What does LES Stand for?

Lambert-Eaton-Rooke Syndrome, also known as LES for short, is a very rare disorder of the nervous system. The LES belongs to the myasthenic syndromes.

What is Lambert-Eaton-Rooke Syndrome?

Lambert -Eaton-Rooke syndrome is also known as pseudomyasthenia. The neurological disease is very rare. It was named after the American physicians Edward Howard Lambert, Lealdes McKendree Eaton and Edward Douglas Rooke. They first reported the disease in the 1950s. Muscle weakness is characteristic of Lambert-Eaton-Rooke syndrome. See AbbreviationFinder for abbreviations related to LES.


In Lambert-Eaton-Rooke syndrome, the B lymphocytes produce antibodies against calcium channels. These are located in front of synapses on the so-called neuromuscular endplates. These motor endplates transmit the excitation from a nerve to a muscle fiber. The calcium tubes on the motor endplates are damaged by the antibodies. The neurotransmitter acetylcholine can no longer be released in sufficient quantities. Thus, the stimulus is only transmitted from the nerve fibers to the muscle cell in a weakened form. As a result, the muscle only reacts very easily and sluggishly.

A malignant tumor can be found in about 60 percent of people with Lambert-Eaton-Rooke syndrome. In most cases, it is a small cell lung cancer (SCLC), a tumor of the prostate, a lymphoma or a tumor of the thymus gland. Since the LES occurs in most cases in connection with tumors, it is also one of the so-called paraneoplastic syndromes.

A paraneoplastic syndrome is a concomitant symptom of cancer. The Lambert-Eaton-Rooke syndrome can occur at a very early stage. Often no tumor is known at the onset of the disease and the LES serves as the first indication of cancer. No tumor is found in about 40 percent of those affected. This form of the syndrome is also known as the idopathic form because the cause is unknown.

The idiopathic form of LES is found in particular in patients who also suffer from other autoimmune diseases, such as systemic lupus erythematosus. Lambert-Eaton syndrome occurs in an average of 3.4 people per million people. Men are affected significantly more often than women. However, since more and more women are also developing lung cancer, the number of women with Lambert-Eaton-Rooke syndrome is also increasing.

Symptoms, Ailments & Signs

Muscle weakness in the extremities is typical of the LES. The arms are more often affected by this muscle weakness than the legs. I
© HANK GREBE – stock.adobe.com

Muscle weakness in the extremities is typical of the LES. The arms are more often affected by this muscle weakness than the legs. In particular, the muscles of the thighs, hips and knees suffer. Patients therefore often notice their first weaknesses when climbing stairs. But the trunk muscles can also be affected in Lambert-Eaton-Rooke syndrome. It is also characteristic that, despite the muscle weaknesses, no sensory disturbances can be found.

When making the diagnosis, the LES is often confused with myasthenia gravis. Muscle weakness also occurs here. However, the paralysis of the eye muscles characteristic of myasthenia gravis is absent in LES. Paralysis of the eyelids (ptosis) is also rather rare. In addition to muscle weakness, symptoms such as dry mouth, headaches, impotence, constipation or bladder emptying disorders can occur.

Cognitive disorders are an indication of involvement of the autonomic nervous system. This occurs in more than 90 percent of cases. The central nervous system can also be affected. Other complaints include decreased sweating, changes in blood pressure, and blurred vision.

Diagnosis & course of disease

The suspicion of Lambert-Eaton-Rooke syndrome is checked with a neurophysiological examination. Decreased motor cumulative action potentials are an indication of muscle weakness. These deviations can also be observed in the muscles that are not (yet) affected by the weakness. If the peripheral nerves are stimulated by means of high frequency or by heavy muscular exertion, it can be observed that the strength in the muscles increases significantly.

This phenomenon is also known as the Lambert sign. The Lambert sign is also used for the differential diagnosis of myasthenia gravis. Muscle fatigue can be observed here with strong stimulation. In addition to these tests, a Tensilon test can also be carried out. A cholinesterase inhibitor is injected intravenously into the patient. He then has to perform various muscle exercises repeatedly.

If the maximum strength of the muscle is higher after the administration of Tensilon than before, the test is positive. A positive test result is found in both myasthenia gravis and Lambert-Eaton-Rooke syndrome. In addition, laboratory tests can confirm the diagnosis. In almost 90 percent of all those affected, the causative antibodies are found in the blood. If the suspicion of the LES is confirmed, a causative tumor should be searched for. More than 95 percent of all malignant tumors are found in the year after diagnosis.


The victims of Lambert-Eaton-Rooke syndrome primarily suffer from severe muscle weakness. The patients appear exhausted and continue to suffer from a German reduced resilience. This leads to significant limitations in various activities in everyday life, so that those affected also find it difficult to walk or climb stairs.

Paralysis of the eyelids can also occur, resulting in various visual problems. Patients also suffer from headaches and impotence due to Lambert-Eaton-Rooke syndrome. This often leads to psychological problems or even depression.

Due to the discomfort in the eyes, those affected also suffer from blurred vision. There is also reduced blood pressure, which can also lead to a loss of consciousness. The patient’s quality of life is significantly reduced and restricted by the Lambert-Eaton-Rooke syndrome.

As a rule, the underlying disease is always treated in Lambert-Eaton-Rooke syndrome. It is generally not possible to universally predict whether the course of the disease will be positive. It is possible that the life expectancy of the patient is also significantly reduced by the Lambert-Eaton-Rooke syndrome.

When should you go to the doctor?

Lambert-Eaton-Rooke syndrome can manifest itself through various health problems that require investigation. If symptoms such as muscle weakness in the extremities, incontinence, constipation or headaches develop, a doctor must be consulted. The same applies to unusual visual disturbances, blood pressure fluctuations and other non-specific symptoms that cannot be clearly traced back to a trigger. Affected people should speak to their family doctor immediately so that the illness can be quickly clarified and treated. If this happens early, long-term damage and serious complications can often be ruled out.

Cancer patients, people with autoimmune diseases and old or debilitated people are particularly susceptible to the development of Lambert-Eaton-Rooke syndrome. Anyone who belongs to these risk groups should go to the responsible doctor with the symptoms described. In addition to the family doctor, the disease of the nervous system must be treated by various specialists such as neurologists, ophthalmologists, orthopedists and internists. In addition, physiotherapists and psychotherapists are involved in the treatment in order to be able to treat any movement disorders or subsequent psychological problems. Regular visits to the doctor are indicated during therapy.

Treatment & Therapy

If the Lambert-Eaton-Rooke syndrome is based on a tumor, it must be treated. This often improves the symptoms of the LES. However, if the muscle weakness continues to progress, drugs such as pyridostigmine, intravenous immunoglobulin or amifampridine can be used. However, the effectiveness of these agents in Lambert-Eaton-Rooke syndrome has not yet been sufficiently scientifically proven.

In the idiopathic form, improvement can be achieved with immunosuppressive drugs such as glucocorticoids or immunoglobulins. Symptomatic therapy is with potassium channel blockers. In addition, the blood can be cleaned of antibodies during plasmapheresis. This also improves the symptoms.

Outlook & Forecast

The prognosis of Lambert-Eaton-Rooke syndrome depends on the causative disorder. In a large number of cases, those affected suffer from a tumor disease. An improvement in health can only be achieved if the tumor has been completely removed. This requires cancer therapy, which is associated with numerous risks and side effects. The surgical removal of the tumor must be carried out and can also be associated with complications. Nevertheless, only curing the tumor brings a prospect of full recovery.

If an autoimmune disease is present, the disease is often chronic. In long-term therapy, medication is administered to alleviate the symptoms. The drugs can have side effects and thus also have a negative impact on the general well-being of the person concerned. Nevertheless, they show the only way that basically leads to an alleviation of Lambert-Eaton-Rooke syndrome. If there is an existing intolerance to an active substance, an alternative preparation should be selected and administered. This reduces the risk of possible side effects.

Since the course of the syndrome is characterized by various symptoms and limitations, various secondary diseases can develop. The emotional burden is so strong for many patients that mental disorders develop. This possible development must be taken into account when making the overall forecast.


Preventing Lambert-Eaton-Rooke syndrome is rather difficult. Since the syndrome is often the result of a lung tumor, the risk factors for lung cancer should be avoided. First and foremost is smoking. A healthy lifestyle, on the other hand, can have a positive effect on the risk of cancer.


The Lambert-Eaton-Rooke syndrome is usually associated with severe complications and symptoms, so that the options for aftercare are very limited in most cases. Those affected should therefore first and foremost consult a doctor so that a quick diagnosis can be made. Only an early diagnosis can prevent further deterioration of the symptoms.

In most cases, patients with Lambert-Eaton-Rooke syndrome are dependent on taking medication to permanently relieve the symptoms. It is always important to ensure that it is taken regularly and that the dosage is correct. If you have any questions or are unclear about the medication, you should always consult a doctor first.

The help and support of one’s own family and acquaintances is also very important with Lambert-Eaton-Rooke syndrome and can prevent psychological problems or even depression. Loving and intensive conversations have a positive effect on the course of the disease. In the case of a tumor, the syndrome usually cannot be completely cured. The life expectancy of the person affected may also be significantly reduced due to the underlying disease.

You can do that yourself

Patients with Lambert-Eaton-Rooke syndrome suffer from significant muscle weakness, which gradually makes it more and more difficult for them to carry out their everyday activities and significantly reduces their perceived quality of life. In order to help themselves, those affected first seek physiotherapy after visiting the doctor in order to explore and specifically strengthen their remaining motor skills. For this purpose, the patients carry out exercises prescribed by the therapist in their own four walls, thereby increasing the success of the physiotherapy.

Patients also get walking aids to help them keep their balance and reduce the risk of falling. Those affected also counteract the increased risk of accidents by paying more attention to physical activities. If the impairments in everyday life are too great, the patients seek the help of a nursing service or relatives.

The treatment of the disease usually also includes the disciplined intake of various medications, which is the responsibility of the patient. In most cases, vision is also affected by the disease, so that special vision aids and eye treatments can help to a certain extent. However, the disease leads to psychological complaints such as depression in a large proportion of those affected, so that the patients turn to a psychological therapist.

Lambert-Eaton-Rooke Syndrome