Definition

Kidney stones are crystallized material in the urine. These stones form in the kidneys or other parts of the urinary tract. Kidney stones may be made up of a variety of minerals in the blood. The most common are calcium, oxalate, or phosphate. Others stones may contain uric acid, struvite, and/or cystine.

Kidney Stone Copyright © Nucleus Medical Media, Inc.

Causes

Some of the known causes of kidney stones in children include:

• Too much oxalate in the urine
• Too much calcium in the urine or blood
• Too much uric acid in the urine
• A stone can form around bacteria
• Inherited abnormality in the way the body handles cystine
• Foreign bodies in the urinary tract, such as stents or catheters
• Abnormal function of the urinary tract, such as neurogenic bladder

Risk Factors

Factors that may increase your child’s chance of developing kidney stones include:

• Dehydration —not drinking enough fluids
• Eating foods high in salt
• Eating a ketogenic diet to help control epilepsy
• Mineral content of water your child drinks (hardness or softness of the water)
• Having family members who have had kidney stones or gout
• Having kidney stones in the past
• Being overweight
• Medical conditions, such as urinary tract infections or metabolic conditions
• Geographic location—residents of the Southeast United States have an increased risk
• Limited physical activity
• Foreign material in the urinary tract, such as a catheter

Symptoms

Occasionally, kidney stones do not cause symptoms, and they leave the body in the urine. Often a kidney stone can cause symptoms such as:

• Sudden, severe pain in the side of the body or mid- or lower back during movement
• Pain in the belly or groin area
• Nausea or vomiting
• Blood in the urine
• Burning pain when urinating
• Fever
• Recurring urinary tract infections

Diagnosis

You will be asked about your child’s symptoms and medical history. A physical exam will be done.

Images of the kidneys and urinary tract may be taken with:

• Ultrasound
• KUB (kidney, ureter, bladder) x-rays
• Spiral CT scan
• Rarely, IV pyelogram (IVP)

A 24-hour urine test may also be done to look for levels of minerals in the urine including calcium, phosphorus, uric acid, oxalate, and citrate.

Treatment

Treatment depends on the size and location of the kidney stone. Treatment may include:

Prevention

Once a child has had one kidney stone, more stones are likely. To help reduce your child's chance of future stones:

• Have your child drink plenty of fluids, especially water. Avoid sodas.
• Make sure your child does not eat too much food that is high in salt, such as potato chips, french fries, or processed meats.
• A calcium-rich diet can help bind oxalate before it reaches the kidney. Encourage milk and yogurt.
• If your child is overweight, work with your child’s doctor to learn the safest way for your child to lose weight.
• Encourage water during sporting activities or other active playtimes.