Kidney Stones—Child

Definition

Kidney stones are crystallized material in the urine. These stones form in the kidneys or other parts of the urinary tract. The kidneys remove waste (in the form of urine) from the body. They also balance the water and salt content in the blood. There are several types of kidney stones:

• The most common type is mostly calcium, along with oxalate or phosphate.
• Others types contain uric acid, struvite, and/or cystine.

Kidney Stone

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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
• Tiny bacteria a stone can form around
• Inherited abnormality in the way the body handles cystine
• Foreign bodies in the urinary tract, like stents or catheters
• Abnormal function of the urinary tract, such as neurogenic bladder

Risk Factors

These factors increase your child’s chance of developing kidney stones:

• 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 (eg, urinary tract infections, metabolic conditions)
• Geographic location (residents of the Southeast United States have an increased risk)
• Limited physical activity
• Foreign material in the urinary tract (eg, catheter)

Symptoms

Occasionally, kidney stones do not cause symptoms, and they leave the body in the urine. The condition can cause severe pain. Symptoms include:

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

Diagnosis

The doctor will ask about your child’s symptoms and medical history. A physical exam will be done.

Tests may include:

• Spiral CT scan—a type of x-ray that uses a computer to make pictures of the inside of the kidney
• KUB (kidney, ureter, bladder)—an x-ray that uses radiation to view the urinary tract
• Ultrasound —a test that uses sound waves to examine the kidneys
• Intravenous pyelogram (IVP) —a special x-ray that produces images of the urinary system (less commonly used today)
• 24-hour urine—a urine test to check levels of many factors, 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 your child has had a kidney stone, he may be more likely to have another. Here are some steps to prevent this condition:

• 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 (eg, potato chips, French fries, processed meats, etc.).
• A calcium-rich diet (eg, milk and yogurt) is fine, but avoid giving your child too much calcium.
• If your child is overweight, work with your child’s doctor to learn the safest way for your child to lose weight.