How is myasthenia gravis treatment developed? – Harvard Health Blog
Myasthenia gravis (MG) – a medical term referred to as “severe muscle weakness” – is a rare neuromuscular disease. In the United States, approximately 30,000 to 60,000 people have this disorder, which affects people of all ages, genders, and ethnicities. Recently updated consensus guidelines we have improved our knowledge of different forms of myasthenia gravis and approaches to treatment.
What are the symptoms of myasthenia gravis?
Myasthenia gravis it impairs the transmission of signals from nerves to muscles at a site called the neuromuscular junction (NMJ), where the nerves interact with the muscle. This causes temporary muscle weakness in use. When the affected muscle or muscle group rests, it regains strength.
Throughout the day, your body uses a variety of muscle groups over and over again; this is true even if you are not particularly active. Due to the weakness associated with use in myasthenia gravis muscle groups, repeated activity of the affected muscles exacerbates the weakness. Weakness improves with rest so that the activity can be repeated as the activity progresses again.
Both affected and muscle groups can vary from person to person. Often, the muscles around the eyes are damaged. Falling eyelids and double vision are common symptoms. People may complain that they are fine when they wake up, but as the day goes on, their eyelids fall out. After a nap, they have their eyes wide open. They might start to see well while driving, but as they progress they develop double vision. They can’t eat a whole bagel because their jaws get tired after a while, they can eat pasta without any problems. Their arms get tired in the middle of a burst of dry hair and they have to stop, let their arms down for a while and move on.
What causes myasthenia gravis?
Various disorders as well as some medications can affect the neuromuscular bond. Here I will pay special attention to the form of myasthenia gravis called MG autoimmune. If you have autoimmune MG, your immune system produces antibodies that improperly attack certain proteins at the intersection. One of these proteins is the acetylcholine receptor (AchR), which is located in the muscle membrane at the junction.
This special protein binds to a chemical messenger called acetylcholine (Ach). Ach releases the terminal nerve when an electrical signal reaches it, contracting a muscle. But AchR antibodies destroy and reduce the amount of AchR, so the impulses from the nerves to the muscle are damaged and muscle weakness is achieved.
Antibodies can also be directed against other important proteins in the neuromuscular binding that would normally help maintain AchR proteins, resulting in the same end result. These two proteins that antibodies can target are muscle-specific kinase (MuSK) and 4 lipoprotein-bound proteins (LRP-4).
How is myasthenia gravis treated?
Treatment is aimed primarily at improving symptoms. The most commonly used drug is pyridostigmine. Pyridostigmine prolongs the time that Ach maintains its neuromuscular binding, thus making it more likely to bind to a reduced number of AchR receptors.
In addition, people with autoimmune MG receive treatment to eliminate an abnormal immune response under the disease. Many approaches are used to achieve this.
In 2016, the Myasthenia Gravis Foundation of America (MGFA) convened an international working group of neuromuscular specialists to develop treatment orientation. This panel updated this guideline in 2020, and added it new recommendations to perform a surgical procedure called thymectomy; MG eye treatment (limited to MG around the eye muscles); and the use of three medications to counteract the abnormal immune response: methotrexate, rituximab, and eculizumab.
- Thymectomy Located in the upper chest between the lungs, the thymus gland is thought to play a role in the MG autoimmune response. During a thymectomy, the gland is surgically removed. A randomized controlled trial has shown that thymectomy is effective in reducing the dose of prednisone (an immunosuppressive medication) required by a particular group of people with MG.
- Methotrexate does not reduce the need for prednisone a randomized controlled trial Among people with MG with AchR antibodies.
- Rituximab it is helpful for people with MuSK MG, according to the consensus report, but less so for those with AchR MG.
- Eculizumab the new drug is the new mechanism of action he has found improve physical function in people with MG who did not respond to previous treatments. Vaccination against meningococcus (a group of bacteria that causes meningitis) is required before treatment. Eculizumab is given as an injection into a vein every five weeks, then every two weeks after this initial period.
Many people with autoimmune MG need long-term immunosuppressive treatment to help them manage their disorder. The best treatment options are decided by controlling the course of the disease and responding to the treatments over time.
MG treatment is complex. Your neurology team will consider several factors, including age, gender, pregnancy and breastfeeding, and other illnesses (such as high blood pressure, diabetes, or liver disease). They will also take into account the presence and type of MG antibodies, the type of MG you are experiencing (MG visual or generalized MG, which affects more than just the eyes) and your preferences and values.
As new information about treatment becomes available, discuss treatment changes with your neurologist to ensure that they match the goals of improving your treatment options and your personal values and priorities.