Myasthenia gravis is a muscle weakness in the body that is expressed in a variety of degrees. Contrary to common thinking, this chronic autoimmune disease does not shorten life expectancy. It is a neuromuscular disease that can be eased by periods of frequent rest and flares up with activity. The muscles that control the facial expressions, breathing, chewing, neck, extremities, the eyes, and swallowing are most often affected.
The causes of myasthenia gravis are due to an abnormality of nerve pathways to the muscles. When the pathways running from the nerves to the muscles are disturbed, the result is muscle weakness. In a person who does not suffer from myasthenia gravis, acetylcholine, a neurotransmitter, is released from the nerve endings after the impulses make their way down the nerve.
This substance then goes through the neuromuscular connection site and adheres itself to the acetylcholine receptors. This process is then activated and produces a contraction of the muscles. In a person afflicted with myasthenia gravis, the acetylcholine receptors are destroyed, blocked, or altered due to the antibodies and thus prevents the contraction of the muscle. The immune system of a person suffering from myasthenia gravis literally attacks itself.
The basic cause of myasthenia gravis lies in the thymus gland, which is beneath the breastbone in the top portion of the chest. The thymus affects the formation of the immune system. The thymus gland starts as rather large in an infant. It then grows until the early teenage years, then decreases in size, and becomes fat as you age into adulthood.
An abnormal thymus gland is responsible for myasthenia gravis. The exact reasons why this happens have not been fully discovered. A thymoma, which is a thymus tumor, is another possible cause of myasthenia gravis. This tumor develops from the epithelial cells of the thymus gland.
Myasthenia gravis can occur at any age, but more commonly affects men in middle age and upwards, and women that are in their 20s.
Treatment for myasthenia gravis is accomplished by symptom relief with medications. Medications that are used are corticosteroids, immunosuppressants, and/or cholinesterase inhibitors. Therapy, similar to dialysis, can also be an option.
However, this will only relieve symptoms for a few weeks. Antibody therapy, known as intravenous immune globulin, is another option. This option, however, will only be effective for a couple of months. If myasthenia gravis is caused due to a tumor then surgical treatment, the removal of the thymus gland is indicated.
Your physician will be your best resource in deciding the appropriate course of treatment for your particular circumstance. Always consult with your physician regarding the best treatment for your health needs.
RESOURCES
MayoClinic: Myasthenia Gravis
National Institute of Neurological Disorders and stroke: Myasthenia Gravis Fact Sheet
Autralian Myasthenic Association: What Causes Myasthenia gravis
NHS Choices: Causes of Myasthenia Gravis