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Myasthenia gravis, or myasthenia gravis, is an autoimmune disease that causes progressive muscle weakness, is more common in women and usually starts between 20 and 40 years of age. Symptoms of myasthenia gravis may start suddenly, but they usually come on and gradually get worse.
The causes of myasthenia gravis are related to an alteration in the immune system that causes antibodies to attack certain structures that are fundamental for muscle control.
Myasthenia gravis does not have a definitive cure, but the treatment adapted to each case, with specific medicines and physical therapy exercises, can improve the quality of life.
The most common early symptoms of myasthenia gravis are:
- Weakness of eyelid and difficulty opening eyes or blinking;
- Weakness of eye muscles, leading to squint and double vision;
- Excessive muscle fatigue after exercise or physical exertion.
As the disease progresses, symptoms worsen and include:
- Weakness of the neck muscles that let the head hang forward or to the side;
- Difficulty climbing stairs, lifting arms, writing;
- Difficulty speaking and swallowing food;
- Weakness of arms and legs, which varies in intensity over hours or days.
In more severe episodes, respiratory muscles may still be compromised, a condition called myasthenic crisis, which is serious and can lead to death if not treated quickly in the hospital.
Normally, symptoms worsen with repeated use of the affected muscle, but it can also happen when exposed to heat, when under stress or anxiety, or when using anxiolytics or antibiotics.
How the diagnosis is made
Most of the time, the doctor suspects the diagnosis of myasthenia gravis by evaluating the symptoms, physical examination and studying the person's he alth history.
However, several tests can be used to rule out other problems and confirm myasthenia gravis. Some of these tests include electroneuromyography, MRI, CT scan, and blood tests.
What causes myasthenia gravis
Myasthenia gravis is caused by a change in the immune system that causes some antibodies to attack receptors present in the muscles. When this happens, the electrical message cannot pass correctly from the neurons to the muscle fibers and, therefore, the muscles do not contract, demonstrating the characteristic weakness of myasthenia.
How the treatment is done
There are several types of treatment that can improve a person's quality of life, depending on the symptoms. Some of the most commonly used forms include:
Medicines are the most used form of treatment because, in addition to being practical, they have excellent results. The most used types of medication are:
- Cholinesterase inhibitors, such as Pyridostigmine: improve the passage of electrical stimulus between neuron and muscle, improving muscle contraction and strength;
- Corticoids, such as Prednisone: decrease the effect of the immune system and, therefore, can reduce various types of symptoms. However, they cannot be used for a long time, as they can have various side effects;
- Immunosuppressants, such as Azathioprine or Cyclosporine: these drugs also decrease the functioning of the immune system, but are used in more severe cases, when symptoms do not improve with other drugs.
In addition to oral medications, the doctor may also indicate the use of intravenous medication, such as monoclonal antibodies, which decrease the amount of some defense cells in the body, improving the symptoms of myasthenia gravis.
Plasmapheresis is a therapy, similar to dialysis, in which blood is taken from the body and passed through a machine that removes excess antibodies that attack muscle receptors, facilitating the passage of the electrical signal between neurons and muscle fibers.
Although it is a treatment with good results, it also has some he alth risks such as bleeding, muscle spasms and even severe allergic reactions.
Surgery is a rarer treatment, but it may be necessary when a tumor is identified in an organ of the immune system that is causing the production of antibodies that generate myasthenia gravis.
Motor and respiratory physiotherapy are also indicated in the treatment of myasthenia gravis with the aim of strengthening muscles, improving range of motion, breathing and preventing respiratory infections.