What Is Myasthenia Gravis?: Causes, Symptoms, and Treatments‌

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Have you felt weakness in your muscles that gets worse throughout the day? Do you experience blurry or double vision? Have you or your loved ones noticed that your eyelids have been drooping? If so, you may have something called myasthenia gravis. So, what is myasthenia gravis? Myasthenia gravis is a condition that causes muscle weakness, and treatments for this condition allow people affected by it to lead normal lives. Read on to learn more about the cause, signs, symptoms, diagnosis, and treatment of myasthenia gravis.

What Is Myasthenia Gravis, and What Causes it?

Myasthenia gravis is an autoimmune condition where proteins in the blood called antibodies attack your muscles so that they receive less nerve signaling and become weak. This muscle weakness tends to get worse after activity but improves after resting. Certain muscles of the body are more likely to be affected by this condition, including the muscles that control the eyes, eyelids, facial expressions, chewing, talking, and swallowing.

Who Is Affected by Myasthenia Gravis?

Myasthenia gravis affects people of all ethnic backgrounds and ages. However, it commonly affects females under 40 and males over 60. Although rare, myasthenia gravis can occur in babies. This condition is called neonatal myasthenia gravis, which happens when mothers who have myasthenia gravis pass antibodies on to their babies during pregnancy. Babies usually recover from neonatal myasthenia gravis 2 to 3 months after birth.

Signs and Symptoms

If you have myasthenia gravis, you may have some of the following signs and symptoms:

Weakness of eye muscles
Eyelid drooping
Blurred or double vision
Changes in normal facial expression
Difficulty chewing and/or swallowing
Shortness of breath
Difficulty speaking
Difficulty walking
Weakness in the arms, hands, fingers, legs, or neck

Myasthenia gravis sometimes may worsen into a myasthenic crisis. This is a medical emergency where the muscles that control breathing become so weak that the person can no longer breathe on their own. A myasthenic crisis can be triggered by many things, including infection, stress, surgery, or a bad reaction to a medication.

The thymus gland is part of the immune system and produces white blood cells called lymphocytes. Many adults with myasthenia gravis have an enlarged thymus gland, which often results in lymphocyte clusters that may develop into thymomas (thymus gland tumors). Thymomas are usually harmless, but they can sometimes become cancerous.

Diagnostic Tests for Myasthenia Gravis

Doctors use several tests to diagnose myasthenia gravis including:

Physical/neurological exam: A doctor will ask you about your symptoms and medical history and perform a physical exam. The doctor will pay special attention to your muscle strength, coordination, sense of touch, and eye movements.
Edrophonium test: In this test, a drug (edrophonium chloride) is given to you to test eye muscle strength.
Blood test: People with myasthenia gravis may have certain antibodies that can be detected in their blood.
Electrodiagnostics: These diagnostic tests use small pulses of electricity to stimulate a person’s nerves and tire specific muscles so that a doctor can evaluate how well they are working. Myasthenia gravis causes muscles to be less responsive to this stimulation. Another more specific electrodiagnostic test, called a single-fiber electromyography (EMG), uses an electrode to measure the electrical activity between a person’s brain and their muscles.
Imaging: Doctors use computed tomography (CT) or magnetic resonance imaging (MRI) to detect the presence of a thymoma.
Pulmonary function tests (PFTs): PFTs show how well your lungs are working. Doctors use it to predict a myasthenic crisis.

Mild cases of myasthenia gravis are difficult to diagnose because muscle weakness is a common symptom in many disorders.

Treatments and Procedures

There are many treatments and procedures that can manage symptoms of myasthenia gravis. These include:

Thymectomy: This procedure is the surgical removal of the thymus gland. It often reduces symptoms or even cures myasthenia gravis in many people.
Monoclonal antibody: Synthetic antibodies, like eculizumab, can treat myasthenia gravis.
Medications: Drugs like pyridostigmine prevent the breakdown of a brain chemical called acetylcholine. Acetylcholine influences muscle movement, so when more of it is available, muscle movement improves. Other medications like prednisone, azathioprine, mycophenolate mofetil, and tacrolimus suppress the immune system to prevent the abnormal production of antibodies associated with myasthenia gravis.
Plasmapheresis: This procedure removes harmful antibodies that attack the muscles from the blood. The effects only last a few weeks, so plasmapheresis is typically only used in severe cases of myasthenia gravis.
Intravenous immunoglobulin (IVIg): IVIg is an injection of antibodies from healthy donors. These antibodies bind to the harmful antibodies that attack the muscles and remove them from circulation. This treatment can also be used in severe cases of myasthenia gravis.

Next Steps

People with myasthenia gravis can lead normal lives when they make lifestyle changes and receive treatment. These lifestyle changes can help you manage your symptoms:

Adjust your eating habits: Avoid foods that require a lot of chewing. Also, take your time chewing your food. Eating several small meals throughout the day may be easier than eating a few big meals.
Take precautions at home: Install grab bars or railings in your home, such as in the bathtub or next to the steps, for support. Keep your floors clear of all objects. Outside the home, clear sidewalks and driveways of any debris that may cause you to trip.
Use electric appliances: Use electric toothbrushes, electric can openers, and other electric tools to make carrying out tasks easier.
Wear an eye patch: Wearing an eye patch can help with double vision. If needed, wear one while writing, reading, or watching television. Switch eyes every once in a while to avoid eye strain.
Plan: If you have things to do, plan to do them when you think you’ll have the most energy.

If you feel you might have myasthenia gravis, tell your doctor about your symptoms and ask them for more information. They’ll let you know which treatments are most appropriate for you.

Resource Links:

“Acetylcholinesterase Inhibitors in Myasthenic Crisis: A Systematic Review of Observational Studies” via Neurocrit Care.
“Myasthenia Gravis Fact Sheet” via NINDS.
“Myasthenia Gravis” via Mayo Clinic.
“Thymoma and Thymic Carcinoma” via Cleveland Clinic.