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Lambert-Eaton Myasthenic Syndrome

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Biology 202, Spring 2005
Second Web Papers
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Lambert-Eaton Myasthenic Syndrome

Flicka Michaels

Lambert-Eaton Myasthenic Syndrome (LEMS) is a rare autoimmune disease which affects the neuromuscular junction and interrupts the connection between nerve cells and the muscles.(1) Less than one in every one million people are diagnosed with this disease every year. (5) It was first described in 1953 by Anderson, who examined a 47 year-old man with oat cell lung cancer. In 1966, Lambert, Eaton, and Rooke did an initial study of the disease, and thus it is named after them. (2) LEMS primarily affects middle-aged adults, but cases in children have been found. Cancer is a factor in about 50% of all cases of LEMS; small-cell lung cancer tends to be present in the majority of them. (2) Some researchers suspect that the cancerous cells cause an excess release of a certain protein in nerve cells, which then causes the formation of anti-bodies to this protein. (1) However, one of the most striking aspects of LEMS is that for patients without cancer, the cause of the disease in unknown.

In order for nerve cells to effectively relay signals to muscles so they can contract,they must emit a neurotransmitter called acetylcholine. The emission of acetylcholine from a nerve cell is dependent on a protein called P/Q type voltage-gated calcium channel (VGCC). VGCC allows admission of calcium into nerve cells and therefore the emission of acetylcholine. About 85-90 percent of people with LEMS have been shown to have antibodies for VGCC, therefore preventing the emission of acetylcholine, and associated weakness of muscles. (1)

Symptoms of LEMS are similar to Myasthenia Gravis. They include weakness of upper leg and arm muscles, problems walking, weakness of the facial muscles, problems talking, swallowing or chewing. Other symptoms include dryness of the mouth, eyes, or skin, and droopy eyelids. (3) The progression of symptoms resulting from LEMS tends to move slowly and can often be mistaken for another disease called Myasthenia Gravis. Like Myasthenia Gravis, LEMS primarily affects adults, and is distinguished by weakness of the muscles. However, with Myasthenia Gravis, the body makes antibodies for
acetylcholine receptors, instead of the protein which allows for the emission of the transmitter. Also unlike Myasthenia Gravis, the weakness associated with LEMS tends to improve after exercise. Some doctors think that the repetitive action causes an increase of calcium in the nerve cells, which then increases the amount of acetylcholine released. (1)

The initial diagnosis of LEMS can be made through a physical examination which will demonstrate the patient's muscle weakness. However, in order to distinguish LEMS from Myasthenia Gravis, a blood test is needed to identify the specific autoimmune antibodies that are being produced. In addition, a test can be given, in which a patient is injected with the edrophonium chloride (Tensilon), and if muscles strengthen as a result, the diagnosis is Myasthenia Gravis. (3) The presence of cancer in a patient is also a sign that LEMS is the diagnosis, as opposed to Myasthenia Gravis.

As I mentioned earlier, about 50% of all LEMS cases are associated with some form of cancer. (2) However, Small-Cell Lung Carcinoma (SCLC) is by far the most common. About 60% of people who have LEMS also have SCLC. (6) Research shows that the connection between the two is most likely due to the antigenetic characteristic of SCLC which triggers body's autoimmune response to the cancer and in turn, the production of antibodies to VGCC. (6) Since this process occurs during the very early stages of the tumor, LEMS is usually detected before the cancer. In some cases, the symptoms of LEMS can appear anywhere from 2-5 years before the symptoms of the cancer. (6) However, when symptoms of LEMS are discovered and the disease is diagnosed, the patient should immediately be tested for cancer, SCLC in particular.

For patients with LEMS and cancer, treatment normally centers on treatments to eliminate the cancerous tumors. However for patients without cancer, a process called Plasmapheresis, in which blood plasma is removed from the patient and replaced by
fluid, tends to ameliorate symptoms. (4) One drug, called Pyridostigmine (or Mestinon), is commonly used for patients with Myasthenia Gravis, and may help increase the release of acetylcholine. However, a commonly recommended drug in cases of LEMS is 3,4-Diaminopyridine, which, like Pyridostigmine, increases the emission of acetylcholine from nerve terminals. (6) For patients with more severe or persistent symptoms, immunosuppressant drugs such as Prednisone, Imuran, and Neoral can also help decrease the formation of antibodies.

So why is LEMS so fascinating? Primarily because (in cases where cancer is not a factor) the cause is unknown. It is an autoimmune disease so we know that the body starts creating antibodies to something it would not normally try to suppress. But why? A research study performed in 2001 by the Dr. Andrew Caton at Wistar Institute in Philadelphia showed that the existence of T cells in the body plays a large role in preventing autoimmune responses. T cells are white blood cells that recognize the body's natural proteins, or the 'self'. (7) Dr. Caton explains that in the case of autoimmune diseases, these T cells are altered so that, instead of working towards the destruction of infected cells, they inhibit the usual immune response. He says, "What's interesting about these regulatory T cells is that, although their purpose is to prevent autoimmunity, they themselves react against the 'self'." (7)

Most of the time, we are trying to figure out how the idea of the "self" fits into the nervous system. We never think of the nervous system as an actual "self" because we usually think that our life battles consist of the nervous system (physical) versus
the "self" (mental). However, if part of the nervous system revolts against its normal routine (as with autoimmune diseases like LEMS), does that not mean that we should entertain the idea that a "self" exists within the nervous system? Perhaps if we stop
viewing the nervous system as one entity that always works perfectly, we might be able to better appreciate its partition and complexity.


1) Muscular Dystrophy Association, Facts about LEMS

2) eMedicine, Very technical, but in depth article about LEMS by Paul Kleinschmidt, MD

3) Rare, facts about LEMS

4) ADAM encyclopedia on, Health Encyclopedia- Treatment for LEMS

5) Cleveland Clinical Health System, Basic overview of LEMS

6) DLD Diagnostika GMBH, Great article that thoroughly discusses and presents visual images of the voltage-gated calcium channels involved in LEMS.

7) Autoimmune Related Diseases Association, Research study abstract



Comments made prior to 2007
I want to praise Flicka Michaels for her very comprehensive and readable paper on LEMS. I've had the autoimmne variety for 26 years and I added this article to my favorites before I noted that it was written by a student. It took two years for a diagnosis in my case, and then Predisone for 11 years allowed me to live a virtually normal life. That is a nasty drug especially long term. I have been on disability retirement since July 2002. I'm now 62 years old and my doctors won't do anything for me, except to schedule IVIG infusions, which do help. I take the DAP and Mestinon every 3 or 4 hours just to keep going.

Dr. Donald B. Sanders at Duke is, I think, the leading authority on LEMS in this country. He did the DAP trials. If you know of any other doctor in this country that is well versed in this disease, please let me know. I am at the end of the road. My local doctor only tells me that I should (already) be dead, I am living on "borrowed time", and that I will die soon. I can't find any information on anyone who has lived with this autoimmune variety as long as me ... Charlotte Kiffer, 6 April 2006


Marjory olson serendip Visitor's picture

My Experience w/ LEMS

I was diagnosed w/ LEMS in 1986, and my decade-later neurologist said mine was the mildest case he'd ever seen, and was because I didn't have cancer, and I had been exercising for years. He put me out at a seminar for medical students at his university, because of the rarity. When iI had gallbladder surgery, several years later, the medical students jockeyed to observe. It has always been a happy thing for me that I have helped train them better. I am now 85, and on my death, my body goes to this same school.

I found this site because my concern about a harmful relationship between the antibiotic cipro and myasthenia gravis -- clearly mentioned in the package insert -- that alarmed me: if there is a myasthenia gravis link, then surely there is also a LEMS link. My health care provider has electronic records, but bells didn't ring when my physician prescribed cipro for a bladder infection. I thus refused to take it.

When anything muscles is of concern -- whatever -- I always think that LEMS has finally caught up with me.

As a habit, I never say that I have it, because I don't feel it identifies me. I'll say 'a rare disease that's of interest' or 'one of the 40 muscular dystrophies.'

When I read all these great comments, I immediately thought I must contribute my story.

Serendip Visitor's picture


My latest neurologist, who is a LEMS specialist, doesn't believe have LEMS because my symptoms are mostly sensory and not muscular. He can't explain my elevated Calcium channel antibody level. I suggested that maybe I have mild LEMS, and he said he never heard of a mild case.
Thanks for your insights of not being defined by an illness. I will try to take that to heart. My symptoms slowly progress, and since I have no diagnosis, I have given in to being where I am and who I am in life.
Thanks for your story. I wish you peace in life and wherever this fascinating process takes us.
All my best to you,

Serendip Visitor's picture

LEMS and the right treatment

My sister was diagnosed with LEMS in March of this year, at present we are still awaiting for funding to be available to go on the DAP regime, she has tried Pyridgostime, might not have spelt that right and also steroid treatment but to no avail, at present awaiting to be funded so my sister is on no medication and is struggling. I thought at first her Consultant was brilliant but now I am not so sure and seems we are in for a long waiting game for medication and it seems so unfair. Has anyone else out there struggled to get proper treatment in place and anyone can assist in regards to living with LEMS I would appreciate feedback. We live in England

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Check out the LEMS facebook page. there is a wonderful and supportive community there with lots of advice to give. Best of luck, Benny

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My wild ride, Is there a fluoroquinolone, LEMS connection?

OK, so here goes. I was given either cipro, avelox (fluoroquinolone antibiotics) or metronidazole about ten years ago by my MD ( I am now 58), and had a severe immediate debilitating reaction, where after three or four days I could hardly walk, as I felt like I was wearing lead boots. I tried to tough it out, but called my MD who told me to stop the drug, as I was having peripheral neuropathy. My symptoms slowly and gradually improved, but never fully went away. As an aside, I have a sister and a cousin with Raynaud's syndrome (poor microcirculation in the extremities, and I always felt that I had a predilection to it, as my hands and feet are always cold and a little numb in the winter). I am a fit tall and thin guy, a frequent gym goer, who always ate well, and who always felt my body type also set me up for my cold extremities. Cut to the late winter of 2009, when I was put on levaquin (another fluoroquinolone antibiotic) for a sinus infection, I believe, and in the spring of 2009, I noticed it odd that the with the warmer weather, my feet were remaining cold and were pretty numb, and this numbness was now ascending up my legs. I went to my MD, who told me that I had classic signs of a b12 deficiency. He gave me a B12 shot, and I did not get better, and blood test showed my B12 level to be normal. He sent me to a neurologist, who told me that I might have a brain tumor, which my later neurlogists have seemingly ruled out. I have since been to three other neurologists, and have been tested for everything from Lyme disease to autoimmune disorders, to heavy metal poisoning, to diabetes, EMG's, MRI's, nerve conducton studies, etc, all of which come back as pretty normal, or just lower than normal, but not worrisomelie so, I am told. My numbness continues to worsen, where I have trouble walking distances, climbing stairs is difficult, and my hands, lips and tongue (occasionally) are numbing. I started searching online, and discovered something people seemingly self diagnose called fluoroquinolone toxicity syndrome, where apparently some people who have taken fluoroquinolone antibiotics have peripheral neuropathies, and a myriad of other neuroloic and muscular symptoms, as this antibiotic apparently crosses the blood/ brain barrier, effects mitochondrial DNA, and can effect lots of systems. I then got my medical record, and my MD has put me on fluoroquinolones nine times in the last ten years, as he feels that regular antibiotics, like amoxicillin, are ineffective in today's world, he has now told me). Most MD's I have now mentioned this to do not believe that fluoroquinolones are causing my worsening numbness, even though the FDA just this past August issued a black box warning against these drugs, for causing permanent peripheral neuropathies, in some patients. My fourth, and recent neurologist sent my blood to the Mayo clinic, out of desperation, after reviewing my record, and conducting lots of tests himself,and I tested positive for LEMS. I am now having CT scans, and other tests, looking for cancer. I have to wonder if there is a connection between LEMS and fluoroquinolone use. Has anyone else with LEMS been on fluoroquinolone antibiotics in the past? The popular ones are levaquin, avelox and cipro, but there are and were many others most of which the FDA has now taken off of the market for severe adverse reactions. Peace, Benny

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I have been diagnosed with LEMS and now that you mentioned it, I was given Fluroquinotenes for sinus infections about two years ago when I started to have problems with weakness. It took the doctors over a year to diagnose me with LEMS and not we are going to look for the cancer. But thank you for bringing this to my attention as I started to have sinus problems about three years ago and there may be a link to this medication.

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I have found the following: Exacerbation of weakness has been described after administration of aminoglycoside or fluoroquinolone antibiotics, magnesium, calcium channel blockers, and iodinated intravenous contrast agents.
So you probably had LEMS already but didn't know, thus the weakness after fluoroquinole.

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Fluoroquinolones and LEMS

Thanks for your insight; it has been considered by me, but again this all started with taking a fluoroquinolone over ten years ago. If I already had LEMS, I had no prior symptoms. I continue to be a puzzle to MD's, and no one takes the fluoroquinolone toxicity possibility seriously. The latest in this saga is that my most recent neurologist says that I don't have LEMS, as my symptoms are mostly sensory and not muscular. I do have elevated Voltage Gated Calcium Channel P/Q antibodies, which are somewhat diagnostic for LEMS, but these numbers aren't very high (my levels are .05 and .04 tested six months apart, while normal is less than .02. I understand that people with LEMS , at least on the facebook LEMS page, have levels more like .11 and .14. I think I have mild LEMS,if there is such a thing, as I have trouble walking distances and up stairs. My legs easily fall asleep if not moved a lot. Most recently, I notice a tingling in my lips and sides of my tongue. I have not been on meds, and things are definitely getting worse. My feet especially and lower legs are always tingling, like I had a shot of novocaine below my knees. A year ago, I developed psoriasis, mostly in the areas where I am numb (lower legs). My latest neurologist will be seeing me again in a month.

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LEMS and Fluoroquinolones

I am more then reasonably convinced that all of this is from fluoroquinolone poisoning, as it all started with a severe drug reaction. Consider joining the LEMS facebook group. They are knowledgeable and supportive. There is also a fluoroquinolone toxicity facebook page, which has many members and symptoms are all over the board, as this medication is the only antibiotic to cross the blood brain barrier and enter the central nervous system. I am still seeking answers. My condition slowly worsens, but I have had these symptoms for so long that I am sort of used to this known unknown factor in my life. I try to keep a positive outlook, eat well, and go forward. I have had tons of cancers ruled out, etc. I hope you are also found to be negative in that regard. My present neurologist just ordered an MRI of my cervical spine (the only place they haven't looked for abnormalities), but this is out of completeness, to rule out any other possible etiologies. He has also said however, that with my tingling lips and tongue, this is not from my spine. I hope you find answers soon. Benny

Donald Semi 's picture

Waiting on VA

Pursuing diagnosis with VA so it takes time. Did you folks have strength loss in legs and arms over a period of a year or so? What led you to seek help? (Symptoms)

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Yes, I started with weakness of my muscles. I couldn't lift things like I used to, then sometimes I would drop things, things would just fall off my hands, then my body began to hurt all over. I knew something was wrong.

Deborah Gaultney's picture

Lambert Eaton and taking Diaminopyridine 3.4

I am taking taking the above medication for two weeks now. I am wondering what are the side effects of people who are currently taking it.
Since it is a orhpan drug no one really knows what the side effects are. I currently have numbness in my lips for about an hour after I take it. It is helping my leg muscles pretty good. I do have small cell lung cancer along with it and am taking chemo.
Really interested in side effects of this med from people who are now taking it.

marty's picture

causes for LEMS

I am a 62 yr old male diagnosed with Lambert-Eaton Myasthenic Syndorme. I do not have cancer. I was in the gulf coast region post Huricane Katrina for a pediod of ten weeks. Is it possible to have contracted this disease from contact with any contaminated air, water or food?

Anonymous's picture


Nonsmoking LEMS patients under the age of 50 only rarely have a tumor! Take it one day at a time. You are going to die old of something else.

Jean's picture

LEMS - newly dx

I am scared. I have just be dx a week ago. My Neurologist is sending me to Mayo in MN in a couple of weeks. I am only 48 with young sons who need their mom. In the past week - I feel like my whole body has been CT-scanned. So far no cancer. What does a LEMS patient do - just wait for a cancer to develope? i feel like my whole world has stopped. I have never smoked and have lived a healthy lifestyle. This is not fair.

Anonymous's picture

11 years and counting

I was diagnosed with LEMS 11 years ago. No cancer.
I take the mestinon and DAP daily and I am now 87 years old. Before I was diagnosed I went through many tests and examinations by my doctor, who prescribed several different treatments and I even knocked over a big pile of cans in the grocery store because I couldn't control my legs. Life for me improved after going on the DAP pills. At first I walked around then I needed a cane and now use a walker, but I am 87. I have never been diagnosed with cancer and have never smoked. You can live with LEMS and be cancer free.

Anonymous's picture

Your story sounds like mine.

Your story sounds like mine. Im 46 with two young children. How have you faired since your post? And, may I ask, by what type of MD were you initially diagnosed and what was the final test that confirmed the LEMS?I ask b/c my reg MD did the diagnosis and I am to see the Neurologist in a few weeks. Mayo in Scottsdale has accepted my case, however, I am on a wait list to see them.

Deborah Gaultney's picture


My symptoms were heavy legs and heavy droopy eylelids. Thats how they knew it was mysesthenia gravis. Then they did a blood test specific to Lambert Eaton Syndrome which told them to look for cancer. I was then diagnosed with Small Cell Lung Cancer and am taking chemo. I am on my last chemo set next week. I will have had 6 sets (1 1/2 hours first day and 1 hour the next two. Two weeks ago they told me I am cancer free. Just because you have Lambert Eaton it doesn't mean you have cancer but best to check it out. The other test ran was EMG test for muscle strength which also told them it was Lambert Eaton. I saw a Neurologist who diagnosed this.
I hope you get to the bottom of this and don't have the cancer
with it. Good Luck.

barbara morhet's picture

i have had LEMS for 3 years

i have had LEMS for 3 years now . i take predisone and mestinone, but still have days when i have trouble moving. i too, wounder how long i will live. i have small cell lung cancer, but the origin has not been found yet. i had the cancer removed from my lymph node and chemo and radiation. i hope there will always be help for people with LEMS

ty jenkins's picture

i am a 33 year old man who

i am a 33 year old man who suffers from lems. i was dx in 2005 and i am currently on dap AND MESTINON.i have good days and bad days.there has never been cancer found but i keep going for the sake of my 5 children,so i say the same to you all,just keep your head up and continue to let God lead you.