How is myasthenia gravis treated?

The treatment of Myasthenia Gravis (MG) is divided into acute and chronic stages.  Most patients with MG require daily, maintenance therapy and during exacerbations (i.e. acute worsening of symptoms) may require additional treatments.

Typically, treatment of MG involves a combination of the listed treatments.

Pyridostigmine and neostigmine are a class of medications called acetylcholinesterase inhibitors, typically taken every 4-6 hours, which treat just the symptoms associated with MG.  As they are symptomatic treatments, they do not alter the long term course of the disease.

Steroids:  The common one used is prednisone.  It suppresses the immune system, can cause worsening of symptoms within the first 48 hours, and is a very effective disease modifying treatment for MG.  It's use is limited by side effects.

Immunosuppressants (examples include azathioprine, mycophenolate mofetil, cyclosporin A, and cyclophosphamide) as their name implies suppress the immune system thus improving the course of the disease and providing for long term control of the symptoms of MG.  Immunosuppressants are often used in conjunction with pyridostigmine and low dose steroids.  They are used to minimize the dose of steroids necessary for control of symptoms, and thus minimize steroid side effects, however do come with their own side effects.

IVIG (intravenous immunoglobulin) is administered as an IV medication over 3-5 days and commonly used to treat exacerbations of MG symptoms parrticularly in the hospital setting.  IVIG is thought to work by removing the antibodies that cause MG.

Plasmaphoresis is also used to treat exacerbations and works by filtering the blood and removing the antibodies that cause MG. 
   

Today, myasthenia gravis can be controlled. There are several therapies available to help reduce and improve muscle weakness. Medications used to treat the disorder include anticholinesterase agents, such as neostigmine and pyridostigmine, which help improve neuromuscular transmission and increase muscle strength. Immunosuppressive drugs, such as prednisone, cyclosporine, and azathioprine, may also be used. These medications improve muscle strength by suppressing the production of abnormal antibodies. They must be used with careful medical follow-up because they may cause major side effects.

Thymectomy, the surgical removal of the thymus gland (which often is abnormal in myasthenia gravis patients), reduces symptoms in more than 70 percent of patients without a thymoma and may cure some individuals, possibly by rebalancing the immune system. Other therapies used to treat myasthenia gravis include plasmapheresis, a procedure in which abnormal antibodies are removed from the blood, and high-dose intravenous immune globulin, which temporarily modifies the immune system and provides the body with normal antibodies from donated blood. These therapies may be used to help individuals during especially difficult periods of weakness. A neurologist will determine which treatment option is best for each individual, depending on the severity of the weakness, the muscles affected, and the individual's age and other associated medical problems.

This answer is based on source information from the National Institute of Neurological Disorders and Stroke.