How is MG diagnosed? 

There are two ways to make the diagnosis. These two tests detect 98% of patients with MG.

• The most sensitive and specific way to make the diagnosis is with a blood test looking for the presence of the antibodies against the acetylcholine receptor. If these are present you have MG. 10-15% of patients with MG can still have antibodies that are not detected by our tests. For these people an EMG/NCS should be performed. This is a test of the way our nerves and muscles work. This has to be performed with “repetitive stimulation” if one is concerned about MG. This also needs to be performed by a person with special training in the test.
• If one still suspects MG then a very special test called a “single fiber EMG” can be performed. This is highly sensitive, meaning everyone with MG will have an abnormal test. However, it is not very sensitive, meaning that it can be abnormal for reasons other than MG. This test is done by only a few very specially trained neurologists.

What Treatments are there?

• Since myasthenia is caused by an abnormal protein in the blood, the acteylcholine receptor antibody (AchR Aby) the best way to treat MG is to get rid of this antibody. This can be done most rapidly by a process called plasmaphresis, which is a form of dialysis or blood washing. This actually removes the AchR Aby from your blood. However, it does not prevent the antibody from being made again. Plasmaphresis is therefore used for people who are very sick from their MG and need to get better quickly.
• The second line of treatments then are drugs we use to prevent the antibodies from being made. This involves medications which suppress our immune system, since antibodies are made by our immune system. There are many choices of medications but the most widely effective choice is steroids. Other drugs such as immuran, cyclosporine, or cellcept are used as well. All of these medications have serious side effects and therefore should only be used by a neurologist familiar with treating this disease.

What is the thymus?

The thymus is a gland in our chests which allows our immune system to mature correctly. Some people with MG have a tumor of the thymus gland called a thymoma. Other people with MG have an overgrowth of their thymus. For the last twenty years neurologists have believed that removing the thymus gland, even if it is not cancerous makes the long term treatment of the disease much easier. There is a well designed trial about to begin to test this theory. Currently , thymectomy is still considered a very good option for anyone with moderate or severe disease who is a good surgical candidate.

Do we know what causes our bodies to produce antibodies to attack our muscles?
There is no known cause for MG. There is a link to other autoimmune diseases such as thyroid disease or diabetes. There may also be a link to the thymus gland, but as of yet there is no answer to why some people make antibodies to the acetylcholine receptor.

How do our muscles recover their strength with no medication if we rest?

MG is caused when the number of receptors for acetylcholine on the muscle falls below a certain level. We need acetylcholine to interact with the receptors to make our muscles move. These receptors are destroyed by the antibodies which are produced in MG. In some people with MG there are enough receptors to make your muscles move once or twice but then the muscles fatigue because the receptors have not gotten ready to be stimulated again. With rest the acetylcholine receptors can prepare themselves to be restimulated so symptoms seem better but then there is fatigue again.

Why do my symptoms come and go?

Symptoms come and go for the reasons mentioned above.

Can Certain Foods trigger MG exacerbation i.e.: salty foods?

There are no foods which we know of that can trigger MG exacerbation.

Why does daylight or bright light cause my eyelids to “shut down”?

There should not be any change in symptoms with daylight, although some people notice a change with temperature. There is another disease cause blepharospasm which causes involunary forced eye closure and this is triggered by sunlight. If the eyelids seem to be forced down as opposed to being weak, then you should consider the possibility of blepharospasm.

Why does excess Mestinon exacerbate my symptoms and make my muscles weaker than they had been without it.

Excess Mestinon can make MG worse because it will cause over stimulation of the acetylcholine receptors which can lead to muscle weakness. If you believe that excess Mestinon is causing your muscle weakness you should discuss this with your doctor because this can be serious. Usually if you have too much Mestinon you will also be sweaty, nauseated, and have diarrhea.

I’m now on 3 grams Cellcept and 125 mg Cyclosporine/day; they seem to control my MG symptoms but my overall strength seems to have diminished over what it had been when I was first diagnosed. Is this MG related or just a coincidence?

The main symptom of MG is muscle weakness, so if you are weak I would be concerned that your MG symptoms are not completely controlled. You should discuss this with your doctor.

Sometimes my tongue feels fat and swollen as well as my throat and everything seems to be closing up and trouble breathing. Am I really swelling or does it only feel that way? If it is really swelling, then why wouldn’t physicians be able to prescribe drugs such as anti allergy drugs to fight this problem?

In MG the tongue and throat can feel thick or swollen because they do not move well. This can be a serious medical problem and so I would say you need to discuss this with your doctor.

Are there any known links or research regarding any kind of connection between MG and Fibromyalgia Syndrome?

There are no known links between Fibromyalgia and MG. MG has a known cause and treatment. Fibromyalgia has not yet been shown to have a known cause or a specific pathology or treatment. Some people that I have seen who have been diagnosed with fibromyalgia are in fact significantly weak and with the correct diagnostic tools are shown to have MG. So i would say if there is a lot of weakness then one should look aggresively for MG.

What do you think about sero-negative MG? Is this widely accepted or not in the neuro community? What would finally get a neuro to give an MG diagnosis, with tests being negative but with MG signs/symptoms?

Sero-negative MG is widely accepted. It is believed approximately 10% of patients with MG are seronegative. However new antibodies are being discovered so this number will decline over the next few years. If you believe someone has MG but has normal blood tests then you need to do a good EMG/NCS including repetitive nerve stimulation and possibly single fiber EMG. If all of these are negative than I don’t believe you can make a diagnosis of MG.

When I eat a meal, I notice that my sinuses seem to clog up and I have to blow my nose constantly. I just assumed that it was me, until I read of another Myasthenic who has the same problem. Is this a common problem?

In MG if your swallowing muscles are weak then eating or drinking can cause the food to come out of the nose. This is also a serious problem because it can be a sign that your breathing muscles are weak. You should discuss this with your doctor.

Can I become pregnant if I have MG?

Pregnancy is complicated by MG but not impossible. There can be problems with the medications people take for MG in terms of fetal development. MG can also be made worse by pregnancy. It is still possible to have a healthy baby with MG but it is best to discuss this with your neurologist BEFORE you get pregnant.

If I am pregnant, should I continue using Imuran and Mestinon?

Mestinon is probably safe in pregnancy. However; other than tylenol and codeine the FDA does not declare any medicine SAFE in pregnancy. Imuran can suppress the immune system and we do not know how it affects the fetus. These issues should be discussed with your doctor.

Will my baby be born with MG just because I have it?

Many babies that are born to mothers with MG have a 4-6 week period right after they are born where the mothers acetylcholine receptor antibodies get into the baby and cause weakness. This can be severe and end up with the baby going on a breathing machine. After the 4-6 weeks the antibodies from the mother are cleared out of the babies system and the baby is normal. It is important for the OB doctors and pediatrician to know the mother has MG so they can be prepared at the time of delivery.

Is MG hereditary?

There are a few rare forms of MG which are hereditary. These are called congenital myasthenia. In autoimmune myasthenia where people have antibodies, it is not genetic.

What are the statistics on thymectomy outcomes; ie: full remission, partial medicated remission, no response etc.?

There are no good data on thymectomy. The largest trial was done out of Duke University in the 1970′s and suggested that after thymectomy MG is easier to control. But there are no data on number of remissions, cures etc. In general in young healthy people with generalized myasthenia we believe the benefits are greater than the risks. There is a large trial getting started to ask this question.

I do not want to try any medication to treat my MG until I try alternative methods of treatment. Can you recommend any forms of treatment that MG patients can try to control MG on their own without using medication?

There are no alternative treatments which have ever been shown to be effective. Treated, all patients with MG should lead a normal life and have a normal life span. Untreated, MG can be fatal.

Do I have to continue taking cellcept and cyclosporine “forever”, or will I someday be able to taper off them, without the MG symptoms returning?

Some patients can be cured, but most patients require treatment of some form for their lifetime.

Mestinon is non specific, that is, it acts upon normal, healthy muscle receptors as well as antibody damaged receptors. What, if any, are the long term effects of mestinon on normal, healthy muscle receptors?

We do not know of ny long term effects of taking mestinon on healthy muscle.

What are the best methods for myasthenics to maintain their muscle tone?

Repeated exercise weakens our muscles as opposed to normal non myasthenic muscles, which strengthen with exercise. Is there a solution to this “catch 22″? Knowing what type of exercise to suggest to people with MG is difficult and there are several studies investigating this question. In general I suggest that people do what is comfortable but not to the point of exhaustion.

If a myasthenic has a thymoma does age play a part in whether to have it removed or not?

If you don’t have it removed for age reasons how do you know if it is cancerous or not? Since the benefits of thymectomy takes years to see, doing it in people over 80 makes little sense but if someone is expected to live more than 10 years it is reasonable to do. If the thymus appears enlarged on CT or MRI (thymoma) it should always come out because cancers are possible.

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The information on this site is intended to provide the reader with general information to be used solely for educational purposes. As such, it does not address individual patient needs, and should not be used as a basis for decision making concerning diagnosis, care, or treatment of any condition. Instead, such decisions should be based upon the advice of a physician or health care professional who is directly familiar with the patient.
The information contained in this site reflects the views of the authors, but not necessarily those of The Jim L. Walker – Arizona Chapter Myasthenia Gravis Foundation
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