Myasthenia Gravis

Myasthenia gravis is an incurable autoimmune disease that affects the muscles and the nerves that control them. It occurs when the parts of the immune system that normally attack bacteria and viruses (antibodies) accidentally attack the connection between the nerve and muscle, also known as the neuromuscular junction. This causes muscle weakness that can become severe enough to interfere with breathing and swallowing saliva or food, resulting in food or saliva going into your airway. Serious complications like these can result in injury or even death if left untreated.

Myasthenia gravis happens more often in young women (under 40) and older men (over 60), but can impact anyone at any age. For pregnant women with the disease, it is very important to follow your doctor’s recommendations for prenatal care. Babies born to mothers with myasthenia gravis usually do not get the disease but may suffer weakness for a few weeks following birth.

The most-common and milder symptoms of myasthenia gravis are:

• Being overly tired
• Drooping eyes and head
• Double vision or difficulty holding a steady gaze
• Trouble talking or hoarseness
• Facial paralysis
• Difficulty chewing, frequent gagging, drooling, or choking on food
• Trouble climbing stairs, lifting things, or standing up from a seated position

Symptoms may get worse as the day goes on or after:

• Strenuous physical activity (for the large muscles
• Eating (for chewing/swallowing muscles)
• Reading (for the eye muscles)

Mild symptoms may get better with rest. Severe symptoms include having trouble breathing and not being able to swallow. This becomes more likely when rest fails to resolve mild symptoms.

Call your doctor If you experience:

• Symptoms that do not resolve with rest
• Severe muscle weakness
• Difficulty breathing or swallowing that is worse than normal

If you have trouble breathing or choke badly, you might need to call 911 and go directly to the emergency room.

With myasthenia gravis, antibodies in the immune system block the production of a chemical in the body called acetylcholine, which is released by nerve endings to activate muscles, creating movement. Blocking this chemical causes weakness.

The disease can result from a tumor in the thymus (an important immune system organ located in the neck that produces a key type of white blood cell).

Risk factors for myasthenia gravis include having a personal or family history of autoimmune diseases. Men over 60 and women under 40 are at higher risk. Additionally, having myasthenia gravis increases the risk of having other autoimmune diseases like rheumatoid arthritis or lupus.

Your doctor will ask you about your symptoms and perform a physical examination to check for muscle weakness, reflexes, and sensation (what you can feel).

You will likely have some blood work and other tests. More blood work might be ordered to look for signs that the immune system might be attacking the muscles.

Your doctor may order a nerve conduction study, called electromyography (or EMG), which is a test that checks the health of the muscles and the nerves that control the muscles.

There is no cure for myasthenia gravis, but people with the disease can experience long-term remission. Treatments include:

• Medicines and Procedures. Mild symptoms are treated with a medicine that increases your body’s levels of acetylcholine, which promotes muscle movement. More-severe or longer-lasting symptoms may be treated with medicines that help control the immune system.
  
  

  Severe episodes may be treated by a procedure that removes plasma (clear part of the blood) with the antibodies and replaces it with donated plasma or other fluids that don’t have these antibodies. An alternate procedure injects healthy antibodies into the plasma.

• Self-Care. Lifestyle changes can also help manage the symptoms of myasthenia gravis. These lifestyle changes can include:
• Scheduling frequent rest periods
• Eating small mouthfuls of soft foods and taking your time chewing
• Staying out of the heat and avoiding unprotected exposure to cold
• Trying to stay free of stress
• Using an eye patch when double vision is bothersome
• Getting lens prisms to improve vision
• Avoiding alcohol
• Washing your hands, avoiding people who are sick, and getting a yearly flu shot
• Asking your doctor if any medicines you take could make your condition worse
• Physical Therapy and Assistive Devices. Balance problems or muscle weakness that increase the risk of falling can be treated with physical therapy or by using a cane, walker, or other type of assistive equipment.
• Surgery. Removing the thymus (thymectomy) may stop symptoms for some time (a remission) or reduce the need to take medicines, especially when there is a tumor present. If you have eye problems, surgery to treat your eye muscles may be an option.

• The Myasthenia Gravis Foundation
• National Institute of Neurological Disorders and Stroke
• American Academy of Neurology
• Medline Plus