For Christina Applegate, being told she didn’t have multiple sclerosis felt like being ‘back at square one.’
The actress, 54, had already spent five years battling debilitating symptoms that left her needing to use a wheelchair and cane.
‘[My doctor] came into my room and said, “Congratulations, you don’t have MS,”‘ she recalled on a podcast this week.
‘I was, like, not happy at all… you don’t get misdiagnosed and then all of a sudden, I’m better. I haven’t gotten better. If anything, I’ve gotten worse.’
As startling as it is, her experience is far from unusual. Data suggests many patients are diagnosed with MS, a condition in which the immune system attacks the protective coating around nerves, only to later be told it was a misdiagnosis.
In fact, studies show that nearly one in five MS patients are later told they don’t actually have the condition – in some cases, after receiving treatment for MS for more than a decade.
‘Misdiagnosis is a common problem that I see in my clinic,’ Dr Dinesh Sivakolundu, a neurologist in Florida who works with MS patients, told the Daily Mail.
‘This week alone, I undiagnosed two patients. It is incredibly common, so I’m glad it is gaining traction now.’
Christina Applegate, pictured in 2023, has revealed her doctor told her she does not have multiple sclerosis despite battling debilitating symptoms for more than five years
Dr Andrew Solomon, a top MS expert at the University of Vermont, also told the Daily Mail: ‘Misdiagnosis appears to be incredibly common.
‘In many cases, patients are told they have been misdiagnosed when they come to clinics not because there was a question about their diagnosis, but because they were establishing care with a new doctor for some reason.’
The big question is, how and why does it happen? First, it’s important to understand what MS is – and why it’s so tricky to diagnose.
The condition occurs when the immune system mistakenly attacks the protective sheath that covers nerve fibers, known as myelin. As this is destroyed, it interrupts communication between these nerve cells, disrupting signals sent from the brain to the rest of the body.
There are four types of MS, with relapsing-remitting MS (RRMS), featuring symptoms that return after periods of remission or recovery, being the most common. It is behind 85 percent of initial diagnoses.
But because symptoms vary depending on where the nerves are being attacked, not all patients have the same warning signs, which can include struggling to walk or move and numbness.
Multiple sclerosis affects nearly one million Americans and is the most common disabling neurological disease among younger adults, typically striking between the ages of 20 and 40.
Women are about three times more likely to be diagnosed with the condition than men. It’s not clear why, but scientists have suggested it is linked to hormones and stress.
Crucially, there is no single definitive test for MS. Instead, Dr Sivakolundu explained that diagnosing MS involves several steps.
Doctors typically begin by taking a detailed medical history, examining the patient and carrying out tests, including blood tests, to rule out other conditions that can cause similar symptoms.
They then use internationally recognized guidelines, known as the McDonald criteria, to assess whether there is sufficient evidence of MS.
This involves looking for evidence of damage to nerves in different parts of the central nervous system, including the brain, spinal cord and optic nerves.
Much of this damage can be seen on MRI scans as bright spots, known as lesions, which indicate areas where the protective coating around nerves has been damaged.
Doctors examine the number, location and pattern of these lesions, alongside other test results and symptoms, to determine whether MS is the likely cause.
But Dr Sivakolundu warned that mistakes can occur when doctors misinterpret these scans or mistake abnormalities caused by other conditions for signs of MS.
For example, he said it was normal for everyone over 40 to have at least one white spot on their brain, but in some cases, doctors interpret this as a potential sign of MS, potentially leading to a misdiagnosis.
‘When the neurologist sees the report, if it is a young patient, they’re more likely to get the diagnosis of MS, because now a young patient is having these white spots,’ he added.
In a study from 2019, scientists found that of 241 patients referred for an MS diagnosis to two major medical centers in California, 17 to 19 percent were later told they had been misdiagnosed. On average, patients had spent four years being treated before receiving the news that they had been misdiagnosed.
In a 2024 review of six studies, including 1,621 patients, scientists found 16 percent of people diagnosed with multiple sclerosis were later found to not have the condition. In one case, a patient spent 16 years thinking they had the disease before being told it was a mistaken diagnosis.
In the 2019 study, scientists said that the most frequent condition misdiagnosed as MS was migraines, behind about 16 percent of cases.
Severe migraines can trigger symptoms that closely resemble MS, including vision changes, numbness, tingling, dizziness and weakness.
Actress Selma Blair revealed her MS diagnosis in 2018
Dr Solomon said: ‘So far, the literature suggests that many common disorders are mistaken for MS, like migraines, or the consequences of high blood pressure on the brain that causes white matter lesions.
‘These are disorders that are frequently referred to neurologists.’
The second-most likely misdiagnosis is radiologically isolated syndrome, behind an estimated nine percent of cases, when anomalies characteristic of MS appear in the brain and spinal cord. These are widely seen as being pre-symptomatic of MS.
Fibromyalgia can also mimic the condition, causing fatigue, pain, tingling and numbness, while psychiatric disorders may present with cognitive difficulties, dizziness and other symptoms that overlap with MS. It can also cause movement problems.
It was not clear what condition Applegate now has. She said she is receiving further tests to determine her diagnosis.
For patients who have been misdiagnosed, doctors say the effect is ‘beyond imaginable.’
‘The medications for MS are not the most benign. These are medications that suppress your immune system, so it puts you at a higher risk for certain infections, and sometimes, can also increase your malignancy and cancer risks,’ Sivakolundu said.
Dr Solomon also noted: ‘Patients have side effects from these medications that didn’t help them and that they didn’t need.
‘Some of them participated in clinical trials for MS therapies, so experimental therapies for MS that they were exposed to, had an enormous amount of unnecessary risk.
‘They also were not treated for the condition that was correct. So in many cases, they were suffering persistently because the correct condition might not have been recognized and treated appropriately.’
There is also a cost element. Care is often covered by insurance but, out of pocket, it can cost anywhere from $20,000 to $100,000 per year.
‘Sometimes insurance covers the majority of it, but it comes with a lot of copay and coinsurance, so the financial burden that falls on the patient without the correct diagnosis is significant,’ Dr Solomon said.
He added: ‘There are many things that could mimic MS in its clinical presentation, the symptoms it presents with, as well as the MRI findings and spinal fluid findings.
‘With testing for the disease, there are different pathways to go down, including spinal fluid testing and optic nerve testing. The results from these can affect the diagnoses.’
Doctors say that if you think you have been misdiagnosed with MS, you should speak to your physician.
‘I think anybody with MS should get a second opinion, because it is a diagnosis that’s life-changing,’ Dr Sivakolundu said.
‘If they’ve seen an MS specialist from the beginning, then I don’t think they have to, but if a general neurologist, or a primary care doctor is suspecting MS or giving one a diagnosis of MS, I would highly encourage them to see someone who’s MS-trained, so they can at least get a second opinion.’
