Expert Calls Myasthenia Gravis a Rare but Treatable Neurological Disease
6 min. read
Baptist Health Marcus Neuroscience Institute
The name itself sounds serious: “myasthenia” (Greek for “muscle weakness”) and “gravis” (Latin for “grave”), although with modern treatment most cases are not as dangerous as the name suggests. The National Institutes of Health (NIH) says that myasthenia gravis, or MG, is an autoimmune disease that occurs when communication between the nerve and muscle is interrupted at the neuromuscular junction – the place where nerve cells connect with the muscles they control.
Few people have ever heard of this rare neuromuscular disease, although there are an estimated 70,000 people living with this condition in the United States. The real number is likely higher as this condition unfortunately remains under-diagnosed. Although serious, neuromuscular specialists say that with the right treatment patients with the disease do very well.
Neurologist Svetlana Faktorovich, M.D., director of the Neuro Infusion Center at Baptist Health Marcus Neuroscience Institute
“A telltale sign of myasthenia gravis is when a patient tells me they have painless muscle weakness that worsens after periods of activity and improves after periods of rest,” says neurologist Svetlana Faktorovich, M.D., director of the Neuro Infusion Center at Baptist Health Marcus Neuroscience Institute, established at Boca Raton Regional Hospital. Dr. Faktorovich is neuromuscular specialist who has extensive experience diagnosing and treating patients with MG.
Muscles controlling certain areas of the body tend to be involved in patients with MG. Some of these include:
- Eyes, causing drooping of the eyelids or double vision
- Face, causing weakness when smiling, blowing out your cheeks or lifting brows
- Throat, causing slurred speech, hoarse/weak voice and difficulty swallowing
- Respiration, causing difficulty breathing with activity or at rest
- Arms and legs, causing difficulty lifting arms overhead, walking or standing from a seated position
Two forms of the disease
Dr. Faktorovich says that there are two main categories of MG, purely ocular and generalized MG. “Purely ocular MG affects only the muscles of the eyes, causes drooping of the eyelids and double vision,” she says. “For those with ocular myasthenia, these symptoms tend to improve with sleep, so they may be okay in the morning but by the afternoon or the end of the day the symptoms develop. Some patients have to use their hands or duct tape to keep the eyelids open to watch television.”
Ocular symptoms, however, are also the most common presenting symptom of generalized myasthenia gravis, which is the more serious form, says Dr. Faktorovich. It’s also important to note that up to 50 percent of patients with the ocular form may develop symptoms of generalized MG within two years, she adds.
“Generalized MG is more dangerous because it can impair the patient’s ability to swallow and to breathe on their own, and if left untreated can be fatal,” Dr. Faktorovich says. “Symptoms of generalized MG also typically worsen during the day and improve in the morning and with sleep.”
According to Dr. Faktorovich, symptoms of generalized MG may include arm and leg weakness; difficulty walking, rising from a chair or reaching for something overhead; shortness of breath; choking while eating and/or difficulty swallowing; slurring of speech; difficulty holding head up as well as the ocular symptoms described earlier. “For some people with generalized MG, their voice becomes weak or hoarse much like a person might experience with a cold,” she says.
Understanding the seriousness of myasthenic crisis
Some people with MG may experience what Dr. Faktorovich calls a “myasthenic crisis,” a life-threatening condition that occurs when the respiratory muscles get too weak to move sufficient air in and out of the lungs.
“When a myasthenic is going into crisis, they’re losing the ability to safely breathe on their own, or to safely swallow, which puts them at risk of respiratory failure and aspiration,” Dr. Faktorovich explains. These patients must be hospitalized and started on emergency infusion therapy, and in severe cases, they must be put on a ventilator to assist with breathing. "However, when an impending crisis is recognized and treated early, this is often preventable. That’s why being educated on the signs and symptoms of an myasthenic crisis is so important for patients with MG.”
Symptoms of impending crisis may include worsening slurring of speech, difficulty breathing, difficulty swallowing (food, water or even saliva), weak cough as well as increased difficulty holding one’s head up. In addition, you may see the muscle of your neck, chest and abdomen pull in when you breathe.
A myasthenic crisis may be triggered by infection, stress, surgery, or an adverse reaction to medication, Dr. Faktorovich notes. According to the NIH, approximately 15 to 20 percent of people with MG experience at least one myasthenic crisis and up to 50 percent may have no obvious cause for their myasthenic crisis.
“If you have MG, you need to make sure you tell your doctors as there are certain medications that can trigger a crisis,” Dr. Faktorovich advises. “Similarly, you need to let your neurologist know if you ever get scheduled for surgery or other procedure requiring anesthesia, so they can work with your doctors to minimize risk of myasthenic complications. The better controlled your myasthenia is, the lower your risk of complications.”
Diagnosing and treating MG
MG most commonly affects young women under age 40 and older men over age 60. However, it can occur at any age, even among children, Dr. Faktorovich says.
Diagnosis is usually made by a neurologist through a detailed history and clinical exam.
"The neurological exam includes but is not limited to evaluating a patient’s eye movements, facial muscle strength, speech, limb muscle strength and tone, coordination and sensation," explains Dr. Faktorovich. Other conditions can mimic myasthenia gravis, she adds, so it’s important to be evaluated by a neurologist to confirm the diagnosis and receive timely treatment.
“Additionally, MG is often associated with detectable antibodies, which are proteins we can test for in the blood,” says Dr. Faktorovich. “Eighty-five percent of patients with generalized MG and 50 percent of those with purely ocular MG have antibodies against the acetylcholine receptor, for example, which is a protein that sits on the muscle membrane,” she explains. “Some patients with the disease do not have detectable antibodies, however. When indicated, we can also use specialized, electrodiagnostic tests to detect impaired nerve-to-muscle transmission.”
While most cases of MG cannot be cured, Dr. Faktorovich says there are many treatment options that can effectively control this disease long-term and even put the patient into remission.
“Common therapies include a steroid such as prednisone, which is the fastest way of getting someone with MG under control and into remission,” the neurologist says. “Then you replace the steroid with a safer, longer acting immunosuppressive therapy designed to bring down your immune system and if possible, taper off the prednisone.”
These drugs improve muscle function by suppressing the production of abnormal antibodies and promoting healing of the muscle membrane, she says. Another medication – pyridostigmine, a cholinesterase inhibitor – treats symptoms of MG but doesn’t put the patient in remission and therefore is usually insufficient for the treatment of generalized MG.
New therapies on the horizon
“This is an exciting time in the field of MG,” says Dr. Faktorovich. “In addition to the multiple, effective steroid-sparing therapies that we have used for many years, new therapies are also being developed.”
Two new drugs have recently been approved by the U.S. Food & Drug Administration (FDA): efgartigimod (Vyvgart) and ravulizumab (Ultomiris), both of which are being used with success in certain patients who have MG, says Dr. Faktorovich.
Another treatment option for some patients with generalized MG is a thymectomy, or surgical removal of their thymus gland, which controls immune function and may be associated with MG. “The thymus gland can be problematic, and there are some patients with MG who actually have a thymoma, or tumor of the thymus, that must be removed,” Dr. Faktorovich says. “Patients with no thymoma but who meet certain criteria may also be candidates for a thymectomy.”
Continued research offers the hope of new therapies for treating MG, putting more people into remission and minimizing a patient’s risk of myasthenic crisis, says Dr. Faktorovich.
“In the past, before we really understood the disease and how to treat it, myasthenia gravis had a high mortality rate. Now, however, we have very effective therapies to treat this disease and the mortality rate has dramatically decreased,” Dr. Faktorovich notes. “Most patients who follow closely with their doctor and get started on treatment have a high quality of life and a normal life expectancy.”
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