Tennis champion Monica Seles reveals incurable disease as doctor shares what to know

Tennis champion Monica Seles is speaking publicly for the first time about her battle with a rare, incurable muscle-weakening disease.

Myasthenia gravis (MG) is a chronic neuromuscular disease that causes weakness in "voluntary muscles," according to the National Institute of Neurological Disorders and Strokes.

Voluntary muscles are the ones that connect to the bones, face, throat and diaphragm. They contract to move the arms and legs and are essential for breathing, swallowing and facial movements.

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"My MG journey over the past five years has not been an easy one," Seles said in a press release announcing her collaboration with the immunology company argenx. 

"I felt isolated and defeated, as many of the activities I enjoyed were no longer physically possible for me."

Seles' partnership with argenx aims to raise awareness and understanding of MG, and to connect those affected with available tools and resources.

Myasthenia gravis is classified as an autoimmune disease, according to Dr. Earnest Lee Murray, a board-certified neurologist at Jackson-Madison County General Hospital in Jackson, Tennessee.

This means the body's own defense system attacks the connection between the nerves and muscles.

"Myasthenia gravis is different from other neuromuscular diseases in that oftentimes, patients' symptoms fluctuate throughout the day," Murray told Fox News Digital.

Overall symptoms range from very mild double vision and droopiness of the eyelids to difficulty walking, breathing and swallowing.

"Some patients who start with only mild eye symptoms can progress to more severe symptoms in the first few years of their diagnosis," the doctor added.

However, some patients only experience eye issues.

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Heat, such as from summer weather or hot showers, can make symptoms worse, according to experts. As physical exertion can also exacerbate symptoms, Murray noted that patients must pace themselves.

Certain health conditions - like COVID-19, the flu or urinary tract infections - can trigger a serious worsening of symptoms, called a "myasthenic crisis," which often leads to hospitalization for closer respiratory monitoring.

It's important for patients to let their physicians know they have myasthenia gravis before starting a new medication, Murray said, as some drugs, including antibiotics, can worsen symptoms. 

"If there is a question, patients can always check with their neurologist," he advised.

Doctors typically manage MG in two ways. First, they may prescribe a medication like pyridostigmine, which can temporarily reduce muscle weakness, according to Mayo Clinic.

They may also prescribe medications that calm the immune system to stop it from attacking the nerves and muscles.

In the past, this immune suppression was done with steroids like prednisone. Now, there are newer medicines that target the disease more directly. These targeted treatments can work well and may cause fewer side effects, according to Murray.

While MG can be serious, the doctor stressed that it's not the end of the road. 

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"Most patients live a fairly normal life, both personally and professionally," he said. "With close management and a neurologist familiar with MG, treatments can be tailored to optimize patients' quality of life."

Anyone who experiences occasional double vision, eyelid drooping or weakness that gets worse with fatigue should talk to their doctor about getting tested, Murray recommends. 

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Diagnosis usually involves blood tests, nerve tests and a neurological evaluation.

Symptoms like trouble breathing, swallowing or holding the head up require immediate emergency care, Murray said.

Fox News Digital reached out to Monica Seles requesting comment.