A kidney stone is a hard deposit of mineral and acid crystals that sometimes forms inside a kidney. Most times, a child has no long-term effects after the stone passes from the body, carried out by urine. But kidney stones can cause extreme pain while they pass. Usually, the worst pain is felt after the stone enters the narrow tube (the ureter) that carries urine from each kidney to the bladder.
How does a kidney stone form? Think of building a snowball: you start with a small amount of snow that forms the snowball’s core. As you pack on more snow, it gradually changes from a loose handful of snowflakes to a tight sphere. This change lets more snow stick. Gradually, the snowball gets bigger.
That’s what happens when a kidney stone forms, except the building blocks are mineral and salt deposits. The kidneys are the body’s main blood-cleaning organs. They filter the mineral and salt deposits out of the blood as waste products. But when these deposits “snowball” in a kidney, they may eventually form a stone.
Kidney stones can pass naturally with good medical advice and attention. When there’s infection, severe pain or an obstruction, expert advice and care are needed to get rid of the stone.
Kidney stones can form in children of any age, even infants. Stones are becoming far more common in school-aged children and teens.
“We don’t understand exactly why, but it is possible that this increase is linked to lifestyle factors, like more children becoming heavier and eating diets higher in salt,” says Edward M. Gong, MD, attending physician, Urology. “Excess salt intake means the kidneys may build up more salt as they do their job of filtering the blood.”
Sometimes, the stone blocks the flow of urine from the body. If this happens, waste products can build to harmful levels. This can create infection in the kidney or throughout the body.
If left untreated, the infection can even lead to permanent kidney damage. “If we suspect any of these complications, we’ll take immediate steps to drain your child’s urine and treat any signs of infection,” says Dr. Gong. “We’ll also talk with you about when and how we’ll need to remove the stone.”
Even in children and teens, kidney stones tend to happen again. We’ll talk to you about what you can do to prevent other kidney stones from forming. Making sure your child drinks enough fluid is extremely important in kidney stone prevention.
The symptoms and treatment depend on where the stone is exactly and how big it is. Some kidney stones stay in the kidney without causing any symptoms.
Sometimes, a kidney stone is discovered when a child gets an abdominal scan for some other reason. When this happens, we may recommend watchful waiting — unless the stone is extremely large or begins causing pain.
Trouble typically starts when a stone moves from the kidney into the ureter. The pressure of urine backing up in the ureter or kidney creates intense pain. The pain stops when the pressure stops, either because the stone passed or was removed.
Here are key symptoms to watch for:
To help the child, we get the medical history, do an exam, get an image and test the urine.
A kidney stone four millimeters in size or smaller is likely to pass on its own, even in very young children. We might allow up to six weeks for this to happen unless there is an infection or persistent pain. A stone larger than five millimeters or so usually needs help getting out of the body. The child’s body size is a factor in how likely a stone is to pass on its own. We’ll base the treatment plan on what we know about the stone’s size, location and composition.
If we get to analyze any pieces of the stone, we can learn what the stone was made of. We look for information in the urine and blood, too. After two weeks or so, the child should be eating and drinking normally, recovered from the pain and any surgery and doing usual activities. After analyzing urine and blood samples, we’ll have information to share with you about what may have caused the stone and future prevention.
Health complications in adult life — such as chronic kidney disease, bone disease and hypertension — may follow after having kidney stones as a child. Kidney stone disease may harm kidney function.
If you’d like to request an appointment with one of our specialists, call 1.800.543.7362 (1.800.KIDS DOC®).
Learn more about kidney stones in children by visiting the following doctor-recommended sites: