Drs dismissing als based on clean emg?

[joebing]

Hi to all,

When a limb has clinical weakness & an emg is done, assuming the emg is negative, how can the nuerologist be confident to say its not als. (The weakness)
Isn't there a time period, since als can progress or since als ALWAYS progresses? How can the Dr quickly dismiss it. Is it not possible for other symptoms to show up in the next few months such as babinski, cramps, twitches, MORE weakness, ect?

I've been trying to research this but I've no luck with my search engine.

Thanks to all

Has anyone had a clean emg then a future dirty one?

 

[ZenArcher]

It's the first requirement in an ALS diagnosis as has been stated on these boards hundreds of times. By the time you notice symptoms 50 - 60% of your motor neurons are gone so it will show on an EMG as has been stated on these boards hundreds of times.

 

[trfogey]

Until there is evidence of both upper and lower motor neuron death, ALS cannot be diagnosed. While clinical weakness can be caused by either lower motor neuron or upper motor neuron damage, other clinical symptoms are usually present that distinguish between the two types of damage. Lower motor neuron damage results in flaccid paralysis, loss of reflexes, and eventual muscle atrophy. Upper motor neuron damage results in hyperreflexia (greatly increased reflexes), cramps, spasticity, and eventually spastic paralysis.

Lower motor neuron damage also results in a characteristic type of abnormal electrical current flow within the nerve fibers that actuate the voluntary muscles. These abnormal impulses are detectable and measurable on an EMG. There is no instrument equivalent to the EMG for measuring the abnormal electrical impulses caused by upper motor neuron damage. Since the abnormal electrical impulses caused by lower motor neuron disease are so readily detectable using the EMG, failure to find those abnormalities indicates that lower motor neuron disease is not present, even if symptoms such as weakness, atrophy, and fasciculations are present. There are other diseases and, more specifically, combinations of conditions that can cause one or more of these symptoms.

It is possible to have clean EMGs and then have dirty ones. If you think about that question for a minute or two outside the context of your own fixation, you'll see how silly and irrelevant that question is. I seriously doubt that you will find very many children that have dirty EMGs, yet we know that a certain number of them will eventually be diagnosed with ALS. So, yes, it is possible for somebody to have clean EMGs and then have dirty ones.

However, in the the context of MND, there is a subtype of patients who do experience clean EMGs followed by dirty ones. That would be patients who start off with exclusively upper motor neuron pathology and no lower motor neuron pathology. Examples of this would be those folks whose initial diagnosis is PLS, but subsequently get lower motor neuron involvement as well, so their diagnosis is then changed to ALS.

That is why you should leave diagnosis to the doctors and wait until you have a firm diagnosis before you do any further Internet-based self-education. At that point, you will have the correct context into which to place what you observe happening in your body and, hopefully, less need to cast such a broad search net that you drag in irrelevant information that both confuses and terrifies you.

Hope this helps.

 

[joebing]

Thank you Zenarcher!

TgFogey, Thankyou for such a great explanation! Wow! It was VERY informative! Much so appreciated!

I do realize that it is said Good/clean emg rules out als but I guess what I was trying to ask in so many words is, if the limb is weak & the emg is clean, then dont you still have to wait & see because als is a progressive disease that may not have progressed just yet? (How can you eliminate weakness if it is the very first symptom)

I dont know if this is wording out right.

Thanks guys!

Joe

 

[rhythman]

Thank you Zenarcher!

TgFogey, Thankyou for such a great explanation! Wow! It was VERY informative! Much so appreciated!

I do realize that it is said Good/clean emg rules out als but I guess what I was trying to ask in so many words is, if the limb is weak & the emg is clean, then dont you still have to wait & see because als is a progressive disease that may not have progressed just yet? (How can you eliminate weakness if it is the very first symptom)

I dont know if this is wording out right.

Thanks guys!

Joe

If you've noticed that the limb is weak, and the emg is clean, the weakness is not caused by als. People on here have explained to me that the emg would notice the weakness long before you would. In fact, it's usually accepted that 50-60% of lower motor neurons die before you notice. The emg would certainly n
'notice' that much damage.

Here's a great explanation by Hal:

https://www.alsforums.com/forum/do-i-have-als-als/11003-emg-weakness-atrophy.html

 

[wright]

ALS weakness is due to denervation of muscles . . . meaning . . . the nerves to the muscles have been lost because the lower motor neurons are dead and dying. The EMG detects denervation. If you have weakness and you have a clean EMG, then the weakness is not due to denervation. It is due to something else. End of story and congratulations you don't have ALS. I wish you luck in finding the cause of your weakness.

 

[joebing]

Ahh, duhhh, Now im embarrased! Got it!

Thankyou, Zenarcher, TgFogey & Wright!

So Ive had an mri & thats normal, still not sure why I have footdrop, guess in my head, theres a part of me worried about als because theres nothing else showing the reason.

Thanks for your support,

 

[trfogey]

Anything that causes damage to the nerves of the lower leg could cause footdrop. Common causes would be strokes, herniated disks in the spine, or injury to the leg. For example, it is far too common among athletes who suffer serious knee injuries, when the the joint is violently dislocated and the segments of the nerves that control the lower leg and pass through the damaged part of the knee are themselves damaged.

 

[joebing]

TY again TrFogey,

So far nothing has come up.

What is the difference between flacid paralysis & spastic? You mentioned these.

Wright has said that my weakness is due to lower motor neuron.

How can I be sure of that, Wright (if you're out there) & know that Im not dealing with an upper motor neuron weakness that emg would not pick up?


THank you

 

[trfogey]

What is the difference between flacid paralysis & spastic? You mentioned these.

Search engines are your friend.

Wright has said that my weakness is due to lower motor neuron.

I don't think Wright has said that. Clean EMGs would not happen if you had lower motor neuron problems.

How can I be sure of that, Wright (if you're out there) & know that Im not dealing with an upper motor neuron weakness that emg would not pick up?

How do you know that you don't have a cancerous brain tumor that could be causing all of your problems? You don't know that for certain, but there is no evidence to suggest it at this point. Similarly, there is no evidence to support the idea that ALS or any other MND is causing your footdrop at this time .

There comes a point where further speculation serves to confuse more than to explain. I think you have reached that point. If you have any more questions about your condition, you should take them up with the doctors who have been treating you. They have all of your test results and their own examination findings to use in answering your questions. You are paying them for their expertise. Make them show exactly what they believe is wrong with you and what evidence they have to support their conclusion. Don't let them off the hook until they have answered your questions fully and in a way you can understand. If your current doctors won't do that, then get a second opinion from a doctor who will.

Good luck.

 

[joebing]

Im sorry, I didnt mean to say that Wright said my weakness is due to a lower motor neuron symptom but has said the weakness I describe if it were als WOULD be a lower motor neuron weakness. (Which emg would pick up)

Only trying to figure out, how one can tell if its weakness due to an upper motor neuron as opposed to lower motor neurons.

I certainly am not putting words in anyones mouth,

TY TgFogey & yes, I know there comes a point where further speculation serves to confuse more than to explain, Im just coming to understand all this & wanted to know the differences. Perhaps someone could explain that to me,

Thankyou for your patience,

 

[trfogey]

Im sorry, I didnt mean to say that Wright said my weakness is due to a lower motor neuron symptom but has said the weakness I describe if it were als WOULD be a lower motor neuron weakness. (Which emg would pick up)

This is the type of unproductive hypothetical that I refer to when I talk about irrelevant and confusing information brought in by speculation. While the formulation "I have condition one and I have condition two which caused condition three" may be valid, stating that "I have condition three. Therefore, I must have conditions one and two as well" is not necessarily a valid statement. Conditions four through one hundred may also cause condition three, and must be explicitly ruled out before the second statement would be valid.

I have given you three other medical problems that can cause a dropped foot. There may literally be hundreds more conditions that cause a dropped foot. If what you have really is a dropped foot and your doctor has recognized it as such, then your doctor has at least a tentative diagnosis or is planning further testing to help make such a diagnosis. You should spend your time harassing your doctor for these answers -- after all, it's what you paid him for.

 

[wright]

Lower motor neuron versus upper motor neuron stuff, is something that I have explained on this forum about a gazillion times. The most recent threads that I have responded to are those of a member known as "Silverlining" and both of those threads (lucky for you) are on the first page of this section. Look at her last two threads . . . both of which asked the same exact questions (lucky you again) . . . and you will have the information that you need. Just so you know, upper motor neuron dysfunction is not going to cause the type of weakness you describe. Once again, good luck to you.

 

[joebing]

Ok Guys, Great! Thx for the info! I still have to figure out whats going on, in the meantime.

Ive done more research than Ive cared to do on als in the last few days.

Ty, if I think of anything else, I hope I can post again.

Joe