Lambert-Eaton-Rooke syndrome, also known as LES for short, is a very rare disorder of the nervous system. LES is one of the myasthenic syndromes.
What is Lambert-Eaton-Rooke syndrome?
Lambert-Eaton-Rooke syndrome is also known as pseudomyasthenia. The neurological disorder is very rare. It was named after American physicians Edward Howard Lambert, Lealdes McKendree Eaton, and Edward Douglas Rooke. They first reported the disease in the 1950s. Characteristic of Lambert-Eaton-Rooke syndrome is muscle weakness.
Causes
In Lambert-Eaton-Rooke syndrome, B lymphocytes produce antibodies against calcium channels. These are located in front of synapses at the so-called neuromuscular endplates. These motor end plates transmit excitation from a nerve to a fiber in the muscles. The antibodies damage the calcium tubules at the motor end plates. The neurotransmitter acetylcholine can no longer be released in sufficient quantities. As a result, the stimulus from the nerve fibers is only transmitted to the muscle cell in a weakened form. As a result, the muscle reacts only very slightly and sluggishly. In about 60 percent of people with Lambert-Eaton-Rooke syndrome, a malignant tumor can be found. In most cases, the tumor is a small cell lung cancer (SCLC), a tumor of the prostate, a lymphoma or a tumor of the thymus. Since LES occurs in most cases in association with tumors, it also belongs to the so-called paraneoplastic syndromes. A paraneoplastic syndrome is an accompanying symptom of cancer. 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. In about 40 percent of those affected, no tumor is found. This form of the syndrome is also called idiopathic form, because the cause is unknown. The idiopathic form of LES is found particularly in patients who also suffer from other autoimmune diseases, such as Systemic Lupus Erythematosus. Lambert-Eaton syndrome occurs on average in 3.4 people per million. Men are affected significantly more often than women. However, as more women also develop lung cancer, the number of women with Lambert-Eaton-Rooke syndrome is also increasing.
Symptoms, complaints, and signs
Typical of LES is muscle weakness in the extremities. The arms are more commonly affected by this muscle weakness than the legs. In particular, the muscles of the thigh, hip, and knee suffer. Patients therefore often notice initial weaknesses when climbing stairs. However, the trunk muscles can also be affected in Lambert-Eaton-Rooke syndrome. It is also characteristic that no sensory disturbances are found despite the muscle weaknesses. LES is often confused with myasthenia gravis at diagnosis. Here, too, muscle weaknesses occur. However, LES lacks the paralysis of the eye muscles that is characteristic of myasthenia gravis. Paralysis of the eyelids (ptosis) is also rare. However, in addition to muscle weakness, symptoms may include dry mouth, headache, impotence, constipation, or bladder emptying problems. Cognitive disturbances are indicative of autonomic nervous system involvement. These occur in more than 90 percent of cases. The central nervous system may also be affected. Other symptoms include decreased sweating, changes in blood pressure and blurred vision.
Diagnosis and course of the disease
Suspected Lambert-Eaton-Rooke syndrome is tested with a neurophysiologic examination. Decreased motor summation action potentials are found as an indication of muscle weakness. These abnormalities can also be observed in muscles that are not (yet) affected by the weakness. If one stimulates the peripheral nerves by means of high frequency or by strong muscular load, it can be observed that the strength in the muscles increases significantly. This phenomenon is also called the Lambert sign. The Lambert sign also serves as a differential diagnosis to myasthenia gravis. In this case, muscle fatigability can be observed when stimulation is strong. In addition to these tests, a tensilon test can also be performed. Here, the patient is injected intravenously with a cholinesterase inhibitor.He must then repeatedly perform various muscle exercises. If the maximum force 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 affected individuals, the causative antibodies are found in the blood. If the suspicion of LES is confirmed, it is imperative to search for a causative tumor. More than 95 percent of all malignant tumors are found in the year after diagnosis.
Complications
As a result of Lambert-Eaton-Rooke syndrome, affected individuals primarily suffer from severe muscle weakness. Patients appear fatigued and also continue to suffer from German reduced exercise tolerance. This leads to significant limitations in various activities of everyday life, so that even ordinary walking or climbing stairs is difficult for the affected person. Likewise, paralysis of the eyelids can occur, resulting in various visual complaints. Furthermore, patients suffer from headaches and impotence due to Lambert-Eaton-Rooke syndrome. As a result, it is not uncommon for psychological complaints or even depression to occur. Due to the discomfort of the eyes, those affected also suffer from blurred vision. Likewise, there is a reduced blood pressure, which can further lead to a loss of consciousness. The patient’s quality of life is significantly reduced and limited by Lambert-Eaton-Rooke syndrome. As a rule, the underlying disease is always treated in Lambert-Eaton-Rooke syndrome. Whether this results in a positive course of the disease cannot usually be universally predicted. It is also possible that Lambert-Eaton-Rooke syndrome will significantly reduce the patient’s life expectancy.
When should you see a doctor?
Lambert-Eaton-Rooke syndrome can manifest itself through a variety of health problems that require evaluation. If symptoms such as muscle weakness of the extremities, incontinence, constipation, or headaches develop, a physician must be consulted. The same applies to unusual visual disturbances, blood pressure fluctuations and other non-specific symptoms that cannot be clearly attributed to a trigger. Affected persons should talk to their family doctor immediately so that the disease can be clarified and treated quickly. If this is done at an early stage, long-term damage and serious complications can often be ruled out. Tumor patients, people with autoimmune diseases, and the elderly or debilitated are particularly susceptible to developing Lambert-Eaton-Rooke syndrome. Those who belong to these risk groups should go to the responsible medical practitioner with the described signs of the disease. 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 psychological secondary complaints. Regular visits to the physician are indicated during therapy.
Treatment and therapy
If Lambert-Eaton-Rooke syndrome is based on a tumor, it must be treated. This often improves the symptoms of LES. However, if the muscle weakness progresses, drugs such as pyridostigmine, intravenous immunoglobulin, or amifampridine may be used. However, the efficacy of these agents in Lambert-Eaton-Rooke syndrome has not yet been sufficiently scientifically proven. In the idiopathic form, improvement can be achieved by immunosuppressive drugs such as glucocorticoids or immunoglobulins. Symptomatic therapy is performed with potassium channel blockers. In addition, the blood can be cleansed of the antibodies during plasmapheresis. This also improves the symptoms.
Outlook and prognosis
The prognosis of Lambert-Eaton-Rooke syndrome depends on the causative disorder. In a large number of cases, affected individuals suffer from tumor disease. Improvement in health can only be achieved if the tumor is completely removed. This requires cancer therapy, which is associated with numerous risks and side effects. Surgical removal of the tumor must take place and can also be accompanied by complications.Nevertheless, only the cure of the tumor disease brings a prospect of complete recovery. If an autoimmune disease is present, the course of the disease is often chronic. In long-term therapy, the symptoms are alleviated by administering drugs. The drugs can have side effects and thus also have a negative impact on the general well-being of the affected person. Nevertheless, they show the only way that basically leads to an alleviation of Lambert-Eaton-Rooke syndrome. In case of an existing intolerance of an active substance, an alternative preparation should be sought out and administered. This will alleviate the risk for possible side effects. Since the course of the syndrome is characterized by various complaints and limitations, different secondary diseases can develop. The emotional burden is so severe for many patients that psychological disorders develop. This possible development must be taken into account when making the overall prognosis.
Prevention
Preventing Lambert-Eaton-Rooke syndrome is rather difficult. Because the syndrome is often the result of a lung tumor, risk factors for lung cancer should be avoided. In the first place, smoking should be mentioned. A healthy lifestyle, on the other hand, can have a positive effect on cancer risk.
Follow-up
Lambert-Eaton-Rooke syndrome is usually associated with severe complications and discomfort, so that in most cases the options for follow-up care are very limited. Affected persons should therefore first and foremost consult a physician so that a rapid diagnosis can be made. Only an early diagnosis can prevent a further worsening of the symptoms. In most cases, patients with Lambert-Eaton-Rooke syndrome are dependent on taking medication to permanently alleviate the symptoms. It is always important to ensure that the medication is taken regularly and in the correct dosage. If there are any questions or uncertainties about the medication, a doctor should always be consulted first. Help and support from family and friends is also very important in Lambert-Eaton-Rooke syndrome and can prevent psychological complaints 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. In this case, the life expectancy of the affected person may also be significantly reduced due to the underlying disease.
What you can do yourself
Patients with Lambert-Eaton-Rooke syndrome suffer from significant muscle weakness that gradually makes it more and more difficult for them to perform their normal daily activities and significantly reduces their perceived quality of life. In order to help themselves, those affected first take advantage of physiotherapy after seeing a doctor, in order to sound out and specifically strengthen the motor skills they still have. To this end, patients perform exercises prescribed by the therapist in their own homes, thereby increasing the success of the physiotherapy. Patients also use walking aids to help them maintain their balance and reduce the risk of falls. Patients also counteract the increased risk of accidents by paying more attention during physical activities. If the impairments in everyday life are too great, patients call on the help of a care service or relatives. The therapy 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 impaired by the disease, so that to a certain extent special visual aids and eye treatments provide relief. However, the disease leads to psychological complaints such as depression in a large proportion of those affected, so that patients turn to a psychological therapist.