A line graph symbolizing the ups and downs a person with MS can experience. There is a woman sleeping on one of the slopes.

Living with Lassitude: Primary Fatigue In MS

Last updated: June 2022

When it comes to discussing the many potential symptoms of multiple sclerosis, you can’t have a complete discussion until you’ve talked about one of the most common and heinous: fatigue. When it comes to fatigue with MS, it’s hard to accurately describe just how debilitating it can be.

MS lassitude

Far from the tiredness that most people have experienced, MS-related fatigue is a level of complete exhaustion that makes accomplishing the simplest of tasks incredibly difficult. The way multiple sclerosis affects our body has the odds stacked against us when it comes to experiencing fatigue. While there are many symptoms that can contribute to this level of exhaustion, the disease itself can also cause fatigue. We call this kind of fatigue “lassitude” and it bears discussion outside of the other potential causes.

MS fatigue can have many causes

One of the reasons fatigue is such a common issue among those with multiple sclerosis, is that there are many potential causes of fatigue. A lot of the other common symptoms have a tendency to interfere with our energy levels. Experience a lot of pain or spasms? Well, painsomnia can interrupt the amount and quality of sleep you get. Bladder issues can do the same (I know I’ve had stretches where I am constantly getting up to use the bathroom at night, leaving me with very little rest). Depression, which is extremely common in those with MS, can also contribute to fatigue.

Reasons for secondary fatigue

Sometimes certain medications can increase fatigue. Sleep apnea can occur in those with MS and can also have an effect on energy levels. Legs weak or have mobility problems? Well, then you likely are using more energy to compensate in order to prevent falls. In fact, many tasks with MS tend to require more energy to complete, making fatigue a natural by-product of life with the disease. Remember, this is a disease where simply taking a shower can be enough to wipe you out for the day; it’s not hard to see all the potential pitfalls we have when it comes to increased fatigue levels. When another symptom or the effect of living with MS is the culprit of our fatigue, we sometimes refer to that as “secondary fatigue.”

Fatigue without a direct cause is called 'lassitude'

When it comes to MS, even if you don’t experience fatigue because of all of those other potential causes, you may still find yourself submerged in the all encompassing thickness of exhaustion. That’s because the disease itself can have fatigue as a symptom (as opposed to being the by-product of other symptoms). We refer to this kind of fatigue as “lassitude” or “primary fatigue” and its unique to those with MS. You can have no other symptoms and still experience lassitude.

Severe levels of exhaustion

You can also have a perfect night’s sleep and still wake up utterly depleted. This kind of fatigue happens seemingly without any other cause. It is also among the most severe levels of exhaustion that one can experience, typically interfering with one’s daily activities. Lassitude also tends to worsen throughout the day or with increased heat and humidity. This is the kind of fatigue that is debilitating and difficult to explain to others. It’s not simply being tired, and it can’t be corrected with additional rest. It’s a whole-body exhaustion that I truly can’t put into words. I know of no language that can truly give justice to the condition of lassitude and what it does to the body.

But what causes lassitude?

Doctors aren’t 100% sure what causes lassitude, but there are a couple of theories. One is that hormones, known as cytokines, which are released by the immune system (and are what make you feel weak and exhausted when you have the flu or an infection) during the inflammatory process are the cause. Another may be the way that MS affects the nerve pathways to the brain, with the myelin around the nerves being damaged or destroyed, the brain then has to utilize more regions to complete a task, draining more energy in the process.

Fighting fatigue

Without really knowing the exact cause of lassitude, it’s difficult to effectively treat. When attempting to fight fatigue, you really need to look at other potential causes first. Is it a sleep issue? Or medication? Or somehow related to other symptoms (or their treatment). Or can I learn to perform tasks differently (physical and occupational therapy can be extremely helpful in combating fatigue)? Many times, re-addressing those other symptoms is an effective (though not foolproof) way to manage fatigue. There are, however, medications (though none are FDA approved specifically for MS fatigue, they are all designed for other conditions) that can be brought into play if you are truly experiencing lassitude (I’ve had some mild, though unexpected, success with Provigil). At the end of the day, lassitude is the kind of fatigue that’s incredibly difficult to treat. It’s also very frustrating to experience. I hope that discussing it here will help shed some light on it and hopefully explain to others that sometimes, you can do everything in your power and still be exhausted.

Thanks so much for reading and always feel free to share!


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