Understanding Eaton Syndrome Causes Symptoms and Treatment Options

Lambert-Eaton syndrome is linked to certain cancers, especially small-cell lung cancer. The connection is thought to be because small-cell cancer cells express voltage-gated calcium channels, the same calcium channels present on nerve endings that trigger acetylcholine release.

The antibodies that cause LEMS interfere with this communication, which leads to muscle weakness. The condition can precede or occur with cancer, but it can also happen without cancer as a paraneoplastic syndrome.


For Lambert-Eaton syndrome to be diagnosed, your healthcare provider will review your symptoms and do a physical exam. They will also order a blood test and a special muscle test called electromyography, which measures how well your muscles work. Your doctor may also order X-rays or a CT scan of your lungs to look for signs of lung cancer. They may also request other tests to rule out conditions like myasthenia gravis, which has symptoms similar to Lambert-Eaton syndrome.

Understanding what is Lambert-Eaton Syndrome is helpful to patients. In Lambert-Eaton syndrome, your immune system’s natural defenses mistakenly attack the contact point between motor nerves and muscle fibers (neuromuscular junction). They bind to and block calcium channels in these nerve cells, which interfere with releasing the chemical messenger acetylcholine and cause weakness.

Symptoms of Lambert-Eaton syndrome typically develop slowly over weeks or months and can get worse as the disease progresses. They can include muscle weakness, especially in your legs and arms. It can affect your hands, swallowing and speech, and automatic body functions, like controlling blood pressure.

Some people with LEMS have no lung tumors, but more than half of those with the condition have small-cell lung cancer or another form of cancer that grows near the lungs. Treating the cancer should improve LEMS symptoms. Your doctor may recommend medicines for muscle weakness, such as amifampridine (Firdapse) or ruxurginib (Ruzurgi). These medicines make your body release more acetylcholine to strengthen nerve signals. They may also prescribe high doses of immunoglobulins or plasma exchange.


Lambert-Eaton syndrome (also known as LEMS) is a disease that affects the nerves and muscles that help you move your legs, arms and other body parts. It happens when your immune system attacks the area where motor nerves connect with muscle cells. Normally, electrical impulses travel down motor nerves and open little gates at the ends of the nerve cells.

These gates allow the release of a chemical called acetylcholine, which causes the muscles to contract. With LEMS, muscle weakness can make standing, walking, and other daily activities difficult. It’s rare, with only about 400 cases in the United States. In most cases, it develops in people with cancer and is caused by the body’s response to fighting the underlying tumor.

The first step in diagnosis is getting an X-ray or CT scan and possibly a chest magnetic resonance imaging (MRI). Your doctor may also order an electromyography test, which measures how well your nerves and muscles work together.

Usually, LEMS happens when you have small-cell lung cancer, but it can happen with certain other types of cancers, such as prostate and lymphoma. If you have cancer, your healthcare provider will treat the tumor or cancer to improve your symptoms of LEMS. You may also be given medicines to suppress your immune system or to help increase the amount of acetylcholine released at the nerve-muscle junction.


A person with LEMS will have weakness in their muscles. The nerves aren’t sending enough “messages” to make the muscle fibers contract. People who have cancer may also develop this disorder. This happens because the tumor destroys the nerve cells communicating with muscle fibers.

Doctors diagnose LEMS by doing a physical exam, reviewing your medical history and checking for signs of cancer. Your doctor will order blood and electromyography tests to see how well your muscles work. These tests can help doctors tell the difference between this disorder and myasthenia gravis, which has similar symptoms.

In LEMS, antibodies attack the contact point between motor nerves and muscle fibers (neuromuscular junction). The antibodies target voltage-gated calcium channels on the end of nerve cells. They block these channels, which causes weakness in the legs that gradually spreads to the arms and breathing muscles.

The treatment for this condition focuses on treating the cancer, if there is one, and improving muscle strength. Your doctor may prescribe medications that can increase the acetylcholine released by nerves to strengthen muscle contractions. These medicines include amifampridine (Firdapse) and ruxolitinib (Ruzurgi). This disorder has no cure, but treatments can improve your symptoms. They include avoiding tobacco and getting support from your family, friends, and an organization for people with muscle disorders.


Lambert-Eaton syndrome is often caused by small-cell lung cancer, but it can happen without a lung tumor. It’s also sometimes related to other types of cancer, including thymoma and lymphoma. The condition affects nerve signals between the brain and muscle fibers that help your muscles contract. This disorder is rare, affecting about 400 people in the United States. Symptoms of Lambert-Eaton syndrome usually begin slowly and get worse over time. They can include weakness, fatigue, and a dry mouth.

Doctors can diagnose the condition by doing tests to check for a tumor, such as an abdomen and pelvic bone ultrasound and a CT scan of the lungs and chest. Your doctor may also do blood tests to find antibodies that attack the neuromuscular junctions. They may also do a test to measure the strength of your muscles by sending electrical currents through them.

Treatment for Lambert-Eaton syndrome includes treating the underlying cancer (if it’s present) and taking medicines that increase the release of acetylcholine to strengthen nerve signals to your muscles. Amifampridine (Firdapse) and a similar medicine called guanidine (Ruzaguri) are the only medicines approved for this use. Both medicines have a small risk of causing seizures in some people.

You can help prevent the symptoms of Lambert-Eaton syndrome by not smoking and getting plenty of rest and exercise. Your doctor can advise you on reducing stress and avoiding heat and cold.