After a weekend of knee boarding and outdoor activity, Laura Nixon noticed a tingling spot in her lower body. At first, she brushed it off as a simple injury.

“I really just thought that I was having some back problems,” she says.

But the tingling began to spread and get worse, so she scheduled an appointment with her doctor. After a referral to a neurologist, Nixon’s care team still didn't know what caused her pain.

“They did an MRI on my back, and they couldn’t find anything,” she says.

During the next few years, Nixon visited neurosurgeons, orthopedic doctors, neurologists, and chiropractors. Once it started to get harder for her to walk and keep her balance, she brought up the possibility of MS. But her doctors didn’t think that her symptoms fit.

“It seemed like it was kind of taboo, no one really wanted to touch that diagnosis,” she says.

With few options left, Nixon’s neurologist suggested a spinal tap. After that, in August of 2019, she got a diagnosis of MS at the age of 50.

“It was a relief to know that I wasn’t crazy, but it was also devastating to know that I had a chronic illness,” Nixon says.

But why did it take 14 years to figure out that she had MS?

A Tough Code to Break

Multiple sclerosis happens when there’s scarring in a part of your central nervous system. But there’s no test or list of symptoms that will definitely signal the disease. Instead, doctors look at symptoms and the results of diagnostic tests, like MRI scans.

“Depending upon where the scarring occurs, whether it’s in the brain or in the spinal cord … you can have very different symptoms that occur,” says Lily J. Henson, MD, who is CEO of Piedmont Henry Hospital in Stockbridge, GA, and a member of the National Multiple Sclerosis Society board of directors.

The possibility of these different symptoms makes it harder for doctors to find MS right away. Some people may have symptoms of the condition and not even know it.

Most people find out they have MS after they have an MRI. In rare cases, including Nixon's, doctors sometimes do something called a lumbar puncture to confirm the condition. That's when doctors take out some fluid around the spinal cord and examine it.

Sometimes, though, a doctor's hunch isn't enough to get the test you need.

“MRI is available in the United States, much more than any country in the world. But it’s still expensive. Health insurance has to cover it,” says Farrah J. Mateen, MD, PhD, an associate professor of neurology at Harvard Medical School.

She says that in addition to insurance, there has to be a really strong case made to do the MRI in the first place.

Criteria to Meet

A set of guidelines known as the McDonald Criteria help doctors diagnose MS.

They'll first determine if you show signs of a typical MS episode. Once that's known, doctors must confirm that you’ve had MS symptoms in multiple places in your nervous system, and that they've happened more than once. Your doctors may call this “dissemination in time and space.”

This process can be simple, but there's no guarantee that it will be.

“It can take 5 minutes, or it can take years," says Aaron E. Miller, MD. “It depends entirely on the circumstances.”

The catch is, to make an MS diagnosis, there must be no better reason for someone’s symptoms.

Copycat Conditions

Signs of MS can vary for each person. A common one is swelling in your eye’s optic nerve, called optic neuritis. Many people might notice numbness, tingling, or weakness on one side of their body. You may have trouble walking, balancing, or going to the bathroom.

But with these symptoms alone, doctors can’t confirm MS. Many other conditions have similar warning signs.

“A vitamin B12 deficiency can mimic MS," Henson says. "Lyme disease, lupus, or Sjogren's -- two other autoimmune diseases -- can also mimic MS. And then there are some very rare, inherited metabolic disorders that can mimic MS."

"It’s important to make sure that you’ve ruled those conditions out.”

Doctors can write off “mimickers” through an MRI of your brain and spinal cord as well as repeated blood tests.

If your doctor finds no other condition and your symptoms meet the McDonald Criteria, you’ll likely get a diagnosis of MS.

The Future of MS Diagnosis

As of now, doctors don’t expect a better method of MS diagnosis to come along any time soon.

“We’d love to have a simple body fluid test, preferably blood or urine," Miller says. "But I don’t think it’s likely to happen.”

But advances in technology offer hope for the future.

Mateen is studying a portable MRI that's basically the size of a computer. This could be a game changer for people in low-income areas who need access to MRI tests.

“What if you could actually make MRI really cheap and really simple for patients and even have it in more convenient locations?”

WebMD Feature Medically Reviewed by Michael W. Smith, MD on January 22, 2021



Laura Nixon, woman with multiple sclerosis, Cumming, GA.

Lily J. Henson, MD, Piedmont Henry Hospital CEO, Stockbridge, GA.

Farrah J. Mateen, MD, PhD, associate professor, Harvard Medical School, Neurological Clinical Research Institute, Boston.

Aaron E. Miller, MD, Mount Sinai School of Medicine, New York City.

National Multiple Sclerosis Society: “Diagnosing MS.”

American Academy of Ophthalmology: “Optic Neuritis.”

MS Trust: "McDonald Criteria."

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