Lambert-Eaton Myasthenic Syndrome


Lambert-Eaton myasthenic syndrome (LEMS) is an autoimmune disease in which the body’s immune system attacks the tissue where nerves and muscles meet, the neuromuscular junction. It is a rare disorder, affecting approximately 400 people in the United States, and is commonly associated with small cell lung cancer. There is no cure for LEMS, but symptoms often subside with successful treatment of the underlying condition.


The primary symptom of LEMS is muscle weakness, primarily in the legs. You may have trouble getting up from a chair or walking up a flight of stairs and tire quickly. Symptoms also include:

  • Blurry or double vision
  • Dizziness upon standing
  • Drooping eyelids
  • Dry mouth
  • Fatigue
  • Gagging or difficulty swallowing
  • Stiffness
  • Tingling sensations in muscles experiencing weakness


The best way to reduce your risk for lung cancer, which is often associated with LEMS, is to not smoke and avoid exposure to cigarette smoke.

Risk Factors

  • Over half the cases of LEMS are in patients with an underlying health disorder, most commonly those with small cell lung cancer caused by years of smoking. These patients are more likely to be male and over the age of 60, and often have symptoms of LEMS well before a cancer diagnosis.
  • Patients who do not have cancer are more likely to develop LEMS around the age of 35. Although the cause and risk factors are unknown, the disease in these patients is thought to have a genetic component.


LEMS is often misdiagnosed because of its rarity, but it can be diagnosed with a series of tests.

  • Medical history and symptom review. Your doctor will review your symptoms and find out if you have any other health conditions that could be contributing to the muscle weakness.
  • Nerve and muscle testing. An electromyography test will record how well your muscles and nerves are functioning.
  • Blood work. Your blood will be tested for the presence of anti-voltage-gated calcium channels antibodies, which are found in 85% of LEMS patients.
  • CT scan. Your doctor will order a CT scan of your chest to check for small cell lung cancer. Sometimes a PET scan will also be ordered.


There is no cure for LEMS, and treatment varies depending on the presence of cancer or another disorder. For some patients with cancer, treatment of that can alleviate LEMS symptoms. Other options may include:

  • Potassium channel blockers. Firdapse and Ruzurgi are the only two drugs approved by the FDA to treat LEMS; they have been shown to improve muscle strength. 
  • Cholinesterase inhibitors. For some patients with LEMS, these types of drugs can help improve symptoms, although they are not effective for many patients.
  • Immunosuppressants. For patients with more severe symptoms, corticosteroids may be used in combination with other drugs.
  • High-dose intravenous immunoglobulin. An IV of antibodies from plasma helps some patients’ immune systems stop attacking.

Follow-up Care

Patients diagnosed with LEMS who do not have lung cancer should schedule regular follow-up CT scans of their chest.

Why Choose UK HealthCare for Neuromuscular Disorders?

If you or a loved one is living with a neuromuscular disorder, neuromuscular doctors with Kentucky Neuroscience Institute can offer the latest and most sophisticated care options. UK HealthCare’s ALS Multidisciplinary Clinic earned accreditation as a Certified Treatment Center of Excellence from the ALS Association. This honor is awarded to facilities that demonstrate competency meeting the clinical care and treatment standards set forth by the ALS Association. These facilities must also take part in ALS research and a comprehensive site review.

Additionally, the Kentucky Neuroscience Institute is ranked 44th in the country by U.S. News & World Report, and our physicians are regularly named to the Best Doctors in America List.