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

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