Myasthenia Gravis and Fatigue

If you have myasthenia gravis (MG), then you are probably very familiar with the feeling of muscle weakness. You may have this feeling either at the end of the day or after using a particular muscle for a period of time. Muscle weakness is a common and well-understood symptom of MG.

However, a similar symptom, fatigue, is less understood. How many people with MG experience fatigue? Is it an actual symptom of MG? If so, what causes it? Luckily, researchers are on the case.

What is it?

One of the reasons that fatigue in MG is not well understood is that fatigue is hard to measure. It cannot be seen on an X-ray or detected with a thermometer. It is a particular experience felt by a person. Your doctor cannot know that you have fatigue unless you tell them.^1,2

What we do know about fatigue is that it can mean feeling tired and lacking both physical and mental energy. Fatigue is not the same as simply feeling tired or sleepy. Fatigue can make it harder to concentrate or complete daily tasks.³

Plus, that is just in the general population. Studies show that fatigue can have major effects in people with autoimmune diseases like MG.³

How common is it?

Studies show that fatigue is extremely common in MG. Up to 82 percent of people studied reported that they regularly feel fatigued. Half of these people felt this fatigue in their mind as well as their body.^1,2,4

People with generalized MG (meaning MG that affects a variety of muscles in the body) were more likely to experience fatigue than people whose MG is restricted to the muscles around the eye.^1,2,4

Fatigue has been found to be more common in women with MG. However, one of the most important findings is that the more severe your MG is, the more likely you are to experience fatigue.^1-4

Impact on quality of life

People with MG who had high rates of fatigue were also found to have high rates of depression and lower quality of life. Quality of life means feeling comfortable, happy, and able to do the things that you like or need to do. Fatigue lowers quality of life, which lowers motivation to get things done.^1,2

Fatigue can also make it harder for people to socialize. The result is higher levels of depression. The cycle does not end there: Higher rates of depression can mean less motivation to get physical exercise. This means that the muscles can lose strength, which is a big problem for those with MG.^1-4

How is it treated?

It is not known exactly what causes fatigue in people with MG, but the studies mentioned above give us important clues. The most important clue is that people in remission from MG or who have few symptoms are less likely to feel fatigued.

This decrease in fatigue leads researchers to believe that fatigue can be treated, similar to other MG symptoms. In fact, in many of these studies, after treatment controlled MG symptoms, fatigue improved.^1-4

While there are no therapies approved specifically to treat fatigue in MG, people with MG have recommended self-care practices. This includes getting plenty of rest, exercising, or getting therapy.

Because fatigue is a common symptom of MG that is related to worse MG symptoms and lower quality of life, it is important that your doctor is aware of it and helps you find treatments that work for you.⁴