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Frequently Asked Questions

Frequently Asked Questions

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What is Lambert-Eaton myasthenic syndrome (LEMS)?
LEMS is a neuromuscular disordera condition that affects the nerves and muscles that typically causes severe, debilitating, and progressivegradual worsening muscle weakness and fatigue.
Does LEMS have other symptoms beyond muscle weakness?
People with LEMS may also experience fatigue, dry mouth, weakness of the head and neck muscles, constipation, dizziness upon standing, dry eyes, and blurred vision. Men may experience impotence erectile dysfunction.
What causes LEMS?
LEMS is an autoimmune diseasea disease caused by a malfunction in the body’s defenses. In LEMS, the body overproduces a particular set of antibodiesproteins made by the immune system that fight infections that mistakenly attack and damage nerve cell endings. These attacks disrupt communication between the nerves and muscles, leading to muscle weakness.
How common is LEMS?
LEMS is a rare condition. It is estimated to affect approximately 3,000 people in the US.
Who usually is affected by LEMS?
LEMS typically affects men and women between the ages of 35 and 60. Both men and women are equally at risk. LEMS is more common, however, in people with preexisting autoimmune disorders.
What type of doctor should I see about my symptoms?
If you’ve already been to your primary care physician and are still searching for answers, you should ask to be referred to a neurologist or neuromuscular specialist. These are physicians who specialize in diseases of the nerves and muscles and will know what tests to administer to identify the cause of your symptoms.

To search for LEMS specialists in your area, use the LEMS Physician Locator.
Can LEMS be treated?
There is currently no cure for LEMS, but there are therapies available for managing symptoms, including one treatment that is FDA-approved and proven clinically effective for the treatment of LEMS in adults. Your neurologist or neuromuscular specialist will recommend the treatment that’s right for you.
How long does it take for the effects of treatment to work?
Today’s recommended oral medications usually provide relief of LEMS symptoms within hours of taking the pill. Treatment must be taken every day in order to maintain this positive response.
Is LEMS easy to diagnose?
LEMS can be difficult to diagnose for several reasons: It is a rare disorder, symptoms may come and go in some patients, and there are other neuromuscular diseases that cause similar symptoms of muscle weakness. In fact, LEMS is most often misdiagnosed as myasthenia gravis (MG), a closely related autoimmune disorder. LEMS is also frequently mistaken for multiple sclerosis, amyotrophic lateral sclerosis, myopathy, and Guillain-Barré syndrome.

The good news is that LEMS can be accurately diagnosed based on the results of a physical examination and confirmatory testing with a blood test or a painless nerve stimulation test known as electromyography.
Is LEMS caused by cancer?
LEMS is caused by an overactive immune system. However, in about 50% of cases, the overactivity is related to an underlying tumor, most often small cell lung cancer. The other 50% of cases are purely related to immune system dysfunction.
Who is most at risk for cancer-related LEMS?
Most cases of cancer-related LEMS occur in people with a history of smoking.
What will happen if I’m diagnosed with cancer-related LEMS?
Your neurologist will refer you to an oncologist for treatment of the cancer, usually chemotherapy. Treating the tumor with chemotherapy may also help improve the symptoms of LEMS.

Achieving successful remission of the underlying tumor does not guarantee relief of your LEMS symptoms. If those symptoms do persist, it’s important to speak to your neurologist about starting (or continuing) therapy that will specifically address your LEMS symptoms.

Caregiver FAQs

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Is LEMS contagious?
No, LEMS is not contagious.
Can LEMS be inherited?
Currently, no direct genetic link has been identified for LEMS, but genetics may play a role in how likely a person is to develop an autoimmune disease.
When would I need to contact my loved one’s doctor?
Reasons to contact your LEMS patient’s physician may include:
Where can I find more information about treatments for LEMS?
Information on treatment options for LEMS is available on the “Testing and Treating” page. The following organizations also offer information about treatments and ongoing research in LEMS:

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