KING

Fifteen-year old Ellen Nadeau has chronic fatigue syndrome.

Fifteen-year old Ellen Nadeau has chronic fatigue syndrome, a condition mostly seen in middle-aged women.

"It is hard to deal with because I have to make sure I get enough sleep and that I don't get sick," she said.

Initially she was misdiagnosed.

"I went to numerous doctors and at first I was told I was lactose intolerant," she said.

For the first time, a pediatric definition for CFS is being presented at an international conference in Fort Lauderdale .

"Some children have things like abdominal pains, rashes, sleep cognitive memory problems so they sometimes have a constellation of problems that are different than the adult population," said Leonard Jason, Ph.D., DePaul University.

CFS in children usually strikes between the ages 10 and 17. About 80 percent recover. That's a much higher percentage than adults. But one in five will remain debilitated. The causes are unclear.

"I mean it could be one of a variety of things. We're not sure. We're certainly looking at different types of causes. It could be some type of bacterial or viral infection that a child gets like flu or mono and they basically just don't recover from it," said Jason.

Differentiating how this disease affects children will make it easier for patient to be diagnosed. Ellen's two sibling also have CFS.

"We had nightmares with the school district. The social services threatened to remove our children from our home because they thought we were just keeping them home on whim," said Ellen's mother, Pam.

Also presented at this conference is promising evidence that antiviral therapy might help some patients, both young and old.

Stanford researchers looked at the anti-viral drug Valcyte, which is used to treat some forms of herpes. It was a small study - only 25 patients - but most showed significant improvement, even after going off the drug.

A much larger study is planned.