Myasthenia Gravis

Myasthenia gravis (MG) is a condition that affects the way the nerves and muscles of the body communicate. In MG, the muscles get weaker throughout the day. The muscles affected are those that help our body move such as muscles that help us walk, breathe, talk, and eat. The muscle weakness usually gets worse after periods of activity and then improves after periods of rest. Because weakness is a common symptom of many other disorders, the diagnosis of MG is often missed or delayed.

What causes myasthenia gravis?

MG is an autoimmune condition, meaning that the body’s immune system is attacking the body for no reason. While the cause of MG is unknown, it is thought that the thymus gland of the body has a role in this process. Myasthenia gravis affects both men and women and occurs across all racial and ethnic groups. It most commonly impacts young adult women (under 40) and older men (over 60), but it can occur at any age, including in childhood. MG is not inherited nor is it contagious. Occasionally, the disease may occur in more than one member of the same family.

What are the symptoms of myasthenia gravis?

The most common muscles that are affected in MG are those that control eye and eyelid movement, facial expression, and swallowing. In many cases, the first noticeable symptom is weakness of the eye muscles which can cause double vision or a droopy eyelid. In other people, difficulty swallowing and slurred speech may be the first signs. The degree of muscle weakness and the muscles involved varies greatly from person to person. More serious symptoms include shortness of breath and generalized weakness.

How is myasthenia gravis diagnosed?

The first step in the diagnosis of MG is a careful medical history and physical examination. A neurological examination will check muscle strength and tone, coordination, sense of touch, and impairment of eye movements. Other tests including an injection of a medicine, blood antibody blood testing, nerve function testing, lung function testing, and/or MRI may be performed.

What is the treatment for myasthenia gravis?

There are several treatment options available, and MG generally can be controlled. The therapies help reduce and improve muscle weakness. The most common treatment involves medications that help the nerves and muscles of the body communicate better.  Other medications can be used to slow the body’s immune system. These drugs can cause significant side effects, however, and must be carefully monitored by a physician.  Finally, a surgery can be performed to remove the thymus gland if it is abnormal.