Types of Pediatric Kidney Stones

There are four main types of kidney stones that form when normal substances found in the urine become highly concentrated.  It is important to know what kind of stones you have because this helps the doctor identify why you are prone to stone formation. The kind of stone that your body makes determines what dietary changes you may need. 

The four main types of kidney stones are:

  • Calcium stones
  • Cystine stones
  • Uric acid stones
  • Struvite stones

The two most common types of kidney stones are calcium stones and cystine stones. 

Calcium Stones

Calcium stones are the most common kidney stones. There are two main types of calcium stones:

  • Calcium oxalate stones − form when your urine has high amounts of calcium and oxalate
  • Calcium phosphate stones − form when your urine has high calcium and alkaline urine, meaning the urine has a high pH  

To prevent calcium stones from forming your child will need to make changes in his or her diet.  A dietitian will help you with specific changes to your child’s diet.  Basic dietary changes include:

  • Drinking more fluids
  • Decreasing salt (sodium)
  • Decreasing animal proteins, such as meats, eggs, and fish
  • Getting enough calcium from foods
  • Avoiding  foods high in oxalate

Sodium or salt can cause the kidneys to get rid of more calcium into the urine.  When there are high levels of calcium in the urine, the calcium combines with the oxalate and phosphorus to form stones.

A dietitian will help you learn the sodium content of foods.  It is important to read food labels for sodium content.  Keeping a sodium diary can help too.

Cystine Stones

Cystine stones develop from genetic defects that prevent the body from reabsorbing certain amino acids.  One of those amino acids is cystine. When cystine builds up in the urine, crystals form, resulting in kidney stones. 

Treatment for cystine stones begins with a combination of medication and changes in your child’s diet.  Diet changes include:

  • Drinking more fluids
  • Reducing salt
  • Reducing amount of protein in diet, like meats, eggs and fish   

People with cystinuria (too much cystine in the urine) should understand that for them water is a necessary medication.  However, once stones have formed, treatment begins with ESWL (extracorporeal shock wave lithotripsy).  If ESWL does not work, surgery may be required.

Other Types of Kidney Stones

Uric acid stones and struvite stones are less common. Uric acid stones form when the urine has too much acid in it.  A diet rich in animal proteins may contribute to this kind of stone. Struvite stones form when someone has frequent urinary tract infections.

Last Updated 03/2017

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The Stone Center team cares for patients with conditions related to stones in the urinary tract.

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