Lambert Eaton myasthenic syndrome (LEMS) is a disorder of the neuromuscular junction. The neuromuscular junction is the site where nerve cells meet muscle cells and help activate the muscles. This syndrome occurs when antibodies interfere with electrical impulses between the nerve and muscle cells. It may be associated with other autoimmune diseases, or more commonly coincide with or precede a diagnosis of cancer such as small cell lung cancer. Symptoms may include muscle weakness, a tingling sensation in the affected areas, fatigue, and dry mouth. Treatment of an underlying disorder or cancer is the first priority of treatment.

In instances where LEMS is associated with cancer, the cause may be related to the body’s attempt to fight the cancer and accidental attack of nerve fiber endings, especially the voltage-gated calcium channels found there. The trigger for the cases not associated with cancer is unknown.

The answer to this question is complex. While the condition is not known to follow a specific pattern of inheritance, there appears to be a genetic predisposition to autoimmune diseases in general. Families with a history of Lambert Eaton myasthenic syndrome may benefit from consulting with a genetics professional.

• Difficulty climbing stairs
• Difficulty lifting objects
• Need to use hands to arise from sitting or lying positions
• Difficulty talking
• Difficulty chewing
• Drooping head
• Swallowing difficulty, gagging, or choking

Vision issues may additionally occur including:

• Blurry vision
• Double vision
• Difficulty maintaining a steady gaze

Other symptoms may include blood pressure changes, dizziness upon rising, and dry mouth.

Medications and therapies that may be used to treat Lambert-Eaton myasthenic syndrome include: 3,4-diaminopyridine (enhances acetylcholine release), anticholinesterase agents (e.g., Pyridostigmine), plasma exchange (where blood plasma is removed and replaced with fluid, protein, or donated plasma), intravenous immunoglobulins (IVIG), and medications that suppress the immune system (e.g., prednisone, azathioprine).

The prognosis for individuals with LEMS varies and is largely dependent on whether there is an underlying cancer or autoimmune disease. The symptoms of LEMS may improve with treatment; however, not all people respond well to treatment and in most instances, symptoms continue to progress over time.

Medications that act upon the transmission of impulses between nerve and muscle cells that may worsen symptoms of LEMS, include muscle relaxants (such as succinylcholine) that may be used during anesthesia as well as the following drugs:

• Some antibiotics (e.g. aminoglycosides, fluoroquinolones, and erythromycin)
• Iodinated contrast agents (used in CT scans, plain XR and X-rayangiography)
• Beta-blockers
• Calcium channel blockers
• Lidocaine
• Medications used to treat cardiac arrhythmias (e.g. bretylium, quinidine, quinine, procainamide)