Expert discusses diagnosis of kidney stones in children

In this video, Katherine Chan, MD, MPH, discusses how kidney stones are diagnosed in children. Chan is vice chair for research, director of the Pediatric Kidney Stone Clinic, director of Pediatric Urology Research, and an associate professor of urology at the University of North Carolina, Chapel Hill.

Transcription:

How are kidney stones diagnosed in children? Are there any special considerations when performing tests or procedures on young patients?

Kidney stones can be diagnosed basically in 2 different ways. One is what we call an incidental finding on an x ray or an ultrasound. This is somebody who just happens to get an ultrasound or maybe a CT scan, and the radiologist identifies a kidney stone. And these children typically don't have any symptoms. They may have some underlying issue that caused the stone, and this is the first time they have become aware of it. Of the other category of people, and particularly children who are diagnosed with kidney stones, are those who actually do present with symptoms, the ones that we discussed previously, such as flank pain, nausea, vomiting, gross hematuria, things like that. As far as the special considerations, I'm so glad you asked. Children are not little adults, as we like to say. And one of the biggest considerations we have in imaging pediatric patients is radiation exposure. And so there's been a lot of attention paid to this in recent years, due to something called the ALARA principle, and that's as low as reasonably achievable in terms of the radiation dose. The mainstay of radiological imaging in the initial acute stone period is really ultrasound. And that's very different from adult patients, where everybody pretty much just gets a CT scan to diagnose them. With the ultrasound, what we do is really look for hydronephrosis or swelling of the kidney. And that, in combination with symptoms like flank pain, vomiting, etc, is almost diagnostic of a kidney stone. Interestingly, we oftentimes won't actually see the stone on ultrasound once it's passed into the ureter. We'll just see the upstream effects, where the actual kidney is swollen because of the blockage. We will sometimes, however, get a CT scan in children as well, and there are, interestingly, some low-dose noncontrast protocols for CTs in children that are specifically created for imaging children who may have kidney stones, and that may happen when perhaps the patient is symptomatic and there's just no stone seen by ultrasound examination or perhaps not much hydronephrosis.

This transcription was edited for clarity.