Negative SFEMG but still have MG?
 

I have a friend in Europe who is negative on BOTH antibody tests -- negative on the EMG and SFEMG -- but, POSITIVE on the Tensilon test AND has great results with Mestinon -- she currently takes 10 tablets per day. She was a competitive tennis player and now runs a day care. She is seeing a highly respected Professor of Medicine -- he ran the SFEMG yesterday -- it was negative for the 2nd time -- and he told her that she did NOT have MG based on that result.

I think that he is wrong -- and she does, too. But, we need reports, journals, EVIDENCE for her to SHOW him. Can you tell me where to find some "hard" written proof?

Sfemg
 

Jana,

I wish it was so simple, there is an excellent review by Michael Ben-Atar, which goes over all the tests that are used for the diagnosis of MG.

there is also another study that shows that in patients with seronegative MG it is not that rare to have a normal SFEMG.

the problem is that many neuromuscular specialists do not accept those studies, or have all kinds of explanations as to why they have such results, and think that it is impossible to have a normal SFMEG in a muscle that is weak by myasthenia.

this is one of the "windmills" I am trying to fight. and it is not going to happen in one day, if at all.

my suggestion to your friend it to find a more open minded neurologist, that does not think that this is an "infalable" test.

alice

Thanks, Alice. My heart breaks for her -- and for all who are fighting "windmills". *sigh*:(

Hi Alice,
 

nice to meet you

Hi Moshe!

So glad you made it over here!! You and Alice (not her real name for obvious reasons) will have lots to talk about!!!

(((HUGS)))
jana

Jana, This is the toughest subject for me. I had a few SFEMG's and no one had told me that the Advair I was taking could make everything look normal. Any steroid a person takes can make EMG's and antibody tests look completely normal. That's their job - to suppress the immune system. Is your friend on any other drugs that would interfere with a SFEMG?

Plus, they do need to test clinically weak muscles. AND the person doing the test needs to be VERY good at it. Often it's done by those doctors who are training to do it.

The congenital myasthenic syndromes, the ones where a person has less acetylcholine (there are some where they have too much), may not show up on SFEMG. It's confusing, I know. The CMS ones are genetic, not autoimmune. They can be milder and may not show up on anything but an exercise EMG or a nasty repetitive nerve stimulation where they keep stimulating the muscle for 5 - 10 minutes. It's horrid, I've had it.

In MG, a person can go along for awhile and be "ok." The threshold where their muscles go "downhill fast" is different for everyone. If they aren't tested at the "downhill" phase of MG, they can look clinically normal and normal on EMG. That's also why some offices actually warm up someone's muscles before they test. And some do the exercise EMG's. Some of the CM syndromes tend to be okay for a long time and then the muscles simply crash. Think of all this as varying degrees of a bell curve. Remember that from school? ;)

None of this is simple. I had a borderline SFEMG but I do have antibodies. My clinical picture is MG. My Tensilon test was highly positive. My neuro-ophthalmologist diagnosed ocular MG (fatigable muscles). I respond to Mestinon and have for almost nine years (with absolutely no side effects or overdose effects). I didn't know until almost a year ago that I had positive antibodies (it was kept from me). So your friend may want to get all her records in case a doctor is doing the old "pooh-poohing" of test results (i.e., only slightly positive results).

CMS is common in Nothern Europeans. Also in some Arab populations. Heck, all our genes are intermixed across the world. They only do testing of it here in the U.S. in 2 places. In Europe, they can do it in England, Germany and France. Italy too really. Not too sure about Sweden.

A negative test, as my diagnosing neuro has said, does him no good! Only positive results and/or positive clinical exam. I am beginning to believe that unless you have MG really bad, a doctor may miss it. There are so many variables that come into play (i.e., time of day you're tested)

I hope this helps. It stinks to not have someone take your bad health seriously. It can wear you down.

Annie

Good to see you again, Moshe.

Annie, this DOES help. I think that I am going to have to see if I can get her "over here". It will be so much better for her to ask these questions -- and to be able to answer them. I'm not sure about the time difference -- I was talking to her about noon today.

CMS -- that really makes a lot of sense.

Alice,

You are so right!

I am a seroneg and 'just' passed the SFEMG. My neuro's exact words were "I hate it when this happens. (deep sigh) But it doesn't really matter, you have MG based on clinical symptoms and your clinical response to Mestinon."

Later I was told that I had jitter(s) - but they were just shy of the accepted level for MG dx.

After meeting all the folks here who are (or have had) so much trouble getting a dx - - I feel really, really fortunate I found this wonderful neuro on my second try!! And even more grateful that my symptoms are extremely mild at this point and well controlled with Mestinon.

Sue

Sue, You bring up another good point. MG is VARIABLE. Fatigable = variable.

The presentation varies. It varies as to what time of day. What you're doing. If you have other complicating factors like hypothyroidism or infection. It runs the spectrum from "able to work" to "being intubated."

And, as I've said before, MG is not inert, like some kind of gas. You add movement or heat and it "explodes." It is not a "static" disease!!! :eek:

I guess MG is a shape-shifter! ;)

So how can neurologists approach MG as if it is this finite disease with these "gold standard" algorithms, as if this disease or diagnosis is a one size fits all?

A lot of doctors are only comfortable with clear cut answers. Not that easy with MG. Lucky us.

Annie

I wanted to add one more thing. The SFEMG "results" are compared against the "mean consecutive difference" or MCD of "average" MCD for different age groups and muscles. For example, let's say the average MCD for age 40 of the frontalis (forehead) muscle is 35. What if YOUR average is lower or higher than that? Higher wouldn't be a problem but if your "normal" is 20, for example, then they will be seeing an increased jitter for you as okay.

No, I'm not saying I know more than doctors!!! Or the SFEMG experts. I'm simply looking at how they analyze the SFEMG by "averages" for specific ages and asking the question. What if you are normally "below average?" This is a simple statistics question, and one of educational standards, that questions what "normal" really means.

There is a pediatric neurologist in England who has seen firsthand that the SFEMG's of many children with MG needed to have the "average" MCD lowered. They obviously had MG but were showing normal on SFEMG.

I compare it to B12 results. My Mom was in the "normal" range of B12, or what the lab calls normal. But she was on the lower end and had parasthesias in her hands and feet. After taking methylcobalamin for a few months, they went away.

I just don't think this is an easy disease to diagnose for LOTS of reasons. And if the test you're using has problems, because not everyone is the same, then how can they expect the results to be accurate? Again, they aren't asking enough questions and have "guidelines" that are simplified to make it easy for them. Well, it's not easy for us, the patients.

Doctors cling to certain standards because THEY need to be right, to know they've made the right decision. But diseases often don't stick to the same standards. They have a mind of their own. And we aren't all the same, thank goodness. And our disease "looks" different on each of us. Cookie cutter thinking is easier but it isn't exactly effective. Or nice.

Annie

http://emedicine.medscape.com/article/1141438-overview


I can't stop thinking about this issue!

Men and women aren't created equally. It takes longer for women to be diagnosed than men (7 to 1 difference!). It has to be more than sexism causing this.

I know that men and women lose weight differently. Women also store estrogen in their fat cells. There's skin on top, then fat, then muscle. I found the article below on the "fatigability" differences between men and women. Very interesting. So, if men fatigue more quickly then maybe their SFEMG's will look more dramatically abnormal. And maybe obesity or being overweight is one issue but maybe the "type" of fat above the muscle is an issue too.

http://ep.physoc.org/content/93/7/843.full

So, maybe women who have "mild" MG, can look normal because their "jitter" doesn't go up as much and may be determined as a negative test when, in fact, it is positive. And maybe because it takes longer to show "fatigue" on an EMG.

If I had more energy, I'd dig around more. This has been nagging at me for awhile now. Please let me know what you think of all this. Thanks for getting me thinking, Jana.