Myasthenia Gravis

Myasthenia gravis (MG) is the most common disease of the synapses (neuromuscular junctions). The synapse allows motor nerves to send signals to the muscle allowing it to contract and move. Myasthenia gravis occurs when the normal communication between the nerve and muscle breaks down. Our Mount Sinai specialists have extensive experience treating patients with MG and conducting research to discover better therapies.

Symptoms of Myasthenia Gravis

If you have been diagnosed with MG, you may experience generalized weakness, fatigue, drooping eyelids, double vision, difficulty chewing and swallowing, slurred speech, trouble walking, and shortness of breath. These symptoms can fluctuate throughout the day, worsen with hot weather, and improve with rest or sleep.

Causes of Myasthenia Gravis

Myasthenia gravis is an autoimmune disorder. Our immune systems produce antibodies that block the signals between the nerve and muscle. In normal conditions, the motor nerve sends a chemical signal the muscle, but certain antibodies can block these signals leading to muscle weakness.

Researchers believe that the thymus gland—a part of the immune system located beneath our breastbone—triggers or maintains production of these antibodies. It is important to have a computed tomography (CT) scan to detect or rule out a tumor of the thymus gland that sometimes occurs with myasthenia. If you have myasthenia gravis during pregnancy, there is a small chance that these antibodies may be passed on to your child, which would cause neonatal myasthenia gravis. Affected infants typically recover within a few months when treated promptly.

There are also rare hereditary forms of myasthenia called congenital myasthenic syndromes.

Treatments for Myasthenia Gravis

We have been involved in treatment of and research on myasthenia gravis since the 1950s. We have introduced many therapies for patients with myasthenia gravis over the years, such as the surgical removal of the thymus (thymectomy) as well as minimally invasive thymectomy.

We currently offer the following treatments for myasthenia gravis:

Oral medications: Steroids and other oral medications help suppress the immune system, and acetylcholinesterase inhibitors improve transmission through the synapses.

Thymectomy: This procedure to remove a malfunctioning thymus can help prevent the weakness caused by MG. Most of the work of the thymus is completed by birth, so its removal does not affect your immune system. You may also require a thymectomy if we detect a tumor inside the thymus gland.

Plasma Exchange (Plasmapheresis): This is a treatment similar to dialysis and can be effective as a short- or long-term therapy. This process enables us to remove damaging antibodies, and it can be administered on either an inpatient or outpatient basis.

Intravenous immunoglobulin infusion treatments: These therapies deliver properly functioning antibodies to counteract the effect of those that are harmful.