FATIGUE
Two types of fatigue can be distinguished.
A persistent sense of tiredness may prevent the accomplishment
of even light tasks. In the other form, the patient generally
feels well at rest, but is overcome by a generalized sensation
of fatigue, usually after a few minutes of physical activity;
this is termed fatigability and often disappears after a short
rest. The most common form of fatigability is in the legs,
when strength deteriorates after walking for a short distance.
Some patients overexert or try to exceed the limits of their
ability by walking with canes when they should be using a
motorized wheelchair for long distances. Fatigability may also
affect the sensory system; for example, visual ability and
clarity deteriorate with prolonged reading, but return after a
short rest.
Both types of fatigue are common in MS,
and both are thought to have both physiologic and
psychological components. The physiologic aspects of fatigue,
especially the phenomenon of fatigability, may be related to a
marginal ability to conduct nerve impulses through plaques and
should be distinguished from psychological fatigue. The latter
is characterized by listlessness, languor, apathy, and
depression and may respond to antidepressant drugs. Fatigue
and other symptoms in MS are characteristically worsened by a
hot bath, increased body temperature, and hot weather. Fatigue
may be the most important aspect of disability in MS and
interferes considerably with activities of daily
living.
The most important approach to the
treatment of fatigue is to teach patients to pace themselves
properly. They should not take on excessive physical activity
without the ability to rest. Another approach is to avoid even
small increases in body temperature by avoiding long periods
of vigorous exercise and warm surroundings. Repeated cold
baths or showers may help. Air conditioning is important in
hot climates.
Several drugs have been reported to help
in some, but not all, patients. These include amantadine;
about half of patients taking this drug believe it helps
maintain energy. Pemoline (Cylert) has been reported to be
beneficial in about two-thirds of patients. Antidepressant
drugs can be helpful in some cases. A recent trial with
4-aminopyridine (4-AP) suggested that this compound can reduce
fatigue and improve strength and balance for a few minutes or
hours; it is still under investigation and is not generally
available.
Reproduced with kind permission from:
Sibley WA. Therapeutic claims in multiple sclerosis: a
guide to treatments; 4th edition. New York: Demos, 1996
A new edition of Therapeutic claims is in press at present
and the information reproduced here will be updated as soon as
the book is published.
