When patients learn they may not have MS after all, it's rarely a relief. Instead, they have more questions
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The Current24:07When you find out you don’t have MS after all
More than 20 years after she was diagnosed with multiple sclerosis, Jackie Pilon learned something she never expected: she didn't have the disease after all.
“I remember walking away feeling shocked, lost, hurt,” Pilon, who lives in Saskatoon, told The Current's guest host Catherine Cullen.
Pilon was 21 when she was diagnosed with MS in 1992, after what she describes as a “very thorough investigation” by her doctors.
At the time, she couldn’t see out of her right eye, a result of optic neuritis — an inflammation of the optic nerve. She started experiencing seizures and other cognitive and behavioural changes, due to encephalitis — a swelling of the brain tissue — and was hospitalized under the care of a neurologist.
This combination of symptoms led doctors to diagnose her with MS, a conclusion she says made sense based on the medical knowledge and diagnostic criteria available at the time.
But in 2016, Pilon was told she didn’t meet the updated criteria for the condition, scoring 0 for 3.
More than two decades after she was diagnosed with MS, Jackie Pilon learned that she didn't have the condition. (Submitted by Jackie Pilon)
Her experience is not uncommon.
A U.S. study by Cedars-Sinai researchers in 2019 found nearly one in five of the 241 MS patients studied had been misdiagnosed, while a 2024 review of six studies published in the Multiple Sclerosis Journal estimated an overall misdiagnosis rate of 15 per cent, with individual studies suggesting it could range from five to 41 per cent.
In late October, American actress Christina Applegate revealed that she had been misdiagnosed with MS, which she said left her frustrated and searching for answers about her symptoms.
Pilon felt similar frustration and recalled moving through the “stages of grief.”
She had spent a considerable amount on medications she may not have needed, including injections every other day that would sometimes have flu-like side effects, like body aches and fatigue, she said. The side effects were sporadic and ended when she stopped the injections.
And she had ongoing questions, and struggled with losing part of her identity.
“It was a sense of, well, ‘What did I have and what happened?’”
Why MS can be difficult to diagnose
Multiple sclerosis is a chronic disease that affects the brain, spinal cord and optic nerves. It happens when the immune system mistakenly attacks myelin, the protective coating around nerve fibres, damaging it and disrupting the signals travelling between the brain and the body.
Symptoms can vary and may include fatigue, headaches, vision problems, slurred speech, difficulty moving, numbness and memory problems.
Getting a diagnosis, while emotional, gives people an explanation for their symptoms and treatment options to manage them, says Julie Fiol, the director of clinical content strategy at the National Multiple Sclerosis Society.
If that’s overturned, patients are not always relieved, she said — instead, it can often create more uncertainty.
“When you lose that diagnosis, you start back at Square 1,” she said. “You have anxiety and stress and potentially depression around having to start this journey over again.”
Julie Fiol is the director of clinical content strategy at the National MS Society and a member of the society's research and medical affairs team. She also has a background in MS nursing and social work. (Submitted by Julie Fiol)
The reason MS can be misdiagnosed, Fiol said, is that its symptoms “really overlap with many other neurological conditions — and other types of conditions.”
“There is no one test that can confirm that someone has MS,” she said. “To be able to give someone a diagnosis more quickly and more accurately … is to [have] more tests that are more specific — or tell us there’s really no better explanation other than MS.”
One of the main tools for diagnosis, says Fiol, is an MRI, which looks for damage to the myelin sheath.
The latest diagnostic criteria, updated in 2024, include “imaging biomarkers” within the areas of damage that are specific to MS. These include the central vein sign, a small vein running through the centre of a lesion, and paramagnetic rim lesions, which appear as a ring around the edge of certain lesions on an MRI.
Those same diagnostic tests are also revealing that people with a previous diagnosis actually don't have the condition, Fiol said.
New data around paramagnetic rim lesions will likely be included in the next update of the criteria, says Fiol, which could potentially help patients get an earlier diagnosis, and provide greater accuracy.
How often are people misdiagnosed?
The evolution of the diagnostic criteria for MS has inspired more study into the accuracy of past diagnoses.
Dr. Jiwon Oh, a neurologist and medical director of the Barlo Multiple Sclerosis Program at St. Michael’s Hospital in Toronto, has conducted research around misdiagnosis and found the rate to be 10 to 20 per cent — figures that she said should be “a wake-up call for clinicians.”
“It's not common, but it's also not exceedingly rare,” Oh said.
Researchers are still “trying to unravel all of [the] puzzle pieces” of what causes MS, she said.
Dr. Jiwon Oh is a neurologist and MS specialist based out of St. Michael's Hospital in Toronto. (Oliver Walters/CBC)
The disease, for example, is more common in countries farther from the equator, she said, a pattern researchers have linked in part to lower sunlight exposure and vitamin D levels.
Research has also linked Epstein-Barr virus to MS, though infection alone is not enough to cause the condition.
Finding a way forward after misdiagnosis
If people find out that they’ve been misdiagnosed, they should get in touch with their doctor or nurse practitioner to investigate what might be causing their symptoms, Fiol said — and whether they should be seen by a specialist.
And she encourages them to lean on family, friends and other support networks.
That can include the National Multiple Sclerosis Society, she said, which has online and peer support to “navigate the complex health-care landscape,” Fiol said.
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Pilon got her rediagnosis after she started having severe migraines. Doctors ordered MRIs to investigate their cause, and the results raised questions about her MS diagnosis.
Instead, her doctor said he believed she had a condition called acute disseminated encephalomyelitis (ADEM) based on reviewing her medical reports from the original diagnosis, though he couldn't be certain. ADEM is typically episodic and, for most patients, will only happen once and causes sudden inflammation of the central nervous system.
But she continues to advocate for people living with MS.
“I would just say to everyone, ‘Do what you think is right for you: ask the questions, be proactive in your health,” she said. “And if you're capable and able, invest in research, support researchers around the community [and] participate in studies.”
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