MS and the Fatigue Factor

by Pamela Martin

I am often reminded of the time I set out for what was to be a short walk.  Struggling with an armload of groceries, I was in a hurry to get home.  Unfortunately, I came upon construction debris in the road, and was forced to take a detour around the mess.

As fate would have it, the path I chose was deceptively circuitous.  As one road led way to another, I discovered that I was going in circles.  My legs grew weary and the load heavier as I continued through the winding course.  By the time I stumbled home, I was completely and deathly exhausted.  In short, I used much more energy navigating through the twisting and zigzagging course than if I’d been able to use the more direct approach.

My experience is illustrative of the process at work in MS.  Myelin-damaged roadblocks force the communication mechanisms of the brain to take less effective, and roundabout routes.  This inefficient detour can result in a burdensome fatigue for the person with MS, both physically and mentally.

Physical Fatigue

When asked about MS-specific fatigue, many sufferers anecdotally describe it as "bone-tired" or a "wearing a suit of armor" feeling.  It differs from normal fatigue in that there is generally no easy correlation between the amount of energy expended and the severity of the weariness.  You would expect someone who just scaled Mt. Olympus to feel extremely exhausted.  You would not expect that same level of exhaustion from someone who merely cooked a simple dinner.  Yet, the problem is not simply an amplification of normal fatigue.  There are many more nuances involved in this symptom.

MS fatigue is often variable, sometimes unrelenting, and generally appears regardless of the amount of sleep the patient gets.  Some patients find that although they regularly get a full night’s sleep, they awaken in the morning unrefreshed.  Many require a scheduled nap in the afternoon when the fatigue is at its worst levels.  For me, I have found no connection between the total rest I get, and the way I feel at any given moment.  There have been times where I have gotten plenty of sleep the night before, but spent the next day in a zombie-like stupor, where even the simplest task requires a superhuman effort.  On the other hand, there have been times where I made it through an unusually busy day, yet felt no ill effects for several days.

Mental Fatigue

Not only does MS fatigue drain a patient physically, but it can also cause mental distress.  Remember the child’s game of trying to pat your head and rub your stomach at the same time?  It was hard to concentrate on both tasks at the same time, so ultimately, you ended up not doing either chore very well.  Many people with MS can relate to that feeling of being mentally overwhelmed.  Often, the dysfunctional nervous system is working overtime, processing the enormous sensory data that we experience daily.  Because the process is disrupted and inefficient, it may be difficult to hold a conversation and listen to background music at the same time.  Or someone may find it impossible to drive at night because the array of lights and sounds are disconcerting.  Similarly, I was once struck dumb and unable to answer a store clerk who simply asked me for my telephone number.  Because my senses were already overloaded from the shopping experience, my brain simply shut down when faced with a simple question.  At that moment I was just mentally worn out.

What Causes MS-related Fatigue?

Although scientists have no definitive answer, a couple of likely theories are presented regarding the cause of MS fatigue.

Location, Location, Location. One theory holds that fatigue is related to the loss of myelin--the protective coating of the nerve fiber.  The locations where the myelin loss occurs are responsible for the severity and type of fatigue.  In this scenario, it is the cerebral abnormalities themselves that contribute to fatigue.  The random placement of myelin lesions or loss could account for the variety of ways people with MS experience the symptoms of fatigue.

Interestingly, a 1999 study found fatigue severity did not correlate with myelin scarring or deterioration as observed on MRI. (1) Correspondingly, a 1998 study suggested that the differences in fatigue levels could not be solely explained by the degree of disease activity or disability. (2)  There is certainly a great need for more study in this area.

Poor Body Functioning. It has also been speculated that the general deterioration of overall functioning as a result of having MS may simply exhaust the body’s storehouse of energy.  Muscle weakness and decreased nerve conduction are the obvious culprits.  But some researchers have noted that altered metabolism and inadequate respiration are other energy-depleters.  Again, further investigation is needed in this area.

Treatments

Above all, patients must consult with their physician or other health care professional to determine the value of treatments available for MS fatigue.  The prescription drug, Neurontin®, which is used to control tremors and spasms, has been reported by some users to relieve fatigue as well (although the reasons for this are not totally understood).  In addition, amantadine (Symmetrel®) and pemoline (Cylert®) have been helpful to a small number of MS patients.  Unfortunately, others have found them to be complete failures at remitting fatigue, and have caused unwanted side effects.

Cephalon, Inc. recently reported positive findings from a new clinical study on the effectiveness of Provigil®.  Generally used for the treatment of narcolepsy, this medication was statistically successful in reducing fatigue in a study of MS patients.

Because these medications are of limited effectiveness, and can be accompanied by unwelcome side effects, many patients combat fatigue in other ways.  Patients learn how to simplify and manage their daily tasks more effectively, so as to save energy.  Physical therapy can teach some how to obtain benefits from using assistive devices to prolong energy.  In addition, avoiding heat, taking scheduled naps, limiting overexertion, managing stress, and monitoring the effects of medication are other steps taken to combat fatigue.

References

(1) Fatigue In Multiple Sclerosis: cross sectional correlation with brain MRI findings in 71 Patients,  Bakshi R; Miletich RS; Henschel K; Shaikh ZA; Janardhan V; Wasay M; Stengel LM; Ekes R; Kinkel PR, Neurology 1999 Sep 22; 53(5):1151-3

(2) Fatigue in Multiple Sclerosis: interrelations between fatigue complaints, cerebral MRI abnormalities and neurological disability,  Van der Werf SP; Jongen PJ; Lycklama a Nijeholt GJ; Barkhof F; Hommes OR; Bleijenberg G, J Neurol Sci 1998 Oct 8; 160(2):164-70

© 2000 Pamela Martin

Pamela Martin was diagnosed with MS in 1993 while working on her Master's degree in HR management.