Kidney stones have become more common in children and teens over the past 20 years. They can occur in children of any age, even premature infants, but most stones occur in teens.
Kidney stones happen when minerals and other substances normally found in urine join together to form a hard stone in the urinary tract. They can also form if there is not enough of other substances in the urine that help stop stones from forming.
Stones typically form in the kidney and ureter, the tube that connects the kidney to the bladder. They rarely form in the bladder.
Types of kidney stones
There are many types of kidney stones, but the most common among U.S. children are calcium oxalate and calcium phosphate stones. Less often, stones are made of uric acid (a waste product from eating certain foods and drinks), an amino acid (a building block of protein) called cystine, or the mineral struvite.
How big are kidney stones?
Kidney stones vary in size, with most about 1/8-1/4 inch. If a child passes a stone while peeing, it is helpful to collect it if possible so your doctor can send it for lab testing. Finding out what the stone is made of can help your child's doctor find ways to stop more stones from forming.
Risk factors for kidney stones
There are many risk factors for forming kidney stones. Some of the most common ones are:
Family tendency to form stones
A diet high in salt, meat, and processed foods, and low in fruits and vegetables
Low urine output from not drinking enough fluid
Other risk factors include:
Specific inherited conditions (hyperoxaluria,
Certain medicines, such as the seizure drug topiramate, for example, or the blood pressure drug furosemide, which removes excess water from the body
Blocked urine flow
Not enough physical activity, as when wearing a cast after surgery. This can cause calcium to leave the bones, so that an excess amount builds up in the urinary tract and contributes to stone formation.
Surgery for weight loss
Signs & symptoms of kidney stones
Stones can form in a child's kidney without causing symptoms for a long time. However, if a stone starts to move down the urinary tract through the tube called the ureter, it can cause symptoms such as:
Sudden, severe pain in back or side
Nausea and vomiting
Groin pain as the stone passes down the urinary tract
Severe stomach pain only (young children especially)
Burning or pain while peeing.
Blood in pee (hematuria)
Fever and urinary tract infection
How are kidney stones diagnosed?
The diagnosis is usually confirmed when a stone is found in a child's urinary tract by x-ray, ultrasound or computed tomography (CT) scan.
The preferred test for a child suspected of having a stone is an ultrasound. That's because an ultrasound is easy to do, can detect most stones, and does not use radiation. A
CT scan can show very small stones, but since this test requires some radiation exposure, many providers will start with an ultrasound. They will then order a CT scan only if a stone is suspected, but not seen with ultrasound.
Treatment for kidney stones in children
If a kidney stone is causing a child pain, the goals are to help ease discomfort and to help the stone pass down into the bladder and out in the urine. This can sometimes be done at home by drinking large amounts of water and other fluids. Over-the-counter pain medicine like acetaminophen and ibuprofen may be helpful to manage pain. Other oral medications may be prescribed to ease the stone's passage. Your child's doctor may recommend using a strainer to help collect the stone from the urine so it can be tested in the lab.
Sometimes, if children are vomiting or have severe pain, they may need to be hospitalized so they can get fluids and stronger pain medicine through a vein.
Children with large stones or stones that will not pass on their own may need the help of a urologist, a doctor who specializes in the urinary tract. The urologist may use lithotripsy, a procedure that uses sound waves to break the stone into tiny pieces, which are then passed down the urinary tract. While it may sound scary, it is quite safe and does not damage the kidney. The urologist may also remove the stone by using a scope that enters the bladder and goes up the ureter while your child is under anesthesia. The urologist can then “grab" the stone and remove it from the body.
How to help preventing kidney stones
There are many things that you can help your child do to reduce the chances of developing more kidney stones. Children with kidney stones should:
Drink a lot of fluid throughout the day (urine should usually look very pale yellow). Ask your healthcare team for an amount that's right for your child. If your child has kidney disease and needs to limit fluid, please discuss this with the team.
salt in the diet.
Eat more fruits and vegetables, especially citrus fruits.
Eat fewer meats, processed foods, fast food, and
Avoid food and drinks with high fructose corn syrup.
Keep a healthy weight.
Eat the recommended amount of calcium-rich foods and drinks. Cutting back calcium in the diet is not recommended and can sometimes actually increase stone risk. On the other hand, don't take a calcium supplement unless your doctor says your child needs one.
Your doctor may also recommend that your child see a
pediatric nephrologist, a kidney specialist who treats children with kidney stones. Blood tests and a 24-hour urine collection test may determine why your child formed a kidney stone. With this information, a registered dietitian nutritionist (RDN) can make specific dietary recommendations and your doctor and health care team can prescribe medicines to reduce your child's risk for making future kidney stones.