Lambert-Eaton Myasthenic Syndrome

Lambert-Eaton Myasthenic Syndrome: Description, Causes and Risk Factors:Abbreviation: LEMS.Alternative Names: Carcinomatous myopathy, Eaton-Lambert syndrome, Lambert syndrome, myasthenic syndrome.Lambert-Eaton Myasthenic SyndromeLEMS is a rare autoimmune disorder of the neuromuscular junction characterized by autoantibodies against VGCC (Voltage-Gated Calcium Channel), against presynaptic voltage-gated P/Q calcium channels. These channels are also designated as active zone of the presynaptic membrane. A transient depolarization of the presynaptic membrane causes the opening of the voltage-gated calcium channels, which allows the local influx of calcium ions into the nerve terminal. This rise in calcium ion concentration results in the release of acetylcholine from the vesicles. Autoantibodies as found in Lambert-Eaton Myasthenic Syndrome lead to a cross-linking of the channels with subsequent internalisation and degradation. As a consequence the number of channels is reduced and, therefore, the release of acetylcholine. The result is an interruption of the impulse transmission to the neuromuscular end-plate of the muscle cell which eventually causes the typical myasthenic syndrome.LEMS occurs when nerves cells do not release enough of a chemical called acetylcholine, which transmits impulses between nerves and muscles. The result is muscle weakness and other symptoms similar to myasthenia gravis. However, as the muscles continue to contract, the chemical (acetylcholine) can build up in sufficient quantities for strength to get slightly better.In myasthenia gravis (MG) the autoimmune process happens on the postsynaptic level at the acetylcholine receptor of the muscle cell. In LEMS the autoimmune process takes place on the presynaptic level at the nerve terminal.Risk Factors:Cancer - Typically small cell lung carcinoma (SCLC) is present when weakness begins, or is later found in 40% of patients. In most cases the cancer is found within 2 years after the onset of Lambert-Eaton Myasthenic Syndrome . Within 4 years in virtually all cases.
  • Smoking and age at onset are major risk factors for cancer in Lambert-Eaton Myasthenic Syndrome . All patients with associated SCLC have a history of long-term smoking. Only half of patients with auto-immune Lambert-Eaton Myasthenic Syndrome are long-term smokers.
Symptoms:Symptoms may include:Difficulty chewing.
  • Difficulty climbing stairs.
  • Difficulty lifting objects.
  • Difficulty talking.
  • Drooping head.
  • Need to use hands to arise from sitting or lying positions.
  • Blurry vision.
  • Double vision.
  • Blood pressure changes.
Diagnosis:Differential Diagnosis:Myasthenia gravis.
  • Acute or chronic inflammatory demyelinating polyradiculopathy.
  • Dermatomyositis/polymyositis.
  • Inclusion body Myositis.
  • Spinal muscular atrophy.
A physical examination shows weakness or paralysis that gets slightly better with activity. Reflexes may be decreased. There may be loss of muscle tissue.Tests to help diagnose and confirm the condition may include:Electromyography (EMG): The doctor checked if you have LEMS by looking for specificneuromuscular changes in a test called electromyography. This is when the nerves are stimulated electrically andthe nerve impulses are measured in the muscles.
  • A blood testfor the antibodies may also have been used to check for Lambert-Eaton Myasthenic Syndrome .
  • Nerve conduction velocity.
  • Tensilon test.
  • As LEMS can be caused by a cancer, the doctor will check forlung cancer, especially in people who have smoked.
Treatment:For patients with small cell lung cancer, treatment of the cancer is the first priority. The surgical removal of the tumour often causes a temporary improvement of the neurological symptoms. Immunosuppressive drugs are usually not indicated.There is no known cure for Lambert-Eaton Myasthenic Syndrome . Treatment is directed at decreasing the autoimmune response through the use of steroids, plasmapheresis (involves removing blood plasma from the body and replaced it with fluid, protein, or donated plasma. This helps to make sure that any harmful proteins that are interfering with nerve function are removed from the body).Medications that suppress the immune response, such as prednisone, may improve symptoms in some cases. Medications may also include:Anticholinesterase medications such as Neostigmine or Pyridostigmine.
  • 3, 4-diaminopyridine, which increase the release of acetylcholine from nerve cells.
Disclaimer: The above information is educational purpose. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition.DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.


Submit a Comment

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Cart Preview

Exposure to Blue Light May Help Decrease High Blood Pressure

Exposure to Blue Light May Help Decrease High Blood Pressure

A new study, recently published in the European Journal of Preventive Cardiology, suggests that exposure to blue light may help reduce high blood pressure. For the study, a team of researchers assessed whether blue light exposure could produce enough nitric oxide to...

[WpProQuiz 1]

Featured Products

The 5 Best Accessories for Sports Fans

It is very entertaining to be a sport fan. There is a big variety of sport games that are extremely interesting to follow. Moreover, it is always fun to anticipate the score and watch the enthusiasm live. One of the benefits of being sports fan is using different...

read more

Exercise May Serve as an Antidepressant

A new study of nearly 18,000 participants found that those with high fitness at middle age were significantly less likely to die from heart disease in later life, even if they were diagnosed with depression. Doctor's Tips: How to Stay Fit While Treating Depression Dr....

read more

MediGoo is attending the largest health/medical industry event in Düsseford, Germany. We welcome you to visit our stand at hall 15 booth E55. Welcome, hope to see you there 15E55.