Cause of kidney stones in children?

My daughter is 12 and just passed another stone and so far from what we know they are calcium stones and the urologist that we went to said her body is making excessive amounts of calium and that we need to see a pedatric urologist as soon as we can.  We have friends telling us that more and more children are getting stones due to diet and too much soda, however she doesn't drink soda and eats very little red meat etc. 

My question is this, is it possible to pin point the cause of kidney stones in a child this young and if so are there any parents out there who have been able to do so? Her stones started at the age of 8 and are now becoming very frequent.

I thought that I might mention that after my daughter had her kidney stone, they did a litholink (24-hour urine collection that is sent to the lab). They found out that her calcium was too high in her urine, which made it low in her blood. She was sent to a nephrologist (kidney doctor), and he did a bone mineral density test and said that she had osteopenia (I hope I spelled it right). This a much milder form of osteoperosis, and she's now on hydrochlorothiazide to get the calcium back in her bones. The doctor said that she should only have to be on this medicine for a year or two. He's going to check it again next year.

I know this isn't an answer to kidney stones in children, but I thought in the longrun it might be helpful.

All we've been told about my daughter's kidney stones (15 years old), is that they're calcium but her diet doesn't go along with getting kidney stones either.

God bless you.

Vickabee

Hi ladies,

My daughter also did the Litholink testing and that is how we figured out she is producing too much calicium and from there we were told to cut back on calcium foods such as milk, ice cream etc. Since January she has had three episodes of stones that we had to take her in for and they found stones on both sides.  At that point we were told she needed to see a pediatric urologist and so we made an appointment and it is coming up this Weds. 

 I had to gather up all of her records and as I went through them, I discovered in the notes that her glucose levels were high every time she had them taken, the last one was with 110 being the upper limit and hers was 127.  Also on several of the office visits, she had protein in her urine.  I'm not sure what to make of these findings since no one ever mentioned them to me at any of the visits?  Also, something is mentioned about a silent obstruction and having another x-ray taken, and it states that the family declines to do so, and I would have remembered this I'm certain!

It is surprising what you find when you have the opportunity to look through your own records, now I'm really worried! 

Thank you for the welcome.