"I started out wobbly, then just kept declining from there," Sarah says. "I couldn't see or walk unassisted for a while. I had no sensation of when I was hungry or full. I couldn't regulate my temperature. I lost everything I knew how to do."

Sarah sought treatment from several medical facilities, including an emergency room. But no one could diagnose the cause of her problems. She was eventually admitted to a hospital in Orange County. At this point, Sarah was slumped in a wheelchair, her mind sharp but her body exhausted. After 4 MRIs in 24 hours, visits with specialists and more tests, they didn't have a solid conclusion. One test suggested multiple sclerosis (MS), a disease that can affect the brain, spinal cord and nerves in the eyes.

Soon after she was released from the hospital with the diagnosis, she lost her vision. Her eye doctor contacted her new primary care doctor immediately, and Sarah returned to the hospital. High doses of steroids restored her vision—though details were less sharp than before.

Sarah didn't feel confident in the MS diagnosis. Her symptoms didn't seem to match what she read about MS and the test results didn't seem conclusive to her.

"Nothing was adding up, and with a diagnosis that serious, I was definitely looking for a second opinion," she says.

Read: Autoimmune Diseases: When Your Body Turns On You

For that second option, she turned to Marwa Kaisey, MD, a neurologist at the Cedars-Sinai Multiple Sclerosis and Neuroimmunology Center. Kaisey reviewed the thick batch of medical records Sarah had acquired in just one month. She re-tested her and came to a different conclusion: a rare and only recently identified neuroimmune disorder called MOG antibody-associated disease.

The disorder causes inflammation in the optic nerve and can also affect the brain and spine. In people with this condition, the immune system attacks MOG, a protein on the surface of the myelin sheaths that insulate nerves.

"I was so relieved," Sarah says. "Even though this disease is so new, there are treatments and there is a very positive prognosis."

She stayed on steroids for close to a year, tapering off the February following her diagnosis. She continued to physical therapy to retrain her body to walk properly. She is on an immune-suppressing medication to keep the disease managed.

In Discoveries: No Time for MS

"It can be tricky to diagnose neuroimmune diseases and MS," Kaisey says. "Misdiagnosing MS is more common than you might think."

A recent study Kaisey led found nearly 18% of patients diagnosed with MS before being referred to major Los Angeles medical centers had been misdiagnosed and had other conditions, such as migraines or different complex neuroimmune diseases.

While it took many months for Sarah to regain her stamina, strength, and agility back Sarah’s family and friends were there every step of the way. Sarah says she is very grateful for her support system, without them she admits she wouldn’t have fully recovered.

Sarah is back to work, where she's the senior area payroll coordinator for a large nursing facility and planning her next travel adventure. She's careful to keep her hands clean and take extra precautions to avoid catching colds and other illnesses.

"I am so appreciative of my life, because I really felt like I lost it," Sarah says. "Relearning how to walk really puts things in perspective. This was my second chance, I had to put me first, and take care of myself."

Read: Virtual Second Opinion: Here’s What to Know