Myasthenia Gravis (MG)

MG is most common in women younger than 40 and men older than 60. Initial symptoms of MG often occur suddenly, causing muscle weakness while active and improving after rest. The intensity of weakness often changes from day to day although most people feel strongest at the start of the day and weakest at the end of the day. 

The Houston Methodist team reviews your symptoms and medical history and will conduct a physical examination that may include a neurological examination to evaluate reflexes, muscle strength and tone, sense of touch and sight, coordination and balance. We will also discover if your muscle fatigue improves with rest.  

Other symptoms of MG include: 

• Double vision 
• Drooping eyelids 
• Difficulty speaking, chewing or swallowing 
• Difficulty moving the neck or holding up the head 
• Limb weakness 
• Trouble walking 
• Your thyroid may be over- or underactive, causing difficulty with extreme temperatures or weight control.  
• Autoimmune conditions like rheumatoid arthritis or lupus are more prevalent in someone with myasthenia gravis. 

A correct diagnosis also includes these other tests:

• A sudden but temporary improvement in strength after an Injection with a chemical that breaks down acetylcholine is a sign of MG. 
• If a droopy eyelid improves after holding a bag of ice on it may show MG.  
• Blood analysis can find an abnormal level of antibodies or MG-specific antibodies. 
• Measuring your nerve's ability to send signals to your muscle using EMG is performed several times to see if the signal decreases with fatigue. 
• EMG will also measure the electrical activity of a single muscle fiber. 
• In rare instances, MG affects muscles in your respiratory system, causing shortness of breath or more serious breathing problems. A pulmonary function test helps determine if MG affects breathing. 
• Imaging scans can detect tumors or other abnormalities. In about 15% of cases, MG causes a non-cancerous tumor in the thymus gland which may require surgical removal.

A combination of treatments personalized for your condition — medications, therapy, surgery and lifestyle changes — can relieve your MG symptoms and some patients may achieve remission. 

• Medications may include cholinesterase inhibitors to increase communication between nerves and muscles, corticosteroids to limit antibody production and immunosuppressing drugs to alter your immune system response. 
• Plasmapheresis filter antibodies out of your blood and intravenous immunoglobulin adds normal antibodies into your blood. 
• Surgery to remove your thymus gland may improve your symptoms over time.

A variety of at home strategies can help improve your enjoyment of life depending on your symptoms. They include eating several smaller meals a day when your strength is good, eating softer foods that require less chewing, installing grab bars in your home to reduce falling mishaps, using power tools and appliances instead of doing tasks by hand, wearing an eye patch to relieve double vision and planning your errands and chores when you feel stronger.