Overview
Fatigue is one of the most common symptoms of MS, occurring in about 80 percent of people. It can significantly interfere with a person's ability to function at home and work, and it is one of the primary causes of early departure from the workforce. Fatigue may be the most prominent symptom in a person who otherwise has minimal activity limitations.
The cause of MS fatigue is currently unknown. Ongoing studies seek an objective test that can be used as a marker for fatigue, and for precise ways to measure it. Some people with MS say that family members, friends, co-workers, or employers sometimes misinterpret their fatigue and think the person is depressed or just not trying hard enough.
Fatigue & Lassitude
Several different kinds of fatigue occur in MS. For example, people who have bladder dysfunction (producing night-time awakenings) or nocturnal muscle spasms may be sleep deprived and suffer from fatigue as a result. People who are depressed may also suffer fatigue. Also, anyone who needs to expend considerable effort just to accomplish daily tasks (e.g., dressing, brushing teeth, bathing, preparing meals) may suffer from additional fatigue as a result.
In addition to these sources of fatigue, there is another kind of fatigue — referred to as lassitude — that is unique to people with MS. Researchers are beginning to outline the characteristics of this so-called "MS fatigue" that make it different from fatigue experienced by persons without MS:
- Generally occurs on a daily basis
- May occur early in the morning, even after a restful night’s sleep
- Tends to worsen as the day progresses
- Tends to be aggravated by heat and humidity
- Comes on easily and suddenly
- Is generally more severe than normal fatigue
- Is more likely to interfere with daily responsibilities
MS-related fatigue does not appear to be directly correlated with either depression or the degree of physical impairment.
Managing Fatigue
Because fatigue can also be caused by treatable medical conditions such as depression, thyroid disease, or anemia; may occur as a side effect of various medications; or may be the result of inactivity, persons with MS should consult a physician if fatigue becomes a problem. A comprehensive evaluation can help identify the factors contributing to fatigue and make it possible to develop an approach suited to the individual’s needs. Options for dealing with fatigue include:
- Occupational therapy to simplify tasks at work and home.
- Physical therapy to learn energy-saving ways of walking (with or without assistive devices) and performing other daily tasks and to develop a regular exercise program.
- Sleep regulation, which might involve treating other MS symptoms that interfere with sleep (e.g., spasticity, urinary problems) and using sleep medications on a short-term basis.
- Psychological interventions, such as stress management, relaxation training, membership in a support group, or psychotherapy.
- Heat management — strategies to avoid overheating and to cool down.
- Medications — amantadine hydrochloride (Symmetrel) and modafinil (Provigil) are the most commonly prescribed. While neither is approved specifically by the U.S Food and Drug Administration (FDA) for the treatment of MS-related fatigue, each has demonstrated some benefit in clinical trials. The most recent trial of modafinil, however, reported no difference between modafinil and placebo in relieving fatigue. Other stimulants such as Adderall or Ritalin can be used.
- Referral to a Sleep Neurologist may also be necessary.