Kidney stones have become more common in children and teenagers over the past 20 years. They can affect children of any age, even in
premature infants, but most stones occur in teenagers.
Kidney stones happen when minerals and other elements normally found in urine join together to form a hard deposit in the urinary tract. They can also form if there are low amounts of other substances in the urine that normally help prevent stones from forming.
Stones typically form in the kidney and ureter, which is the tube that connects the kidney to the bladder. Rarely, they can form in the bladder.
Types of kidney stones
There are many different types of kidney stones, but the most common types among U.S. children are made of the minerals calcium oxalate and calcium phosphate. More rarely, stones are made of uric acid (a digestive waste product), an amino acid called cystine or the mineral struvite.
How big are kidney stones?
Kidney stones can range in size, with most measuring around 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 laboratory testing. Figuring 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.
diet that is 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,
medications such as the seizure drug topiramate, for example, or the diuretic (water pill) furosemide.
partial blockage of urine flow.
immobilization, as when wearing a cast after surgery, which can cause bones to release calcium.
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 stone passes down urinary tract.
severe stomachache 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 the majority of 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 by 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 medications 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 laboratory.
Sometimes, if children are vomiting or have severe pain, they may need to be hospitalized so they can get fluids and stronger pain medications through an IV.
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 prevent kidney stones
There are many things that you can help your child do to reduce the chances of developing more kidney stones. All children with kidney stones should:
Drink a lot fluid throughout the day (urine should usually look very pale yellow).
salt in the diet.
Eat more fruits and vegetables, especially citrus fruits.
Eat fewer meats, processed foods, fast food, and
soda or soft drinks.
Keep a healthy weight and
body mass index (BMI).
Eat the recommended amount of calcium-containing foods; cutting back on these foods is
not recommended and can sometimes actually increase stone risk.
Your doctor may also recommend that your child see a
pediatric nephrologist, a kidney specialist with experience treating 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, your child's provider may be able to make additional dietary recommendations or prescribe medications to reduce your child's risk of making future kidney stones.