Myasthenia gravis is an autoimmune disorder that affects the neuromuscular junction—the connection between nerve cells and muscles. When a person has myasthenia gravis, the body’s immune system attacks and impairs receptors for a neurotransmitter called acetylcholine. As a result, nerves cannot transmit signals to muscles, and a person will experience fluctuating muscle weakness.
While the condition is different for every person, weakness commonly occurs in the muscles that support movement in the eyes, face, throat, neck, and limbs. The disorder can affect vision, swallowing, speech, and facial expressions. It is also associated with weakness in the neck and limbs as well as fatigue.
What causes myasthenia gravis?
The exact cause of myasthenia gravis is not known. Only a small percentage of people with the condition have a family history of myasthenia gravis or another autoimmune disorder. The condition can affect individuals of any age, but onset most commonly occurs in females under age 40 and males over age 50. The condition occurs more frequently in females.
There is no cure for myasthenia gravis, but there are numerous therapies that are used to manage symptoms and improve quality of life for people living with the condition.
Medications for myasthenia gravis
Medications are a mainstay of treatment for myasthenia gravis. The type of medication used will depend on a person’s symptoms, the results of antibody testing, their medical history and overall health, and how they responded to previous treatments. The medications used can be divided into a few broad categories:
- Acetylcholinesterase inhibitors. Also called cholinesterase inhibitors. These drugs help block the normal breakdown of acetylcholine and are used to temporarily relieve symptoms. This means more acetylcholine will be available for use at the neuromuscular junction. This helps improve communication between the nervous system and muscles.
- Immunosuppressive drugs. Glucocorticoids (a type of steroid) and other immunosuppressive drugs are typically used when acetylcholine inhibitors are not effective. They are also used to help get symptoms under control during a flare. Because these drugs suppress the immune system, careful monitoring by a healthcare provider is required.
- Biologic therapies. These drugs also work by suppressing the immune system—but instead of suppressing all immune system activity, biologic therapies target and act on specific proteins or pathways in the immune system. As with other drugs that act on the immune system, this approach requires careful monitoring by a healthcare provider.
The results of antibody testing are a key component of determining what medications to use. Antibody testing refers to blood tests that look for antibodies that are produced by the immune system when a person has myasthenia gravis. For example, biologic therapies may only be used when a person tests positive for an antibody called acetylcholine receptor (AChR) antibody. This antibody is found in most cases of myasthenia gravis.
Research into treatment for myasthenia gravis is ongoing, and several new medications have become FDA-approved in recent years. Additional medications and combinations of medications are under development.
Other treatments and therapies
In addition to medications, treatment of myasthenia gravis can also include surgery to remove the thymus gland. Plasma exchange and intravenous infusions of immunoglobulin (healthy antibodies collected from donors) can be used to get symptoms under control during exacerbations, or while waiting for other medications to take effect.
Avoiding anything that can exacerbate symptoms or cause complications is another key aspect of treatment. Ask your healthcare providers for a list of medications and other factors that can lead to an exacerbation of symptoms. Always tell your healthcare providers about any and all medications you take, including prescriptions, over-the-counter medications, and supplements.
