Woman Spent Nearly Two Decades Treating Misdiagnosed MS Before Rare Condition Was Revealed

POLICY WIRE — White Plains, USA — For nearly two decades, DeMonica Amerson believed her diagnosis of multiple sclerosis was a fixed reality. It was not until 2019 that medical professionals determined she actually suffered from a rare autoimmune disorder, effectively erasing the existence of her long-standing label.

Amerson received her initial MS diagnosis in 2001 shortly after graduating from college. At the time, no family member had ever suffered from the condition, and the diagnostic process was complex.

Medical staff initially suspected optic neuritis due to her eye-related symptoms. Later, lupus was considered as a possibility before a spinal tap confirmed the MS diagnosis.

Already in the prime of her life, Amerson was forced to adjust to daily injections to manage the disease. “I was mad, I was hurt, I was nervous, confused, all the things,” she said.

Over the following years, her approach to the condition evolved. Treatment protocols shifted from daily shots to monthly infusions, facilitated by a port implanted in her chest.

She became actively involved in advocacy and fundraising with the MS National Foundation. Amerson also got married, had two daughters, and worked as a school administrator, stating she just kept going despite occasional relapses, which she attributed to the progressive nature of the disease.

A significant flare-up occurred in 2019, leaving her lethargic with numb legs. She rushed to the hospital, missing her daughter’s birthday party, where she experienced pressure in her eyes and vomiting.

An on-call neurologist in the emergency room examined her and ordered a specialized blood test. After her condition stabilized, she was discharged, but a few days later, the neurologist called to inform her he suspected a rare autoimmune disorder.

Amerson felt horrified to face another diagnosis alongside MS. Her neurologist referred her to a specialist for follow-up testing.

The specialist’s results were shocking: Amerson never had multiple sclerosis. She had been suffering from neuromyelitis optica spectrum disorder, or NMOSD.

This topic gained mainstream attention earlier this month when actress Christina Applegate revealed on her MeSsy podcast that she had been incorrectly diagnosed with MS for almost five years.

Applegate, who uses mobility aids, stated that doctors remain uncertain about the specific cause of her symptoms.

Misdiagnoses often occur when abnormalities on brain scans are misinterpreted, according to Bermel. New diagnostic criteria published in 2025 aim to reduce these errors.

Gutman noted that the diagnostic process requires significant interpretation by physicians. “it is sort of the story, combined with MRI imaging, combined with other markers like spinal fluid, that help us make the MS diagnosis,” Gutman said. “it is not like diabetes, where there is one blood test and if it is above this number, it is diabetes, if it is below this number, it is not. there is a lot of things going into the diagnosis.”

Although Amerson had sometimes wondered if her medication was correct, she had never doubted the diagnosis itself. It had been such a fundamental part of her life for so long that she accepted it as fact.

Dr. Mark Tullman, associate director of the White Plains Hospital MS Center, explained that NMOSD is a rare autoimmune disease affecting the central nervous system, particularly the spinal cord and optic nerves.

Tullman, who did not treat Amerson, stated that NMOSD symptoms, such sudden vision loss, muscle weakness, and bowel or bladder issues, closely mimic those of MS but tend to be more severe.

While there is no single diagnostic test for MS, many patients with NMOSD have a detectable antibody in their blood. When physicians specifically test for this antibody, it can help confirm an NMOSD diagnosis, similar to the test performed on Amerson.

Announcing that she did not have MS, Amerson said she was so mad that (she) walked out of the doctor’s office.

“I had been dealing with this since I was 21 years old, and now, almost 20 years later, here comes something different,” Amerson recalled thinking. “I did not know there was another disease that mimics MS at all.”

Determined not to focus on the negativity, Amerson found a way to move forward. “I was mad. I do not want to say I got over it, but I accepted it,” she said. “I said, ‘I have to move forward. What does that look like?'”