MINOCQUA - When complications from type 1 diabetes threatened 6-year-old Hannah Grzejka's [Jay-ka's] life, her big sister knew just what to do.

Juvenile diabetes requires constant monitoring to keep under control and even then, blood sugar can drop dangerously and require immediately action.

Thankfully for Hannah, her 9 year-old sister was ready when things took a turn for the worse on the bus ride home.

"I was feeling a little bit bad," says Hannah Grzejka.

"I said, 'Do you feel low or high?' and she said 'I think I'm low' so then I gave her a glucose tablet," says Hailey Grzejka.

And that action, may have saved Hannah's life.

"My heart just stopped [when the school called me] because I guess Hannah was about at 50, which is really low, and if it would have went any further, she probably would have went into a seizure... It's a good thing Hailey caught it," says Dawn Grzejka, the girls' mother.

Like a good big sister, Hailey has always kept a close eye on Hannah, and from an early age has soaked in information about her sister's serious condition.

"It makes me feel scared because she can pass out and she can die while she's passed out," says Hailey.

But in good, big sister fashion, Hailey put years of learning into action.

"Mom's been doing this since Hannah was two, [when she was diagnosed] so I've been watching this since 2005," says Hailey.

"I've told Hailey, if your sister goes low on the bus, this is what you do... And she listened! I'm very proud of her," says Dawn.

While Hannah's diabetes likely won't ever be cured, and will require continuous careful monitoring, their mother knows she has another pair of watchful eyes, ready to help.

"Even if they're playing outside, she'll come in and tell me, 'Hannah's not feeling good', or 'Hannah looks funny' She does keep a really good watch on her sister," says Dawn.

On May 8th Arbor Vitae Woodruff elementary will hold a 'Walk to Cure Diabetes' supporting the Juvenile Diabetes Research Foundation. If you'd like to support the walk you can turn in donations to the school by Friday May 4th.

Story By: Kailey Burton