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Lambert-Eaton Syndrome: Causes, Symptoms and Treatments

Published: 2015/12/27 - Updated: 2020/11/26
Author: Thomas C. Weiss - Contact: Disabled World (
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Synopsis: General information regarding Lambert-Eaton syndrome, a condition in which the human immune system attacks the neuromuscular junctions. The symptoms of Lambert-Eaton syndrome usually start insidiously, with a number of people remaining un-diagnosed for months or even years. Treatments aimed at improving LEMS symptoms directly include pyridostigmine, 3,4-diaminopyridine (amifampridine) and guanidine, which work to improve neuromuscular transmission.


Main Digest

Lambert–Eaton myasthenic syndrome (LEMS, Lambert–Eaton syndrome, Eaton–Lambert syndrome) is defined as a rare autoimmune disorder characterized by muscle weakness of the limbs. LEMS is often associated with lung cancer (50–70%), making LEMS a paraneoplastic syndrome LEMS may also be associated with autoimmune diseases, such as hypothyroidism (an underactive thyroid gland) or diabetes mellitus type 1.

Treatments aimed at improving LEMS symptoms directly include pyridostigmine, 3,4-diaminopyridine (amifampridine) and guanidine, which work to improve neuromuscular transmission.

The prevalence of Lambert–Eaton myasthenic syndrome is approx. 3.4 cases per million.


The condition is often times associated with a certain type of cancer called, 'small cell lung cancer.'

The syndrome might result from your body's efforts to fight the underlying cancer.

In some of the remaining instances, Lambert-Eaton syndrome develops following another autoimmune disease. At times, the cause is not known.

Symptoms of Lambert-Eaton Syndrome

The symptoms of Lambert-Eaton syndrome usually start insidiously, with a number of people remaining un-diagnosed for months or even years.

Weakness is a major symptom; usually in the proximal muscles of the lower limb affecting a person's gait.

An affected person's muscles might be tender and ache. Oropharyngeal and ocular muscles are usually mildly affected. A person's bulbar and respiratory muscles are usually spared.

Autonomic symptoms such as dry mouth, impotence in men, as well as postural hypotension may be seen.

Signs of Lambert-Eaton Syndrome

Some different signs are associated with Lambert-Eaton syndrome. These signs may include the following:

A person with Lambert-Eaton syndrome may find their deep tendon reflexes are reduced, or even absent.

Sensory examination is average, unless there is a coincident peripheral neuropathy associated with an underlying cancer.

Risk Factors

Cancer; usually small cell lung cancer, is present when weakness starts, or is later found in around half of those affected. In the majority of instances, the cancer is found within two years after the onset of Lambert-Eaton syndrome - within four years in nearly every instance. Smoking and age at onset are major risk factors for cancer in this syndrome.

Every person with associated small cell lung cancer has a history of long-term smoking. Only half of people with autoimmune Lambert-Eaton syndrome are long-term smokers, such as a person who is under the age of fifty, who does not have a cancer discovered in the first two years following diagnosis. Such a person most likely has underlying lung cancer.

Diagnosing Lambert-Eaton Syndrome

A doctor will review your symptoms with you and perform a physical examination. A certain blood test might show that you have this condition. You might also undergo a test called, 'electromyography,' which shows how well your muscles are working. Due to the fact that Lambert-Eaton syndrome is associated with lung cancer, a doctor might order X-rays or a CT scan of your lungs.

If a doctor finds that you have Lambert-Eaton syndrome, you will be checked for lung cancer and other forms of cancer, such as lymphoma. If cancer is not found at first, you might need regular check-ups to keep looking for an underlying cancer because Lambert-Eaton syndrome may appear as much as three years prior to a cancer diagnosis.


If you have cancer, a doctor might treat it with radiation, surgery, or chemotherapy. If you have cancer and respond well to treatment, Lambert-Eaton syndrome is more likely to improve.

A doctor may also prescribe medications to suppress your immune system, or to help improve the signals between your muscle and nerve cells.

You may also undergo a type of treatment called, 'plasmapheresis.' Plasmapheresis involves replacing the plasma in a person's blood. Doing so removes harmful immune system proteins from your blood that may be involved in Lambert-Eaton syndrome.


Because the exact cause of Lambert-Eaton syndrome is not fully understood, it is not entirely clear how to prevent the disease.

The best way to reduce your risk for lung cancer - often associated with Lambert-Eaton syndrome, is not to smoke. Additional steps that might help to lower your risk of lung cancer include the following:

Living With Lambert-Eaton Syndrome

Symptoms of Lambert-Eaton syndrome might worsen when you are warm or have a fever. Due to this, avoid taking hot baths or showers and contact a doctor if you begin developing signs of a cold or the flu.

Exercising on a regular basis and receiving enough sleep might also help you to manage the symptoms you do experience.

Author Credentials:

Thomas C. Weiss is a researcher and editor for Disabled World. Thomas attended college and university courses earning a Masters, Bachelors and two Associate degrees, as well as pursing Disability Studies. As a Nursing Assistant Thomas has assisted people from a variety of racial, religious, gender, class, and age groups by providing care for people with all forms of disabilities from Multiple Sclerosis to Parkinson's; para and quadriplegia to Spina Bifida.

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Cite This Page (APA): Thomas C. Weiss. (2015, December 27). Lambert-Eaton Syndrome: Causes, Symptoms and Treatments. Disabled World. Retrieved October 4, 2023 from

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