fatiguability vs. fluctuating weakness
 

I definitely have fluctuating weakness. Sometimes I walk normally, and sometimes I can't walk at all. Often I experience both states in the same day.

But I am not sure I have muscle fatigabilty. How can I tell if my muscles are fatiguable, or if they're just weak? How can I tell whether my muscles have fatigued, or whether I'm having a spell of fluctuating weakness?

Thanks.

Abby

fatiguability vs. fluctuating weakness
 

Have you had a repetitive muscle stimulation test? That's what first clued my neuro on to my MG after the regular EMG and everything else turned up negative.

I'm not sure. Can you describe the test? I got my diagnosis from a SFEMG. It was my third one. The first two (performed by a different doctor) came back borderline and mildly abnormal. But the third one seemed strongly positive for MG to the doctor who did it.

Abby

Muscle fatigability and fluctuating weakness is the same thing.

Think about this way.
When I was a kid my grandfather had a small cinema. He would sometimes let me look at movies frame by frame by rolling them slowly or we could move them very fast.

Think about a charlie chaplin movie where you see (in normal speed) how the cake flies over the room and sticks to someone's face. In slow motion you will see the cake slowly moving over the room. In very fast motion it seems to just appear on the other person's face.

Muscles don't just abruptly stop. The question is how fast those changes occur.

In patients with "classical" MG this process is slow and gradual and can easily be detected by someone looking at it.

In more "crazy" variants of this illness, it is more like the charlie chaplin movie I described.
I know that for me, fatigability is not linear. At first it is very slow and delayed, but at some point it becomes very rapid.

You can compare it to a charlie chaplin movie in which you initially move the film frame by frame, so slowly that you can hardly detect any difference in the place of the plate and then when it becomes totally boring and everyone loses interest you start moving it so fast that it seems the plate just got stuck on the person's face from the middle of no-where.

That is why almost every neurologist who examined me thought I had a completely normal neurological examination and could not understand why I was unable to move, talk or breath after it. Or one neurologist who had to score my QMG was very puzzled by the fact that I had no ptosis when she asked me to look up, but my eye was nearly closed at the end of her examination. She couldn't decide if she should score it as 0 (no ptosis) or 3 (spontaneous ptosis) and she shared her dillema with me. (that is how I know about it).

I hope this clarifies it a bit.

Am I responsible for this quandry? I questioned whether you had fatigable weakness that was demonstrated by a clinical exam - which obviously you have had. And your SFEMG demonstrates that as well.

What I was trying to point out in my other post was that MG has weakness that clearly fatigues upon exertion or repetitive activity. Like Alice said, paraphrasingly, "Do this, that happens."

I asked the question because you can have muscle weakness from a fluctuating thyroid condition or electrolytes being off but it won't specifically be related to an activity. I certainly didn't ask in order to make you doubt the basics.

It's possible for you to have BOTH.

With MG, however, you have to see it in "action" in order to know how it is behaving. Like Alice said too, just sitting in an exam room might not show a doctor how weak you are. Except for that time you pushed for a longer period of time and got weaker. The best neuros put a suspected MG patient through a veritable workout.

I'm sorry if I added to your questions instead of helping.

Annie

I think I go through this just about every day but certainly every week. It's like an ongoing surprise party my muscles are throwing for me.

Annie,

I personally think what you did is great. When trying to understand you have to ask questions and those lead to further questions and brain storming.
It obviously create an uneasy feeling (because we all feel better walking on solid ground) but this is the way we learn and gain a better and more solid understanding eventually.

I can fully understand Abby's concerns. I know that I stopped worrying about what my illness is (autoimmune or congenital) only after I decided (together with my neurologist) that it is not going to make any difference with regards to management of my illness. And also knowing that with the currently available tools I will probably not be able to get a clear answer any how.

Admittedly, having MuSK antibodies (even if those were not detected with the usual tests) and gradually learning that although my illness is not "classical MG" it is quite classical MuSK MG did make things somewhat easier for me. (it did not make my illness any "nicer" but it did help me feel more comfortable about it and knowing what to expect/hoping for better treatments which will be developed eventually etc.).

I keep on saying that the name of the illness doesn't really matter. But, it reality this is not entirely so. We live in a world of names and titles and life is easier with them. Furthermore, if is quite understandable that if you take treatment (with potential side effects) you want to know it is justified.

Abby,

I do hope you will eventually find better answers that will put you at ease. Sometimes you need time and patience, until the right test is developed or more experience is gained with your type of illness. (mostly if it is very rare).

Practically, Clearly you do not have classical AchR MG, and you also don't seem to be typical MuSK MG. But, there are still antibodies which may be found in the future so autoimmune MG is a viable possibility.

You seem to have a good response to immunomodulatory treatment (even if you are not among those who are fortunate enough to have a full remission) and also have other autoimmune disease (and a family history), which makes it more likely that you have another autoimmune and not a congenital disease. So, I think that at this point you should be content with that. (even if it is not perfect).

It is good to always keep in the back of your mind other options, but don't drive yourself crazy about it.

It also sounds that you have a good, sensible and caring neurologist you can discuss things with.

I personally think that it is more likely that an elderly aunt had a minor stroke than suddenly developed minor signs of congenital myasthenia.
If fact, my neurological told me that even in an elderly patient with known MS they would first think of a stroke, if he/she suddenly presents with an acute event during a stable period.

Thank you, Annie and Alice! I want you all to understand that this discussion doesn't upset me or make me anxious. I find it energizing.

I have two main symptom-groups. First, is a feeling of heaviness and tiredness in my arms, and a feeling of tiredness in my neck. This is pretty consistently there, though it's worse as the day wears on.

Second, I get spells of weakness. I feel them coming on. I say to my husabnd, "Oops, I'm getting weak," and he knows what that means! Usually I don't have enough time to get up the stairs to bed before I'm so weak that it's hard to get up the stairs. Then, after some time (20 minutes to an hour) I feel it lift, and then I can walk, though I'm tired.

So, it occurred to me that any time I'm so weak that it's hard to walk, I'm having a "spell." If I have four "spells" between, say, 5:00 and 11:00 p.m., I might not notice they're individual events, especially if I'm sitting on the couch through them. But if I pay attention, I think I can feel them coming and liflting.

If I'm having a good day--less heaviness, and no spells--I can go walk around the mall for two hours and not wear out. I'll be tired than a normal person, but it won't necessarily bring on a "spell." Then again, if I do too much, I think it triggers a flare-up, in which I have more frequent, and more severe, "spells."

So, I want to distinguish between fatiguability, which builds up, and "episodes," which come on suddenly, and may be unrelated to how much I've been using my muscles.

Does that make sense?

Abby

I don't think you can really make this distinction. Because, the effect of using your muscles can sometimes only be seen after some delay.
The chemical reactions involved in muscle contraction are very complex and involve multiple proteins and regulatory cycles.
It may also be related to other factors, such as how much protein you had in your food.

For instance, in MuSK MG (which I am not saying you have), the antibodies interfere with signaling pathways (as opposed to what happens in classical AchR MG were they destroy the receptors). This causes abnormalities and instability in the assembly of the NMJ (even if there is an adequate number of receptors), abnormalities in the function of acetyl-choline esterase, and possibly other abnormalities (including in muscle energy production).

So, the effect of exercise may only be seen after a few hours of even days.

I believe that this misconception regarding the immediate effect of exercise is one of the reasons that so many patients with myasthenic syndromes are not diagnosed properly or that some of their symptoms are not seen as related to their illness.

I think it may be also the reason that patients fail to recognize the relation between over-exertion and exacerbation of their illness. ( I know it was so for me, until I gradually realized that things are much more complex than they seem).

I think that there is classical AchR MG which has a relatively simple mechanism and many other much more complex and less easy to understand myasthenic syndromes. And from the way you describe your illness you have one of them.

Thanks very much, Alice. That's very clear and helpful. Whenever I have a new idea (I guess this is just human nature), my mind tends to filter out all the parts that don't fit, and only concentrate on the parts that do. So I get a false picture. I'm happy with the idea of experimenting with my diet to see if I can avoid whatever is triggering those 5:00 p.m. attacks--as a start. And journaling.

I did read a while ago that people with rheumatoid arthritis feel worse at certain times during the day, and the article put it down to circadian rhythms: evidently the immune system sends out surges of antibodies in the early evening. That's a trigger I can't do much about.

Abby

This may not help but I can't tell when I'm weak until I try to do something. I have to test it out. I may stand up and be shocked at how strong my legs are, or at how weak they are...I can't feel it coming though. It could change also after a few steps, minutes, or a couple hours. I never know really what's coming. Until I actually go to use the muscles, though, I don't know how they are going to behave.

we all do that. we carve our order by leaving the disorderly parts out. our mind is limited in its ability to comprehend.
Yet, we have to be aware of doing that and gradually put back those missing pieces or else we may end up having a partial and even distorted picture.

Think about it: in a 10 minute period one cell in our body is more busy than a very large factory. Numerous changes occur each femtosecond. And this is only one cell. Think of the complex orchestration required to co-ordinate the function of numerous cells in one organ and then the cross-talk between those organs and finally the rapid response to changes in the outside environment.

Our understanding of those complex biological systems is truly amazing and our ability to change and control some of them is even more so. But, should it come as a surprise that there is so much we still don't understand and don't know?

Modern medicine and modern society have given us the illusion that we can understand and control those processes. We can do better than nature. But the reality is that we are part of nature and we can't do better. We can utilize nature for our needs (and this too has to be done cautiously), but we can't improve it.

This is somewhat philosophical, but what my illness has taught me is that we have limited reserves. If we use them wisely, they can last longer and enable us to do what we want. This is true not only for us and our body, but for the entire human population.

A superficial understanding and trying to use our reserves in the (supposedly) most efficient way, can eventually lead to the exact opposite.

I don't think we should stop searching or stop trying to gain a better understanding. But, I think we should be humble and realize that we only have the tip of a very large ice-berg, even if we think we have found all the answers.

Many times I ask my neurologist questions. Many times he doesn't have an answer. But, this in itself is an answer. I feel much better knowing that he too doesn't know. If he has seen numerous MG patients and doesn't know the answer, how am I expected to know? If he can't find treatment which will control my illness and change its course, how can I be expected to do so?

He keeps on telling me that MG (and even more so MuSK) is the most unusual, hard to understand, crazy disease. I keep on telling him that this is because they know so little about it and every illness would appear so if it was so poorly understood. But practically,we are both saying the same thing.

I have a research collaborator who suffers from an illness in my realm of practice. A while ago I shared my frustrations with him. I told him that in his illness there are thousands of clinical trials and a lot of research, whereas in my illness there is none.

He said-that may be true, but do you fully understand my illness and do you have a cure for it? I had to admit that with all our understanding and novel treatments we really don't yet. The more we learn and understand the more we realize how little we truly know.

It is hard to accept the fact that we have an illness in which many people fully recover and can lead a completely normal life and yet we don't. It makes us feel that maybe we are missing some important clue which could be the ultimate answer. It makes us inevitably think that maybe we or our physicians are not trying hard enough.

But, first, we don't have the same illness, even if it has a similar name. Second, there is no disease in which everyone responds to treatment and everyone is cured, because even if we don't yet know how to recognize them there are subtle differences among patients with the seemingly same disease.

We are fortunate that our illness doesn't lead to immediate death and that despite its disabling symptoms, we can find ways to work around them.
we can occasionally find a certain trigger we can avoid, we can find better symptomatic treatment and supportive care and all those can significantly improve our life.

But, with that we have to accept the reality and realize that its not because we are missing something relatively simple (because with our relentless searching we would have found it by now) or because we (or others) are not doing enough.

Tracy, what you say is very interesting. Because sometime ago, I discussed the fact that MG patients do not only have motor problems, but also sensory problems. We lose our ability to automatically know what is heavy or light or how strong our muscles are and we have to find ways to compensate for that (just like a person with sensory deficits).

There is a possible complicated physiological explanation for why that happens.
A rather simplistic explanation is that our brain gets confusing information from our muscles because on the one hand it has to fire more to get it moving (which makes us think that something is heavy) and on the other hand the tone of the muscle spindle is decreased (which makes us think that something is light).

I know that in the early days of my illness I would have no idea if the cup I tried to pick up was heavy or light. It was a true "alice in wonderland" experience. I felt as if I lost the ability to navigate. I had to teach myself how to know. I eventually learned to do it so well that I could tell what my peak flow is going to be quite accurately before measuring it. (even I was so surprised by this ability).

But, if I don't concentrate on what I am doing or am distracted by something, I totally lose my ability to know how strong I am and exactly like you describe I can be surprised at how strong or weak I am. I can choke on my food if I forget to concentrate on my eating. Probably just like a blind man would if he forgot to use his cane or other senses that compensate for his disability.

Tracy, I'm familiar with what you describe. Sometimes I stand up from my computer chair, forgetting to be careful, and rush towards the door, and after two steps I hit the floor. But other times I feel the weakness coming over me. I'm not sure if I only feel it when it's more intense, or when I'm paying closer attention, or if there's something else going on. But I've definitely said, many times, to my husband, "Wait, let me stand up and see if I can walk."

Abby

I also don't have a clue whether I will be strong or weak until it happens. I have learned to be cautious and test out my legs before walking so that I don't hit the floor. I don't get any sensory clue that my muscles are about to quit.

Abby, We are mammals. Mammals are supposed to nap. ;)

Perhaps your cortisol levels are tanking earlier every day. They are at their highest in the morning - which is why they should be tested at that time - and decrease throughout the day. Maybe it's time to see your endo to have a thorough look at everything.

In science, there are a lot of axioms they refer to, such as Occam's Razor or parsimony. Basically, "Keep it simple, stupid." Often the most simple explanation is the right or best one. Of course, they probably weren't referring to MG.

Annie

Alice, exactly...I have lost the ability to navigate! I have no idea how heavy things are as well. I often ask a normal family member to lift something to ask them if it's heavy to see if I'm just weak or if it is really heavy! Or to open a door, etc to see if it's me or the door!:eek:

I thought all the posts on this thread were rather interesting.

I personally remembered that a cup of coffee felt like it was a heavy object when holding it in my hands a couple of years ago. But the posts made me think about how it was in more detail.

The first few seconds of holding a cup it felt like its normal weight (of pre myasthenia times)
But by 6 seconds, holding that same cup of coffee now felt like holding the weight of a bucket of concrete -
away from the body.

That was quite a stable pattern for many months with diurnal fluctuations, which to me at that time just meant my coffee would turn into concrete much faster by the end of the day!!!

These days I don´t notice the weight of the coffee anymore but I do notice the weight of my own arms changing from day to day when engaged in an activity above my head. So some days they feel 10 times as heavy as other days - but that I can actually do tasks with arms at a 90+ degree angle away from the body makes me an extremely grateful person :)

I know I´m not the only one to experience this, but it got me thinking about describing the sensation of weight and also about speed, it takes a longer time to reach those old myasthenic thresholds these days and my symptoms are milder yet fluctuating faster than they did previously (at least where the deltoids are concerned.....)


Anacrusis

Alice;

“So, the effect of exercise may only be seen after a few hours of even days”

The most typical posting here about fatigue seems to be that one of us did something that pushed there limits and ending up paying for it later in the same day.

Last week I told my neuro that I pushed myself to the limits with 20 to minutes of exercise on my Total Gym. No standing with a Total Gym even though leg exercises are part of the workout. I told him that the rest of the day was not was not bad at all but the following day I suffered with very severe muscle fatigue.

He thought it was unusual that I did suffer that day.

Your conclusion that the effect of exercise may only be seen after a few hours or even days aligns at times with the effect of exercise or exertion has on me.

I am curious if anybody else here has noticed this because I can't remember, even though there may have been postings.

scrubbs

My impression is that it's very common, from what I've read here, for people to feel the fatigue the next day, or even the second or third day, after exertion! It's certainly true for me.

Neuros don't know everything. Mine told me today that myasthenic fatigue is "muscle specific," and that if I tire one muscle, it won't affect another muscle. The evidence that he's wrong is not just anecdotal. I learned on this board (from Alice) about the Mary Walker phenomenon. And it's true. On Saturday I spent way too much time on my feet. On Sunday, my eye muscles were fatigued.

Abby

I know this is an old thread, but a very helpful one to me! I certainly notice a decline in muscle strength and an increase in other symptoms the next day or two after what formerly used to be "normal", but increased activity. It is comforting to hear the experiences of others, especially if I can relate.