and heart, lung, liver, or kidney disease.  These medical problems can be diagnosed by working with your physician or other healthcare provider.

·        “Handicap fatigue”:  In people with weakness, walking difficulties, and incoordination, it may take extra effort to perform physical activities.  This may result in fatigue.  Working with occupational and physical therapists can be helpful to manage this type of fatigue. 

·        Physical deconditioning:  Being “out of shape” may contribute significantly to fatigue through a variety of mechanisms, including decreased muscle strength.  Working with a physical therapist is an excellent way to develop an individualized exercise program.

·        Muscle fatigue:  In some people with MS, limited physical activity provokes feelings of fatigue or weakness.  This often occurs with walking, where leg weakness develops after a walking for a particular distance.  Developing an exercise program and taking breaks during physical activity may help this type of fatigue.

·        Medications:  Medications may cause or worsen fatigue.  This may occur especially with drugs used to treat pain and spasticity, such as tizanidine (Zanaflex), lioresal (Baclofen), and clonazepam (Klonopin).  Some antidepressant and seizure medications also have this effect.  Identifying these drug effects requires working with your physician or other healthcare provider.  If drugs are causing fatigue, then it may be possible to lower the medication dose or use a less sedating medication. 

HOW CAN FATIGUE BE TREATED?

The treatment of fatigue must be tailored to the individual since different people have different causes for their fatigue.  As a result, the first step is to identify the cause or causes.  As noted, some fatigue management strategies depend on addressing the underlying problem, such as depression, sleep disorders, other medical problems, or sedating medication.

For fatigue that is directly related to MS, some other strategies may be effective:

·        Medications:  Several studies indicate that amantadine (Symmetrel) is effective for treating MS fatigue.  An exciting new development in this area has been a study showing that modafinil (Provigil), a drug originally developed for narcolepsy or “sleeping sickness,” relieves MS fatigue.  This drug may be effective at relatively low doses.  Provigil may decrease the effectiveness of birth control pills.  Another drug that is sometimes used is pemoline (Cylert), but studies have not shown significant benefits with this medication and it may have side effects, which include liver toxicity.  Antidepressant medications may have an energizing effect, but there is limited information about the use of these drugs for MS fatigue.  Some people with MS report improved fatigue after starting treatment with one of the “A, B, C” drugs (Avonex (interferon-beta-1a, Betaseron (interferon-beta-1b), Copaxone (glatiramer acetate)).  A recent preliminary study suggests that this effect may be greatest with Copaxone.  Two related drugs, 4-aminopyridine (4AP) and 3,4-diaminopyridine (DAP), have produced promising results but are not approved for use; they may provoke seizures.

·        Cooling:  There are garments available that provide cooling.  Limited studies with these garments indicate that they may improve fatigue.

·        Exercise:  Exercise may be one of the most paradoxical treatments for fatigue—it is one of the last activities that someone with fatigue might consider.  However, several recent studies indicate that it is helpful for MS fatigue.  One recent study of an unconventional form of exercise, t’ai chi, indicated that this reduced fatigue in a small group of people with MS.

·        Energy conservation:  This refers to limiting the amount of energy that is devoted to activities through the day.  This may include modifying work or home activities and even simple measures, such as taking naps.  An occupational therapist can be help develop energy conservation strategies.

More limited information has been obtained for other fatigue therapies:

·        Caffeine:  Some people with MS believe that caffeine improves their fatigue.  There are studies indicating that caffeine improves mental alertness, but, surprisingly, there are not any studies of caffeine for MS-related fatigue.  Caffeine may be obtained from many sources, including coffee, tea, chocolate, cola drinks, and guarana (a South American herb).

·        Magnets:  One study based at the University of Washington evaluated the effects of magnet therapy on MS symptoms.  This treatment involved pulsing electromagnetic therapy, which involves wearing a small device that emits a weak electromagnetic field.  In this study, multiple symptoms, including fatigue, improved.  Further studies are needed. 

·        Prokarin (Procarin):  This is a treatment that has recently been claimed to be effective for multiple MS symptoms.  It is a skin patch that contains caffeine and another chemical, histamine.  A recent small study indicates that it may relieve MS fatigue, and that this effect is not necessarily related to caffeine.  Larger studies of Prokarin are needed.

A variety of other strategies have sometimes been claimed to be effective for MS fatigue, but well-designed studies have not been done.  There are no published clinical studies of acupuncture for MS fatigue.  However, a clinical study of the effects of acupuncture and Chinese herbal medicine on MS fatigue is currently underway in Oregon. 

Some dietary supplements are claimed to be effective for MS fatigue, but they have never been studied for this condition and may pose risks for people with MS.  These dietary supplements include:

·        Asian and Siberian ginseng:  possibly immune-stimulating and therefore a theoretical risk for people with MS.

·        Androstenedione:  may cause liver toxicity and may increase the risk of heart disease, stroke, and some forms of cancer.

·        DHEA:  also known as dehydroepiandrosterone; may cause liver toxicity and may increase the risk of heart disease and cancer.

·        Spirulina:  may contain contaminants, including heavy metals and bacteria.

CONCLUSION

In MS, fatigue is common and may be due to a variety of causes.  One should not immediately assume that fatigue is directly related to MS.  Instead, the cause or causes should be identified and a personalized approach should be developed.  Working with a physician or other healthcare professional can help identify and treat the appropriate conditions.