Myasthenia Gravis (MG) is a chronic autoimmune neuromuscular disease characterized by fluctuating muscle weakness and fatigability. One of the distinguishing factors is ptosis, or drooping of the upper eyelid. It is most frequently caused by circulating antibodies that either block or destroy receptors that facilitate muscular function.
Scientists theorize that these antibodies are produced in the hyperplastic germinal centers in the thymus gland. The antibodies get rid of the receptor sites faster than the body can form new ones. With the lack of sites, the neurotransmitter, acetylcholine, cannot perform its function (activating muscles) effectively.
Treatment for Myasthenia Gravis
Standard treatment for MG usually begins with medication, typically an acetylcholinesterase inhibitor. It acts to prolong the life of the neurotransmitter (acetylcholine) and provide temporary symptomatic relief of muscle weakness. Immunosuppressive drugs are often added to the regimen to reduce the autoimmune response. Unfortunately, over time, most drug regimens lose their effectiveness and may cause severe side effects.
The surgical management of MG has a long track record of success, dating back to 1941 at Johns Hopkins and first performed by Dr. Alfred Blalock. The surgical treatment for MG involves the removal of the thymus gland (thymectomy). The thymus gland plays a major role in developing the immune system during infancy and childhood. As an adult, however, there is very little thymic function; the gland actually reduces in size and becomes replaced by fatty tissue. A portion of patients with MG has a tumor on the thymus gland. This tumor is known as a thymoma, and can either be benign or malignant.
The thymus gland in an adult can be removed with no ill effects. Successful removal of the entire gland has shown to be more than 95% effective in improvement of the disease. Studies show that approximately 80% of patients experience complete resolution of symptoms after surgery with more than half able to come off all medications.
Patients undergoing a VATS (video assisted thoracic surgery) thymectomy report to the hospital on the morning of surgery and typically go home the following day. Full recovery is usually achieved within two weeks of the procedure.