At one point in her mid-twenties, Priscilla Forrester, now 33, realized she could no longer walk in the five-inch heels she loved to wear on nights out with friends. “As soon as I put them on, my legs would feel wobbly,” she says.

Her arms and hands also began to feel strange. Even when she tried to carry light items, she'd immediately drop them. Another time, when she was washing her face, she realized she couldn't make circular motions with her hands.

After a few months of these symptoms, Forrester went to see a neurologist, who suggested she might have a slipped disc or muscle spasm and referred her for physical therapy. The sessions were torturous. Within minutes of starting an exercise, she'd be exhausted. Not one to give up, she continued with physical therapy for three years. “I started questioning whether it was all in my head,” says Forrester, an accountant in Alexandria, VA.

In March 2020, she sought the advice of another neurologist. After taking an entire history, ordering blood work, and performing a nerve-conduction study and electromyography (EMG), which measures electrical activity in muscle when it's been stimulated by a nerve, the neurologist diagnosed Forrester with myasthenia gravis. In this autoimmune disease, antibodies disrupt the connections between nerves and muscles, causing weakness, especially in muscles that control the eyes, mouth, throat, arms, and legs.

Forrester manages her disease with medication. She's also considering surgery to remove her thymus gland, which may be involved in triggering antibodies. Removing it can curtail symptoms in some people. Thanks to several research advances over the last decades, Forrester and other people with myasthenia gravis have more options than ever to manage their disease.

Myasthenia gravis is a rare, chronic disease; an estimated 36,000 to 60,000 people in the United States have it. Women are more commonly diagnosed than men and tend to develop it in their twenties and thirties. Men generally develop symptoms after age 60. It's unclear why the immune system makes antibodies that damage muscle-receptor sites and block a neurotransmitter called acetylcholine.

“The condition used to be very difficult to treat,” says Brian Callaghan, MD, FAAN, associate professor of neurology at the University of Michigan Medical School in Ann Arbor. “Most patients were hospitalized and placed on ventilators. Nowadays, patients do quite well with treatment.” And most can expect to have normal life spans.

To diagnose the disorder, doctors order blood tests that may reveal the presence of antibodies. They also perform neurologic examinations in which they check patients' reflexes, muscle strength, coordination, and balance. Neurologists may do a nerve-conduction test—sending small electrical pulses through the skin—to see how well the nerves transmit signals to the muscles. During an EMG, a fine needle is inserted into a muscle to measure electrical signals between muscles and the brain.

A person who develops droopy eyelid—a common symptom of myasthenia gravis—might be asked to apply an ice pack to the eyelid for a few minutes to see if the drooping decreases. If it does, this supports a diagnosis, as cold briefly improves nerve-muscle communication.

Therapy Options

Treatment depends on how a patient's immune system attacks the communication between nerves and muscles, says Nicholas J. Silvestri, MD, FAAN, associate professor of neurology at the Jacobs School of Medicine and Biomedical Sciences in Buffalo, NY. Most people with the condition produce an antibody called immunoglobulin G that blocks the receptors on the muscle surface that receive the acetylcholine signal from the nerve. When acetylcholine binds to the receptor, it signals the muscle to generate a contraction.

A very small number of people with myasthenia gravis have antibodies that block the function of a protein called muscle-specific receptor tyrosine kinase, which is involved in organizing the acetylcholine receptors on the muscle surface. Antibodies against another protein, called lipoprotein-related protein 4, also may play a part in the disease. “Some people have antibodies we can't identify yet,” Dr. Silvestri says. Patients may try many treatments before finding the right one or combination, he adds.

One way of treating myasthenia gravis is with anticholinesterase inhibitors, which prevent the breakdown of acetylcholine. Most people start on pyridostigmine (Mestinon). Other drugs in this class include neostigmine (Prostigmin) and ambenonium chloride (Mytelase). Side effects include stomach cramps, diarrhea, muscle twitching, and excessive sweating.

Another type of medication that may be prescribed is an immunosuppressant, such as azathioprine (Azasan, Imuran), mycophenolate mofetil (CellCept, Myfenax), methotrexate (Trexall), cyclosporine (Sandimmune, Neoral), cyclophosphamide (Cytoxan), or tacrolimus (Prograf). As the name suggests, immunosuppressants tamp down the immune system to prevent the creation of antibodies that disrupt the nerve-muscle communication pathways. The drugs make patients more vulnerable to infections, requiring them to be vigilant about avoiding germs.

Corticosteroids, such as prednisone, also prevent the creation of antibodies that attack the nerve-muscle connection. Prednisone is typically prescribed for mild cases of myasthenia gravis in gradually increasing doses until improvement is observed. Using the lowest dose possible mitigates side effects, which can include weight gain, high blood pressure, acne, mood problems, osteoporosis, glaucoma, cataracts, and, in some people with certain risk factors, diabetes. Prednisone is often prescribed in combination with other drugs.

Patients who have antibodies that interfere with acetylcholine are often given monoclonal antibodies—including eculizumab (Soliris), efgartigimod (Vyvgart), which the US Food and Drug Administration approved in December 2021, and ravulizumab (Ultomiris), which was approved in April 2022. These are likely to cause fewer side effects than older medications do, Dr. Silvestri says. “Steroids and immunosuppressants work very broadly, affecting multiple tissues and the whole immune system,” he explains. “Newer therapeutics target certain points in the immune response.”

Eculizumab and efgartigimod, which are administered by intravenous (IV) infusion, may be less convenient than the oral medications. These drugs are also expensive. Eculizumab costs $653,100 a year for an initial series of four weekly infusions followed by infusions every two weeks.

The Institute for Clinical and Economic Review (ICER), a nonprofit organization that analyzes the value of medical treatments, compared the price of the new drugs with the benefits expected and estimated that eculizumab should cost 98 percent less to be worth the price. The prices of efgartigimod and ravulizumab are not yet known, but ICER estimated that efgartigimod should cost $18,300 to $28,400 a year based on its potential effects.

Patients may consider the cost worth it if these drugs help them avoid the serious side effects such as diabetes and bone disease caused by other treatments, says James F. Howard, MD, FAAN, distinguished professor of neuromuscular disease at the University of North Carolina School of Medicine in Chapel Hill.

“These targeted therapies are going to transform how we treat our patients,” says Dr. Howard, an investigator on the efgartigimod trials.

Monoclonal antibody drugs have been tested only against placebos and not against other medications for myasthenia gravis, says Dr. Callaghan. Once studies have been completed that compare drugs, the risks and benefits will be better understood, he says.

Acute Treatment

Myasthenia gravis can cause life-threatening problems with breathing and swallowing—a condition known as myasthenic crisis. When that happens, or when patients are waiting for a new medication to take effect, doctors may prescribe IV infusions of immunoglobulin therapy or plasmapheresis. During immunoglobulin therapy, patients are infused with antibodies purified from the blood of healthy donors, which reduces symptoms for a few weeks. Side effects may include headaches, allergic reactions, and infections.

Plasmapheresis, which takes a few hours, involves removing blood from the body and stripping the antibodies that cause myasthenia gravis, then transferring the altered blood and a blood product called albumin back into the body. Most people need several treatments over the course of a few days to see improvement that usually lasts a few weeks. Side effects might include lower blood pressure, nausea, and headaches.

For some patients, a thymectomy (removal of the thymus gland, which is part of the immune system) reduces or eliminates symptoms. Evidence suggests that the gland produces antibodies that interfere with the muscle messenger acetylcholine, so removing it may help those with high levels of immunoglobulin G antibodies. Most patients continue to take prednisone after the surgery, although some can taper to lower doses. Thymectomy combined with prednisone is more effective at reducing symptoms than prednisone alone, according to a 2016 study in the New England Journal of Medicine.

Dr. Callaghan says younger people who are healthy enough to undergo surgery are good candidates for it.

Such surgery was life-changing for Bob Rosecrans, 73, a biochemist from Glen Ellyn, IL. Diagnosed with myasthenia gravis in 2002, he had a myasthenic crisis two years later. During his hospitalization, his doctor recommended a thymectomy. After the operation in 2006, Rosecrans says, his symptoms eased dramatically. He serves as chair of the patient group Conquer Myasthenia Gravis and has even taken up ballroom dancing.

The Role of Self-Care

Cultivating healthy habits is key to managing myasthenia gravis, says Dr. Silvestri. He recommends mild exercise to all his patients.

He also encourages them to maintain a healthy weight. Excess weight puts strain on the body and makes it harder to fight disease, he says. Eating well and drinking plenty of water also aid muscle function. “Muscles need proteins and energy sources like fats and carbohydrates to stay healthy,” Dr. Silvestri says. “Hydration improves blood flow to all muscles and helps remove toxins caused by activity.”

Many people with the disease lead active lives, says Michael K. Hehir, MD, division chief of neuromuscular medicine at the University of Vermont Medical Center in Burlington.

Two years after her diagnosis, Priscilla Forrester says taking regular walks, incorporating more leafy greens into her diet, and eating less meat have improved her energy levels. So has becoming an advocate. In 2021, she helped organize a walk to raise money for research and became active in several online support groups.

Talk therapy is also part of her care. Forrester says it helps her sort through her emotions. “I'm along for the ride with this disease,” she says, “but still figuring it out.”

What to Do When Choosing Treatment

With so many medications available for treating myasthenia gravis, patients have to consider various factors and may need to try more than one drug to find the most suitable treatment. “Patients not doing well on one medication should definitely try another,” says Brian Callaghan, MD, FAAN, associate professor of neurology at the University of Michigan Medical School in Ann Arbor.

These tips can help when you're seeking treatment.

Do the research. Learn everything you can about the disease and the different ways to treat it. Then discuss the pros and cons of each with your doctor.

Assess side effects. Even a seemingly minor side effect like diarrhea can greatly affect your quality of life if it occurs regularly, says James F. Howard, MD, FAAN, distinguished professor of neuromuscular disease at the University of North Carolina School of Medicine in Chapel Hill. And risks tend to increase the longer you're on a drug—something to consider for drugs that may cause diabetes or osteoporosis. “If you're an otherwise healthy 25-year-old and plan to be on a certain drug for decades, you should consider the risk for diabetes. For patients in their seventies or eighties, that may not be as serious a risk,” Dr. Howard says. “Older people would want to avoid drugs that weaken their bones and could cause falls.”

Share pregnancy plans. Women with myasthenia gravis should discuss any childbearing plans with their doctors. “It's important that they talk about this with their physicians in case their medicines need to be changed in light of the pregnancy,” says Michael K. Hehir, MD, division chief of neuromuscular medicine at the University of Vermont Medical Center in Burlington.

This article was updated on August 15, 2022.

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