Seven years ago, Kristie Tunick had a promising future. She was single, beautiful, healthy and active in sports and dance. Then her life got even better when she met Brian Mendenhall.
"He's drop-dead gorgeous," Tunick told her friend the night she met Mendenhall, when he was working at a bar at a nightclub in Las Vegas.
Mendenhall said he was equally attracted. Tunick "had this glow about her. Smile. Genuineness. And just made you feel good," he said.
Today the couple is not only still together, they are even engaged. Yet their fairytale story is tinged with sadness.
In 2006, when Tunick was only 29, her health started to deteriorate inexplicably. What began as stomach issues, led to the removal of her gallbladder and slowly snowballed into even more severe symptoms: The muscles in her body began to lock up, virtually paralyzing her for hours and causing excruciating pain. Sometimes, she would even stop breathing.
CLICK HERE to see more photos of Tunick before mysterious illness
In and out of hospitals many times, Tunick was a real-life medical mystery who stumped the doctors who tried to diagnose her.
Today, this once active girl is now a prisoner in her own bed, and it is Mendenhall who takes care of her.
"I've never loved anyone like I've loved her. ... I'm not the type of person to just close my eyes, turn my back, and walk out. ... So I'm here by her side ... no matter what," he told ABC News correspondent Bob Brown.
As the couple searches for a solid diagnosis and waits anxiously for a specialty clinic to admit Tunick, Mendenhall has had to watch his fiancee be robbed of the life they once knew.
"We liked to play tennis. We loved to golf. We golfed all the time," he said.
Tunick's autoimmune disease now not only leaves golf out of the question, but sometimes even walking to the bathroom is a herculean task for her.
For more information on SPS from Johns Hopkins University, click here.
"Every day is torture," she said, "Every day is -- I feel like I'm being tortured. I feel like this is prison. ... I'm a prisoner in my body. I'm a prisoner in bed."
Many of Tunick's symptoms are similar to those of a person with stiff person syndrome, or SPS. Dr. Beth Murinson, a leading expert in SPS at Johns Hopkins University Hospital, said the key features of this complex disease are "episodic muscle spasms and ... persistent stiffness."
But not everyone's symptoms are as debilitating as Tunick's. Some people living with SPS are "bedridden or in a wheelchair while others are out playing tennis," Murinson said.
While blood tests aid in diagnosing this disease, they are not definitive: The doctor needs to know the history and physical condition of the patient before making a firm conclusion.
Harder still is finding a doctor who is familiar enough with the syndrome to make a confident diagnosts. According to Murinson, fewer than five in a million people have SPS, which makes finding a doctor who specializes in this disease also a rarity.
"I've been denied by at least four neurologists in town because they all felt I needed to be at a specialty ... clinic," Tunick said. "They're too scared to touch me."