Research suggests that Lambert-Eaton myasthenic syndrome may be an autoimmune disorder. It usually begins in late adulthood, and the true incidence of the syndrome is not known.
Symptoms
Symptoms of Lambert-Eaton myasthenic syndrome develop slowly. They include:
- Weakness of the upper legs and upper arms that gets worse over time
- Dry mouth, eyes, or skin
- Eyelid drooping or double vision (25% of individuals)
Individuals with Lambert-Eaton myasthenic syndrome who are long-term smokers are at high risk for cancer, especially small cell lung cancer. Individuals who develop the syndrome at an older age also have a greater risk of cancer. A cancerous tumor may increase the amount of muscle weakness, as well as cause fatigue and weight loss.
Diagnosis
Physical examination will provide evidence of muscle weakness of the upper
legs and upper arms. For example, the individual with Lambert-Eaton may
have a waddling gait and have difficulty raising his arms. A blood test
for specific autoimmune antibodies can be performed. Repetitive nerve
stimulation studies, which test the conduction of nerve impulses to
muscles, can help confirm the diagnosis and differentiate Lambert-Eaton
myasthenic syndrome from [link
url=http://http://rarediseases.about.com/cs/myastheniagravis/a/071901.htm]myasthenia
gravis[/link].
All individuals with Lambert-Eaton should be screened for cancer, particularly those people who are long-term smokers. A computed tomography (CT) scan of the chest, and possible a lung biopsy, are performed to look for lung tumors.
Treatment
If cancer is present, treatment should focus on cancer therapy. In some
cases, the muscle weakness of Lambert-Eaton will improve as the cancer
treatment progresses. In individuals with the syndrome but without cancer,
immunosuppressive drugs such as prednisone and azathioprine can be used
to reduce the autoimmune response and lessen symptoms.
Neuromuscular drugs can help improve muscle strength and reduce symptoms in some individuals with Lambert-Eaton. These drugs include pyridostigmine bromide (Mestinon), 3,4-diaminopyridine (DAP), and guanidine. Muscle weakness may increase with hot weather, use of hot tubs or hot showers, fever, or illness.
Information for this article was taken from:
Sanders, D. B. (2003). Lambert-Eaton myasthenic syndrome. eMedicine,
accessed at http://www.emedicine.com/neuro/topic181.htm
