Myasthenia Gravis (MG) is an autoimmune disease where the body's defense system attacks the body itself. The antibodies which are supposed to attack foreign invaders work the other way around by attacking the cells, tissues, organs, etc. In the case of Myasthenia Gravis, it is the neuromuscular junction that is affected, thus impairing the transmission of nerve impulses.
Neuromuscular Transmission is affected because the enzyme acetylcholine that binds to acetylcholine receptors to create muscle contraction cannot do its function, because the receptors are destroyed by the antibodies.
The cause of MG is unknown and that is why it is sometimes mistaken as simple fatigue. Determining the disease will take a long time because numerous tests are given to ensure proper diagnosis.
- The very first symptom that can be noticed in the patient is ptosis or drooping of the eyelids because it is the eye muscles that are initially impaired.
- Facial muscles are also affected and this can be seen by changes of facial expression, impaired speech, double vision and difficulty in swallowing.
- Danger sets in if the symptoms are left untreated because generalized form of myasthenia may occur. That is, the weakness travels down to the chest muscles and will make the patient gasp for breath. Continuous shortness of breath indicates myasthenic crisis because there is no more ventilation. Prompt intervention is required or the patient may die from asphyxiation.
With the advancement of technology nowadays, several tests are already available to diagnose the disease.
- Physicians will conduct some tests to rule out simple fatigue and work-stress.
- If the weakness is unexplainable, the patient will undergo edrophonium test. Edrophonium Chloride is a medication that can temporarily alleviate the body weaknesses. If the patient is found to respond well to the medication, it can be concluded that he or she has MG.
- Another test that can be performed is nerve stimulation. Affected nerves in the area where there is weakness is stimulated repeatedly and if the electrical potential of the muscle cells do not respond well, it might indicate the presence of MG. For normal individuals, nerve stimulation that is done repeatedly increases the muscle action potential.
Once accurate diagnosis is achieved, several medications will be given to alleviate the symptoms and prevent medical emergency.
- Anticholinesterase agents are given to patients to improve muscle strength.
- Methotrexate is also given in combination with prednisone therapy to improve patient's condition.
- Immunosuppressive drugs are sometimes administered to lessen the production of antibodies that destroy the transmission of impulses in the neuromuscular junction.
Aside from medication, other treatments are available.
- Plasmapheresis is one example and it involves cleansing of the blood to take away the large number of antibodies circulating in it.
- Surgery is also employed for patients with thymus hyperplasia. The thymus gland is removed if a tumor has grown on it to halt large production of antibodies that attack the body system.