Lambert Eaton Myasthenic Syndrome (LEMS) is a disorder of the neuromuscular junction. The neuromuscular junction is the site where nerve cells meet muscle cells and help activate the muscles.








LEMS occurs when antibodies interfere with impulses between the nerve and muscle cells. It may be associated with other autoimmune diseases, or more commonly coincide with or precede a diagnosis of cancer such as small cell lung cancer.

Symptoms may include muscle weakness, a tingling sensation in the affected areas, fatigue and dry mouth. Treatment of an underlying disorder or cancer is the first priority of treatment.



"Living with Lambert-
Eaton Myasthenic Syndrome"
Booklet.

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Lambert Eaton Myasthenic
Syndrome(LEMS)

is an autoimmune disorder
  This means that antibodies similar to those which normally help to fight infections have started to attack the body. In LEMS, these antibodies attack the ends of the nerves at muscles and stop them from releasing acetylcholine, a messenger that tells muscles what to do.
There are two different
type of LEMS:


About half of people have a cancer, the majority of whom have a "small cell" lung cancer (SCLC), which mainly happens in people who smoke. In this type of LEMS the antibodies start by attacking the cancer and then get "confused" and attack the nerves as well. This type usually starts when patients are over 50 years old. This form of LEMS is referred to as paraneoplastic LEMS

In other people, there is no tumour and this type of LEMS usually starts after the age of 50 but it can start in children under the age of 10. Doctors are not sure why the antibodies start to attack the nerves in this type of LEMS. This form of LEMS is referred to as non-paraneoplastic LEMS

 
What are the symptoms
of LEMS?
The main symptom of LEMS is weakness in the muscles, the legs feel heavy (almost like walking through water) and it can affect the arms.

Very often, there are also problems with "automatic" bodily functions; this can cause dry mouth or constipation.

Sometimes (but not as often) it can also affect the muscles that enable talking, chewing and swallowing or even breathing.

How is LEMS diagnosed?
Sometimes the doctor checks to see if a patient has LEMS by looking for specific neuromuscular changes in a test called electromyography (EMG). This is when the nerves are stimulated electrically and the nerve impulses are measured in the muscles.

A blood test for the antibodies may also be used to check for LEMS.

Because LEMS can be caused by a cancer, the doctor will check for lung cancer, especially in people who have smoked. When they check for cancer, the LEMS can often be a valuable early warning of the cancer.
How is LEMS treated?

Treatments for LEMS work in one of three ways:

By reducing the number of antibodies - if there are fewer antibodies to attack the nerves, muscles will work better:
  - Intravenous immunoglobulin - mops up a lot of the antibodies
- Plasmapheresis - a process where the blood is filtered to remove the antibodies
- Corticosteroids, cyclosporine or azathioprine - used to suppress the immune system
- Monoclonal Antibodies - attaches to the antibodies and stops them from working


By increasing number of nerve impulses received by the muscle:

- Cholinesterase inhibitors - make the nerve impulse break down more slowly so more of the signal generated reaches the muscle


By increasing the number of nerve impulses sent by making sure that more acetylcholine is released:
  - Aminopyridines - cause more of the nerve impulse to be released and so increase the muscle activity




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