Myasthenia gravis is an autoimmune disease that causes muscle weakness and complete muscle failure. There is no cure, but in some cases the symptoms subside on their own. If they do not, surgery is necessary.
Here you will find further information as well as a selection of specialists and centers for myasthenia gravis.
With an incidence of four to five patients per 100,000 people, myasthenia gravis is considered a rare disease. Most people who develop the condition are between the ages of 30 and 40. In the juvenile form, however, the first symptoms can appear as early as childhood or adolescence.
Myasthenia gravis is not a disease of the muscles themselves. It is a neurological disorder in which the transmission of signals between nerve cells and muscle cells is disrupted.
At the onset of the disease, those affected often notice a decrease in vision. They see double vision, especially as the day progresses and when they are tired. Due to fatigue of the upper eyelids, they can no longer open their eyes completely.
In about 90 percent of patients, the paralysis associated with this so-called ocular myasthenia spreads. This leads to
As a rule, the symptoms are more pronounced during exertion and in the evening than in the morning.
Myasthenia gravis | Source: Wikipedia / License: Creative Commons 2.0
After a period of rest, the symptoms appear to subside. As myasthenia gravis progresses further, the extremities are also affected by weakness and paralysis. The symptoms then manifest primarily in the arms.
Breathing is also impaired. Patients with severe symptoms may then only be able to sleep while sitting or may even require mechanical ventilation.
In particularly severe cases, a myasthenic crisis may develop. This life-threatening neurological emergency is characterized by
.
However, thanks to the therapeutic options available today, only about 10 percent of all myasthenia gravis patients experience such severe courses of the disease.
This neuromuscular transmission disorder—that is, the disruption of signal transmission between nerves and muscles—is caused by so-called autoantibodies. These antibodies attack the body’s own tissues. In myasthenia gravis, the autoantibodies target a part of the neuromuscular junction that is responsible for transmitting nerve signals from the nerves to the muscles.
In more than 85 percent of cases, the receptor for the neurotransmitter acetylcholine is affected. Acetylcholine is a neurotransmitter that transmits signals from nerves to muscles, causing muscle contraction and, consequently, movement.
If the receptor—that is, the binding site for this neurotransmitter—is blocked or destroyed by the antibodies, the muscles receive few or, in severe cases, no signals at all from the brain. As a result, the muscle responds only weakly or is even completely paralyzed.
How and why these autoantibodies develop has not yet been fully elucidated. However, researchers suspect a connection between myasthenia gravis and the thymus. This is an organ in which various immune cells are produced during the first years of life. In adulthood, this gland no longer performs any functions.
About 10 percent of all patients with myasthenia gravis have a tumor in the thymus gland. Furthermore, more than half of all patients show evidence of thymitis—that is, inflammation of the gland accompanied by increased activity.
Various factors can also influence the severity of symptoms. These include:
The diagnostic process begins with a review of the patient’s medical history (anamnesis). During this process, the doctor asks where exactly the muscle weakness occurs and how long the patient has been experiencing the symptoms.
If myasthenia gravis is suspected, the doctor may perform various tests. In the Simpson test, the patient must look upward for as long as possible while keeping their eyes wide open. Rapid fatigue of the eyelids indicates muscle weakness.
Furthermore, individual nerves are stimulated to confirm the diagnosis. A special device records the muscle’s response, revealing characteristic changes in muscle activity. Laboratory analysis can confirm the suspicion of myasthenia gravis.
For example, specific autoantibodies can be detected in a blood sample from the majority of patients. However, a laboratory examination of muscle tissue is significantly more reliable than a blood test. The changes in the thymus that are characteristic of the disease, on the other hand, can only be detected using computed tomography.
Myasthenia gravis is incurable, so treatment is aimed solely at alleviating symptoms.
In some patients, a spontaneous reduction in symptoms (remission) occurs within one year of the onset of the first symptoms. Remission may be temporary or permanent. In milder forms of myasthenia gravis, a “wait-and-see” approach is therefore taken initially.
If remission does not occur, removal of the thymus gland—known as a thymectomy—is the standard treatment. A tumor in the thymus gland also requires surgery.
To improve signal transmission from the nerves to the muscles, the doctor prescribes acetylcholinesterase inhibitors. These inhibitors prevent or slow the breakdown of the neurotransmitter. As a result, its levels are temporarily increased, allowing it to fulfill its role as a messenger substance.
Glucocorticoids are also available as a form of drug therapy. They can mitigate the effects of the antibodies.
In particularly severe cases, plasmapheresis may be beneficial. In this procedure, the blood of myasthenia gravis patients is cleansed of circulating antibodies. This can alleviate the symptoms, at least temporarily.
Myasthenia gravis follows a wide variety of courses, making it nearly impossible to provide a universal prognosis. The majority of patients respond well to appropriate treatment and can lead normal lives with only minor limitations.
However, if left untreated, the condition can lead to serious complications that may be fatal. Today, however, the disease is usually detected and treated early. As a result, such life-threatening courses of the disease are relatively rare.
Myasthenia gravis is a disorder of the nervous system. The appropriate specialist for patients with this condition is therefore a neurologist. After completing medical school, a neurologist undergoes five years of training to become a board-certified specialist in neurology.
Neurology is the medical specialty that deals with the nervous system.
