Beyond Just Tired: Figuring Out MS-Related Fatigue

Is fatigue often one of the first signs of MS?

Oftentimes people present very early on with fatigue as their sole symptom.  I think it occurs a lot more frequently than we think because people are misdiagnosed with chronic fatigue syndrome or said to be distressed or working too hard.  It's usually attributed to something else.

Is fatigue due to the disease process itself?

Yes, there is evidence that MS-related fatigue is associated with the disease process itself.  There has been evidence for decreased blood sugar metabolism in certain areas of the brain in MS patients who experience fatigue.  The study in the Archives of Neurology supports that theory.  There was also evidence of nerve cell destruction in the brains of MS patients who suffered from fatigue.  In the future, we may be able to use neuro-protective agents to prevent or slow this destruction to have a greater impact on the treatment of MS fatigue.

Does heat exacerbate fatigue?

Certainly most, though not all, MS patients report that their symptoms either worsen or they have a feeling of increased fatigue when they overheat.  Heat slows down nerve conduction, and people with MS already have abnormal nerve conduction.  Even as little as a half a degree increased body temperature can create problems, and that increase could be from fever, working out, or environmental temperature increase.

How do you know if the fatigue is MS related?

People can experience fatigue as a relapse, or as an exacerbation, of MS, or they can just have it as an everyday baseline symptom that can be pretty steady.  Or sometimes people have daily fatigue at a certain level that can then increase during the period of a flare-up or an exacerbation.

But fatigue, depression, and cognitive deficits are so intimately related it's very difficult sometimes to sift out the primary problem.  Most people who are fatigued experience cognitive problems.  And depression can actually present as fatigue.  So it can be very difficult to see if fatigue is the primary problem, or whether a sleep disturbance due to depression is the primary problem, or even if other medical non-MS related issues are to blame.

Sometimes people who have MS aren't always treated as if they have a whole body and may have other medical issues.  We always have to make sure that the fatigue is not caused by some other medical problem, such as a thyroid condition, or medicines that they're taking for other conditions.