Groton – In the fall of 2014, Margaret Twitty was volunteering at Horses Healing Humans in Stonington when a horse stepped on her foot.

She pulled the horse off and kept going. But it hurt for weeks, so she went to a doctor. He took X-rays and saw no fracture, but told her she had a bunion and that might be causing her pain. So she went in for a routine surgery to fix it.

Within three nights, it hit her — burning pain that was accompanied with strange symptoms. Her foot turned purple. It began to shake. Her skin became thin and glossy.

The surgeon was stumped, and sent her to a New London neurologist who recognized the symptoms as those of a rare disease called Complex Regional Pain Syndrome, formerly known as Reflex Sympathetic Dystrophy. The illness can be so baffling it's been featured on the documentary drama "Mystery Diagnosis," which tells the stories of people who suffer years with mysterious medical problems before getting answers.

Twitty, 24, wants to make the disease less of a mystery.

"I felt like this intensive pain, like someone was putting a lighter to my toes and it would not go away," she said. "It was this feeling of fire."

She had been a gymnast before the injury, but now was unable to walk. She'd become totally dependent on her mother to care for her.

Complex Regional Pain Syndrome, or CRPS, is a progressive disease that typically occurs after an injury to a limb, can spread and become debilitating. Doctors aren't sure what causes it, but after the initial injury something goes wrong in the nervous system. 

Dr. Laurence Radin, the New London neurologist treating Twitty, diagnosed her on Feb. 17, 2015. He said the syndrome changes the surrounding tissue so, although it's rare, it's recognizable. The color, skin texture and temperature of the limb typically changes, so it looks different than the other limbs, he said.

"It's kind of one of those things that when you see it, you know it," he said. The disease causes extreme pain, often accompanied by swelling, skin changes and spasms, according to the American RSDHope website. Patients describe the pain as feeling like something is literally on fire.

The disease doesn't go away, so preventing it from spreading is the best patients can hope for, he said. Radin said the syndrome is extremely rare; for every 10 people who think they have it, only one actually does.

He gets several referrals each year for the condition, but has diagnosed it only about a dozen times in more than 20 years, he said. People misdiagnosed with the disease end up with inappropriate treatment when a different course would help them, he said.

"It's very important to get a proper diagnosis, even if it takes two or three opinions," Radin said. "Because a lot of people think they have it and they do not have it."

Although the diagnosis was difficult for Twitty, she said not knowing was worse.

"I couldn't do anything, really. I couldn't walk. I was homebound," she said.

She remembers her mother, who served 20 years in the Navy and now works as a civilian at Naval Submarine Base, crying as she drove her daughter home from the neurologist's office.

Judy Twitty said she had wanted the doctor to say something else.

"I was disappointed that he made that diagnosis. I wished that we were wrong," she said.

When she and Margaret got home, they both went their separate ways for a bit. It was as if they had to grieve separately first.

Since Twitty's diagnosis, she has had six nerve blocks, in which local anesthetic is injected directly into a nerve to block pain. She takes anti-seizure medication and has been to about 80 physical therapy appointments, and is now able to get up. Today, though she still suffers from pain, she walks. She started driving short distances about two months ago.

Twitty, who graduated from Robert E. Fitch High School in 2010, can't do gymnastics anymore and spends a lot of time at home, she said. But she keeps in contact with her teachers from Fitch and her friends via social media.

"It's a very cruel diagnosis to have because it's not just you who has it," she said. "It's your caregiver or person who lives with you who also has it."

"This disorder, it's an invisible disorder to some degree," Judy Twitty said. "So some people don't see Margaret as having such a drastic disorder. Because she doesn't have her foot in a cast anymore. But it's still there."

Margaret Twitty wants to spread awareness of the condition, to help others feel less isolated and alone.

"It helps to show that this is real, because there are doctors that aren't aware of it," she said. "They'll just say, 'Oh, it's in your head and you need to see a psychologist." She was lucky to have a scar on her foot to prove she was injured, she said.

"It can take years to get a diagnosis. So they'll be living in pain for years, and I don't want (any) person to go through that," she said. "I want people to know that there is someone in their corner fighting for them."

d.straszheim@theday.com