Myasthenia gravis is an autoimmune disease that affects the neuromuscular junction, the contact point between the nerves and muscles. Antibodies block the receptors of the carrier molecule of this information, acetylcholine. Thus, they do not react properly and quickly dwindle. We can distinguish myasthenia gravis and myasthenic syndromes that present themselves in a way that is similar to myasthenia gravis, but are due to other causes: Lambert-Eaton syndrome due to antibodies preventing the transmission of information, botulism due to the action a toxin at the transmission area, or certain drugs or genetic causes. Myasthenia itself appears at any age, but most commonly affects young women.
Myasthenia gravis occurs as follows:
- onset of fatigue, usually after an unusually non-intense effort;
- tiredness increases during the day and is severe at night. It is reduced by rest and cold;
- a drooping of the upper eyelid called ptosis;
- disturbances of vision, such as double vision;
- difficulty chewing and swallowing, and even breathing.
The diagnosis of myasthenia gravis is made through questioning and physical exams to detect the abnormality. A doctor will notice a decrease in muscle strength in the presence of an abnormally low physical effort. A simple test consists of applying ice to the drooping eyelid: an immediate reduction of ptosis is very evocative. A definitive diagnosis is made by another test using a molecule whose effects oppose the breakdown of acetylcholine, which is positive if symptoms improve. Electromyography, studying the spontaneous and stimulated activity of a muscle, is also possible. Finally, the search for the presence of antibodies confirms the diagnosis.
Myasthenia gravis is not a disease that can be permanently cured. However, it can be controlled with appropriate treatments such as anticholinesterase drugs, which reduce the breakdown of acetylcholine. The use of immunosuppressive therapy is also possible. In case of major crisis of myasthenia gravis, hospitalization is essential to prevent complications of the disease that can be fatal. The patient should also be educated on the disease and receive a list of drugs that should not be taken.