Woman Discovers 20-Year MS Diagnosis Was Actually Rare Neuromyelitis Optica
DeMonica Amerson lived with a multiple sclerosis diagnosis for nearly two decades before discovering in 2019 that she actually suffered from neuromyelitis optica spectrum disorder. Experts note that 15% to 20% of MS patients are eventually misdiagnased, a risk highlighted recently by actor Christina Applegate's public disclosure of her own incorrect diagnosis.
Key points
- Amerson received an MS diagnosis in 2001 after ruling out optic neuritis and lupus, leading to nearly 20 years of treatment, advocacy, and daily management of the condition.
- In 2019, a severe flare-up led to a hospital visit where a neurologist ordered a specialized blood test, eventually revealing she had neuromyelitis optica spectrum disorder (NMOSD) instead of MS.
- Dr. Robert Bermel of Cleveland Clinic states that 15% to 20% of MS patients are later found not to have the condition, often due to misinterpreted brain scans or overlapping symptoms with other autoimmune diseases.
- The issue gained mainstream attention when actor Christina Applegate revealed on her podcast in October 2026 that she had been incorrectly diagnosed with MS for nearly five years, though doctors remain unsure of her current condition.
- Amerson, now 46, transitioned to a new medication called Uplinza and is now advocating for NMOSD awareness, emphasizing the importance of moving forward despite the shock of a late-life diagnostic correction.
Background
Recent health news has highlighted the complexities of chronic illness and diagnosis, including the death of oncologist Rachna Shroff from the cancer she studied, and Vanessa Trump's announcement of being cancer-free. These stories underscore the ongoing challenges in medical diagnosis and treatment, though they are unrelated to the specific issue of autoimmune misdiagnosis.
Why it matters
This case illustrates the significant risks of misdiagnosis in autoimmune conditions, where symptoms often overlap and diagnostic criteria rely on interpretation rather than a single definitive test. It highlights the importance of new diagnostic criteria and specialized testing to prevent patients from living with incorrect diagnoses for decades.
What to watch
Amerson is continuing her treatment with Uplinza and focusing on advocacy for NMOSD. Medical experts are implementing new diagnostic criteria published in 2025 to reduce the rate of misdiagnosis, while patients like Amerson and Christina Applegate are using their platforms to raise awareness about the complexities of autoimmune conditions.
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