Lambert-Eaton syndrome is a disorder in which faulty communication between nerves and muscles leads to muscle weakness.
Myasthenic syndrome; Eaton-Lambert syndrome; Lambert-Eaton myasthenic syndrome; LEMS
Lambert-Eaton syndrome is an autoimmune disorder. This means your immune system mistakenly targets healthy cells and tissues in the body. In this syndrome, antibodies produced by the immune system attack nerve cells. This makes nerves cells unable to release enough of a chemical called acetylcholine. This chemical transmits impulses between nerves and muscles.
The result is muscle weakness.
Symptoms may include:
- Weakness or loss of movement that can be more or less severe, including difficulty chewing, difficulty climbing stairs, difficulty lifting objects, difficulty talking, drooping of the head, and the need to use the hands to get up from a sitting or lying position
- Swallowing difficulty, gagging, or choking
- Vision changes, such as blurry vision, double vision, and problems keeping a steady gaze
Symptoms related to the autonomic nervous system usually occur, and include:
- Blood pressure changes
- Dizziness upon standing
- Dry mouth
Exams and Tests
A detailed medical history will be taken to determine risk factors, such as a history of certain cancers.
A physical examination shows:
- Decreased reflexes
- Possible loss of muscle tissue
- Weakness or paralysis that gets slightly better with activity
Tests to help diagnose and confirm the condition may include:
- Blood tests to look for the antibodies that attack the nerves
- Electromyography (EMG) to test the health of the muscle fibers
- Nerve conduction velocity (NCV) to test the speed of electrical activity along nerves
The main goals of treatment are to:
- Identify and treat any underlying disorders, such as lung cancer
- Give treatment to help with the weakness
A treatment called plasma exchange or plasmapheresis usually improves symptoms. This involves removing blood plasma from the body and replacing it with other proteins (such as albumin) or with donated plasma. This helps make sure that any harmful proteins (antibodies) 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 (although these are not very effective when given alone)
- 3, 4-diaminopyridine, which increases the release of acetylcholine from nerve cells
The symptoms of Lambert-Eaton syndrome may improve by treating the underlying disease, suppressing the immune system, or removing the antibodies. However, not everyone responds well to treatment.
- Difficulty breathing, including respiratory failure
- Difficulty swallowing
- Infections, such as pneumonia
- Injuries from falls and problems with coordination
When to Contact a Medical Professional
Call your health care provider if symptoms of this condition develop.
Meriggioli MN, Sanders DB. Disorders of neuromuscular transmission. In: Daroff RB, Fenichel GM, Jankovic J, Mazziotta JC, eds. Bradley's Neurology in Clinical Practice. 6th ed. Philadelphia, PA: Elsevier Saunders; 2012:chap 78.
Vincent A, Evoli A. Disorders of neuromuscular transmission. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 430.