Knoxville (WVLT) - It is a relatively new phenomenon that's hard to diagnose and even harder to treat.

Doctors call it "double diabetes", and it's increasingly showing up in children.

In this week's Healthy Tennessean, Medical Reporter Jessa Goddard explains why double diabetes poses double the threat.

The mix can strike at any age, and come in many forms.

For example, children who depend on insulin injections because of Type I Diabetes gain weight, and then in a vicious cycle, get the Type II form, in which their bodies become insulin resistant.

"She has Type I, with features of adult Type II. She now takes insulin and pills," says Nannette Zepeda, whose daughter is double Diabetic.

Eight-year-old Alexis Zepeda was born with Type I Diabetes, a disease she had learned to manage.

But last year, she began to show symptoms that didn't respond to insulin injections.

"If my sugar's high, I get bad headaches. And if my sugar's low, I get very, very dizzy," says Alexis.

Alexis is one of a growing number of children doctors are diagnosing with double diabetes.

With the Type I form, the patient's own immune system attacks the insulin-producing cells in the pancreas.

With the Type II form, the body loses its ability to use insulin properly, even though the pancreas pumps out extra.

The mix of the two only complicates treatment.

"In this situation, she doesn't make it first of all, and the stuff that we're giving her, the insulin we're giving her, isn't being utilized as well as it needs to be because of that resistance," says Cathy Van Ostrand, RN, a diabetes clinical specialist.

Most children with diabetes are overweight, so there is universal agreement the best approach is prevention.

Still, in children and adolescents, diabetes of both types has increased two to three fold over the past several decades.

And in fact, depending on age and cultural background, research finds as many as one in four children will eventually be diagnosed with both...

"I was terrified. I'm still terrified. It's not right that these kids have to suffer like... She's not the only one," says Nannette.

While Type II Diabetes has gotten more attention recently, because it's an epidemic fueled by increasing obesity, Type I has been quietly increasing as well, and doctors aren't quite sure why.

Both forms can lead to heart and kidney disease, blindness and amputations and can be fatal if not treated properly.

Special treatment for double diabetes has not yet been developed.