What is Lambert-Eaton Myasthenic Syndrome?

Lambert-Eaton myasthenic syndrome (LEMS) is a syndrome of weakness and fatigue often associated with cancer, particularly lung cancer. There may be symptoms of LEMS before the cancer is diagnosed and once the diagnosis of LEMS has been made, the patient must be followed for the development of cancer. Symptoms of LEMS are related to weakness of the muscles, mostly in the arms, legs, thighs and hips, but also related to the neck, swallowing, breathing, speaking, etc. Early symptoms are problems going up stairs, getting up from the sitting position, and lifting arms over the head. It can also have an impact on involuntary body functions, causing dry mouth and impotence.

What causes Lambert-Eaton Myasthenic Syndrome?

LEMS is caused by antibodies that are produced by the body. These antibodies destroy nerve endings that help regulate the amount of a neurotransmitter that is released. Not enough of the neurotransmitter is released, which does not allow the muscles to contract.

Who gets Lambert-Eaton Myasthenic Syndrome?

LEMS is not hereditary. The symptoms usually begin in young adults. It is not often seen in children. Approximately 1 in one million people have LEMS. 40% of those have cancer.

How is Lambert-Eaton Myasthenic Syndrome diagnosed?

LEMS is diagnosed multiple ways. Blood tests and Tensilon tests can be administered, as well as EMGs and NCVs.

How is Lambert-Eaton Myasthenic Syndrome treated?

Currently no cure exists for LEMS. The most effective treatment if cancer is present is eradication of the cancer, though other medications have been used with some success. Treatment through medication is directed at relieving the symptoms. Drugs can be taken to release more of the neurotransmitter the muscles aren’t getting enough of. Other drugs can be taken that slow down the production of the antibodies produced. These antibodies are what initially causes the muscles to stop contracting. Another treatment option is plasmapheresis. In this process, the blood plasma is removed and replaced.

More information on Lambert-Eaton Myasthenic Syndrome

Muscular Dystrophy Association
The Cleveland Clinic
United States National Library of Medicine