What are pediatric kidney stones?
Kidney stones in children occur when chemicals in the urine become concentrated to the point that they form solid crystals. Larger stones may become lodged in the urinary tract, causing pain, blockage or infection. Kidney stones in children are far less common than in adults but they occur for the same reasons. Minerals form crystal deposits in the kidneys which grow into stones, most of which are about the size of a grain of sand.
Most pediatric kidney stones remain in the kidney but up to a third may migrate from the kidney to lodge in the ureters, the tubes that lead from the kidney to the bladder. Stones that remain in the kidney, although often painless, can be the source of recurrent urinary tract infections. Those that lodge in the ureter can create a severe colicky pain.
Another symptom is blood in the urine (hematuria). Most of these stones can be treated with extra-corporeal shock wave lithotripsy (SWL), a completely non-invasive procedure. The child is placed under anesthesia and sound waves of specific frequencies are focused on the stones to shatter them into fragments small enough to be easily passed during urination.
In instances in which the stones are too large to be treated with SWL or fail to respond to SWL, Cleveland Clinic has developed a number of minimally invasive procedures that allow the stones to be removed. These operations are so efficient and so minimally traumatic that it is not unusual for the child to return home on the same day the procedure is conducted.
Are kidney stones common in children?
Pediatric kidney stones are not common in children. However, while rare, many physicians have reported seeing an increase in the number of pediatric kidney stone incidents in recent years. Experts are not sure what is causing the rise in pediatric kidney stones. If your child is exhibiting symptoms of kidney stones (especially hematuria) seek medical attention.
What causes kidney stones in children?
The type of kidney stone will indicate to your doctor what the root cause of your kidney stone production is. Four types of stones and the chemical abnormalities that cause them are:
- Calcium Stones: people who form this type of stone either have too much of one type of three chemicals in their urine, or not enough of another. In particular, they have either too much calcium, oxalate, or urate in their urine, or too little citrate. Eating too much salt may cause too much calcium to stay in the urine A few patients will have kidney stones from overproduction of the calcium controlling hormone, parathormone. Drinking milk does not cause kidney stones.
- Struvite Stones: Chronic infection of the urine generally causes these stones. The bacteria responsible for the infection cause a chemical alteration of urine which leads to this type of stone.
- Uric Acid Stones: This type of stone forms when the urine is too acidic, which causes excessive uric acid production.
- Cystine Stones: These stones form because of an inherited condition in which the body cannot clear a chemical called cystine from the blood. Usually, other family members have the same condition.
Knowing the type of kidney stone is important to prescribing treatment to prevent other stones from forming.
Additional factors can play a role in kidney stone formation in children. Defects in the urinary tract can block the flow of urine allowing the chemicals that create kidney stones to accumulate. Approximately one-third of children who suffer from kidney stones have an abnormality in their urinary tract.
Just like in adults, diet also plays an important role in kidney stone formation. When children have bad eating habits, such as drinking too little water or too much caffeine risk of kidney stones increase.
How are kidney stones in children diagnosed?
If a child is suspected of having kidney stones, either because of pain or blood in the urine, the physician may order x-rays or an ultrasound examination of the kidneys, ureters (tubes that carry urine from the kidneys to the bladder) and the bladder. If present, most kidney stones can be seen on an x-ray, although sometimes an ultrasound examination is necessary to see other types of kidney stones.
What are the symptoms of kidney stones in children?
The most common symptoms of kidney stones are blood in the urine or pain. Pain severity and location of pain might vary depending on such factors as stone location and degree of obstruction. Other symptoms include:
- Severe colicky pain
- Inability to urinate (when a stone blocks the urinary tract)
- Cloudy, foul smelling urine, fever, chills, or weakness might be a sign of a serious infection
- Blood in the urine
Some kidney stones are called "silent stones" because they do not cause symptoms.
To learn more, please visit our health information page about kidney stones.