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 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 they are depressed or just not trying hard enough.
People with MS can experience fatigue that is unrelated to having MS. Other medical conditions and vitamin deficiencies, for example, can cause fatigue. It is important to ensure that your fatigue is a result of your MS and not something else that has a different treatment.
Several different kinds of fatigue occur in people with MS. For example, people who have bladder dysfunction (producing night-time awakenings) or nocturnal muscle spasms, may be sleep deprived and experience fatigue as a result. People who are depressed may also have fatigue. Anyone who needs to expend considerable effort just to accomplish daily tasks (e.g., dressing, brushing teeth, bathing, preparing meals) may also experience 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. Lassitude or "MS fatigue" is different from other types of fatigue in that it:
- 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.
Fatigue can also be caused by treatable medical, side effects of medications or from inactivity. Persons with MS should consult their healthcare provider if fatigue becomes a problem. Early identification of the cause of fatigue can lead to an effective treatment plan. Your healthcare provider can complete a comprehensive evaluation to identify the factors contributing to your fatigue and work with you to develop a treatment plan specific to your needs. Some strategies to manage fatigue include:
- Occupational therapy to simplify tasks at work and home and conserve energy use.
- Physical therapy to learn energy-saving ways of walking (with or without assistive devices) and performing other daily tasks.
- Physical therapy to develop a regular exercise program to prevent deconditioning.
- Sleep regulation, which might involve treating other MS symptoms that interfere with sleep (e.g., spasticity, urinary problems).
- 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 can be used although none are currently approved by the U.S Food and Drug Administration (FDA) specifically for the treatment of MS-related fatigue. Clinical trials of these medications have shown mixed results but they are commonly used off-label for fatigue from MS.