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Testing and Treating LEMS

Understanding how your doctor will diagnose and treat your symptoms

Once you’ve found a neuromuscular specialist, the next steps on the road to feeling better are diagnosis and treatment. In this section, you’ll learn about some of the diagnostic tests that your doctor may use to identify the cause of your symptoms. If you are diagnosed with Lambert-Eaton myasthenic syndrome (LEMS), your doctor will prescribe a treatment based on the type of LEMS that you have.

Testing for LEMS

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There are 3 common testing methods that your specialist may use to diagnose your symptoms. After testing, your doctor will be able to tell you whether you have LEMS, MG, or another disorder.

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A physical exam

to evaluate your symptoms and test your reflexes. A diagnosis can be suspected based on this physical exam.

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To confirm diagnosis, your doctor may order additional tests

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A blood test

to check for the presence of certain antibodies (special proteins made by your immune system).

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An electrodiagnostic test

to measure how well your muscles and nerves are communicating with each other.


What these tests will reveal

The results of LEMS testing will point your doctor to one of two different treatment paths:


A positive result will signal your doctor to start treatment for LEMS.*


A negative result will tell your doctor to look for a cause other than LEMS for your symptoms.

*A hidden cause of LEMS

In some cases, LEMS may be caused by an underlying cancer—usually in people with a long history of tobacco smoking. In those cases, the doctor may do a special screening test first to rule out cancer as a cause of LEMS. Read more about this type of LEMS on the next page.

Treating LEMS

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There are several types of therapies that have been used to treat LEMS. Here are two options your doctor may consider:

Oral medicine

LEMS is usually treated with an oral medicine called amifampridine [am-ee-FAM-per-deen] that is prescribed to help nerve signals reach the muscles.

Some important things to know about amifampridine:

  • It is FDA-approved for the treatment of adults with LEMS
  • It has been proven effective in clinical trials to relieve the symptoms of LEMS
  • It must be taken daily to maintain its positive effects

Prior to approval of amifampridine, other unapproved medications were used for the treatment of LEMS,including antimyasthenic agents.

Infusion treatments


Discover an FDA-approved treatment option for LEMS

Learn more about this amifampridine-based therapy now.

Stay informed

More content is on the way for LEMS Aware, including video stories with real patients who are living and thriving with LEMS. Sign up to stay informed about new additions to the website as well as other resources that become available.

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