Myasthenia Gravis Awareness

June is Myasthenia Gravis awareness month. This disorder continues to be underdiagnosed due to the main symptom which is weakness. This symptom can be attributed to many other disorders. Bringing awareness to Myasthenia Gravis may lead to earlier diagnosis and less interruption to the lives of those who live with it.

What is Myasthenia Gravis and who gets it?

Myasthenia Gravis comes from the Greek and Latin words meaning "grave muscular weakness." The most common form of myasthenia gravis is a chronic autoimmune neuromuscular disorder. The main symptom is fluctuating weakness of the voluntary muscle groups in the body.

In myasthenia gravis the immune system makes antibodies that destroy or block receptor sites in the muscles. These receptor sites are at the junction between the nerve ending and the muscle. Nerve impulses travel from the brain to these junctions releasing a chemical. When enough of the chemical is present, this is what makes the muscle contract.

Myasthenia gravis can occur at any age in both men and women. The most common age for women is between the ages of 20 and 40 and between 50 and 70 for men. It affects approximately 36,000 to 60,000 people in the United States.

What are the symptoms of Myasthenia Gravis?

The most common symptoms of myasthenia gravis are a drooping eyelid, blurred or double vision, slurred speech, difficulty chewing or swallowing, weakness in arms and legs, chronic muscle fatigue and for some, difficulty breathing.

The weakness will often increase with activity and improve when resting. Symptoms vary from person to person and not all people will have the same symptoms. Symptoms may fluctuate throughout the day. Because of the nature of the symptoms, myasthenia gravis is difficult to diagnose in the beginning.

How is Myasthenia Gravis diagnosed?

Myasthenia gravis is diagnosed by reviewing the medical history, conducting physical and neurological examinations. If the doctor suspects the patient may have myasthenia gravis, several tests can be done to confirm the diagnosis.

There are two blood tests that can be done to help confirm the diagnosis of myasthenia gravis. The first is a test called Acetylcholine Receptor Antibody test. In 85% of patients with myasthenia gravis, they carry this antibody.

For the other 15% of patients, there is the Anti-MuSK Antibody blood test. For people who test negative on the Receptor Antibody test, they will usually test positive on this one. People with ocular or eyes forms of myasthenia gravis will not have these antibodies in their blood.

Another test is the IV injection of a drug which contains a chemical that can improve muscle strength immediately for a short time.

Other tests include an EMG/NCV test. During these tests, the nerves and muscles are stimulated by electrical impulses. The results show where the muscles have a weakened response. A CT scan may be done to find out if the thymus gland is abnormal or has a tumor on it. The doctor may order a pulmonary function test. This can show if breathing strength is weakened. Based on the result, the doctor can then determine whether the individual may develop a myasthenic crisis. This is a condition which may lead to putting the patient on a respirator.

How is Myasthenia Gravis treated?

At this time there is no cure. There are treatments which are effective and allow almost all people with myasthenia gravis to lead full lives.

Common treatments are medications which allow the chemical that causes the muscle to contract allowing normal function. Other medications are ones that suppress the abnormal function of the immune system. When taking these medications, follow up with the doctor is necessary. They may cause an individual to experience major side effects.

A surgical procedure called a thymectomy may be done if a tumor is found on the thymus gland. It may also be done without the presence of a tumor. Many people with myasthenia gravis improve when the thymus gland is removed. Stable, long-lasting complete remissions are the goal of a thymectomy.

Plasmapheresis is a procedure that removes the abnormal antibodies from blood plasma, and transfered back into the patient through an IV.

What is the prognosis?

The prognosis for those with myasthenia gravis is a good one. Most patients will have significant improvement in muscle weakness allowing them to lead a full life. Some patients may go into remission and no treatment will be needed unless it returns.

Resources

http://www.webmd.com/brain/understanding-myasthenia-gravis-basics

http://www.myasthenia.org/amg_whatismg.cfm