Actor Christina Applegate announced on Tuesday that she has Misdiagnosed as multiple sclerosis For years she believed she had the disease, and experts say her experience is more common than many people realize.
Applegate shared the news on her podcast MeSsy, where she and actor Jamie-Lynn Sigler discuss life with multiple sclerosis. In a follow-up report, Dr. Marva Casey, associate professor in the Department of Neurology at Cedars-Sinai Medical Center, said that almost one in five people who are told they have multiple sclerosis “do not actually have the disease.”
No single test can confirm multiple sclerosis, a disease in which the body’s immune system attacks the central nervous system. Symptoms vary from person to person and may develop in different ways, according to the Multiple Sclerosis Society of America.
How to spot MS misdiagnosis?
CBS News spoke with Dr. Robert Brumel, director of the Mellon Multiple Sclerosis Center at the Cleveland Clinic, a multidisciplinary center that cares for more than 11,000 MS patients, about the risks of MS misdiagnosis and what patients need to know.
Misdiagnosis is most often discovered when a person seeks a second opinion because symptoms have not improved, he said. This doesn’t always mean the diagnosis is wrong, but can be an indicator for more advanced testing. (Brummel said most MS treatments, especially the most commonly used ones, are “very safe” and do not put a person’s health at risk.)
When misdiagnosis occurs, the root cause is usually that abnormalities in brain scans have been misinterpreted, Brummel said. Brain damage is considered a hallmark of multiple sclerosis, but can also be caused by high blood pressure, smoking or other medical problems such as migraines. More advanced MRI sequences could help distinguish MS lesions from those caused by other diseases, Brummel said.
When there is concern about a possible misdiagnosis, the next steps usually involve performing specialized tests. These could include advanced MRI sequences to study lesions more closely, MRI of the spinal cord or spinal fluid analysis that can identify specific abnormal immune proteins, Brummel said.
How common is MS misdiagnosis?
On MeSsy, Casey described MS misdiagnosis as “pretty common.” Brummel said the largest studies of the risk of misdiagnosis show that 15 to 20 percent of patients diagnosed with MS do not actually have the disease.
Dr. Joseph Gutman, director of NYU Langone Long Island Comprehensive Multiple Sclerosis Care Center, told CBS News that the wide range of symptoms caused by multiple sclerosis makes the disease difficult to diagnose.
“It’s important to remember that in many ways these symptoms are not necessarily specific. It’s the kind of story that, combined with MRI imaging, combined with other markers like spinal fluid, helps us make a diagnosis of multiple sclerosis,” Gutman said. “It’s not like diabetes, where you just do a blood test and if it’s above that number, it’s diabetes, if it’s below that number, it’s not diabetes. There are a lot of factors that go into the diagnosis.”
New multiple sclerosis diagnostic criteria, to be published in 2025 and developed by an international group of experts in the field, aim to reduce this risk. Brummel said the standards are more specific than before, especially when it comes to interpreting brain lesions.
“We really put a lot of emphasis on getting the diagnosis right from the beginning so that we can be very confident that we can treat MS effectively and efficiently,” Brummel said.
What happens when MS is misdiagnosed?
If a patient is found to have been misdiagnosed with multiple sclerosis, doctors will start looking for other potential causes of symptoms, Brummel said.
They may have an autoimmune disease that causes joint pain, swelling, and inflammation throughout the body. Fibromyalgia is a “common multiple sclerosis-like diagnosis,” Brummell said. Migraine is also a possible diagnosis because migraines can cause lesions and other neurological symptoms. Chronic pain or fatigue syndrome may also “masquerade as multiple sclerosis,” Brummel said.
Sometimes, a person may have not just one disease but multiple conditions, Brummel said, noting that a wrong diagnosis “can really throw things off course.”
“For patients with multiple symptoms, multiple sclerosis is sometimes a satisfactory solution because it is considered to be some single, isolated root cause,” he said. He added that he has seen some patients whose fatigue was caused by sleep or thyroid disease, while rheumatoid disease or fibromyalgia caused pain and swelling.
Applegate said on her podcast that learning her diagnosis was wrong made the situation even more difficult because there is currently no explanation for the debilitating symptoms that impact her daily life and ability to move around.
“You don’t get misdiagnosed and then all of a sudden I’m better,” Applegate said. “If anything, I’ve gotten worse. So I’m back to square one, I don’t know what happened to me. It’s going to be an online investigation that my doctor will conduct just to find out what has happened since 2021, why is this happening?”
When to seek a second opinion
While only a minority of patients are misdiagnosed, anyone concerned about their diagnosis should feel free to seek a second opinion, Brummel said. He noted that even if the initial diagnosis is correct, a second opinion can help patients find additional resources.
“Multiple sclerosis is a life-changing diagnosis, and whenever someone is faced with something similar, I always think it may be time to seek a second opinion,” Brummel said.
Patients can also seek assistance from multiple sclerosis specialists, Brummel said. The National Multiple Sclerosis Society maintains an online registry and map of care centers and MS specialists nationwide. Brummel called the list a “very good starting point” for identifying nearby resources.
Multiple sclerosis specialists are likely to be aware of the latest diagnostic criteria, Gutman said. They are also more likely to be familiar with conditions that mimic multiple sclerosis and be able to perform more specific tests to help confirm the diagnosis.