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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
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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. Often a kidney stone can cause severe pain and symptoms such as:

  • Sudden, severe pain in the side of the body or mid- or lower back when it moves
  • 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.

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

  • Ultrasound—to examine the kidneys
  • KUB (kidney, ureter, bladder)—an x-ray to view the urinary tract
  • Spiral CT scan—to make pictures of the inside of the kidney
  • Intravenous pyelogram (IVP)—a special x-ray that produces images of the urinary system (rarely used)

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:

Water

For small kidney stones, having your child drink plenty of water will help her body pass the stone in the urine. The doctor may provide a special cup to catch the stone when it passes so that it can be analyzed. If your child is having a hard time keeping fluids down, she may need to be hospitalized to receive fluids in her vein. The doctor may also give your child pain medicine and antibiotics until the stone passes.

Medication

Your child may be advised to take:

  • Over-the-counter pain relivers
  • Prescription pain relievers
  • Medication to dissolve the kidney stone

Surgery

Surgery may be needed if the stone is:

  • Very large or growing larger
  • Causing bleeding or damage to the kidney
  • Causing infection
  • Blocking the flow of urine
  • Unable to pass on its own

Types of surgery include:

  • Extracorporeal shock wave lithotripsy (ESWL)—uses shock waves to break up stones that are too large to pass
  • Ureteroscopy and stone basketing or laser lithotripsy—camera is used to locate the stone
    • Stone basketing—A tiny basket is used to remove the stone.
    • Laser lithotripsy—The stone is broken into smaller pieces with a laser if it is too large to remove.
  • Percutaneous nephrolithotomy—uses a scope placed through a small tube in the back to remove a large stone (rare)
  • Lithotomy—open surgery to remove a stone (rarely used now)

Prevention

Your child is likely to have another kidney stone if they had one before. Here are some steps that may help to prevent 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, processed meats, etc.
  • 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.

Revision Information

  • Reviewer: Kari Kassir, MD
  • Review Date: 03/2014 -
  • Update Date: 06/23/2014 -
  • National Institute of Diabetes and Digestive and Kidney Diseases

    http://www.niddk.nih.gov

  • Urology Care Foundation

    http://www.urologyhealth.org

  • Health Canada

    http://www.hc-sc.gc.ca

  • The Kidney Foundation of Canada

    http://www.kidney.ab.ca

  • Bladder/kidney stones. Cincinnati Children’s Hospital website. Available at: http://www.cincinnatichildrens.org/health/info/urinary/diagnose/bladder-kidney-stones.htm#causes. Updated January 2011. Accessed June 25, 2013.

  • Borghi L, Meschi T, Maggiore U, Prati B. Dietary therapy in idiopathic nephrolithiasis. Nutr Rev. 2006;64:301-312.

  • Kidney stones. National Kidney Foundation website. Available at: http://www.kidney.org/atoz/content/kidneystones.cfm. Accessed June 25, 2013.

  • Nephrolithiasis. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed. Updated May 17, 2013. Accessed June 25, 2013.

  • 6/23/2014 DynaMed's systematic Literature Surveillance http://www.ebscohost.com/dynamed. Elderwy AA, Kurkar A, et al. Dissolution therapy versus shock wave lithotripsy for radiolucent renal stones in children: a prospective study. J Urol. 2014 May;191(5 Suppl):1491-1495.