Experts Explain How MS Misdiagnoses Can Occur

Christina Applegate recently revealed that she was misdiagnosed with multiple sclerosis (MS) nearly five years ago, a situation that highlights the diagnostic challenges associated with the autoimmune disease. Dr. Barbara S. Giesser, director of the MS Comprehensive Care Clinic at the Pacific Neuroscience Institute, explained that there isn't a single definitive test for MS.

"There's no one test that we can do and say yes or no 100 percent," Giesser told Page Six. "We have guidelines, we have rules, we have what are called formal diagnostic criteria, and they get updated all the time."

Doctors typically rely on a combination of criteria, including evidence of nerve damage in the central nervous system, while simultaneously ruling out other conditions that can mimic MS symptoms. Common symptoms such as numbness, tingling, fatigue, weakness, and imbalance can manifest in various other medical issues.

"MS is not the only thing that can cause many of the symptoms that people with MS can have," Giesser noted. MRI scans, a common diagnostic tool for MS, can also show abnormalities caused by other diseases.

Studies indicate that MS misdiagnoses can occur in up to 20% of cases. Giesser elaborated that conditions like lupus and other autoimmune diseases, as well as certain infections, can present symptoms similar to MS. Additionally, some rare neurodegenerative diseases, including hereditary ones, can also resemble MS.

Giesser mentioned that advancements in medical imaging have improved diagnostic accuracy over time. "We have gotten much better at imaging, and we now have new imaging metrics, which again are not 100 percent specific for MS, but they’re pretty accurate," she said. "And so it may be that a person gets rescanned and does not meet the MRI criteria, it might be that the person develops a very atypical symptom that would not be expected with MS."

Dr. Bruce Bebo, Chief Research and Medical Affairs Officer at The National MS Society, echoed these sentiments, stating that symptoms associated with MS can overlap with other neurological, autoimmune, and medical conditions. "Because there is no single test for MS, clinicians must look at the complete picture, including symptoms, neurological examination findings, imaging and laboratory results, while also considering other possible explanations," Bebo said. "The focus is always on reaching the most accurate diagnosis possible so people can receive the most appropriate care."

Applegate disclosed on her "MeSsy" podcast that she recently learned she does not have MS, despite having been diagnosed in 2021. She shared that the news was devastating rather than relieving, as her health has continued to decline and she still experiences debilitating symptoms that affect her mobility. She recounted her doctor informing her, "Congratulations, you don’t have MS," to which she responded with tears, expressing that she was "not happy at all."