What is Myasthenia Gravis?
It is a most common primary disorder of neuromuscular transmission. The common cause is a problem in the immune system but may also result from genetic abnormalities. Patients present with muscle weakness.
How does Myasthenia Gravis occur?
Due to a problem in the immune system antibodies are formed that prevent transmission of signal from the nerves to the muscles. These antibodies block certain receptor at the junction of the nerves and muscles. (These receptors are stimulated by release a chemical called as acetyl choline which activates the muscles to function). As a result acetyl choline cannot attach to the receptors and the muscles get exhausted and then become weak.
What are the symptoms of Myasthenia Gravis?
Generally patients complain of specific muscle weakness such as difficulty in chewing, swallowing or talking. Later weakness in the hands, eyes, seeing can occur. Patients usually get weakness in the evenings in early stages of the disease and the first complaint may be of squint and double vision in the evenings. With progressive untreated disease, difficulty in breathing can occur due to weakness in the muscles of respiration.
How is the diagnosis of Myasthenia Gravis made?
Diagnosis of Myasthenia Gravis can be made by measuring the acetyl choline receptor antibody levels in the blood. Other tests that can be done are edrophonium chloride test which is performed by injecting this chemical into a vein. Improvement of muscle strength immediately after the injection provides strong support for the diagnosis. Other tests are Electromyography (EMG).
What is the treatment of Myasthenia Gravis?
Treatment goal must be individualized according to the severity of disease, the patient’s age and sex and the degree of functional impairment. The response to any form of treatment is difficult to assess because the severity of symptoms fluctuates. Spontaneous improvement, even remissions, occur without specific therapy, especially during the early stages of the disease. Common treatments include medications such as Anticholinesterase agents that prevent destruction of acetyl choline and allows it to remain at the nerve-muscle junction longer than usual, thymectomy (removal of thymus as thymus is one of the organs responsible for immune system and Myasthenia gravis is a problem due to immune dysfunction) and plasmapheresis (removal of antibodies from the blood but this procedure has results which are short lived as antibodies can form again)
How can Myasthenia Gravis be prevented?
There is no specific prevention procedure for Myasthenia Gravis at present.
What is the prognosis?
Although the treatments will not cure Myasthenia Gravis, most patients will have significant improvement in their muscle weakness
Last updated on 01-03-2007