An In-Depth Look into Myasthenia Gravis

Myasthenia gravis (MG)—a combination of Latin and Greek wording that means grave muscular weakness—is a disorder that causes a breakdown in communication between the nerves and voluntary muscles in the body. It is known to affect one in 5,000 Americans but is thought to be severely underdiagnosed.

In honor of Myasthenia Gravis Awareness Month, we would like to shed some light on this relatively unknown condition in the hopes that those living with it (or those who think they may have it) will know that there are options available to alleviate its effects. 

What are the causes of myasthenia gravis?

Your nerves communicate with your muscles by releasing neurotransmitters (chemicals). The neurotransmitters fit perfectly into a receptor site located on the muscle cells where the nerves and muscles meet (nerve-muscular junction). In those with MG, the communication is disrupted, because the body releases antibodies that destroy or block the receptor sites for a particular neurotransmitter called acetylcholine. As a result, the muscles receive fewer signals from the nerves, causing muscle weakness.

The antibodies may also stop the function of a protein known as the muscle-specific receptor tyrosine kinase. This protein helps to form the nerve-muscular junction. The inhibition of this protein’s function can result in MG, as well.

What are the symptoms of myasthenia gravis?

Though MG impacts any of the voluntary muscles, some muscles groups are more heavily affected than others. These include:

Eye Muscles

Problems with eye muscles are typically the first sign of MG in over half of the patients with the condition. These can include ptosis—a drooping of one or both of the eyelids—and double vision.

Facial and Throat Muscles

In approximately 15 percent of patients with MG, the first symptoms include the muscles that control the face and throat, resulting in:

  • Altered speaking capabilities, making the voice sound nasal-y or soft
  • Difficulty with swallowing, making choking easy
  • Issues with chewing, especially with something that is challenging to chew
  • Restricted facial expressions, particularly smiling

Muscles in the Neck and Limbs

Issues with the neck and limbs are the rarest. When they do occur, symptoms of these muscle groups include difficulty holding up the head, waddling when walking or controlling the arms.

Are there diagnostic tests for myasthenia gravis?

In addition to the presence of symptoms, there are several diagnostic tests to confirm an  MG diagnosis. This includes a nerve conduction study, a test often performed to assess if nerve damage if present by measuring the speed an electrical impulse travels through a nerve. A blood assay may also be done to measure the level of antibodies associated with MG.

How is myasthenia gravis treated?

Most often, the first line of treatment for MG is medication, including:

  • Cholinesterase inhibitors, which improve the communication between the nerves and muscles to reduce contractions and increase strength
  • Corticosteroids to limit antibody production
  • Immunosuppressants that change how the immune system functions

Intravenous therapy may also be recommended, which includes:

  • Plasmapheresis to remove the antibodies causing the issues
  • Intravenous immunoglobulin (also known as IVIG) to alter the immune system response by providing new antibodies
  • Monoclonal antibody infusion, which depletes the white blood cells, altering the immune response to improve symptoms

The problem with these therapies is that, in addition to the many side effects that can occur, their efficacy is usually only temporary. In fact, many patients’ bodies adjust to the treatment over time, rendering them ineffective. When that occurs, surgery may become the next necessary step to relieve symptoms.

Surgery to remove the thymus gland—known as a thymectomy—may be recommended when all other treatment modalities have failed (or a tumor has developed, which can occur in about 15 percent of MG patients). The thymus gland is a small gland located in the chest underneath the breastbone that can trigger or maintain the production of antibodies that block acetylcholine.

A thymectomy may be performed as a minimally invasive surgery or as an open surgery. The open surgery is known as a sternotomy, a procedure in which a vertical incision is made in the chest, and the sternum is divided (cracked). Since a sternotomy is the most often recommended surgical approach (due to lack of awareness of other options), many patients instead choose to live with the dwindling effects of other therapies rather than have the gland surgically removed.

The Minimally Invasive Specialists

At Thoracic Group, our surgeons have decades of experience in performing video-assisted thoracic surgery (VATS), a minimally invasive approach to thymectomy. Using VATS, our experts are able to remove the gland through a small incision in the neck using a video endoscope. In doing so, patients like Ashley Grandell are able to leave the hospital sooner and recover significantly faster (than those who underwent open surgery).

Just like Ashley, scores of other patients come to our practice after being diagnosed with MG (following a full neurological workup) but have not experienced good results with medication or intravenous therapy and are in search of an alternative to open surgery.

For more information about VATS or to schedule a consultation with one of our specialists, contact us today.